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MC9S08AC16 MC9S08AC8 MC9S08AW16A MC9S08AW8A
Data Sheet
HCS08 Microcontrollers
MC9S08AC16 Rev. 8 9/2009
freescale.com
MC9S08AC16 Series Features
MC9S08AC16 Series Devices
* Consumer & Industrial -- MC9S08AC16 -- MC9S08AC8 Automotive -- MC9S08AW16A -- MC9S08AW8A 40-MHz HCS08 CPU (central processor unit) 20-MHz internal bus frequency HC08 instruction set with added BGND instruction Background debugging system Breakpoint capability to allow single breakpoint setting during in-circuit debugging (plus two more breakpoints in on-chip debug module) Debug module containing two comparators and nine trigger modes. Eight deep FIFO for storing change-of-flow addresses and event-only data. Debug module supports both tag and force breakpoints. Support for up to 32 interrupt/reset sources Up to 16 KB of on-chip in-circuit programmable FLASH memory with block protection and security options Up to 1 KB of on-chip RAM Clock source options include crystal, resonator, external clock, or internally generated clock with precision NVM trimming Optional computer operating properly (COP) reset with option to run from independent internal clock source or bus clock Low-voltage detection with reset or interrupt Illegal opcode detection with reset Illegal address detection with reset Wait plus two stops
Peripherals
* * * * ADC -- 8-channel, 10-bit analog-to-digital converter with automatic compare function SCI -- Two serial communications interface modules with optional 13-bit break SPI -- Serial peripheral interface module IIC -- Inter-integrated circuit bus module to operate at up to 100 kbps with maximum bus loading; capable of higher baud rates with reduced loading Timers -- Three 16-bit timer/pulse-width modulator (TPM) modules -- Two 2-channel and one 4-channel; each has selectable input capture, output compare, and edge-aligned PWM capability on each channel. Each timer module may be configured for buffered, centered PWM (CPWM) on all channels KBI -- 7-pin keyboard interrupt module Up to 38 general-purpose input/output (I/O) pins Software selectable pullups on ports when used as inputs Software selectable slew rate control on ports when used as outputs Software selectable drive strength on ports when used as outputs Master reset pin and power-on reset (POR) Internal pullup on RESET, IRQ, and BKGD/MS pins to reduce customer system cost 48-pin quad flat no-lead package (QFN) 44-pin low-profile quad flat package (LQFP) 42-pin shrink dual-in-line package (SDIP) 32-pin low-profile quad flat package (LQFP)
*
8-Bit HCS08 Central Processor Unit (CPU)
* * * * * *
*
* * * * * * *
Input/Output
* *
Memory Options
* *
Clock Source Options
Package Options
* * * *
System Protection
*
* * * *
Power-Saving Modes
MC9S08AC16 Series Data Sheet
Covers MC9S08AC16 MC9S08AC8 MC9S08AW16A MC9S08AW8A
MC9S08AC16 Rev. 8 9/2009
Revision History
To provide the most up-to-date information, the revision of our documents on the World Wide Web will be the most current. Your printed copy may be an earlier revision. To verify you have the latest information available, refer to: http://freescale.com/ The following revision history table summarizes changes contained in this document. For your convenience, the page number designators have been linked to the appropriate location.
Revision Number 0 1 2 3 4 5 6 Revision Date 12/2007 12/2007 2/2008 3/2008 5/2008 6/2008 7/2008 Initial Release. Updated the package designators for the 32 LQFP and 44 LQFP to be LC and LD respectively. Corrected the SPI block module to be V3. AC market launch.Verified that the ADC Temp Sensor values were correct. Incorporated general release edits and updates, revised the Stop2 and Stop3 max values, added the RoHS logo, and updated the back cover addresses. Corrected the note in the TPM introduction. Changed all instances of S9S08AWxxA to MC9S08AWxxA except in Appendix B. Added 42SDIP package option.
Corrected SPI registers in Table 4-2. Added VBG in Table A-6. Corrected title of Table 6-3, Figure 6-13, Figure 6-14, Table 6-5 and Figure 6-19. Added errata for the following sections: * Throughout (remove stop1 instances) * Table 4-1 * Table 4-2 * Section 9.2, "Keyboard Pin Sharing" * Section 9.3, "Features * Table A-6 * Table A-7 * Figure A-12 Updated the whole document for MC9S08AW16A/MC9S08AW8A to support the third TPM module.
Description of Changes
7
5/2009
8
9/1/2009
This product incorporates SuperFlash(R) technology licensed from SST. FreescaleTM and the Freescale logo are trademarks of Freescale Semiconductor, Inc. (c) Freescale Semiconductor, Inc., 2007-2009. All rights reserved.
MC9S08AC16 Series Data Sheet, Rev. 8 6 Freescale Semiconductor
List of Chapters
Chapter Title Page
Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Appendix A Appendix B
Introduction.............................................................................. 19 Pins and Connections ............................................................. 25 Modes of Operation ................................................................. 35 Memory ..................................................................................... 41 Resets, Interrupts, and System Configuration ..................... 63 Parallel Input/Output ............................................................... 81 Central Processor Unit (S08CPUV2) .................................... 107 Internal Clock Generator (S08ICGV4) .................................. 127 Keyboard Interrupt (S08KBIV1) ............................................ 153 Timer/PWM (S08TPMV3) ....................................................... 159 Serial Communications Interface (S08SCIV4)..................... 189 Serial Peripheral Interface (S08SPIV3) ................................ 209 Inter-Integrated Circuit (S08IICV2) ....................................... 225 Analog-to-Digital Converter (S08ADC10V1)........................ 243 Development Support ........................................................... 271 Electrical Characteristics and Timing Specifications ....... 293 Ordering Information and Mechanical Drawings............... 319
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 7
Contents
Section Number Title Page
Chapter 1 Introduction
1.1 1.2 1.3 Overview .........................................................................................................................................19 MCU Block Diagrams .....................................................................................................................20 System Clock Distribution ..............................................................................................................22
Chapter 2 Pins and Connections
2.1 2.2 2.3 Introduction .....................................................................................................................................25 Device Pin Assignment ...................................................................................................................25 Recommended System Connections ...............................................................................................30 2.3.1 Power (VDD, 2 x VSS, VDDAD, VSSAD) ...........................................................................32 2.3.2 Oscillator (XTAL, EXTAL) ..............................................................................................32 2.3.3 RESET ..............................................................................................................................32 2.3.4 Background/Mode Select (BKGD/MS) ............................................................................33 2.3.5 ADC Reference Pins (VREFH, VREFL) .............................................................................33 2.3.6 External Interrupt Pin (IRQ) .............................................................................................33 2.3.7 General-Purpose I/O and Peripheral Ports ........................................................................34
Chapter 3 Modes of Operation
3.1 3.2 3.3 3.4 3.5 3.6 Introduction .....................................................................................................................................35 Features ...........................................................................................................................................35 Run Mode ........................................................................................................................................35 Active Background Mode ...............................................................................................................35 Wait Mode .......................................................................................................................................36 Stop Modes ......................................................................................................................................36 3.6.1 Stop2 Mode .......................................................................................................................37 3.6.2 Stop3 Mode .......................................................................................................................38 3.6.3 Active BDM Enabled in Stop Mode .................................................................................38 3.6.4 LVD Enabled in Stop Mode ..............................................................................................39 3.6.5 On-Chip Peripheral Modules in Stop Modes ....................................................................39
Chapter 4 Memory
4.1 MC9S08AC16 Series Memory Map ...............................................................................................41 4.1.1 Reset and Interrupt Vector Assignments ...........................................................................42
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 9
Section Number
4.2 4.3 4.4
Title
Page
4.5 4.6
Register Addresses and Bit Assignments ........................................................................................43 RAM ................................................................................................................................................49 FLASH ............................................................................................................................................50 4.4.1 Features .............................................................................................................................50 4.4.2 Program and Erase Times .................................................................................................50 4.4.3 Program and Erase Command Execution .........................................................................51 4.4.4 Burst Program Execution ..................................................................................................52 4.4.5 Access Errors ....................................................................................................................54 4.4.6 FLASH Block Protection ..................................................................................................54 4.4.7 Vector Redirection ............................................................................................................55 Security ............................................................................................................................................55 FLASH Registers and Control Bits .................................................................................................57 4.6.1 FLASH Clock Divider Register (FCDIV) ........................................................................57 4.6.2 FLASH Options Register (FOPT and NVOPT) ................................................................58 4.6.3 FLASH Configuration Register (FCNFG) .......................................................................59 4.6.4 FLASH Protection Register (FPROT and NVPROT) ......................................................60 4.6.5 FLASH Status Register (FSTAT) ......................................................................................60 4.6.6 FLASH Command Register (FCMD) ...............................................................................61
Chapter 5 Resets, Interrupts, and System Configuration
5.1 5.2 5.3 5.4 5.5 Introduction .....................................................................................................................................63 Features ...........................................................................................................................................63 MCU Reset ......................................................................................................................................63 Computer Operating Properly (COP) Watchdog .............................................................................64 Interrupts .........................................................................................................................................65 5.5.1 Interrupt Stack Frame .......................................................................................................66 5.5.2 External Interrupt Request (IRQ) Pin ...............................................................................66 5.5.3 Interrupt Vectors, Sources, and Local Masks ...................................................................67 Low-Voltage Detect (LVD) System ................................................................................................69 5.6.1 Power-On Reset Operation ...............................................................................................69 5.6.2 LVD Reset Operation ........................................................................................................69 5.6.3 LVD Interrupt Operation ...................................................................................................69 5.6.4 Low-Voltage Warning (LVW) ...........................................................................................69 Real-Time Interrupt (RTI) ...............................................................................................................69 MCLK Output .................................................................................................................................70 Reset, Interrupt, and System Control Registers and Control Bits ...................................................70 5.9.1 Interrupt Pin Request Status and Control Register (IRQSC) ............................................71 5.9.2 System Reset Status Register (SRS) .................................................................................72 5.9.3 System Background Debug Force Reset Register (SBDFR) ............................................73 5.9.4 System Options Register (SOPT) .....................................................................................74 5.9.5 System MCLK Control Register (SMCLK) .....................................................................75
MC9S08AC16 Series Data Sheet, Rev. 8 10 Freescale Semiconductor
5.6
5.7 5.8 5.9
Section Number
5.9.6 5.9.7 5.9.8 5.9.9 5.9.10
Title
Page
System Device Identification Register (SDIDH, SDIDL) ................................................75 System Real-Time Interrupt Status and Control Register (SRTISC) ................................76 System Power Management Status and Control 1 Register (SPMSC1) ...........................77 System Power Management Status and Control 2 Register (SPMSC2) ...........................79 System Options Register 2 (SOPT2) ................................................................................80
Chapter 6 Parallel Input/Output
6.1 6.2 6.3 Introduction .....................................................................................................................................81 Features ...........................................................................................................................................83 Pin Descriptions ..............................................................................................................................83 6.3.1 Port A ................................................................................................................................83 6.3.2 Port B ................................................................................................................................84 6.3.3 Port C ................................................................................................................................84 6.3.4 Port D ................................................................................................................................85 6.3.5 Port E ................................................................................................................................85 6.3.6 Port F .................................................................................................................................86 6.3.7 Port G ................................................................................................................................86 Parallel I/O Control .........................................................................................................................87 Pin Control ......................................................................................................................................88 6.5.1 Internal Pullup Enable ......................................................................................................88 6.5.2 Output Slew Rate Control Enable .....................................................................................88 6.5.3 Output Drive Strength Select ............................................................................................88 Pin Behavior in Stop Modes ............................................................................................................89 Parallel I/O and Pin Control Registers ............................................................................................89 6.7.1 Port A I/O Registers (PTAD and PTADD) ........................................................................89 6.7.2 Port A Pin Control Registers (PTAPE, PTASE, PTADS) .................................................90 6.7.3 Port B I/O Registers (PTBD and PTBDD) ........................................................................92 6.7.4 Port B Pin Control Registers (PTBPE, PTBSE, PTBDS) .................................................93 6.7.5 Port C I/O Registers (PTCD and PTCDD) ........................................................................94 6.7.6 Port C Pin Control Registers (PTCPE, PTCSE, PTCDS) .................................................95 6.7.7 Port D I/O Registers (PTDD and PTDDD) .......................................................................97 6.7.8 Port D Pin Control Registers (PTDPE, PTDSE, PTDDS) ................................................98 6.7.9 Port E I/O Registers (PTED and PTEDD) ........................................................................99 6.7.10 Port E Pin Control Registers (PTEPE, PTESE, PTEDS) ................................................100 6.7.11 Port F I/O Registers (PTFD and PTFDD) .......................................................................102 6.7.12 Port F Pin Control Registers (PTFPE, PTFSE, PTFDS) .................................................103 6.7.13 Port G I/O Registers (PTGD and PTGDD) .....................................................................104 6.7.14 Port G Pin Control Registers (PTGPE, PTGSE, PTGDS) ..............................................105
6.4 6.5
6.6 6.7
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 11
Section Number
Title Chapter 7 Central Processor Unit (S08CPUV2)
Page
7.1 7.2
7.3
7.4
7.5
Introduction ...................................................................................................................................107 7.1.1 Features ...........................................................................................................................107 Programmer's Model and CPU Registers .....................................................................................108 7.2.1 Accumulator (A) .............................................................................................................108 7.2.2 Index Register (H:X) ......................................................................................................108 7.2.3 Stack Pointer (SP) ...........................................................................................................109 7.2.4 Program Counter (PC) ....................................................................................................109 7.2.5 Condition Code Register (CCR) .....................................................................................109 Addressing Modes .........................................................................................................................110 7.3.1 Inherent Addressing Mode (INH) ................................................................................... 111 7.3.2 Relative Addressing Mode (REL) ..................................................................................111 7.3.3 Immediate Addressing Mode (IMM) ..............................................................................111 7.3.4 Direct Addressing Mode (DIR) ......................................................................................111 7.3.5 Extended Addressing Mode (EXT) ................................................................................ 111 7.3.6 Indexed Addressing Mode ..............................................................................................111 Special Operations .........................................................................................................................112 7.4.1 Reset Sequence ...............................................................................................................113 7.4.2 Interrupt Sequence ..........................................................................................................113 7.4.3 Wait Mode Operation ......................................................................................................114 7.4.4 Stop Mode Operation ......................................................................................................114 7.4.5 BGND Instruction ...........................................................................................................114 HCS08 Instruction Set Summary ..................................................................................................115
Chapter 8 Internal Clock Generator (S08ICGV4)
8.1 Introduction ...................................................................................................................................129 8.1.1 Features ...........................................................................................................................129 8.1.2 Modes of Operation ........................................................................................................130 8.1.3 Block Diagram ................................................................................................................131 External Signal Description ..........................................................................................................131 8.2.1 EXTAL -- External Reference Clock / Oscillator Input ................................................131 8.2.2 XTAL -- Oscillator Output ............................................................................................131 8.2.3 External Clock Connections ...........................................................................................132 8.2.4 External Crystal/Resonator Connections ........................................................................132 Register Definition ........................................................................................................................132 8.3.1 ICG Control Register 1 (ICGC1) ....................................................................................133 8.3.2 ICG Control Register 2 (ICGC2) ....................................................................................134 8.3.3 ICG Status Register 1 (ICGS1) .......................................................................................135 8.3.4 ICG Status Register 2 (ICGS2) .......................................................................................136 8.3.5 ICG Filter Registers (ICGFLTU, ICGFLTL) ..................................................................136
MC9S08AC16 Series Data Sheet, Rev. 8 12 Freescale Semiconductor
8.2
8.3
Section Number
8.4
Title
Page
8.5
8.3.6 ICG Trim Register (ICGTRM) ........................................................................................137 Functional Description ..................................................................................................................137 8.4.1 Off Mode (Off) ................................................................................................................138 8.4.2 Self-Clocked Mode (SCM) .............................................................................................138 8.4.3 FLL Engaged, Internal Clock (FEI) Mode .....................................................................139 8.4.4 FLL Engaged Internal Unlocked ....................................................................................140 8.4.5 FLL Engaged Internal Locked ........................................................................................140 8.4.6 FLL Bypassed, External Clock (FBE) Mode ..................................................................140 8.4.7 FLL Engaged, External Clock (FEE) Mode ...................................................................140 8.4.8 FLL Lock and Loss-of-Lock Detection ..........................................................................141 8.4.9 FLL Loss-of-Clock Detection .........................................................................................142 8.4.10 Clock Mode Requirements .............................................................................................143 8.4.11 Fixed Frequency Clock ...................................................................................................144 8.4.12 High Gain Oscillator .......................................................................................................144 Initialization/Application Information ..........................................................................................144 8.5.1 Introduction .....................................................................................................................144 8.5.2 Example #1: External Crystal = 32 kHz, Bus Frequency = 4.19 MHz ...........................146 8.5.3 Example #2: External Crystal = 4 MHz, Bus Frequency = 20 MHz ..............................148 8.5.4 Example #3: No External Crystal Connection, 5.4 MHz Bus Frequency ......................150 8.5.5 Example #4: Internal Clock Generator Trim ..................................................................152
Chapter 9 Keyboard Interrupt (S08KBIV1)
9.1 9.2 9.3 9.4 Introduction ...................................................................................................................................153 Keyboard Pin Sharing ...................................................................................................................153 Features .........................................................................................................................................153 9.3.1 KBI Block Diagram ........................................................................................................155 Register Definition ........................................................................................................................155 9.4.1 KBI Status and Control Register (KBISC) .....................................................................156 9.4.2 KBI Pin Enable Register (KBIPE) ..................................................................................157 Functional Description ..................................................................................................................157 9.5.1 Pin Enables .....................................................................................................................157 9.5.2 Edge and Level Sensitivity .............................................................................................157 9.5.3 KBI Interrupt Controls ....................................................................................................158
9.5
Chapter 10 Timer/PWM (S08TPMV3)
10.1 Introduction ...................................................................................................................................159 10.2 Features .........................................................................................................................................159 10.3 TPMV3 Differences from Previous Versions ................................................................................161 10.3.1 Migrating from TPMV1 ..................................................................................................163 10.3.2 Features ...........................................................................................................................164
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 13
Section Number
Title
Page
10.4 10.5
10.6
10.7
10.8
10.9
10.3.3 Modes of Operation ........................................................................................................164 10.3.4 Block Diagram ................................................................................................................165 Signal Description .........................................................................................................................167 10.4.1 Detailed Signal Descriptions ..........................................................................................167 Register Definition ........................................................................................................................171 10.5.1 TPM Status and Control Register (TPMxSC) ................................................................171 10.5.2 TPM-Counter Registers (TPMxCNTH:TPMxCNTL) ....................................................172 10.5.3 TPM Counter Modulo Registers (TPMxMODH:TPMxMODL) ....................................173 10.5.4 TPM Channel n Status and Control Register (TPMxCnSC) ..........................................174 10.5.5 TPM Channel Value Registers (TPMxCnVH:TPMxCnVL) ..........................................176 Functional Description ..................................................................................................................177 10.6.1 Counter ............................................................................................................................178 10.6.2 Channel Mode Selection .................................................................................................179 Reset Overview .............................................................................................................................183 10.7.1 General ............................................................................................................................183 10.7.2 Description of Reset Operation .......................................................................................183 Interrupts .......................................................................................................................................183 10.8.1 General ............................................................................................................................183 10.8.2 Description of Interrupt Operation .................................................................................183 The Differences from TPM v2 to TPM v3 ....................................................................................185
Chapter 11 Serial Communications Interface (S08SCIV4)
11.1 Introduction ...................................................................................................................................189 11.1.1 Features ...........................................................................................................................191 11.1.2 Modes of Operation ........................................................................................................191 11.1.3 Block Diagram ................................................................................................................192 11.2 Register Definition ........................................................................................................................194 11.2.1 SCI Baud Rate Registers (SCIxBDH, SCIxBDL) ..........................................................194 11.2.2 SCI Control Register 1 (SCIxC1) ...................................................................................195 11.2.3 SCI Control Register 2 (SCIxC2) ...................................................................................196 11.2.4 SCI Status Register 1 (SCIxS1) ......................................................................................197 11.2.5 SCI Status Register 2 (SCIxS2) ......................................................................................199 11.2.6 SCI Control Register 3 (SCIxC3) ...................................................................................200 11.2.7 SCI Data Register (SCIxD) .............................................................................................201 11.3 Functional Description ..................................................................................................................201 11.3.1 Baud Rate Generation .....................................................................................................201 11.3.2 Transmitter Functional Description ................................................................................202 11.3.3 Receiver Functional Description ....................................................................................203 11.3.4 Interrupts and Status Flags ..............................................................................................205 11.3.5 Additional SCI Functions ...............................................................................................206
MC9S08AC16 Series Data Sheet, Rev. 8 14 Freescale Semiconductor
Section Number
Title Chapter 12 Serial Peripheral Interface (S08SPIV3)
Page
12.1 Introduction ...................................................................................................................................209 12.1.1 Features ...........................................................................................................................211 12.1.2 Block Diagrams ..............................................................................................................211 12.1.3 SPI Baud Rate Generation ..............................................................................................213 12.2 External Signal Description ..........................................................................................................214 12.2.1 SPSCK -- SPI Serial Clock ............................................................................................214 12.2.2 MOSI -- Master Data Out, Slave Data In ......................................................................214 12.2.3 MISO -- Master Data In, Slave Data Out ......................................................................214 12.2.4 SS -- Slave Select ..........................................................................................................214 12.3 Modes of Operation .......................................................................................................................215 12.3.1 SPI in Stop Modes ..........................................................................................................215 12.4 Register Definition ........................................................................................................................215 12.4.1 SPI Control Register 1 (SPI1C1) ....................................................................................215 12.4.2 SPI Control Register 2 (SPI1C2) ....................................................................................216 12.4.3 SPI Baud Rate Register (SPI1BR) ..................................................................................217 12.4.4 SPI Status Register (SPI1S) ............................................................................................218 12.4.5 SPI Data Register (SPI1D) .............................................................................................219 12.5 Functional Description ..................................................................................................................220 12.5.1 SPI Clock Formats ..........................................................................................................220 12.5.2 SPI Interrupts ..................................................................................................................223 12.5.3 Mode Fault Detection .....................................................................................................223
Chapter 13 Inter-Integrated Circuit (S08IICV2)
13.1 Introduction ...................................................................................................................................225 13.1.1 Features ...........................................................................................................................227 13.1.2 Modes of Operation ........................................................................................................227 13.1.3 Block Diagram ................................................................................................................227 13.2 External Signal Description ..........................................................................................................228 13.2.1 SCL -- Serial Clock Line ...............................................................................................228 13.2.2 SDA -- Serial Data Line ................................................................................................228 13.3 Register Definition ........................................................................................................................228 13.3.1 IIC Address Register (IIC1A) .........................................................................................229 13.3.2 IIC Frequency Divider Register (IIC1F) ........................................................................229 13.3.3 IIC Control Register (IIC1C1) ........................................................................................232 13.3.4 IIC Status Register (IIC1S) .............................................................................................232 13.3.5 IIC Data I/O Register (IIC1D) ........................................................................................233 13.3.6 IIC Control Register 2 (IIC1C2) .....................................................................................234 13.4 Functional Description ..................................................................................................................235 13.4.1 IIC Protocol .....................................................................................................................235
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 15
Section Number
Title
Page
13.4.2 10-bit Address .................................................................................................................238 13.4.3 General Call Address ......................................................................................................239 13.5 Resets ............................................................................................................................................239 13.6 Interrupts .......................................................................................................................................239 13.6.1 Byte Transfer Interrupt ....................................................................................................239 13.6.2 Address Detect Interrupt .................................................................................................240 13.6.3 Arbitration Lost Interrupt ................................................................................................240 13.7 Initialization/Application Information ..........................................................................................241
Chapter 14 Analog-to-Digital Converter (S08ADC10V1)
14.1 Overview .......................................................................................................................................243 14.2 Channel Assignments ....................................................................................................................243 14.2.1 Alternate Clock ...............................................................................................................244 14.2.2 Hardware Trigger ............................................................................................................244 14.2.3 Temperature Sensor ........................................................................................................245 14.2.4 Features ...........................................................................................................................247 14.2.5 Block Diagram ................................................................................................................247 14.3 External Signal Description ..........................................................................................................248 14.3.1 Analog Power (VDDAD) ..................................................................................................249 14.3.2 Analog Ground (VSSAD) .................................................................................................249 14.3.3 Voltage Reference High (VREFH) ...................................................................................249 14.3.4 Voltage Reference Low (VREFL) ....................................................................................249 14.3.5 Analog Channel Inputs (ADx) ........................................................................................249 14.4 Register Definition ........................................................................................................................249 14.4.1 Status and Control Register 1 (ADC1SC1) ....................................................................249 14.4.2 Status and Control Register 2 (ADC1SC2) ....................................................................251 14.4.3 Data Result High Register (ADC1RH) ...........................................................................252 14.4.4 Data Result Low Register (ADC1RL) ............................................................................252 14.4.5 Compare Value High Register (ADC1CVH) ..................................................................253 14.4.6 Compare Value Low Register (ADC1CVL) ...................................................................253 14.4.7 Configuration Register (ADC1CFG) ..............................................................................253 14.4.8 Pin Control 1 Register (APCTL1) ..................................................................................255 14.4.9 Pin Control 2 Register (APCTL2) ..................................................................................256 14.4.10Pin Control 3 Register (APCTL3) ..................................................................................257 14.5 Functional Description ..................................................................................................................258 14.5.1 Clock Select and Divide Control ....................................................................................258 14.5.2 Input Select and Pin Control ...........................................................................................259 14.5.3 Hardware Trigger ............................................................................................................259 14.5.4 Conversion Control .........................................................................................................259 14.5.5 Automatic Compare Function .........................................................................................262 14.5.6 MCU Wait Mode Operation ............................................................................................262
MC9S08AC16 Series Data Sheet, Rev. 8 16 Freescale Semiconductor
Section Number
Title
Page
14.5.7 MCU Stop3 Mode Operation ..........................................................................................262 14.5.8 MCU Stop1 and Stop2 Mode Operation .........................................................................263 14.6 Initialization Information ..............................................................................................................263 14.6.1 ADC Module Initialization Example .............................................................................263 14.7 Application Information ................................................................................................................265 14.7.1 External Pins and Routing ..............................................................................................265 14.7.2 Sources of Error ..............................................................................................................267
Chapter 15 Development Support
15.1 Introduction ...................................................................................................................................271 15.1.1 Features ...........................................................................................................................272 15.2 Background Debug Controller (BDC) ..........................................................................................272 15.2.1 BKGD Pin Description ...................................................................................................273 15.2.2 Communication Details ..................................................................................................274 15.2.3 BDC Commands .............................................................................................................278 15.2.4 BDC Hardware Breakpoint .............................................................................................280 15.3 On-Chip Debug System (DBG) ....................................................................................................281 15.3.1 Comparators A and B .....................................................................................................281 15.3.2 Bus Capture Information and FIFO Operation ...............................................................281 15.3.3 Change-of-Flow Information ..........................................................................................282 15.3.4 Tag vs. Force Breakpoints and Triggers .........................................................................282 15.3.5 Trigger Modes .................................................................................................................283 15.3.6 Hardware Breakpoints ....................................................................................................285 15.4 Register Definition ........................................................................................................................285 15.4.1 BDC Registers and Control Bits .....................................................................................285 15.4.2 System Background Debug Force Reset Register (SBDFR) ..........................................287 15.4.3 DBG Registers and Control Bits .....................................................................................288
Appendix A Electrical Characteristics and Timing Specifications
Introduction ....................................................................................................................................293 Parameter Classification.................................................................................................................293 Absolute Maximum Ratings...........................................................................................................293 Thermal Characteristics..................................................................................................................294 ESD Protection and Latch-Up Immunity .......................................................................................295 DC Characteristics..........................................................................................................................296 Supply Current Characteristics.......................................................................................................301 ADC Characteristics.......................................................................................................................304 Internal Clock Generation Module Characteristics ........................................................................307 A.9.1 ICG Frequency Specifications .........................................................................................308 A.10 AC Characteristics..........................................................................................................................311
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 17
A.1 A.2 A.3 A.4 A.5 A.6 A.7 A.8 A.9
Section Number
Title
Page
A.10.1 Control Timing ................................................................................................................311 A.10.2 Timer/PWM (TPM) Module Timing ...............................................................................312 A.11 SPI Characteristics .........................................................................................................................314 A.12 FLASH Specifications....................................................................................................................316 A.13 EMC Performance..........................................................................................................................317
Appendix B Ordering Information and Mechanical Drawings
B.1 Ordering Information .....................................................................................................................319 B.2 Orderable Part Numbering System ................................................................................................319 B.3 Mechanical Drawings.....................................................................................................................320
MC9S08AC16 Series Data Sheet, Rev. 8 18 Freescale Semiconductor
Chapter 1 Introduction
1.1 Overview
The MC9S08AC16 Series devices are members of the low-cost, high-performance HCS08 Family of 8-bit microcontroller units (MCUs). All MCUs in the family use the enhanced HCS08 core and are available with a variety of modules, memory sizes, memory types, and package types. Refer to Table 1-1 for memory sizes and package types. * * NOTE The MC9S08AC16 and MC9S08AC8 devices are qualified for, and are intended to be used in, consumer and industrial applications. The MC9S08AW16A and MC9S08AW8A devices are qualified for, and are intended to be used in, automotive applications.
Table 1-1 summarizes the feature set available in the MCUs.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 19
Chapter 1 Introduction
Table 1-1. Features by MCU and Package
Consumer and Industrial "AC" Devices Feature FLASH size (bytes) RAM size (bytes) Pin quantity ADC channels TPM1 channels TPM2 channels TPM3 channels KBI pins GPIO pins Consumer & Industrial Qualified Automotive Qualified MC9S08AC16 16K 1024 MC9S08AC8 8K 768
48
8 4 2 2 7 38
44
8 4 2 2 6 34 yes no
42
8 4 2 2 6 32
32
6 2 2 2 4 22
48
8 4 2 2 7 38
44
8 4 2 2 6 34 yes no
42
8 4 2 2 6 32
32
6 2 2 2 4 22
Automotive "AW" Devices Feature FLASH size (bytes) RAM size (bytes) Pin quantity ADC channels TPM1 channels TPM2 channels TPM3 channels KBI pins GPIO pins Consumer & Industrial Qualified Automotive Qualified MC9S08AW16A 16K 1024 MC9S08AW8A 8K 768
48
8 4 2 2 7 38
44
8 4 2 2 6 34 no yes
32
6 2 2 2 4 22
48
8 4 2 2 7 38
44
8 4 2 2 6 34 no yes
32
6 2 2 2 4 22
1.2
MCU Block Diagrams
The block diagram shows the structure of the MC9S08AC16 Series MCU.
MC9S08AC16 Series Data Sheet, Rev. 8 20 Freescale Semiconductor
Chapter 1 Introduction
VDDAD VSSAD VREFL VREFH HCS08 CORE BKGD/MS BDC CPU
10-BIT ANALOG-TO-DIGITAL CONVERTER (ADC1) DEBUG MODULE (DBG)
4 AD1P11-AD1P8
PORT A
4 AD1P3-AD1P0
PTA7 PTA2 PTA1 PTA0 PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 PTB0/TPM3CH0/AD1P0 PTC5/RxD2 PTC4 PTC3/TxD2 PTC2/MCLK PTC1/SDA1 PTC0/SCL1 PTD3/KBIP6/AD1P11 PTD2/KBIP5/AD1P10 PTD1/AD1P9 PTD0/AD1P8
SDA1 IIC MODULE (IIC1) SCL1 PORT C PORT D
RESET IRQ/TPMCLK
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION POWER MANAGEMENT RTI IRQ COP LVD
INTERNAL CLOCK GENERATOR (ICG) LOW-POWER OSCILLATOR 7-BIT KEYBOARD INTERRUPT MODULE (KBI)
EXTAL XTAL
2 KBIP6-KBIP5 5 KBIP4-KBIP0 RxD1 TxD1 RxD2 TxD2 SPSCK1 MOSI1 MISO1 SS1 TPM1CH1 TPM1CH0 TPM1CH3 TPM1CH2 TPM2CH1 TPM2CH0 TPM3CH1 TPM3CH0
TPMCLK
SERIAL COMMUNICATIONS INTERFACE MODULE (SCI1) SERIAL COMMUNICATIONS INTERFACE MODULE (SCI2) SERIAL PERIPHERAL INTERFACE MODULE (SPI1)
PORT B
USER FLASH 16,384 BYTES OR 8192 BYTES
PTE7/SPSCK1 PTE6/MOSI1 PTE5/MISO1 PTE4/SS1 PTE3/TPM1CH1 PTE2/TPM1CH0 PTE1/RxD1 PTE0/TxD1
USER RAM 1024 BYTES OR 768 BYTES VDD VSS VOLTAGE REGULATOR
2-CHANNEL TIMER/PWM MODULE (TPM2)
PORT F
4-CHANNEL TIMER/PWM MODULE (TPM1)
PORT E
PTF6 PTF5/TPM2CH1 PTF4/TPM2CH0 PTF1/TPM1CH3 PTF0/TPM1CH2
= Not available on 32-, 42-, or 44-pin packages = Not available on 32- or 42-pin packages = Not available on 32-pin packages
Notes: 1. Port pins are software configurable with pullup device if input port. 2. Pin contains software configurable pullup/pulldown device if IRQ is enabled (IRQPE = 1). Pulldown is enabled if rising edge detect is selected (IRQEDG = 1) 3. IRQ does not have a clamp diode to VDD. IRQ should not be driven above VDD. 4. Pin contains integrated pullup device. 5. PTD3, PTD2, and PTG4 contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is selected (KBEDGn = 1).
Figure 1-1. MC9S08AC16 Block Diagram
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 21
PORT G
2-CHANNEL TIMER/PWM MODULE (TPM3)
PTG6/EXTAL PTG5/XTAL PTG4/KBIP4 PTG3/KBIP3 PTG2/KBIP2 PTG1/KBIP1 PTG0/KBIP0
Chapter 1 Introduction
Table 1-2 lists the functional versions of the on-chip modules.
Table 1-2. Versions of On-Chip Modules
Module Analog-to-Digital Converter Internal Clock Generator Inter-Integrated Circuit Keyboard Interrupt Serial Communications Interface Serial Peripheral Interface Timer Pulse-Width Modulator Central Processing Unit (ADC) (ICG) (IIC) (KBI) (SCI) (SPI) (TPM) (CPU) Version 1 4 2 1 4 3 3 2
1.3
System Clock Distribution
SYSTEM CONTROL LOGIC RTI TPMCLK
ICGERCLK FFE
TPM1
TPM2
IIC1
SCI1
SCI2
SPI1
2 ICG XCLK** COP ICGOUT ICGLCLK* 2 BUSCLK 1 kHz
CPU
BDC
TPM3
ADC1
RAM
FLASH FLASH has frequency requirements for program and erase operation. See the Electricals appendix.
* ICGLCLK is the alternate BDC clock source for the MC9S08AC16 Series. ** XCLK is the fixed-frequency clock.
ADC has min and max frequency requirements. See the Electricals appendix and the ADC chapter.
Figure 1-2. System Clock Distribution Diagram
Some of the modules inside the MCU have clock source choices. Figure 1-2 shows a simplified clock connection diagram. The ICG supplies the clock sources: * ICGOUT is an output of the ICG module. It is one of the following: -- The external crystal oscillator -- An external clock source -- The output of the digitally-controlled oscillator (DCO) in the frequency-locked loop sub-module
MC9S08AC16 Series Data Sheet, Rev. 8 22 Freescale Semiconductor
Chapter 1 Introduction
*
* *
-- Control bits inside the ICG determine which source is connected. FFE is a control signal generated inside the ICG. If the frequency of ICGOUT > 4 x the frequency of ICGERCLK, this signal is a logic 1 and the fixed-frequency clock will be ICGERCLK/2. Otherwise the fixed-frequency clock will be BUSCLK. ICGLCLK -- Development tools can select this internal self-clocked source (~ 8 MHz) to speed up BDC communications in systems where the bus clock is slow. ICGERCLK -- External reference clock can be selected as the real-time interrupt clock source. Can also be used as the ALTCLK input to the ADC module.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 23
Chapter 1 Introduction
MC9S08AC16 Series Data Sheet, Rev. 8 24 Freescale Semiconductor
Chapter 2 Pins and Connections
2.1 Introduction
This chapter describes signals that connect to package pins. It includes a pinout diagram, a table of signal properties, and detailed discussion of signals.
2.2
Device Pin Assignment
37 PTG4/KB1IP4 PTA2 24 42 PTG6/EXTAL 46 PTC2/MCLK
Figure 2-1 shows the 48-pin QFN pin assignments for the MC9S08AC16 Series device.
45 PTC1/SDA1 41 PTG5/XTAL 48 PTC5/RxD2 44 PTC0/SCL1 47 PTC3/TxD2 40 BKGD/MS
38 VREFH PTA1 23
39 VREFL
43 VSS
PTC4 1 IRQ/TPMCLK 2 RESET 3 PTF0/TPM1CH2 4 PTF1/TPM1CH3 5 PTF4/TPM2CH0 6 PTF5/TPM2CH1 7 PTF6 8 PTE0/TxD1 9 PTE1/RxD1 10 PTE2/TPM1CH0 11 PTE3/TPM1CH1 12 PTE4/SS1 13 PTE5/MISO1 14 PTE6/MOSI1 15 PTE7/SPSCK1 16 VSS 17
36 PTG3/KBIP3 35 PTD3/KBIP6/AD1P11 34 PTD2/KBIP5/AD1P10 33 VSSAD 32 VDDAD
48-Pin QFN
31 PTD1/AD1P9 30 PTD0/AD1P8 29 PTB3/AD1P3 28 PTB2/AD1P2 27 PTB1/TPM3CH1/AD1P1 26 PTB0/TPM3CH0/AD1P0 25 PTA7
VDD 18
PTG0/KBIP0 19
PTG1/KBIP1 20
PTG2/KBIP2 21
Figure 2-1. MC9S08AC16 Series in 48-Pin QFN Package
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 25
PTA0 22
Chapter 2 Pins and Connections
Figure 2-2. shows the 44-pin LQFP pin assignments for the MC9S08AC16 Series device.
PTC2/MCLK PTG6/EXTAL PTC5/RxD2 PTC1/SDA1 PTC3/TxD2 PTG5/XTAL PTC0/SCL1
BKGD/MS
44 PTC4 1 IRQ/TPMCLK RESET PTF0/TPM1CH2 PTF1/TPM1CH3 PTF4/TPM2CH0 PTF5/TPM2CH1 PTE0/TxD1 PTE1/RxD1 PTE2/TPM1CH0 PTE3/TPM1CH1 11 13 12 PTE4/SS1 PTE7/SPSCK1 VSS VDD PTG0/KBIP0 PTG1/KBIP1 PTG2/KBIP2 PTA0 PTE5/MISO1 PTE6/MOSI1 14 15 16 17 18 19 20 21 2 3 4 5 6 7 8 9 10 43 42 41 40 39 38 37 36 35
VREFH 34 33 PTG3/KBIP3 32 31 30 29 PTD3/KBIP6/AD1P11 PTD2/KBIP5/AD1P10 VSSAD VDDAD PTD1/AD1P9 PTD0/AD1P8 PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 23 PTB0/TPM3CH0/AD1P0 22 PTA1 28 27 26 25 24
44-Pin LQFP
Figure 2-2. MC9S08AC16 Series in 44-Pin LQFP Package
MC9S08AC16 Series Data Sheet, Rev. 8 26 Freescale Semiconductor
VREFL
VSS
Chapter 2 Pins and Connections
Figure 2-3 shows the 42-pin SDIP pin assignments for the MC9S08AC16 Series device.
PTC0/SCL1 PTC1/SDA1 PTC2/MCLK PTC3/TxD2 PTC5/RxD2 IRQ/TPMCLK RESET PTF0/TPM1CH2 PTF1/TPM1CH3 PTF4/TPM2CH0 PTF5/TPM2CH1 PTE0/TxD1 PTE1/RxD1 PTE2/TPM1CH0 PTE3/TPM1CH1 PTE4/SS1 PTE5/MISO1 PTE6/MOSI1 PTE7/SPSCK1 VSS VDD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 42 41 40 39 38 VSS PTG6/EXTAL PTG5/XTAL BKGD/MS VREFL VREFH PTG3/KBIP3 PTD3/KBIP6/AD1P11 PTD2/KBIP5/AD1P10 VSSAD VDDAD PTD1/AD1P9 PTD0/AD1P8 PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 PTB0/TPM3CH0/AD1P0 PTA0 PTG2/KBIP2 PTG1/KBIP1 PTG0/KBIP0
42-Pin SDIP
37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22
Figure 2-3. MC9S08AC16 Series in 42-Pin SDIP Package
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 27
Chapter 2 Pins and Connections
Figure 2-4 shows the 32-pin LQFP pin assignments for the MC9S08AC16 Series device.
PTG6/EXTAL PTC1/SDA1 PTC0/SCL1 PTG5/XTAL
BKGD/MS
32 IRQ/TPMCLK 1 RESET PTF4/TPM2CH0 PTF5/TPM2CH1 PTE0/TxD1 PTE1/RxD1 PTE2/TPM1CH0 PTE3/TPM1CH1 2 3 4 5 6 7 8 10 9 PTE5/MISO1 PTE7/SPSCK1 VSS PTE4/SS1 VDD PTG0/KBIP0 PTE6/MOSI1 PTG1/KBIP1 11 12 13 14 15 16 31 30 29 28 27 26 25 23 22 24 PTD3/AD1P11/KBIP6 PTD2/AD1P10/KBIP5 VSSAD VDDAD PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 PTB0/TPM3CH0/AD1P0
VREFH 21 20 19 18 17
32-Pin LQFP
Figure 2-4. MC9S08AC16 Series in 32-Pin LQFP Package
MC9S08AC16 Series Data Sheet, Rev. 8 28 Freescale Semiconductor
VREFL
VSS
Chapter 2 Pins and Connections
Table 2-1. Pin Availability by Package Pin-Count
Pin Number 48 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 44 1 2 3 4 5 6 7 -- 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 -- 42 -- 6 7 8 9 10 11 -- 12 13 14 15 16 17 18 19 20 21 22 23 24 25 -- -- 32 <-- Lowest Port Pin Priority Alt 1 --> Highest Alt 2 Pin Number 48 25 IRQ TPM1CH2 TPM1CH3 TPM2CH0 TPM2CH1 TxD1 RxD1 TPM1CH0 TPM1CH1 SS1 MISO1 MOSI1 SPSCK1 VSS VDD KBIP0 KBIP1 KBIP2 TPMCLK RESET 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 44 -- 23 24 25 26 27 28 29 30 31 32 33 -- 34 35 36 37 38 39 40 41 42 43 44 42 -- 26 27 28 29 30 31 32 33 34 35 36 -- 37 38 39 40 41 42 1 2 3 4 5 32 <-- Lowest Port Pin Priority Alt 1 --> Highest Alt 2
-- PTC4 1 2 -- PTF0 -- PTF1 3 4 5 6 7 8 9 PTF4 PTF5 PTE0 PTE1 PTE2 PTE3 PTE4
-- PTA7 17 PTB0 18 PTB1 19 PTB2 20 PTB3 -- PTD0 -- PTD1 21 22 23 PTD2 24 PTD3 -- PTG3 -- PTG4 25 26 27 BKGD 28 PTG5 29 PTG6 30 31 PTC0 32 PTC1 -- PTC2 -- PTC3 -- PTC5 MS XTAL EXTAL VSS SCL1 SDA1 MCLK TxD2 RxD2 KBIP4 VREFH VREFL AD1P10 AD1P11 TPM3CH0 TPM3CH1 AD1P2 AD1P3 AD1P8 AD1P9 VDDAD VSSAD KBIP5 KBIP6 KBIP3 AD1P0 AD1P1
-- PTF6
10 PTE5 11 PTE6 12 PTE7 13 14 15 PTG0 16 PTG1 -- PTG2 -- PTA0 -- PTA1 -- PTA2
Table 2-2. Pin Function Reference
Signal Function Port Pins Serial peripheral interface Keyboard interrupts Timer/PWM Inter-integrated circuit Serial communications interface Oscillator/clocking Analog-to-digital Power/core Reset and interrupts Example(s) PTAx, PTBx SS, MISO, MOSI, SPSCK KBIPx TCLK, TPMCHx SCL, SDA TxD, RxD EXTAL, XTAL ADPx BKGD/MS, VDD, VSS RESET, IRQ Reference Chapter 6, "Parallel Input/Output" Chapter 12, "Serial Peripheral Interface (S08SPIV3)" Chapter 9, "Keyboard Interrupt (S08KBIV1)" Chapter 10, "Timer/PWM (S08TPMV3)" Chapter 13, "Inter-Integrated Circuit (S08IICV2)" Chapter 11, "Serial Communications Interface (S08SCIV4)" Chapter 8, "Internal Clock Generator (S08ICGV4)" Chapter 14, "Analog-to-Digital Converter (S08ADC10V1)" Chapter 2, "Pins and Connections" Chapter 5, "Resets, Interrupts, and System Configuration"
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 29
Chapter 2 Pins and Connections
2.3
Recommended System Connections
Figure 2-5 shows pin connections that are common to almost all MC9S08AC16 Series application systems.
MC9S08AC16 Series Data Sheet, Rev. 8 30 Freescale Semiconductor
Chapter 2 Pins and Connections
VREFH CBYAD 0.1 F SYSTEM POWER + 5V VDD CBLK + 10 F VDDAD
MC9S08AC16 PTA0
VSSAD VREFL VDD CBY 0.1 F VSS (x2)
PORT A
PTA1 PTA2 PTA7 PTB0/AD1P0/TPM3CH0
PORT B
PTB1/AD1P1/TPM3CH1 PTB2/AD1P2 PTB3/AD1P3
NOTE 1
RF C1 X1 C2
RS
XTAL NOTE 2 EXTAL NOTE 2 PORT C
PTC0/SCL1 PTC1/SDA1 PTC2/MCLK PTC3/TxD2 PTC4 PTC5/RxD2 I/O AND PERIPHERAL INTERFACE TO APPLICATION
BACKGROUND HEADER VDD BKGD/MS VDD 4.7 k-10 k 0.1 F OPTIONAL MANUAL RESET RESET NOTE 3 PORT D
PTD0/AD1P8 PTD1/AD1P9 PTD2/AD1P10/KBIP5 PTD3/AD1P11/KBIP6 PTE0/TxD1 PTE1/RxD1 PTE2/TPM1CH0 PORT E PTE3/TPM1CH1 PTE4/SS1 PTE5/MISO1 PTE6/MOSI1 PTE7/SPSCK1 PTF0/TPM1CH2 PORT F PTF1/TPM1CH3 PTF4/TPM2CH0 PTF5/TPM2CH1 PTF6
SYSTEM
VDD 4.7 k- 10 k 0.1 F
ASYNCHRONOUS INTERRUPT INPUT
TPMCLK/IRQ NOTE 3
PTG0/KBIP0 PTG1/KBIP1 PTG2/KBIP2 PTG3/KBIP3 PTG4/KBIP4 PTG5/XTAL PTG6/EXTAL PORT G
NOTES: 1. Not required if using the internal clock option. 2. XTAL and EXTAL are PTG5 and PTG6 respectively. 3. RC filters on RESET and IRQ are recommended for EMC-sensitive applications.
Figure 2-5. Basic System Connections
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 31
Chapter 2 Pins and Connections
2.3.1
Power (VDD, 2 x VSS, VDDAD, VSSAD)
VDD and VSS are the primary power supply pins for the MCU. This voltage source supplies power to all I/O buffer circuitry and to an internal voltage regulator. The internal voltage regulator provides regulated lower-voltage source to the CPU and other internal circuitry of the MCU. Typically, application systems have two separate capacitors across the power pins. In this case, there should be a bulk electrolytic capacitor, such as a 10-F tantalum capacitor, to provide bulk charge storage for the overall system and a 0.1-F ceramic bypass capacitor located as near to the paired VDD and VSS power pins as practical to suppress high-frequency noise. The MC9S08AC16 has a second VSS pin. This pin should be connected to the system ground plane or to the primary VSS pin through a low-impedance connection. VDDAD and VSSAD are the analog power supply pins for the MCU. This voltage source supplies power to the ADC module. A 0.1-F ceramic bypass capacitor should be located as near to the analog power pins as practical to suppress high-frequency noise.
2.3.2
Oscillator (XTAL, EXTAL)
Out of reset the MCU uses an internally generated clock (self-clocked mode -- fSelf_reset) equivalent to about 8-MHz crystal rate. This frequency source is used during reset startup and can be enabled as the clock source for stop recovery to avoid the need for a long crystal startup delay. This MCU also contains a trimmable internal clock generator (ICG) module that can be used to run the MCU. For more information on the ICG, see the Chapter 8, "Internal Clock Generator (S08ICGV4)." The oscillator in this MCU is a Pierce oscillator that can accommodate a crystal or ceramic resonator in either of two frequency ranges selected by the RANGE bit in the ICGC1 register. Rather than a crystal or ceramic resonator, an external oscillator can be connected to the EXTAL input pin. Refer to Figure 2-5 for the following discussion. RS (when used) and RF should be low-inductance resistors such as carbon composition resistors. Wire-wound resistors, and some metal film resistors, have too much inductance. C1 and C2 normally should be high-quality ceramic capacitors that are specifically designed for high-frequency applications. RF is used to provide a bias path to keep the EXTAL input in its linear range during crystal startup and its value is not generally critical. Typical systems use 1 M to 10 M. Higher values are sensitive to humidity and lower values reduce gain and (in extreme cases) could prevent startup. C1 and C2 are typically in the 5-pF to 25-pF range and are chosen to match the requirements of a specific crystal or resonator. Be sure to take into account printed circuit board (PCB) capacitance and MCU pin capacitance when sizing C1 and C2. The crystal manufacturer typically specifies a load capacitance which is the series combination of C1 and C2 which are usually the same size. As a first-order approximation, use 10 pF as an estimate of combined pin and PCB capacitance for each oscillator pin (EXTAL and XTAL).
2.3.3
RESET
RESET is a dedicated pin with a pullup device built in. It has input hysteresis, a high current output driver, and no output slew rate control. Internal power-on reset and low-voltage reset circuitry typically make
MC9S08AC16 Series Data Sheet, Rev. 8 32 Freescale Semiconductor
Chapter 2 Pins and Connections
external reset circuitry unnecessary. This pin is normally connected to the standard 6-pin background debug connector so a development system can directly reset the MCU system. If desired, a manual external reset can be added by supplying a simple switch to ground (pull reset pin low to force a reset). Whenever any reset is initiated (whether from an external signal or from an internal system), the reset pin is driven low for approximately 34 bus cycles. The reset circuitry decodes the cause of reset and records it by setting a corresponding bit in the system control reset status register (SRS). In EMC-sensitive applications, an external RC filter is recommended on the reset pin. See Figure 2-5 for an example.
2.3.4
Background/Mode Select (BKGD/MS)
While in reset, the BKGD/MS pin functions as a mode select pin. Immediately after reset rises the pin functions as the background pin and can be used for background debug communication. While functioning as a background/mode select pin, the pin includes an internal pullup device, input hysteresis, a standard output driver, and no output slew rate control. If nothing is connected to this pin, the MCU will enter normal operating mode at the rising edge of reset. If a debug system is connected to the 6-pin standard background debug header, it can hold BKGD/MS low during the rising edge of reset which forces the MCU to active background mode. The BKGD pin is used primarily for background debug controller (BDC) communications using a custom protocol that uses 16 clock cycles of the target MCU's BDC clock per bit time. The target MCU's BDC clock could be as fast as the bus clock rate, so there should never be any significant capacitance connected to the BKGD/MS pin that could interfere with background serial communications. Although the BKGD pin is a pseudo open-drain pin, the background debug communication protocol provides brief, actively driven, high speedup pulses to ensure fast rise times. Small capacitances from cables and the absolute value of the internal pullup device play almost no role in determining rise and fall times on the BKGD pin.
2.3.5
ADC Reference Pins (VREFH, VREFL)
The VREFH and VREFL pins are the voltage reference high and voltage reference low inputs respectively for the ADC module.
2.3.6
External Interrupt Pin (IRQ)
The IRQ pin is the input source for the IRQ interrupt and is also the input for the BIH and BIL instructions. If the IRQ function is not enabled, this pin does not perform any function. In EMC-sensitive applications, an external RC filter is recommended on the IRQ pin. See Figure 2-5 for an example.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 33
Chapter 2 Pins and Connections
2.3.7
General-Purpose I/O and Peripheral Ports
The remaining pins are shared among general-purpose I/O and on-chip peripheral functions such as timers and serial I/O systems. Immediately after reset, all of these pins are configured as high-impedance general-purpose inputs with internal pullup devices disabled. NOTE To avoid extra current drain from floating input pins, the reset initialization routine in the application program should either enable on-chip pullup devices or change the direction of unused pins to outputs so the pins do not float. For information about controlling these pins as general-purpose I/O pins, see Chapter 6, "Parallel Input/Output." For information about how and when on-chip peripheral systems use these pins, refer to the appropriate chapter from Table 2-2. When an on-chip peripheral system is controlling a pin, data direction control bits still determine what is read from port data registers even though the peripheral module controls the pin direction by controlling the enable for the pin's output buffer. See the Chapter 6, "Parallel Input/Output" chapter for more details. Pullup enable bits for each input pin control whether on-chip pullup devices are enabled whenever the pin is acting as an input even if it is being controlled by an on-chip peripheral module. When the PTD3, PTD2, and PTG4 pins are controlled by the KBI module and are configured for rising-edge/high-level sensitivity, the pullup enable control bits enable pulldown devices rather than pullup devices. Similarly, when IRQ is configured as the IRQ input and is set to detect rising edges, the pullup enable control bit enables a pulldown device rather than a pullup device. NOTE When an alternative function is first enabled it is possible to get a spurious edge to the module, user software should clear out any associated flags before interrupts are enabled. Table 2-1 illustrates the priority if multiple modules are enabled. The highest priority module will have control over the pin. Selecting a higher priority pin function with a lower priority function already enabled can cause spurious edges to the lower priority module. It is recommended that all modules that share a pin be disabled before enabling another module.
MC9S08AC16 Series Data Sheet, Rev. 8 34 Freescale Semiconductor
Chapter 3 Modes of Operation
3.1 Introduction
The operating modes of the MC9S08AC16 Series are described in this chapter. Entry into each mode, exit from each mode, and functionality while in each of the modes are described.
3.2
* *
Features
Active background mode for code development Wait mode: -- CPU shuts down to conserve power -- System clocks running -- Full voltage regulation maintained Stop modes: -- System clocks stopped; voltage regulator in standby -- Stop2 -- Partial power down of internal circuits, RAM contents retained -- Stop3 -- All internal circuits powered for fast recovery
*
3.3
Run Mode
This is the normal operating mode for the MC9S08AC16 Series. This mode is selected when the BKGD/MS pin is high at the rising edge of reset. In this mode, the CPU executes code from internal memory with execution beginning at the address fetched from memory at 0xFFFE:0xFFFF after reset.
3.4
Active Background Mode
The active background mode functions are managed through the background debug controller (BDC) in the HCS08 core. The BDC, together with the on-chip debug module (DBG), provide the means for analyzing MCU operation during software development. Active background mode is entered in any of five ways: * When the BKGD/MS pin is low at the rising edge of reset * When a BACKGROUND command is received through the BKGD pin * When a BGND instruction is executed * When encountering a BDC breakpoint * When encountering a DBG breakpoint
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 35
Chapter 3 Modes of Operation
After entering active background mode, the CPU is held in a suspended state waiting for serial background commands rather than executing instructions from the user's application program. Background commands are of two types: * Non-intrusive commands, defined as commands that can be issued while the user program is running. Non-intrusive commands can be issued through the BKGD pin while the MCU is in run mode; non-intrusive commands can also be executed when the MCU is in the active background mode. Non-intrusive commands include: -- Memory access commands -- Memory-access-with-status commands -- BDC register access commands -- The BACKGROUND command * Active background commands, which can only be executed while the MCU is in active background mode. Active background commands include commands to: -- Read or write CPU registers -- Trace one user program instruction at a time -- Leave active background mode to return to the user's application program (GO) The active background mode is used to program a bootloader or user application program into the FLASH program memory before the MCU is operated in run mode for the first time. When the MC9S08AC16 Series is shipped from the Freescale Semiconductor factory, the FLASH program memory is erased by default unless specifically noted so there is no program that could be executed in run mode until the FLASH memory is initially programmed. The active background mode can also be used to erase and reprogram the FLASH memory after it has been previously programmed. For additional information about the active background mode, refer to Chapter 15, "Development Support."
3.5
Wait Mode
Wait mode is entered by executing a WAIT instruction. Upon execution of the WAIT instruction, the CPU enters a low-power state in which it is not clocked. The I bit in CCR is cleared when the CPU enters the wait mode, enabling interrupts. When an interrupt request occurs, the CPU exits the wait mode and resumes processing, beginning with the stacking operations leading to the interrupt service routine. While the MCU is in wait mode, there are some restrictions on which background debug commands can be used. Only the BACKGROUND command and memory-access-with-status commands are available when the MCU is in wait mode. The memory-access-with-status commands do not allow memory access, but they report an error indicating that the MCU is in either stop or wait mode. The BACKGROUND command can be used to wake the MCU from wait mode and enter active background mode.
3.6
Stop Modes
One of two stop modes is entered upon execution of a STOP instruction when the STOPE bit in the system option register is set. In both stop modes, all internal clocks are halted. If the STOPE bit is not set when
MC9S08AC16 Series Data Sheet, Rev. 8 36 Freescale Semiconductor
Chapter 3 Modes of Operation
the CPU executes a STOP instruction, the MCU will not enter either of the stop modes and an illegal opcode reset is forced. The stop modes are selected by setting the appropriate bits in SPMSC2. HCS08 devices that are designed for low voltage operation (1.8V to 3.6V) also include stop1 mode. The MC9S08AC16 Series family of devices does not include stop1 mode. Table 3-1 summarizes the behavior of the MCU in each of the stop modes.
Table 3-1. Stop Mode Behavior
CPU, Digital Peripherals, FLASH Off Standby
Mode
PPDC
RAM
ICG
ADC
Regulator
I/O Pins
RTI
Stop2 Stop3
1
1 0
Standby Standby
Off Off1
Disabled Optionally on
Standby Standby
States held States held
Optionally on Optionally on
Crystal oscillator can be configured to run in stop3. Please see the ICG registers.
3.6.1
Stop2 Mode
The stop2 mode provides very low standby power consumption and maintains the contents of RAM and the current state of all of the I/O pins. To enter stop2, the user must execute a STOP instruction with stop2 selected (PPDC = 1) and stop mode enabled (STOPE = 1). In addition, the LVD must not be enabled to operate in stop (LVDSE = LVDE = 1). If the LVD is enabled in stop, then the MCU enters stop3 upon the execution of the STOP instruction regardless of the state of PPDC. Before entering stop2 mode, the user must save the contents of the I/O port registers, as well as any other memory-mapped registers which they want to restore after exit of stop2, to locations in RAM. Upon exit of stop2, these values can be restored by user software before pin latches are opened. When the MCU is in stop2 mode, all internal circuits that are powered from the voltage regulator are turned off, except for the RAM. The voltage regulator is in a low-power standby state, as is the ADC. Upon entry into stop2, the states of the I/O pins are latched. The states are held while in stop2 mode and after exiting stop2 mode until a logic 1 is written to PPDACK in SPMSC2. Exit from stop2 is done by asserting either of the wake-up pins: RESET or IRQ/TPMCLK, or by an RTI interrupt. IRQ/TPMCLK is always an active low input when the MCU is in stop2, regardless of how it was configured before entering stop2. Upon wake-up from stop2 mode, the MCU will start up as from a power-on reset (POR) except pin states remain latched. The CPU will take the reset vector. The system and all peripherals will be in their default reset states and must be initialized. After waking up from stop2, the PPDF bit in SPMSC2 is set. This flag may be used to direct user code to go to a stop2 recovery routine. PPDF remains set and the I/O pin states remain latched until a logic 1 is written to PPDACK in SPMSC2. To maintain I/O state for pins that were configured as general-purpose I/O, the user must restore the contents of the I/O port registers, which have been saved in RAM, to the port registers before writing to the PPDACK bit. If the port registers are not restored from RAM before writing to PPDACK, then the
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 37
Chapter 3 Modes of Operation
register bits will assume their reset states when the I/O pin latches are opened and the I/O pins will switch to their reset states. For pins that were configured as peripheral I/O, the user must reconfigure the peripheral module that interfaces to the pin before writing to the PPDACK bit. If the peripheral module is not enabled before writing to PPDACK, the pins will be controlled by their associated port control registers when the I/O latches are opened.
3.6.2
Stop3 Mode
To enter stop3, the user must execute a STOP instruction with stop3 selected (PPDC = 0) and stop mode enabled (STOPE = 1). Upon entering the stop3 mode, all of the clocks in the MCU, including the oscillator itself, are halted. The ICG enters its standby state, as does the voltage regulator and the ADC. The states of all of the internal registers and logic, as well as the RAM content, are maintained. The I/O pin states are not latched at the pin as in stop2. Instead they are maintained by virtue of the states of the internal logic driving the pins being maintained. Exit from stop3 is done by asserting RESET or by an interrupt from one of the following sources: the real-time interrupt (RTI), LVD system, ADC, IRQ, KBI, or SCI. If stop3 is exited by means of the RESET pin, then the MCU will be reset and operation will resume after taking the reset vector. Exit by means of an asynchronous interrupt or the real-time interrupt will result in the MCU taking the appropriate interrupt vector. A separate self-clocked source (1 kHz) for the real-time interrupt allows a wakeup from stop2 or stop3 mode with no external components. When RTIS2:RTIS1:RTIS0 = 0:0:0, the real-time interrupt function and this 1-kHz source are disabled. Power consumption is lower when the 1-kHz source is disabled, but in that case the real-time interrupt cannot wake the MCU from stop.
3.6.3
Active BDM Enabled in Stop Mode
Entry into the active background mode from run mode is enabled if the ENBDM bit in BDCSCR is set. This register is described in Chapter 15, "Development Support" of this data sheet. If ENBDM is set when the CPU executes a STOP instruction, the system clocks to the background debug logic remain active when the MCU enters stop mode so background debug communication is still possible. In addition, the voltage regulator does not enter its low-power standby state but maintains full internal regulation. If the user attempts to enter stop2 with ENBDM set, the MCU will instead enter stop3. Most background commands are not available in stop mode. The memory-access-with-status commands do not allow memory access, but they report an error indicating that the MCU is in either stop or wait mode. The BACKGROUND command can be used to wake the MCU from stop and enter active background mode if the ENBDM bit is set. After entering background debug mode, all background commands are available. Table 3-2 summarizes the behavior of the MCU in stop when entry into the background debug mode is enabled.
MC9S08AC16 Series Data Sheet, Rev. 8 38 Freescale Semiconductor
Chapter 3 Modes of Operation
Table 3-2. BDM Enabled Stop Mode Behavior
CPU, Digital Peripherals, FLASH Standby
Mode
PPDC
RAM
ICG
ADC
Regulator
I/O Pins
RTI
Stop3
0
Standby
Active
Optionally on
Active
States held
Optionally on
3.6.4
LVD Enabled in Stop Mode
The LVD system is capable of generating either an interrupt or a reset when the supply voltage drops below the LVD voltage. If the LVD is enabled in stop by setting the LVDE and the LVDSE bits, then the voltage regulator remains active during stop mode. If the user attempts to enter stop2 with the LVD enabled for stop, the MCU will instead enter stop3. Table 3-3 summarizes the behavior of the MCU in stop when the LVD is enabled.
Table 3-3. LVD Enabled Stop Mode Behavior
CPU, Digital Peripherals, FLASH Standby
Mode
PPDC
RAM
ICG
ADC
Regulator
I/O Pins
RTI
Stop3
0
Standby
Off
Optionally on
Active
States held
Optionally on
3.6.5
On-Chip Peripheral Modules in Stop Modes
When the MCU enters any stop mode, system clocks to the internal peripheral modules are stopped. Even in the exception case (ENBDM = 1), where clocks are kept alive to the background debug logic, clocks to the peripheral systems are halted to reduce power consumption. Refer to Section 3.6.2, "Stop3 Mode" for specific information on system behavior in stop modes. I/O Pins * All I/O pin states remain unchanged when the MCU enters stop3 mode. * If the MCU is configured to go into stop2 mode, all I/O pins states are latched before entering stop. Memory * All RAM and register contents are preserved while the MCU is in stop3 mode. * All registers will be reset upon wake-up from stop2, but the contents of RAM are preserved and pin states remain latched until the PPDACK bit is written. The user may save any memory-mapped register data into RAM before entering stop2 and restore the data upon exit from stop2. * The contents of the FLASH memory are non-volatile and are preserved in any of the stop modes. ICG -- In stop3 mode, the ICG enters its low-power standby state. The oscillator may be kept running when the ICG is in standby by setting OSCSTEN. In stop2 mode, the ICG is turned off. The oscillator cannot be kept running in stop2 even if OSCSTEN is set. If the MCU is configured to go into stop2 mode, the ICG will be reset upon wake-up from stop and must be reinitialized.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 39
Chapter 3 Modes of Operation
TPM -- When the MCU enters stop mode, the clock to the TPM1 and TPM2 modules stop. The modules halt operation. If the MCU is configured to go into stop2 mode, the TPM modules will be reset upon wake-up from stop and must be reinitialized. ADC -- When the MCU enters stop mode, the ADC will enter a low-power standby state unless the asynchronous clock source, ADACK, is enabled. Conversions can occur in stop3 if ADACK is enabled. If the MCU is configured to go into stop2 mode, the ADC will be reset upon wake-up from stop and must be re-initialized. KBI -- During stop3, the KBI pins that are enabled continue to function as interrupt sources that are capable of waking the MCU from stop3. The KBI is disabled in stop2 and must be reinitialized after waking up. SCI -- When the MCU enters stop mode, the clocks to the SCI1 and SCI2 modules stop. The modules halt operation. If the MCU is configured to go into stop2 mode, the SCI modules will be reset upon wake-up from stop and must be reinitialized. SPI -- When the MCU enters stop mode, the clocks to the SPI module stop. The module halts operation. If the MCU is configured to go into stop2 mode, the SPI module will be reset upon wake-up from stop and must be reinitialized. IIC -- When the MCU enters stop mode, the clocks to the IIC module stops. The module halts operation. If the MCU is configured to go into stop2 mode, the IIC module will be reset upon wake-up from stop and must be reinitialized. Voltage Regulator -- The voltage regulator enters a low-power standby state when the MCU enters either of the stop modes unless the LVD is enabled in stop mode or BDM is enabled.
MC9S08AC16 Series Data Sheet, Rev. 8 40 Freescale Semiconductor
Chapter 4 Memory
4.1 MC9S08AC16 Series Memory Map
Figure 4-1 shows the memory maps for the MC9S08AC16 Series MCUs. On-chip memory in the MC9S08AC16 Series of MCU consists of RAM, FLASH program memory for nonvolatile data storage, plus I/O and control/status registers. The registers are divided into three groups: * Direct-page registers (0x0000 through 0x006F) * High-page registers (0x1800 through 0x185F) * Nonvolatile registers (0xFFB0 through 0xFFBF)
0x0000 0x006F 0x0070 0x046F 0x0470 DIRECT PAGE REGISTERS RAM 1024 BYTES UNIMPLEMENTED 5008 BYTES 0x17FF 0x1800 HIGH PAGE REGISTERS 0x185F 0x1860 0x185F 0x1860 0x17FF 0x1800 HIGH PAGE REGISTERS 0x0000 0x006F 0x0070 0x036F 0x0370 0x046F 0x0470 DIRECT PAGE REGISTERS RAM 768 BYTES RESERVED -- 256 BYTES UNIMPLEMENTED 5008 BYTES
UNIMPLEMENTED 42,912 BYTES
UNIMPLEMENTED 42,912 BYTES
0xBFFF 0xC000 FLASH 16,384 BYTES
0xBFFF 0xC000 0xDFFF 0xE000
RESERVED 8192 BYTES FLASH 8192 BYTES MC9S08AC8 and MC9S08AW8A
0xFFFF MC9S08AC16 and MC9S08AW16A
0xFFFF
Figure 4-1. MC9S08AC16 Series Memory Maps
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 41
Chapter 4 Memory
4.1.1
Reset and Interrupt Vector Assignments
Figure 4-1 shows address assignments for reset and interrupt vectors. The vector names shown in this table are the labels used in the Freescale-provided equate file for the MC9S08AC16 Series. For more details about resets, interrupts, interrupt priority, and local interrupt mask controls, refer to Chapter 5, "Resets, Interrupts, and System Configuration."
Table 4-1. Reset and Interrupt Vectors
Address (High/Low) 0xFFC0:FFC1 through 0xFFC4:FFC5 0xFFC6:FFC7 0xFFC8:FFC9 0xFFCA:FFCB 0xFFCC:FFCD 0xFFCE:FFCF 0xFFD0:FFD1 0xFFD2:FFD3 0xFFD4:FFD5 0xFFD6:FFD7 0xFFD8:FFD9 0xFFDA:FFDB 0xFFDC:FFDD 0xFFDE:FFDF 0xFFE0:FFE1 0xFFE2:FFE3 0xFFE4:FFE5 0xFFE6:FFE7 0xFFE8:FFE9 0xFFEA:FFEB 0xFFEC:FFED 0xFFEE:FFEF 0xFFF0:FFF1 0xFFF2:FFF3 0xFFF4:FFF5 0xFFF6:FFF7 0xFFF8:FFF9 0xFFFA:FFFB 0xFFFC:FFFD 0xFFFE:FFFF Vector Unused Vector Space (available for user program) TPM3 overflow TPM3 channel 1 TPM3 channel 0 RTI IIC1 ADC1 Conversion KBI SCI2 Transmit SCI2 Receive SCI2 Error SCI1 Transmit SCI1 Receive SCI1 Error SPI1 TPM2 Overflow TPM2 Channel 1 TPM2 Channel 0 TPM1 Overflow Unused Unused TPM1 Channel 3 TPM1 Channel 2 TPM1 Channel 1 TPM1 Channel 0 ICG Low Voltage Detect IRQ SWI Reset Vector Name -- Vtpm3ovf Vtpm3ch1 Vtpm3ch0 Vrti Viic1 Vadc1 Vkeyboard1 Vsci2tx Vsci2rx Vsci2err Vsci1tx Vsci1rx Vsci1err Vspi1 Vtpm2ovf Vtpm2ch1 Vtpm2ch0 Vtpm1ovf -- -- Vtpm1ch3 Vtpm1ch2 Vtpm1ch1 Vtpm1ch0 Vicg Vlvd Virq Vswi Vreset
MC9S08AC16 Series Data Sheet, Rev. 8 42 Freescale Semiconductor
Chapter 4 Memory
4.2
Register Addresses and Bit Assignments
The registers in the MC9S08AC16 Series are divided into these three groups: * Direct-page registers are located in the first 112 locations in the memory map, so they are accessible with efficient direct addressing mode instructions. * High-page registers are used much less often, so they are located above 0x1800 in the memory map. This leaves more room in the direct page for more frequently used registers and variables. * The nonvolatile register area consists of a block of 16 locations in FLASH memory at 0xFFB0-0xFFBF. Nonvolatile register locations include: -- Three values which are loaded into working registers at reset -- An 8-byte backdoor comparison key which optionally allows a user to gain controlled access to secure memory Because the nonvolatile register locations are FLASH memory, they must be erased and programmed like other FLASH memory locations. Direct-page registers can be accessed with efficient direct addressing mode instructions. Bit manipulation instructions can be used to access any bit in any direct-page register. Table 4-2 is a summary of all user-accessible direct-page registers and control bits. The direct page registers in Table 4-2 can use the more efficient direct addressing mode which only requires the lower byte of the address. Because of this, the lower byte of the address in column one is shown in bold text. In Table 4-3 and Table 4-4 the whole address in column one is shown in bold. In Table 4-2, Table 4-3, and Table 4-4, the register names in column two are shown in bold to set them apart from the bit names to the right. Cells that are not associated with named bits are shaded. A shaded cell with a 0 indicates this unused bit always reads as a 0. Shaded cells with dashes indicate unused or reserved bit locations that could read as 1s or 0s.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 43
Chapter 4 Memory
Table 4-2. Direct-Page Register Summary (Sheet 1 of 3)
Address Register Name Bit 7 PTAD7 PTADD7 R R 0 0 R R PTED7 PTEDD7 R R 0 0 -- -- COCO ADACT 0 ADR7 0 ADCV7 ADLPC ADPC7 ADPC15 ADPC23 -- -- 0 -- 0 0 TOF Bit 15 Bit 7 Bit 15 Bit 7 CH0F Bit 15 Bit 7 6 R R R R R R R R PTED6 PTEDD6 PTFD6 PTFDD6 PTGD6 PTGDD6 -- -- AIEN ADTRG 0 ADR6 0 ADCV6 ADPC6 ADPC14 ADPC22 -- -- IRQPDD -- KBEDG6 KBIPE6 TOIE 14 6 14 6 CH0IE 14 6 ADIV ADPC5 ADPC13 ADPC21 -- -- IRQEDG -- KBEDG5 KBIPE5 CPWMS 13 5 13 5 MS0B 13 5 5 R R R R PTCD5 PTCDD5 R R PTED5 PTEDD5 PTFD5 PTFDD5 PTGD5 PTGDD5 -- -- ADCO ACFE 0 ADR5 0 ADCV5 ACFGT 0 ADR4 0 ADCV4 ADLSMP ADPC4 ADPC12 ADPC20 -- -- IRQPE -- KBEDG4 KBIPE4 CLKSB 12 4 12 4 MS0A 12 4 0 0 ADR3 0 ADCV3 ADPC3 ADPC11 ADPC19 -- -- IRQF -- KBF KBIPE3 CLKSA 11 3 11 3 ELS0B 11 3 MODE ADPC2 ADPC10 ADPC18 -- -- 0 -- KBACK KBIPE2 PS2 10 2 10 2 ELS0A 10 2 4 R R R R PTCD4 PTCDD4 R R PTED4 PTEDD4 PTFD4 PTFDD4 PTGD4 PTGDD4 -- -- 3 R R PTBD3 PTBDD3 PTCD3 PTCDD3 PTDD3 PTDDD3 PTED3 PTEDD3 R R PTGD3 PTGDD3 -- -- 2 PTAD2 PTADD2 PTBD2 PTBDD2 PTCD2 PTCDD2 PTDD2 PTDDD2 PTED2 PTEDD2 R R PTGD2 PTGDD2 -- -- ADCH 0 0 ADR2 0 ADCV2 R ADR9 ADR1 ADCV9 ADCV1 ADPC1 ADPC9 ADPC17 -- -- IRQIE -- KBIE KBIPE1 PS1 9 1 9 1 0 9 1 R ADR8 ADR0 ADCV8 ADCV0 ADPC0 ADPC8 ADPC16 -- -- IRQMOD -- KBIMOD KBIPE0 PS0 Bit 8 Bit 0 Bit 8 Bit 0 0 Bit 8 Bit 0 1 PTAD1 PTADD1 PTBD1 PTBDD1 PTCD1 PTCDD1 PTDD1 PTDDD1 PTED1 PTEDD1 PTFD1 PTFDD1 PTGD1 PTGDD1 -- -- Bit 0 PTAD0 PTADD0 PTBD0 PTBDD0 PTCD0 PTCDD0 PTDD0 PTDDD0 PTED0 PTEDD0 PTFD0 PTFDD0 PTGD0 PTGDD0 -- --
0x0000 0x0001 0x0002 0x0003 0x0004 0x0005 0x0006 0x0007 0x0008 0x0009 0x000A 0x000B 0x000C 0x000D 0x000E- 0x000F 0x0010 0x0011 0x0012 0x0013 0x0014 0x0015 0x0016 0x0017 0x0018 0x0019 0x001A- 0x001B 0x001C 0x001D 0x001E 0x001F 0x0020 0x0021 0x0022 0x0023 0x0024 0x0025 0x0026 0x0027
PTAD PTADD PTBD PTBDD PTCD PTCDD PTDD PTDDD PTED PTEDD PTFD PTFDD PTGD PTGDD Reserved ADC1SC1 ADC1SC2 ADC1RH ADC1RL ADC1CVH ADC1CVL ADC1CFG APCTL1 APCTL2 APCTL3 Reserved IRQSC Reserved KBISC KBIPE TPM1SC TPM1CNTH TPM1CNTL TPM1MODH TPM1MODL TPM1C0SC TPM1C0VH TPM1C0VL
ADICLK
MC9S08AC16 Series Data Sheet, Rev. 8 44 Freescale Semiconductor
Chapter 4 Memory
Table 4-2. Direct-Page Register Summary (Sheet 2 of 3)
Address Register Name Bit 7 CH1F Bit 15 Bit 7 CH2F Bit 15 Bit 7 CH3F Bit 15 Bit 7 -- LBKDIE SBR7 LOOPS TIE TDRE LBKDIF R8 Bit 7 LBKDIE SBR7 LOOPS TIE TDRE LBKDIF R8 Bit 7 HGO LOLRE CLKST 0 0 0 0 6 CH1IE 14 6 CH2IE 14 6 CH3IE 14 6 -- RXEDGIE SBR6 SCISWAI TCIE TC RXEDGIF T8 6 RXEDGIE SBR6 SCISWAI TCIE TC RXEDGIF T8 6 RANGE 5 MS1B 13 5 MS2B 13 5 MS3B 13 5 -- 0 SBR5 RSRC RIE RDRF 0 TXDIR 5 0 SBR5 RSRC RIE RDRF 0 TXDIR 5 REFS MFD REFST 0 0 LOLS 0 0 FLT TRIM -- SPIE 0 0 SPRF Bit 7 -- SPE 0 SPPR2 0 6 -- SPTIE 0 SPPR1 SPTEF 5 -- MSTR MODFEN SPPR0 MODF 4 -- CPOL BIDIROE 0 0 3 -- CPHA 0 SPR2 0 2 -- SSOE SPISWAI SPR1 0 1 -- LSBFE SPC0 SPR0 0 Bit 0 4 MS1A 12 4 MS2A 12 4 MS3A 12 4 -- SBR12 SBR4 M ILIE IDLE RXINV TXINV 4 SBR12 SBR4 M ILIE IDLE RXINV TXINV 4 CLKS LOCRE LOCK 0 LOCS 0 FLT 3 ELS1B 11 3 ELS2B 11 3 ELS3B 11 3 -- SBR11 SBR3 WAKE TE OR RWUID ORIE 3 SBR11 SBR3 WAKE TE OR RWUID ORIE 3 2 ELS1A 10 2 ELS2A 10 2 ELS3A 10 2 -- SBR10 SBR2 ILT RE NF BRK13 NEIE 2 SBR10 SBR2 ILT RE NF BRK13 NEIE 2 OSCSTEN 1 0 9 1 0 9 1 0 9 1 -- SBR9 SBR1 PE RWU FE LBKDE FEIE 1 SBR9 SBR1 PE RWU FE LBKDE FEIE 1 LOCD RFD ERCS 0 ICGIF DCOS Bit 0 0 Bit 8 Bit 0 0 Bit 8 Bit 0 0 Bit 8 Bit 0 -- SBR8 SBR0 PT SBK PF RAF PEIE Bit 0 SBR8 SBR0 PT SBK PF RAF PEIE Bit 0 0
0x0028 0x0029 0x002A 0x002B 0x002C 0x002D 0x002E 0x002F 0x0030 0x0031- 0x0037 0x0038 0x0039 0x003A 0x003B 0x003C 0x003D 0x003E 0x003F 0x0040 0x0041 0x0042 0x0043 0x0044 0x0045 0x0046 0x0047 0x0048 0x0049 0x004A 0x004B 0x004C 0x004D 0x004E 0x004F 0x0050 0x0051 0x0052 0x0053 0x0054
TPM1C1SC TPM1C1VH TPM1C1VL TPM1C2SC TPM1C2VH TPM1C2VL TPM1C3SC TPM1C3VH TPM1C3VL Reserved SCI1BDH SCI1BDL SCI1C1 SCI1C2 SCI1S1 SCI1S2 SCI1C3 SCI1D SCI2BDH SCI2BDL SCI2C1 SCI2C2 SCI2S1 SCI2S2 SCI2C3 SCI2D ICGC1 ICGC2 ICGS1 ICGS2 ICGFLTU ICGFLTL ICGTRM Reserved SPI1C1 SPI1C2 SPI1BR SPI1S SPI1D
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 45
Chapter 4 Memory
Table 4-2. Direct-Page Register Summary (Sheet 3 of 3)
Address Register Name Bit 7 -- -- AD7 MULT IICEN TCF GCAEN -- -- TOF Bit 15 Bit 7 Bit 15 Bit 7 CH0F Bit 15 Bit 7 CH1F Bit 15 Bit 7 -- -- IICIE IAAS ADEXT -- -- TOIE 14 6 14 6 CH0IE 14 6 CH1IE 14 6 -- -- MST BUSY 0 -- -- CPWMS 13 5 13 5 MS0B 13 5 MS1B 13 5 -- -- TX ARBL DATA 0 -- -- CLKSB 12 4 12 4 MS0A 12 4 MS1A 12 4 -- -- 0 -- -- CLKSA 11 3 11 3 ELS0B 11 3 ELS1B 11 3 -- -- AD10 -- -- PS2 10 2 10 2 ELS0A 10 2 ELS1A 10 2 -- -- AD9 -- -- PS1 9 1 9 1 0 9 1 0 9 1 -- -- AD8 -- -- PS0 Bit 8 Bit 0 Bit 8 Bit 0 0 Bit 8 Bit 0 0 Bit 8 Bit 0 -- -- TXAK 0 6 -- -- AD6 5 -- -- AD5 4 -- -- AD4 3 -- -- AD3 ICR RSTA SRW 0 IICIF 0 RXAK 2 -- -- AD2 1 -- -- AD1 Bit 0 -- -- 0
0x0055- 0x0057 0x0058 0x0059 0x005A 0x005B 0x005C 0x005D 0x005E- 0x005F 0x0060 0x0061 0x0062 0x0063 0x0064 0x0065 0x0066 0x0067 0x0068 0x0069 0x006A 0x006B- 0x006F
Reserved IIC1A IIC1F IIC1C1 IIC1S IIC1D IIC1C2 Reserved TPM2SC TPM2CNTH TPM2CNTL TPM2MODH TPM2MODL TPM2C0SC TPM2C0VH TPM2C0VL TPM2C1SC TPM2C1VH TPM2C1VL Reserved
High-page registers, shown in Table 4-3, are accessed much less often than other I/O and control registers so they have been located outside the direct addressable memory space, starting at 0x1800.
Table 4-3. High-Page Register Summary (Sheet 1 of 3)
Address Register Name Bit 7 POR 0 COPE 0 -- -- REV3 ID7 RTIF LVDF LVWF -- 6 PIN 0 COPT 0 -- -- REV2 ID6 RTIACK LVDACK LVWACK -- 5 COP 0 STOPE 0 -- -- REV1 ID5 RTICLKS LVDIE LVDV -- 4 ILOP 0 -- MPE -- -- REV0 ID4 RTIE LVDRE LVWV -- 3 ILAD 0 0 0 -- -- ID11 ID3 0 LVDSE PPDF -- -- -- ID10 ID2 RTIS2 LVDE PPDACK -- 2 ICG 0 0 1 LVD 0 -- MCSEL -- -- ID9 ID1 RTIS1 01 -- -- -- -- ID8 ID0 RTIS0 BGBE PPDC -- Bit 0 0 BDFR --
0x1800 0x1801 0x1802 0x1803 0x1804 - 0x1805 0x1806 0x1807 0x1808 0x1809 0x180A 0x180B
SRS SBDFR SOPT SMCLK Reserved SDIDH SDIDL SRTISC SPMSC1 SPMSC2 Reserved
MC9S08AC16 Series Data Sheet, Rev. 8 46 Freescale Semiconductor
Chapter 4 Memory
Table 4-3. High-Page Register Summary (Sheet 2 of 3)
Address Register Name Bit 7 COPCLKS -- -- Bit 15 Bit 7 Bit 15 Bit 7 Bit 15 Bit 7 DBGEN TRGSEL AF -- -- DIVLD KEYEN -- 0 FPS7 FCBEF FCMD7 -- -- TOF Bit 15 Bit 7 Bit 15 Bit 7 CH0F Bit 15 Bit 7 CH1F Bit 15 Bit 7 -- -- PTAPE7 PTASE7 PTADS7 -- 6 -- -- -- 14 6 14 6 14 6 ARM BEGIN BF -- -- PRDIV8 FNORED -- 0 FPS6 FCCF FCMD6 -- -- TOIE 14 6 14 6 CH0IE 14 6 CH1IE 14 6 -- -- R R R -- 5 -- -- -- 13 5 13 5 13 5 TAG 0 ARMF -- -- DIV5 0 -- KEYACC FPS5 FPVIOL FCMD5 -- -- CPWMS 13 5 13 5 MS0B 13 5 MS1B 13 5 -- -- R R R -- 4 -- -- -- 12 4 12 4 12 4 BRKEN 0 0 -- -- DIV4 0 -- 0 FPS4 FACCERR FCMD4 -- -- CLKSB 12 4 12 4 MS0A 12 4 MS1A 12 4 -- -- R R R -- 3 -- -- -- 11 3 11 3 11 3 RWA TRG3 CNT3 -- -- DIV3 0 -- 0 FPS3 0 FCMD3 -- -- CLKSA 11 3 11 3 ELS0B 11 3 ELS1B 11 3 -- -- R R R -- 2 -- -- -- 10 2 10 2 10 2 RWAEN TRG2 CNT2 -- -- DIV2 0 -- 0 FPS2 FBLANK FCMD2 -- -- PS2 10 2 10 2 ELS0A 10 2 ELS1A 10 2 -- -- PTAPE2 PTASE2 PTADS2 -- 1 -- -- -- 9 1 9 1 9 1 RWB TRG1 CNT1 -- -- DIV1 SEC01 -- 0 FPS1 0 FCMD1 -- -- PS1 9 1 9 1 0 9 1 0 9 1 -- -- PTAPE1 PTASE1 PTADS1 -- Bit 0 -- -- -- Bit 8 Bit 0 Bit 8 Bit 0 Bit 8 Bit 0 RWBEN TRG0 CNT0 -- -- DIV0 SEC00 -- 0 FPDIS 0 FCMD0 -- -- PS0 Bit 8 Bit 0 Bit 8 Bit 0 0 Bit 8 Bit 0 0 Bit 8 Bit 0 -- -- PTAPE0 PTASE0 PTADS0 --
0x180C 0x180D- 0x180F 0x1810 0x1811 0x1812 0x1813 0x1814 0x1815 0x1816 0x1817 0x1818 0x1819- 0x181F 0x1820 0x1821 0x1822 0x1823 0x1824 0x1825 0x1826 0x1827- 0x182F 0x1830 0x1831 0x1832 0x1833 0x1834 0x1835 0x1836 0x1837 0x1838 0x1839 0x183A 0x183B 0x183F 0x1840 0x1841 0x1842 0x1843
SOPT2 Reserved DBGCAH DBGCAL DBGCBH DBGCBL DBGFH DBGFL DBGC DBGT DBGS Reserved FCDIV FOPT Reserved FCNFG FPROT FSTAT FCMD Reserved TPM3SC TPM3CNTH TPM3CNTL TPM3MODH TPM3MODL TPM3C0SC TPM3C0VH TPM3C0VL TPM3C1SC TPM3C1VH TPM3C1VL Reserved PTAPE PTASE PTADS Reserved
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 47
Chapter 4 Memory
Table 4-3. High-Page Register Summary (Sheet 3 of 3)
Address Register Name Bit 7 R R R -- 0 0 0 -- R R R -- PTEPE7 PTESE7 PTEDS7 -- R R R -- 0 0 0 -- -- 6 R R R -- R R R -- R R R -- PTEPE6 PTESE6 PTEDS6 -- PTFPE6 PTFSE6 PTFDS6 -- PTGPE6 PTGSE6 PTGDS6 -- -- 5 R R R -- PTCPE5 PTCSE5 PTCDS5 -- R R R -- PTEPE5 PTESE5 PTEDS5 -- PTFPE5 PTFSE5 PTFDS5 -- PTGPE5 PTGSE5 PTGDS5 -- -- 4 R R R -- PTCPE4 PTCSE4 PTCDS4 -- R R R -- PTEPE4 PTESE4 PTEDS4 -- PTFPE4 PTFSE4 PTFDS4 -- PTGPE4 PTGSE4 PTGDS4 -- -- 3 PTBPE3 PTBSE3 PTBDS3 -- PTCPE3 PTCSE3 PTCDS3 -- PTDPE3 PTDSE3 PTDDS3 -- PTEPE3 PTESE3 PTEDS3 -- R R R -- PTGPE3 PTGSE3 PTGDS3 -- -- 2 PTBPE2 PTBSE2 PTBDS2 -- PTCPE2 PTCSE2 PTCDS2 -- PTDPE2 PTDSE2 PTDDS2 -- PTEPE2 PTESE2 PTEDS2 -- R R R -- PTGPE2 PTGSE2 PTGDS2 -- -- 1 PTBPE1 PTBSE1 PTBDS1 -- PTCPE1 PTCSE1 PTCDS1 -- PTDPE1 PTDSE1 PTDDS1 -- PTEPE1 PTESE1 PTEDS1 -- PTFPE1 PTFSE1 PTFDS1 -- PTGPE1 PTGSE1 PTGDS1 -- -- Bit 0 PTBPE0 PTBSE0 PTBDS0 -- PTCPE0 PTCSE0 PTCDS0 -- PTDPE0 PTDSE0 PTDDS0 -- PTEPE0 PTESE0 PTEDS0 -- PTFPE0 PTFSE0 PTFDS0 -- PTGPE0 PTGSE0 PTGDS0 -- --
0x1844 0x1845 0x1846 0x1847 0x1848 0x1849 0x184A 0x184B 0x184C 0x184D 0x184E 0x184F 0x1850 0x1851 0x1852 0x1853 0x1854 0x1855 0x1856 0x1857 0x1858 0x1859 0x185A 0x185B- 0x185F
1
PTBPE PTBSE PTBDS Reserved PTCPE PTCSE PTCDS Reserved PTDPE PTDSE PTDDS Reserved PTEPE PTESE PTEDS Reserved PTFPE PTFSE PTFDS Reserved PTGPE PTGSE PTGDS Reserved
This reserved bit must always be written to 0.
Nonvolatile FLASH registers, shown in Table 4-4, are located in the FLASH memory. These registers include an 8-byte backdoor key which optionally can be used to gain access to secure memory resources. During reset events, the contents of NVPROT and NVOPT in the nonvolatile register area of the FLASH memory are transferred into corresponding FPROT and FOPT working registers in the high-page registers to control security and block protection options.
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Chapter 4 Memory
Table 4-4. Nonvolatile Register Summary
Address Register Name Bit 7 6 5 4 3 2 1 Bit 0
0xFFB0 - NVBACKKEY 0xFFB7 0xFFB8 - Reserved 0xFFBB 0xFFBC Reserved for storage of 250 kHz ICGTRM value NVPROT Reserved for storage of 243 kHz ICGTRM value NVOPT
-- -- -- FPS7 -- KEYEN -- -- -- FPS6 -- FNORED -- -- -- FPS5 -- 0
8-Byte Comparison Key -- -- -- FPS4 -- 0 -- -- -- FPS3 -- 0 -- -- -- FPS2 -- 0 -- -- -- FPS1 -- SEC01 -- -- -- FPDIS -- SEC00
0xFFBD 0xFFBE
0xFFBF
Provided the key enable (KEYEN) bit is 1, the 8-byte comparison key can be used to temporarily disengage memory security. This key mechanism can be accessed only through user code running in secure memory. (A security key cannot be entered directly through background debug commands.) This security key can be disabled completely by programming the KEYEN bit to 0. If the security key is disabled, the only way to disengage security is by mass erasing the FLASH if needed (normally through the background debug interface) and verifying that FLASH is blank. To avoid returning to secure mode after the next reset, program the security bits (SEC01:SEC00) to the unsecured state (1:0).
4.3
RAM
The MC9S08AC16 Series includes static RAM. The locations in RAM below 0x0100 can be accessed using the more efficient direct addressing mode, and any single bit in this area can be accessed with the bit manipulation instructions (BCLR, BSET, BRCLR, and BRSET). Locating the most frequently accessed program variables in this area of RAM is preferred. The RAM retains data when the MCU is in low-power wait, stop2, or stop3 mode. At power-on, the contents of RAM are uninitialized. RAM data is unaffected by any reset provided that the supply voltage does not drop below the minimum value for RAM retention. For compatibility with older M68HC05 MCUs, the HCS08 resets the stack pointer to 0x00FF. In the MC9S08AC16 Series, it is usually best to re-initialize the stack pointer to the top of the RAM so the direct page RAM can be used for frequently accessed RAM variables and bit-addressable program variables. Include the following 2-instruction sequence in your reset initialization routine (where RamLast is equated to the highest address of the RAM in the Freescale-provided equate file).
LDHX TXS #RamLast+1 ;point one past RAM ;SP<-(H:X-1)
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 49
Chapter 4 Memory
When security is enabled, the RAM is considered a secure memory resource and is not accessible through BDM or through code executing from non-secure memory. See Section 4.5, "Security" for a detailed description of the security feature.
4.4
FLASH
The FLASH memory is intended primarily for program storage. In-circuit programming allows the operating program to be loaded into the FLASH memory after final assembly of the application product. It is possible to program the entire array through the single-wire background debug interface. Because no special voltages are needed for FLASH erase and programming operations, in-application programming is also possible through other software-controlled communication paths. For a more detailed discussion of in-circuit and in-application programming, refer to the HCS08 Family Reference Manual, Volume I, Freescale Semiconductor document order number HCS08RMv1/D.
4.4.1
Features
Features of the FLASH memory include: * FLASH Size -- MC9S08AC16 and MC9S08AW16A-- 16,384 bytes (32 pages of 512 bytes each) -- MC9S08AC8 and MC9S08AW8A-- 8192 bytes (16 pages of 512 bytes each) * Single power supply program and erase * Command interface for fast program and erase operation * Up to 100,000 program/erase cycles at typical voltage and temperature * Flexible block protection * Security feature for FLASH and RAM * Auto power-down for low-frequency read accesses
4.4.2
Program and Erase Times
Before any program or erase command can be accepted, the FLASH clock divider register (FCDIV) must be written to set the internal clock for the FLASH module to a frequency (fFCLK) between 150 kHz and 200 kHz (see Section 4.6.1, "FLASH Clock Divider Register (FCDIV)"). This register can be written only once, so normally this write is done during reset initialization. FCDIV cannot be written if the access error flag, FACCERR in FSTAT, is set. The user must ensure that FACCERR is not set before writing to the FCDIV register. One period of the resulting clock (1/fFCLK) is used by the command processor to time program and erase pulses. An integer number of these timing pulses are used by the command processor to complete a program or erase command. Table 4-5 shows program and erase times. The bus clock frequency and FCDIV determine the frequency of FCLK (fFCLK). The time for one cycle of FCLK is tFCLK = 1/fFCLK. The times are shown as a number of cycles of FCLK and as an absolute time for the case where tFCLK = 5 s. Program and erase times shown include overhead for the command state machine and enabling and disabling of program and erase voltages.
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Chapter 4 Memory
Table 4-5. Program and Erase Times
Parameter Byte program Byte program (burst) Page erase Mass erase
1
Cycles of FCLK 9 4 4000 20,000
Time if FCLK = 200 kHz 45 s 20 s1 20 ms 100 ms
Excluding start/end overhead
4.4.3
Program and Erase Command Execution
The steps for executing any of the commands are listed below. The FCDIV register must be initialized and any error flags cleared before beginning command execution. The command execution steps are: 1. Write a data value to an address in the FLASH array. The address and data information from this write is latched into the FLASH interface. This write is a required first step in any command sequence. For erase and blank check commands, the value of the data is not important. For page erase commands, the address may be any address in the 512-byte page of FLASH to be erased. For mass erase and blank check commands, the address can be any address in the FLASH memory. Whole pages of 512 bytes are the smallest block of FLASH that may be erased. In the 60K version, there are two instances where the size of a block that is accessible to the user is less than 512 bytes: the first page following RAM, and the first page following the high page registers. These pages are overlapped by the RAM and high page registers respectively. NOTE Do not program any byte in the FLASH more than once after a successful erase operation. Reprogramming bits to a byte which is already programmed is not allowed without first erasing the page in which the byte resides or mass erasing the entire FLASH memory. Programming without first erasing may disturb data stored in the FLASH. 2. Write the command code for the desired command to FCMD. The five valid commands are blank check (0x05), byte program (0x20), burst program (0x25), page erase (0x40), and mass erase (0x41). The command code is latched into the command buffer. 3. Write a 1 to the FCBEF bit in FSTAT to clear FCBEF and launch the command (including its address and data information). A partial command sequence can be aborted manually by writing a 0 to FCBEF any time after the write to the memory array and before writing the 1 that clears FCBEF and launches the complete command. Aborting a command in this way sets the FACCERR access error flag which must be cleared before starting a new command. A strictly monitored procedure must be obeyed or the command will not be accepted. This minimizes the possibility of any unintended changes to the FLASH memory contents. The command complete flag (FCCF) indicates when a command is complete. The command sequence must be completed by clearing FCBEF to launch the command. Figure 4-2 is a flowchart for executing all of the commands except for
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Chapter 4 Memory
burst programming. The FCDIV register must be initialized before using any FLASH commands. This only must be done once following a reset.
WRITE TO FCDIV (Note 1) FLASH PROGRAM AND ERASE FLOW Note 1: Required only once after reset.
START
FACCERR ? 1 CLEAR ERROR
0
WRITE TO FLASH TO BUFFER ADDRESS AND DATA WRITE COMMAND TO FCMD
WRITE 1 TO FCBEF TO LAUNCH COMMAND AND CLEAR FCBEF (Note 2) YES
Note 2: Wait at least four bus cycles before checking FCBEF or FCCF.
FPVIOL OR FACCERR ? NO 0
ERROR EXIT
FCCF ? 1 DONE
Figure 4-2. FLASH Program and Erase Flowchart
4.4.4
Burst Program Execution
The burst program command is used to program sequential bytes of data in less time than would be required using the standard program command. This is possible because the high voltage to the FLASH array does not need to be disabled between program operations. Ordinarily, when a program or erase command is issued, an internal charge pump associated with the FLASH memory must be enabled to supply high voltage to the array. Upon completion of the command, the charge pump is turned off. When a burst program command is issued, the charge pump is enabled and then remains enabled after completion of the burst program operation if these two conditions are met: * The next burst program command has been queued before the current program operation has completed.
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Chapter 4 Memory
*
The next sequential address selects a byte on the same physical row as the current byte being programmed. A row of FLASH memory consists of 64 bytes. A byte within a row is selected by addresses A5 through A0. A new row begins when addresses A5 through A0 are all zero.
The first byte of a series of sequential bytes being programmed in burst mode will take the same amount of time to program as a byte programmed in standard mode. Subsequent bytes will program in the burst program time provided that the conditions above are met. In the case the next sequential address is the beginning of a new row, the program time for that byte will be the standard time instead of the burst time. This is because the high voltage to the array must be disabled and then enabled again. If a new burst command has not been queued before the current command completes, then the charge pump will be disabled and high voltage removed from the array.
WRITE TO FCDIV (Note 1) FLASH BURST PROGRAM FLOW START Note 1: Required only once after reset.
FACCERR ? 1 CLEAR ERROR
0
FCBEF ? 1
0
WRITE TO FLASH TO BUFFER ADDRESS AND DATA WRITE COMMAND (0x25) TO FCMD WRITE 1 TO FCBEF TO LAUNCH COMMAND AND CLEAR FCBEF (Note 2) YES
Note 2: Wait at least four bus cycles before checking FCBEF or FCCF.
FPVIO OR FACCERR ? NO YES NEW BURST COMMAND ? NO 0
ERROR EXIT
FCCF ? 1 DONE
Figure 4-3. FLASH Burst Program Flowchart
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Chapter 4 Memory
4.4.5
Access Errors
An access error occurs whenever the command execution protocol is violated. Any of the following specific actions will cause the access error flag (FACCERR) in FSTAT to be set. FACCERR must be cleared by writing a 1 to FACCERR in FSTAT before any command can be processed. * Writing to a FLASH address before the internal FLASH clock frequency has been set by writing to the FCDIV register * Writing to a FLASH address while FCBEF is not set (A new command cannot be started until the command buffer is empty.) * Writing a second time to a FLASH address before launching the previous command (There is only one write to FLASH for every command.) * Writing a second time to FCMD before launching the previous command (There is only one write to FCMD for every command.) * Writing to any FLASH control register other than FCMD after writing to a FLASH address * Writing any command code other than the five allowed codes (0x05, 0x20, 0x25, 0x40, or 0x41) to FCMD * Writing any FLASH control register other than the write to FSTAT (to clear FCBEF and launch the command) after writing the command to FCMD. * The MCU enters stop mode while a program or erase command is in progress (The command is aborted.) * Writing the byte program, burst program, or page erase command code (0x20, 0x25, or 0x40) with a background debug command while the MCU is secured (The background debug controller can only do blank check and mass erase commands when the MCU is secure.) * Writing 0 to FCBEF to cancel a partial command
4.4.6
FLASH Block Protection
The block protection feature prevents the protected region of FLASH from program or erase changes. Block protection is controlled through the FLASH protection register (FPROT). When enabled, block protection begins at any 512 byte boundary below the last address of FLASH, 0xFFFF. (See Section 4.6.4, "FLASH Protection Register (FPROT and NVPROT)"). After exit from reset, FPROT is loaded with the contents of the NVPROT location, which is in the nonvolatile register block of the FLASH memory. FPROT cannot be changed directly from application software so a runaway program cannot alter the block protection settings. Because NVPROT is within the last 512 bytes of FLASH, if any amount of memory is protected, NVPROT is itself protected and cannot be altered (intentionally or unintentionally) by the application software. FPROT can be written through background debug commands, which allows a way to erase and reprogram a protected FLASH memory. The block protection mechanism is illustrated in Figure 4-4. The FPS bits are used as the upper bits of the last address of unprotected memory. This address is formed by concatenating FPS7:FPS1 with logic 1 bits as shown. For example, to protect the last 1536 bytes of memory (addresses 0xFA00 through 0xFFFF), the FPS bits must be set to 1111 100, which results in the value 0xF9FF as the last address of unprotected
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Chapter 4 Memory
memory. In addition to programming the FPS bits to the appropriate value, FPDIS (bit 0 of NVPROT) must be programmed to logic 0 to enable block protection. Therefore the value 0xF8 must be programmed into NVPROT to protect addresses 0xFA00 through 0xFFFF.
FPS7 FPS6 FPS5 FPS4 FPS3 FPS2 FPS1 1 1 1 1 1 1 1 1 1
A15
A14
A13
A12
A11
A10
A9
A8 A7 A6 A5 A4 A3 A2 A1 A0
Figure 4-4. Block Protection Mechanism
One use for block protection is to block protect an area of FLASH memory for a bootloader program. This bootloader program then can be used to erase the rest of the FLASH memory and reprogram it. Because the bootloader is protected, it remains intact even if MCU power is lost in the middle of an erase and reprogram operation.
4.4.7
Vector Redirection
Whenever any block protection is enabled, the reset and interrupt vectors will be protected. Vector redirection allows users to modify interrupt vector information without unprotecting bootloader and reset vector space. Vector redirection is enabled by programming the FNORED bit in the NVOPT register located at address 0xFFBF to zero. For redirection to occur, at least some portion but not all of the FLASH memory must be block protected by programming the NVPROT register located at address 0xFFBD. All of the interrupt vectors (memory locations 0xFFC0-0xFFFD) are redirected, though the reset vector (0xFFFE:FFFF) is not. For example, if 512 bytes of FLASH are protected, the protected address region is from 0xFE00 through 0xFFFF. The interrupt vectors (0xFFC0-0xFFFD) are redirected to the locations 0xFDC0-0xFDFD. Now, if an SPI interrupt is taken for instance, the values in the locations 0xFDE0:FDE1 are used for the vector instead of the values in the locations 0xFFE0:FFE1. This allows the user to reprogram the unprotected portion of the FLASH with new program code including new interrupt vector values while leaving the protected area, which includes the default vector locations, unchanged.
4.5
Security
The MC9S08AC16 Series includes circuitry to prevent unauthorized access to the contents of FLASH and RAM memory. When security is engaged, FLASH and RAM are considered secure resources. Direct-page registers, high-page registers, and the background debug controller are considered unsecured resources. Programs executing within secure memory have normal access to any MCU memory locations and resources. Attempts to access a secure memory location with a program executing from an unsecured memory space or through the background debug interface are blocked (writes are ignored and reads return all 0s). Security is engaged or disengaged based on the state of two nonvolatile register bits (SEC01:SEC00) in the FOPT register. During reset, the contents of the nonvolatile location NVOPT are copied from FLASH into the working FOPT register in high-page register space. A user engages security by programming the NVOPT location which can be done at the same time the FLASH memory is programmed. The 1:0 state
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Chapter 4 Memory
disengages security and the other three combinations engage security. Notice the erased state (1:1) makes the MCU secure. During development, whenever the FLASH is erased, it is good practice to immediately program the SEC00 bit to 0 in NVOPT so SEC01:SEC00 = 1:0. This would allow the MCU to remain unsecured after a subsequent reset. The on-chip debug module cannot be enabled while the MCU is secure. The separate background debug controller can still be used for background memory access commands, but the MCU cannot enter active background mode except by holding BKGD/MS low at the rising edge of reset. A user can choose to allow or disallow a security unlocking mechanism through an 8-byte backdoor security key. If the nonvolatile KEYEN bit in NVOPT/FOPT is 0, the backdoor key is disabled and there is no way to disengage security without completely erasing all FLASH locations. If KEYEN is 1, a secure user program can temporarily disengage security by: 1. Writing 1 to KEYACC in the FCNFG register. This makes the FLASH module interpret writes to the backdoor comparison key locations (NVBACKKEY through NVBACKKEY+7) as values to be compared against the key rather than as the first step in a FLASH program or erase command. 2. Writing the user-entered key values to the NVBACKKEY through NVBACKKEY+7 locations. These writes must be done in order starting with the value for NVBACKKEY and ending with NVBACKKEY+7. STHX should not be used for these writes because these writes cannot be done on adjacent bus cycles. User software normally would get the key codes from outside the MCU system through a communication interface such as a serial I/O. 3. Writing 0 to KEYACC in the FCNFG register. If the 8-byte key that was just written matches the key stored in the FLASH locations, SEC01:SEC00 are automatically changed to 1:0 and security will be disengaged until the next reset. The security key can be written only from secure memory (either RAM or FLASH), so it cannot be entered through background commands without the cooperation of a secure user program. The backdoor comparison key (NVBACKKEY through NVBACKKEY+7) is located in FLASH memory locations in the nonvolatile register space so users can program these locations exactly as they would program any other FLASH memory location. The nonvolatile registers are in the same 512-byte block of FLASH as the reset and interrupt vectors, so block protecting that space also block protects the backdoor comparison key. Block protects cannot be changed from user application programs, so if the vector space is block protected, the backdoor security key mechanism cannot permanently change the block protect, security settings, or the backdoor key. Security can always be disengaged through the background debug interface by taking these steps: 1. Disable any block protections by writing FPROT. FPROT can be written only with background debug commands, not from application software. 2. Mass erase FLASH if necessary. 3. Blank check FLASH. Provided FLASH is completely erased, security is disengaged until the next reset. To avoid returning to secure mode after the next reset, program NVOPT so SEC01:SEC00 = 1:0.
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Chapter 4 Memory
4.6
FLASH Registers and Control Bits
The FLASH module has nine 8-bit registers in the high-page register space, three locations in the nonvolatile register space in FLASH memory which are copied into three corresponding high-page control registers at reset. There is also an 8-byte comparison key in FLASH memory. Refer to Table 4-3 and Table 4-4 for the absolute address assignments for all FLASH registers. This section refers to registers and control bits only by their names. A Freescale-provided equate or header file normally is used to translate these names into the appropriate absolute addresses.
4.6.1
FLASH Clock Divider Register (FCDIV)
Bit 7 of this register is a read-only status flag. Bits 6 through 0 may be read at any time but can be written only one time. Before any erase or programming operations are possible, write to this register to set the frequency of the clock for the nonvolatile memory system within acceptable limits.
7 6 5 4 3 2 1 0
R W Reset
DIVLD PRDIV8 0 0 DIV5 0 DIV4 0 DIV3 0 DIV2 0 DIV1 0 DIV0 0
= Unimplemented or Reserved Figure 4-5. FLASH Clock Divider Register (FCDIV) Table 4-6. FCDIV Register Field Descriptions
Field 7 DIVLD Description Divisor Loaded Status Flag -- When set, this read-only status flag indicates that the FCDIV register has been written since reset. Reset clears this bit and the first write to this register causes this bit to become set regardless of the data written. 0 FCDIV has not been written since reset; erase and program operations disabled for FLASH. 1 FCDIV has been written since reset; erase and program operations enabled for FLASH. Prescale (Divide) FLASH Clock by 8 0 Clock input to the FLASH clock divider is the bus rate clock. 1 Clock input to the FLASH clock divider is the bus rate clock divided by 8. Divisor for FLASH Clock Divider -- The FLASH clock divider divides the bus rate clock (or the bus rate clock divided by 8 if PRDIV8 = 1) by the value in the 6-bit DIV5:DIV0 field plus one. The resulting frequency of the internal FLASH clock must fall within the range of 200 kHz to 150 kHz for proper FLASH operations. Program/Erase timing pulses are one cycle of this internal FLASH clock which corresponds to a range of 5 s to 6.7 s. The automated programming logic uses an integer number of these pulses to complete an erase or program operation. See Equation 4-1, Equation 4-2, and Table 4-6.
6 PRDIV8 5:0 DIV[5:0]
if PRDIV8 = 0 -- fFCLK = fBus / ([DIV5:DIV0] + 1) if PRDIV8 = 1 -- fFCLK = fBus / (8 x ([DIV5:DIV0] + 1))
Eqn. 4-1 Eqn. 4-2
Table 4-7 shows the appropriate values for PRDIV8 and DIV5:DIV0 for selected bus frequencies.
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Chapter 4 Memory
Table 4-7. FLASH Clock Divider Settings
fBus 20 MHz 10 MHz 8 MHz 4 MHz 2 MHz 1 MHz 200 kHz 150 kHz PRDIV8 (Binary) 1 0 0 0 0 0 0 0 DIV5:DIV0 (Decimal) 12 49 39 19 9 4 0 0 fFCLK 192.3 kHz 200 kHz 200 kHz 200 kHz 200 kHz 200 kHz 200 kHz 150 kHz Program/Erase Timing Pulse (5 s Min, 6.7 s Max) 5.2 s 5 s 5 s 5 s 5 s 5 s 5 s 6.7 s
4.6.2
FLASH Options Register (FOPT and NVOPT)
During reset, the contents of the nonvolatile location NVOPT are copied from FLASH into FOPT. Bits 5 through 2 are not used and always read 0. This register may be read at any time, but writes have no meaning or effect. To change the value in this register, erase and reprogram the NVOPT location in FLASH memory as usual and then issue a new MCU reset.
7 6 5 4 3 2 1 0
R W Reset
KEYEN
FNORED
0
0
0
0
SEC01
SEC00
This register is loaded from nonvolatile location NVOPT during reset.
= Unimplemented or Reserved Figure 4-6. FLASH Options Register (FOPT) Table 4-8. FOPT Register Field Descriptions
Field 7 KEYEN Description Backdoor Key Mechanism Enable -- When this bit is 0, the backdoor key mechanism cannot be used to disengage security. The backdoor key mechanism is accessible only from user (secured) firmware. BDM commands cannot be used to write key comparison values that would unlock the backdoor key. For more detailed information about the backdoor key mechanism, refer to Section 4.5, "Security." 0 No backdoor key access allowed. 1 If user firmware writes an 8-byte value that matches the nonvolatile backdoor key (NVBACKKEY through NVBACKKEY+7 in that order), security is temporarily disengaged until the next MCU reset. Vector Redirection Disable -- When this bit is 1, then vector redirection is disabled. 0 Vector redirection enabled. 1 Vector redirection disabled. Security State Code -- This 2-bit field determines the security state of the MCU as shown in Table 4-9. When the MCU is secure, the contents of RAM and FLASH memory cannot be accessed by instructions from any unsecured source including the background debug interface. For more detailed information about security, refer to Section 4.5, "Security."
6 FNORED 1:0 SEC0[1:0]
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Chapter 4 Memory
Table 4-9. Security States
SEC01:SEC00 0:0 0:1 1:0 1:1 Description secure secure unsecured secure
SEC01:SEC00 changes to 1:0 after successful backdoor key entry or a successful blank check of FLASH.
4.6.3
FLASH Configuration Register (FCNFG)
Bits 7 through 5 may be read or written at any time. Bits 4 through 0 always read 0 and cannot be written.
7 6 5 4 3 2 1 0
R W Reset
0
0 KEYACC
0
0
0
0
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved Figure 4-7. FLASH Configuration Register (FCNFG) Table 4-10. FCNFG Register Field Descriptions
Field 5 KEYACC Description Enable Writing of Access Key -- This bit enables writing of the backdoor comparison key. For more detailed information about the backdoor key mechanism, refer to Section 4.5, "Security." 0 Writes to 0xFFB0-0xFFB7 are interpreted as the start of a FLASH programming or erase command. 1 Writes to NVBACKKEY (0xFFB0-0xFFB7) are interpreted as comparison key writes.
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4.6.4
FLASH Protection Register (FPROT and NVPROT)
During reset, the contents of the nonvolatile location NVPROT are copied from FLASH into FPROT. This register can be read at any time. If FPDIS = 0, protection can be increased, i.e., a smaller value of FPS can be written. If FPDIS = 1, writes do not change protection.
7 6 5 4 3 2 1 0
R W Reset
1
FPS1 This register is loaded from nonvolatile location NVPROT during reset. Background commands can be used to change the contents of these bits in FPROT.
FPDIS1
Figure 4-8. FLASH Protection Register (FPROT) Table 4-11. FPROT Register Field Descriptions
Field 7:1 FPS[7:1] 0 FPDIS Description FLASH Protect Select Bits -- When FPDIS = 0, this 7-bit field determines the ending address of unprotected FLASH locations at the high address end of the FLASH. Protected FLASH locations cannot be erased or programmed. FLASH Protection Disable 0 FLASH block specified by FPS[7:1] is block protected (program and erase not allowed). 1 No FLASH block is protected.
4.6.5
FLASH Status Register (FSTAT)
Bits 3, 1, and 0 always read 0 and writes have no meaning or effect. The remaining five bits are status bits that can be read at any time. Writes to these bits have special meanings that are discussed in the bit descriptions.
7 6 5 4 3 2 1 0
R FCBEF W Reset 1
FCCF FPVIOL 1 0 FACCERR 0
0
FBLANK
0
0
0
0
0
0
= Unimplemented or Reserved Figure 4-9. FLASH Status Register (FSTAT)
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Chapter 4 Memory
Table 4-12. FSTAT Register Field Descriptions
Field 7 FCBEF Description FLASH Command Buffer Empty Flag -- The FCBEF bit is used to launch commands. It also indicates that the command buffer is empty so that a new command sequence can be executed when performing burst programming. The FCBEF bit is cleared by writing a one to it or when a burst program command is transferred to the array for programming. Only burst program commands can be buffered. 0 Command buffer is full (not ready for additional commands). 1 A new burst program command may be written to the command buffer. FLASH Command Complete Flag -- FCCF is set automatically when the command buffer is empty and no command is being processed. FCCF is cleared automatically when a new command is started (by writing 1 to FCBEF to register a command). Writing to FCCF has no meaning or effect. 0 Command in progress 1 All commands complete Protection Violation Flag -- FPVIOL is set automatically when FCBEF is cleared to register a command that attempts to erase or program a location in a protected block (the erroneous command is ignored). FPVIOL is cleared by writing a 1 to FPVIOL. 0 No protection violation. 1 An attempt was made to erase or program a protected location. Access Error Flag -- FACCERR is set automatically when the proper command sequence is not obeyed exactly (the erroneous command is ignored), if a program or erase operation is attempted before the FCDIV register has been initialized, or if the MCU enters stop while a command was in progress. For a more detailed discussion of the exact actions that are considered access errors, see Section 4.4.5, "Access Errors." FACCERR is cleared by writing a 1 to FACCERR. Writing a 0 to FACCERR has no meaning or effect. 0 No access error. 1 An access error has occurred. FLASH Verified as All Blank (erased) Flag -- FBLANK is set automatically at the conclusion of a blank check command if the entire FLASH array was verified to be erased. FBLANK is cleared by clearing FCBEF to write a new valid command. Writing to FBLANK has no meaning or effect. 0 After a blank check command is completed and FCCF = 1, FBLANK = 0 indicates the FLASH array is not completely erased. 1 After a blank check command is completed and FCCF = 1, FBLANK = 1 indicates the FLASH array is completely erased (all 0xFF).
6 FCCF
5 FPVIOL
4 FACCERR
2 FBLANK
4.6.6
FLASH Command Register (FCMD)
Only five command codes are recognized in normal user modes as shown in Table 4-14. Refer to Section 4.4.3, "Program and Erase Command Execution" for a detailed discussion of FLASH programming and erase operations.
7 6 5 4 3 2 1 0
R W Reset
0 FCMD7
0 FCMD6
0 FCMD5
0 FCMD4
0 FCMD3
0 FCMD2
0 FCMD1
0 FCMD0
0
0
0
0
0
0
0
0
Figure 4-10. FLASH Command Register (FCMD)
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Chapter 4 Memory
Table 4-13. FCMD Register Field Descriptions
Field
7:0 FCMD[7:0]
Description FLASH Command Bits -- See Table 4-14
Table 4-14. FLASH Commands
Command Blank check Byte program Byte program -- burst mode Page erase (512 bytes/page) Mass erase (all FLASH) FCMD 0x05 0x20 0x25 0x40 0x41 Equate File Label mBlank mByteProg mBurstProg mPageErase mMassErase
All other command codes are illegal and generate an access error. It is not necessary to perform a blank check command after a mass erase operation. Only blank check is required as part of the security unlocking mechanism.
MC9S08AC16 Series Data Sheet, Rev. 8 62 Freescale Semiconductor
Chapter 5 Resets, Interrupts, and System Configuration
5.1 Introduction
This chapter discusses basic reset and interrupt mechanisms and the various sources of reset and interrupts in the MC9S08AC16 Series. Some interrupt sources from peripheral modules are discussed in greater detail within other chapters of this data manual. This chapter gathers basic information about all reset and interrupt sources in one place for easy reference. A few reset and interrupt sources, including the computer operating properly (COP) watchdog and real-time interrupt (RTI), are not part of on-chip peripheral systems with their own sections but are part of the system control logic.
5.2
Features
Reset and interrupt features include: * Multiple sources of reset for flexible system configuration and reliable operation: -- Power-on detection (POR) -- Low voltage detection (LVD) with enable -- External RESET pin -- COP watchdog with enable and two timeout choices -- Illegal opcode -- Illegal address -- Serial command from a background debug host * Reset status register (SRS) to indicate source of most recent reset * Separate interrupt vectors for each module (reduces polling overhead) (see Table 5-11)
5.3
MCU Reset
Resetting the MCU provides a way to start processing from a known set of initial conditions. During reset, most control and status registers are forced to initial values and the program counter is loaded from the reset vector (0xFFFE:0xFFFF). On-chip peripheral modules are disabled and I/O pins are initially configured as general-purpose high-impedance inputs with pullup devices disabled. The I bit in the condition code register (CCR) is set to block maskable interrupts so the user program has a chance to initialize the stack pointer (SP) and system control settings. SP is forced to 0x00FF at reset. The following sources of reset are available on the MC9S08AC16 Series: * Power-on reset (POR) * Low-voltage detect (LVD)
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 63
Chapter 5 Resets, Interrupts, and System Configuration
* * * * * *
Computer operating properly (COP) timer Illegal opcode detect Illegal address detect Background debug forced reset The reset pin (RESET) Clock generator loss of lock and loss of clock reset
Each of these sources, with the exception of the background debug forced reset, has an associated bit in the system reset status register.
5.4
Computer Operating Properly (COP) Watchdog
The COP watchdog is intended to force a system reset when the application software fails to execute as expected. To prevent a system reset from the COP timer (when it is enabled), application software must reset the COP counter periodically. If the application program gets lost and fails to reset the COP counter before it times out, a system reset is generated to force the system back to a known starting point. After any reset, the COPE becomes set in SOPT enabling the COP watchdog (see Section 5.9.4, "System Options Register (SOPT)," for additional information). If the COP watchdog is not used in an application, it can be disabled by clearing COPE. The COP counter is reset by writing any value to the address of SRS. This write does not affect the data in the read-only SRS. Instead, the act of writing to this address is decoded and sends a reset signal to the COP counter. The COPCLKS bit in SOPT2 (see Section 5.9.10, "System Options Register 2 (SOPT2)," for additional information) selects the clock source used for the COP timer. The clock source options are either the bus clock or an internal 1-kHz clock source. With each clock source, there is an associated short and long time-out controlled by COPT in SOPT. Table 5-1 summaries the control functions of the COPCLKS and COPT bits. The COP watchdog defaults to operation from the bus clock source and the associated long time-out (218 cycles).
Table 5-1. COP Configuration Options
Control Bits Clock Source COPCLKS 0 0 1 1
1
COP Overflow Count 25 cycles (32 ms)1 28 cycles (256 ms)1 213 cycles 218 cycles
COPT 0 1 0 1 ~1 kHz ~1 kHz Bus Bus
Values are shown in this column based on tRTI = 1 ms. See tRTI in the appendix Section A.10.1, "Control Timing," for the tolerance of this value.
Even if the application will use the reset default settings of COPE, COPCLKS, and COPT, the user must write to the write-once SOPT and SOPT2 registers during reset initialization to lock in the settings. That way, they cannot be changed accidentally if the application program gets lost. The initial writes to SOPT and SOPT2 will reset the COP counter.
MC9S08AC16 Series Data Sheet, Rev. 8 64 Freescale Semiconductor
Chapter 5 Resets, Interrupts, and System Configuration
The write to SRS that services (clears) the COP counter must not be placed in an interrupt service routine (ISR) because the ISR could continue to be executed periodically even if the main application program fails. In background debug mode, the COP counter will not increment. When the bus clock source is selected, the COP counter does not increment while the system is in stop mode. The COP counter resumes as soon as the MCU exits stop mode. When the 1-kHz clock source is selected, the COP counter is re-initialized to zero upon entry to stop mode. The COP counter begins from zero after the MCU exits stop mode.
5.5
Interrupts
Interrupts provide a way to save the current CPU status and registers, execute an interrupt service routine (ISR), and then restore the CPU status so processing resumes where it left off before the interrupt. Other than the software interrupt (SWI), which is a program instruction, interrupts are caused by hardware events such as an edge on the IRQ pin or a timer-overflow event. The debug module can also generate an SWI under certain circumstances. If an event occurs in an enabled interrupt source, an associated read-only status flag will become set. The CPU will not respond until and unless the local interrupt enable is a logic 1 to enable the interrupt. The I bit in the CCR is 0 to allow interrupts. The global interrupt mask (I bit) in the CCR is initially set after reset which masks (prevents) all maskable interrupt sources. The user program initializes the stack pointer and performs other system setup before clearing the I bit to allow the CPU to respond to interrupts. When the CPU receives a qualified interrupt request, it completes the current instruction before responding to the interrupt. The interrupt sequence obeys the same cycle-by-cycle sequence as the SWI instruction and consists of: * * * * Saving the CPU registers on the stack Setting the I bit in the CCR to mask further interrupts Fetching the interrupt vector for the highest-priority interrupt that is currently pending Filling the instruction queue with the first three bytes of program information starting from the address fetched from the interrupt vector locations
While the CPU is responding to the interrupt, the I bit is automatically set to avoid the possibility of another interrupt interrupting the ISR itself (this is called nesting of interrupts). Normally, the I bit is restored to 0 when the CCR is restored from the value stacked on entry to the ISR. In rare cases, the I bit may be cleared inside an ISR (after clearing the status flag that generated the interrupt) so that other interrupts can be serviced without waiting for the first service routine to finish. This practice is not recommended for anyone other than the most experienced programmers because it can lead to subtle program errors that are difficult to debug. The interrupt service routine ends with a return-from-interrupt (RTI) instruction which restores the CCR, A, X, and PC registers to their pre-interrupt values by reading the previously saved information off the stack.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 65
Chapter 5 Resets, Interrupts, and System Configuration
NOTE For compatibility with the M68HC08, the H register is not automatically saved and restored. It is good programming practice to push H onto the stack at the start of the interrupt service routine (ISR) and restore it immediately before the RTI that is used to return from the ISR. When two or more interrupts are pending when the I bit is cleared, the highest priority source is serviced first (see Table 5-2).
5.5.1
Interrupt Stack Frame
Figure 5-1 shows the contents and organization of a stack frame. Before the interrupt, the stack pointer (SP) points at the next available byte location on the stack. The current values of CPU registers are stored on the stack starting with the low-order byte of the program counter (PCL) and ending with the CCR. After stacking, the SP points at the next available location on the stack which is the address that is one less than the address where the CCR was saved. The PC value that is stacked is the address of the instruction in the main program that would have executed next if the interrupt had not occurred.
UNSTACKING ORDER 7 5 4 3 2 1 1 2 3 4 5 CONDITION CODE REGISTER ACCUMULATOR INDEX REGISTER (LOW BYTE X)* PROGRAM COUNTER HIGH PROGRAM COUNTER LOW STACKING ORDER TOWARD HIGHER ADDRESSES SP BEFORE THE INTERRUPT TOWARD LOWER ADDRESSES
0
SP AFTER INTERRUPT STACKING
* High byte (H) of index register is not automatically stacked.
Figure 5-1. Interrupt Stack Frame
When an RTI instruction is executed, these values are recovered from the stack in reverse order. As part of the RTI sequence, the CPU fills the instruction pipeline by reading three bytes of program information, starting from the PC address recovered from the stack. The status flag causing the interrupt must be acknowledged (cleared) before returning from the ISR. Typically, the flag should be cleared at the beginning of the ISR so that if another interrupt is generated by this same source, it will be registered so it can be serviced after completion of the current ISR.
5.5.2
External Interrupt Request (IRQ) Pin
External interrupts are managed by the IRQ status and control register, IRQSC. When the IRQ function is enabled, synchronous logic monitors the pin for edge-only or edge-and-level events. When the MCU is in
MC9S08AC16 Series Data Sheet, Rev. 8 66 Freescale Semiconductor
Chapter 5 Resets, Interrupts, and System Configuration
stop mode and system clocks are shut down, a separate asynchronous path is used so the IRQ (if enabled) can wake the MCU.
5.5.2.1
IRQ Pin Configuration Options
The IRQ pin enable (IRQPE) control bit in IRQSC must be 1 in order for the IRQ pin to act as the interrupt request (IRQ) input. As an IRQ input, the user can choose the polarity of edges or levels detected (IRQEDG), whether the pin detects edges-only or edges and levels (IRQMOD), and whether an event causes an interrupt or only sets the IRQF flag which can be polled by software. The IRQ pin, when enabled, defaults to use an internal pull device (IRQPDD = 0), the device is a pull-up or pull-down depending on the polarity chosen. If the user desires to use an external pull-up or pull-down, the IRQPDD can be written to a 1 to turn off the internal device. BIH and BIL instructions may be used to detect the level on the IRQ pin when the pin is configured to act as the IRQ input. NOTE This pin does not contain a clamp diode to VDD and should not be driven above VDD. The voltage measured on the internally pulled up IRQ pin may be as low as VDD - 0.7 V. The internal gates connected to this pin are pulled all the way to VDD. NOTE When enabling the IRQ pin for use, the IRQF will be set, and should be cleared prior to enabling the interrupt. When configuring the pin for falling edge and level sensitivity in a 5V system, it is necessary to wait at least 6 cycles between clearing the flag and enabling the interrupt.
5.5.2.2
Edge and Level Sensitivity
The IRQMOD control bit reconfigures the detection logic so it detects edge events and pin levels. In the edge and level detection mode, the IRQF status flag becomes set when an edge is detected (when the IRQ pin changes from the deasserted to the asserted level), but the flag is continuously set (and cannot be cleared) as long as the IRQ pin remains at the asserted level.
5.5.3
Interrupt Vectors, Sources, and Local Masks
Table 5-2 provides a summary of all interrupt sources. Higher-priority sources are located toward the bottom of the table. The high-order byte of the address for the interrupt service routine is located at the first address in the vector address column, and the low-order byte of the address for the interrupt service routine is located at the next higher address. When an interrupt condition occurs, an associated flag bit becomes set. If the associated local interrupt enable is 1, an interrupt request is sent to the CPU. Within the CPU, if the global interrupt mask (I bit in the CCR) is 0, the CPU will finish the current instruction, stack the PCL, PCH, X, A, and CCR CPU registers, set the I bit, and then fetch the interrupt vector for the highest priority pending interrupt. Processing then continues in the interrupt service routine.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 67
Chapter 5 Resets, Interrupts, and System Configuration
Table 5-2. Vector Summary
Vector Priority Lower Vector No. 29 - 31 28 27 26 25 24 23 22 21 20 19 Address (High/Low) 0xFFC0/FFC1 - 0xFFC4/0xFFC5 0xFFC6/FFC7 0xFFC8/FFC9 0xFFCA/FFCB 0xFFCC/FFCD 0xFFCE/FFCF 0xFFD0/FFD1 0xFFD2/FFD3 0xFFD4/FFD5 0xFFD6/FFD7 0xFFD8/FFD9 Vector Name Module Source Enable Description
Vtpm3ovf Vtpm3ch1 Vtpm3ch0 Vrti Viic1 Vadc1 Vkeyboard 1 Vsci2tx Vsci2rx Vsci2err
TPM3 TPM3 TPM3 System control IIC1 ADC1 KBI SCI2 SCI2 SCI2
Unused vector space (available for user program) TOF TOIE CH1F CH1IE CH0F CH0IF RTIF RTIE IICIF IICIE COCO AIEN KBF KBIE TDRE TIE TC TCIE IDLE ILIE RDRF RIE OR ORIE NF NFIE FE FEIE PF PFIE TDRE TIE TC TCIE IDLE ILIE RDRF RIE OR ORIE NF NFIE FE FEIE PF PFIE SPIF SPIE MODF SPIE SPTEF SPTIE TOF TOIE CH1F CH1IE CH0F CH0IE TOF TOIE Unused vector space Unused vector space CH3F CH3IE CH2F CH2IE CH1F CH1IE CH0F CH0IE ICGIF LOLRE/LOCRE (LOLS/LOCS) LVDF LVDIE IRQF SWI Instruction COP LVD RESET pin Illegal opcode IRQIE -- COPE LVDRE -- --
TPM3 overflow TPM3 channel 1 TPM3 channel 0 Real-time interrupt IIC1 ADC1 KBI pins SCI2 transmit SCI2 receive SCI2 error
18 17 16
0xFFDA/FFDB 0xFFDC/FFDD 0xFFDE/FFDF
Vsci1tx Vsci1rx Vsci1err
SCI1 SCI1 SCI1
SCI1 transmit SCI1 receive SCI1 error
15
0xFFE0/FFE1
Vspi1
SPI1
SPI1
14 13 12 11 10 9 8 7 6 5 4 3 2 1 Higher 0
0xFFE2/FFE3 0xFFE4/FFE5 0xFFE6/FFE7 0xFFE8/FFE9 0xFFEA/FFEB 0xFFEC/FFED 0xFFEE/FFEF 0xFFF0/FFF1 0xFFF2/FFF3 0xFFF4/FFF5 0xFFF6/FFF7 0xFFF8/FFF9 0xFFFA/FFFB 0xFFFC/FFFD 0xFFFE/FFFF
Vtpm2ovf Vtpm2ch1 Vtpm2ch0 Vtpm1ovf
TPM2 TPM2 TPM2 TPM1
TPM2 overflow TPM2 channel 1 TPM2 channel 0 TPM1 overflow
Vtpm1ch3 Vtpm1ch2 Vtpm1ch1 Vtpm1ch0 Vicg Vlvd Virq Vswi Vreset
TPM1 TPM1 TPM1 TPM1 ICG System control IRQ Core System control
TPM1 channel 3 TPM1 channel 2 TPM1 channel 1 TPM1 channel 0 ICG Low-voltage detect IRQ pin Software interrupt Watchdog timer Low-voltage detect External pin Illegal opcode
MC9S08AC16 Series Data Sheet, Rev. 8 68 Freescale Semiconductor
Chapter 5 Resets, Interrupts, and System Configuration
5.6
Low-Voltage Detect (LVD) System
The MC9S08AC16 Series includes a system to protect against low voltage conditions in order to protect memory contents and control MCU system states during supply voltage variations. The system is comprised of a power-on reset (POR) circuit and an LVD circuit with a user selectable trip voltage, either high (VLVDH) or low (VLVDL). The LVD circuit is enabled when LVDE in SPMSC1 is high and the trip voltage is selected by LVDV in SPMSC2. The LVD is disabled upon entering any of the stop modes unless the LVDSE bit is set. If LVDSE and LVDE are both set, then the MCU cannot enter stop2, and the current consumption in stop3 with the LVD enabled will be greater.
5.6.1
Power-On Reset Operation
When power is initially applied to the MCU, or when the supply voltage drops below the VPOR level, the POR circuit will cause a reset condition. As the supply voltage rises, the LVD circuit will hold the chip in reset until the supply has risen above the VLVDL level. Both the POR bit and the LVD bit in SRS are set following a POR.
5.6.2
LVD Reset Operation
The LVD can be configured to generate a reset upon detection of a low voltage condition by setting LVDRE to 1. After an LVD reset has occurred, the LVD system will hold the MCU in reset until the supply voltage has risen above the level determined by LVDV. The LVD bit in the SRS register is set following either an LVD reset or POR.
5.6.3
LVD Interrupt Operation
When a low voltage condition is detected and the LVD circuit is configured for interrupt operation (LVDE set, LVDIE set, and LVDRE clear), then LVDF will be set and an LVD interrupt will occur.
5.6.4
Low-Voltage Warning (LVW)
The LVD system has a low voltage warning flag to indicate to the user that the supply voltage is approaching, but is still above, the LVD voltage. The LVW does not have an interrupt associated with it. There are two user selectable trip voltages for the LVW, one high (VLVWH) and one low (VLVWL). The trip voltage is selected by LVWV in SPMSC2. Setting the LVW trip voltage equal to the LVD trip voltage is not recommended. Typical use of the LVW would be to select VLVWH and VLVDL.
5.7
Real-Time Interrupt (RTI)
The real-time interrupt function can be used to generate periodic interrupts. The RTI can accept two sources of clocks, the 1-kHz internal clock or an external clock if available. The 1-kHz internal clock source is completely independent of any bus clock source and is used only by the RTI module and, on some MCUs, the COP watchdog. To use an external clock source, it must be available and active. The RTICLKS bit in SRTISC is used to select the RTI clock source.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 69
Chapter 5 Resets, Interrupts, and System Configuration
Either RTI clock source can be used when the MCU is in run, wait or stop3 mode. When using the external oscillator in stop3, it must be enabled in stop (OSCSTEN = 1) and configured for low bandwidth operation (RANGE = 0). Only the internal 1-kHz clock source can be selected to wake the MCU from stop2 mode. The SRTISC register includes a read-only status flag, a write-only acknowledge bit, and a 3-bit control value (RTIS2:RTIS1:RTIS0) used to disable the clock source to the real-time interrupt or select one of seven wakeup periods. The RTI has a local interrupt enable, RTIE, to allow masking of the real-time interrupt. The RTI can be disabled by writing each bit of RTIS to zeroes, and no interrupts will be generated. See Section 5.9.7, "System Real-Time Interrupt Status and Control Register (SRTISC)," for detailed information about this register.
5.8
MCLK Output
The PTC2 pin is shared with the MCLK clock output. Setting the pin enable bit, MPE, causes the PTC2 pin to output a divided version of the internal MCU bus clock. The divide ratio is determined by the MCSEL bits. When MPE is set, the PTC2 pin is forced to operate as an output pin regardless of the state of the port data direction control bit for the pin. If the MCSEL bits are all 0s, the pin is driven low. The slew rate and drive strength for the pin are controlled by PTCSE2 and PTCDS2, respectively. The maximum clock output frequency is limited if slew rate control is enabled, see the electrical chapter for pin rise and fall times with slew rate enabled.
5.9
Reset, Interrupt, and System Control Registers and Control Bits
One 8-bit register in the direct page register space and eight 8-bit registers in the high-page register space are related to reset and interrupt systems. Refer to the direct-page register summary in Chapter 4, "Memory," of this data sheet for the absolute address assignments for all registers. This section refers to registers and control bits only by their names. A Freescale-provided equate or header file is used to translate these names into the appropriate absolute addresses. Some control bits in the SOPT and SPMSC2 registers are related to modes of operation. Although brief descriptions of these bits are provided here, the related functions are discussed in greater detail in Chapter 3, "Modes of Operation."
MC9S08AC16 Series Data Sheet, Rev. 8 70 Freescale Semiconductor
Chapter 5 Resets, Interrupts, and System Configuration
5.9.1
Interrupt Pin Request Status and Control Register (IRQSC)
This direct page register includes status and control bits which are used to configure the IRQ function, report status, and acknowledge IRQ events.
7 6 5 4 3 2 1 0
R W Reset
0 IRQPDD 0 0 IRQEDG 0 IRQPE
IRQF
0 IRQIE IRQACK IRQMOD 0
0
0
0
0
= Unimplemented or Reserved
Figure 5-2. Interrupt Request Status and Control Register (IRQSC) Table 5-3. IRQSC Register Field Descriptions
Field 6 IRQPDD Description Interrupt Request (IRQ) Pull Device Disable-- This read/write control bit is used to disable the internal pull-up/pull-down device when the IRQ pin is enabled (IRQPE = 1) allowing for an external device to be used. 0 IRQ pull device enabled if IRQPE = 1. 1 IRQ pull device disabled if IRQPE = 1. Interrupt Request (IRQ) Edge Select -- This read/write control bit is used to select the polarity of edges or levels on the IRQ pin that cause IRQF to be set. The IRQMOD control bit determines whether the IRQ pin is sensitive to both edges and levels or only edges. When the IRQ pin is enabled as the IRQ input and is configured to detect rising edges, it has a pull-down. When the IRQ pin is enabled as the IRQ input and is configured to detect falling edges, it has a pull-up. 0 IRQ is falling edge or falling edge/low-level sensitive. 1 IRQ is rising edge or rising edge/high-level sensitive. IRQ Pin Enable -- This read/write control bit enables the IRQ pin function. When this bit is set the IRQ pin can be used as an interrupt request. 0 IRQ pin function is disabled. 1 IRQ pin function is enabled. IRQ Flag -- This read-only status bit indicates when an interrupt request event has occurred. 0 No IRQ request. 1 IRQ event detected. IRQ Acknowledge -- This write-only bit is used to acknowledge interrupt request events (write 1 to clear IRQF). Writing 0 has no meaning or effect. Reads always return 0. If edge-and-level detection is selected (IRQMOD = 1), IRQF cannot be cleared while the IRQ pin remains at its asserted level. IRQ Interrupt Enable -- This read/write control bit determines whether IRQ events generate an interrupt request. 0 Interrupt request when IRQF set is disabled (use polling). 1 Interrupt requested whenever IRQF = 1. IRQ Detection Mode -- This read/write control bit selects either edge-only detection or edge-and-level detection. The IRQEDG control bit determines the polarity of edges and levels that are detected as interrupt request events. See Section 5.5.2.2, "Edge and Level Sensitivity" for more details. 0 IRQ event on falling edges or rising edges only. 1 IRQ event on falling edges and low levels or on rising edges and high levels.
5 IRQEDG
4 IRQPE
3 IRQF 2 IRQACK 1 IRQIE
0 IRQMOD
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 71
Chapter 5 Resets, Interrupts, and System Configuration
5.9.2
System Reset Status Register (SRS)
This register includes seven read-only status flags to indicate the source of the most recent reset. When a debug host forces reset by writing 1 to BDFR in the SBDFR register, none of the status bits in SRS will be set. Writing any value to this register address clears the COP watchdog timer without affecting the contents of this register. The reset state of these bits depends on what caused the MCU to reset.
7 6 5 4 3 2 1 0
R W POR
POR
PIN
COP
ILOP
ILAD
ICG
LVD
0
Writing any value to SRS address clears COP watchdog timer. 1 U 0 0 0 Note1 0 0 Note1 0 0 Note1 0 0 0 0 0 Note1 1 1 0 0 0 0
LVR: Any other reset:
U = Unaffected by reset
1
Any of these reset sources that are active at the time of reset will cause the corresponding bit(s) to be set; bits corresponding to sources that are not active at the time of reset will be cleared.
Figure 5-3. System Reset Status (SRS) Table 5-4. SRS Register Field Descriptions
Field 7 POR Description Power-On Reset -- Reset was caused by the power-on detection logic. Because the internal supply voltage was ramping up at the time, the low-voltage reset (LVR) status bit is also set to indicate that the reset occurred while the internal supply was below the LVR threshold. 0 Reset not caused by POR. 1 POR caused reset. External Reset Pin -- Reset was caused by an active-low level on the external reset pin. 0 Reset not caused by external reset pin. 1 Reset came from external reset pin. Computer Operating Properly (COP) Watchdog -- Reset was caused by the COP watchdog timer timing out. This reset source may be blocked by COPE = 0. 0 Reset not caused by COP timeout. 1 Reset caused by COP timeout. Illegal Opcode -- Reset was caused by an attempt to execute an unimplemented or illegal opcode. The STOP instruction is considered illegal if stop is disabled by STOPE = 0 in the SOPT register. The BGND instruction is considered illegal if active background mode is disabled by ENBDM = 0 in the BDCSC register. 0 Reset not caused by an illegal opcode. 1 Reset caused by an illegal opcode.
6 PIN 5 COP
4 ILOP
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Chapter 5 Resets, Interrupts, and System Configuration
Table 5-4. SRS Register Field Descriptions (continued)
Field 3 ILAD Description Illegal Address -- Reset was caused by an attempt to access a designated illegal address. 0 Reset not caused by an illegal address access. 1 Reset caused by an illegal address access. Illegal address areas in the MC9S08AC16 are:
0x0470 - 0x17FF -- Gap from end of RAM to start of high page registers
0x1860 - 0xBFFF -- Gap from end of high page registers to start of Flash memory Unused and reserved locations in register areas are not considered illegal addresses and do not trigger illegal address resets. 2 ICG 1 LVD Internal Clock Generation Module Reset -- Reset was caused by an ICG module reset. 0 Reset not caused by ICG module. 1 Reset caused by ICG module. Low Voltage Detect -- If the LVDRE and LVDSE bits are set and the supply drops below the LVD trip voltage, an LVD reset will occur. This bit is also set by POR. 0 Reset not caused by LVD trip or POR. 1 Reset caused by LVD trip or POR.
5.9.3
System Background Debug Force Reset Register (SBDFR)
This register contains a single write-only control bit. A serial background command such as WRITE_BYTE must be used to write to SBDFR. Attempts to write this register from a user program are ignored. Reads always return 0x00.
7 6 5 4 3 2 1 0
R W Reset
0
0
0
0
0
0
0
0 BDFR1
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
1
BDFR is writable only through serial background debug commands, not from user programs.
Figure 5-4. System Background Debug Force Reset Register (SBDFR) Table 5-5. SBDFR Register Field Descriptions
Field 0 BDFR Description Background Debug Force Reset -- A serial background command such as WRITE_BYTE may be used to allow an external debug host to force a target system reset. Writing logic 1 to this bit forces an MCU reset. This bit cannot be written from a user program.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 73
Chapter 5 Resets, Interrupts, and System Configuration
5.9.4
System Options Register (SOPT)
This register may be read at any time. Bits 3 and 2 are unimplemented and always read 0. This is a write-once register so only the first write after reset is honored. Any subsequent attempt to write to SOPT (intentionally or unintentionally) is ignored to avoid accidental changes to these sensitive settings. SOPT should be written during the user's reset initialization program to set the desired controls even if the desired settings are the same as the reset settings.
7 6 5 4 3 2 1 0
R COPE W Reset 1 1 0 1 COPT STOPE
0
0
0
0
1
1
= Unimplemented or Reserved
Figure 5-5. System Options Register (SOPT) Table 5-6. SOPT Register Field Descriptions
Field 7 COPE 6 COPT 5 STOPE Description COP Watchdog Enable -- This write-once bit defaults to 1 after reset. 0 COP watchdog timer disabled. 1 COP watchdog timer enabled (force reset on timeout). COP Watchdog Timeout -- This write-once bit defaults to 1 after reset. 0 Short timeout period selected. 1 Long timeout period selected. Stop Mode Enable -- This write-once bit defaults to 0 after reset, which disables stop mode. If stop mode is disabled and a user program attempts to execute a STOP instruction, an illegal opcode reset is forced. 0 Stop mode disabled.1Stop mode enabled.
MC9S08AC16 Series Data Sheet, Rev. 8 74 Freescale Semiconductor
Chapter 5 Resets, Interrupts, and System Configuration
5.9.5
System MCLK Control Register (SMCLK)
This register is used to control the MCLK clock output.
7 6 5 4 3 2 1 0
R W Reset
0
0
0 MPE
0 MCSEL 0 0 0 0
0
0
0
0
= Unimplemented or Reserved Figure 5-6. System MCLK Control Register (SMCLK) Table 5-7. SMCLK Register Field Descriptions
Field 4 MPE 2:0 MCSEL Description MCLK Pin Enable -- This bit is used to enable the MCLK function. 0 MCLK output disabled. 1 MCLK output enabled on PTC2 pin. MCLK Divide Select -- These bits are used to select the divide ratio for the MCLK output according to the formula below when the MCSEL bits are not equal to all zeroes. In the case that the MCSEL bits are all zero and MPE is set, the pin is driven low. See Equation 5-1.
MCLK frequency = Bus Clock frequency / (2 * MCSEL)
Eqn. 5-1
5.9.6
System Device Identification Register (SDIDH, SDIDL)
This read-only register is included so host development systems can identify the HCS08 derivative and revision number. This allows the development software to recognize where specific memory blocks, registers, and control bits are located in a target MCU.
7 6 5 4 3 2 1 0
R W Reset
ID11
ID10
ID9
ID8
--
--
--
--
0
0
0
0
= Unimplemented or Reserved Figure 5-7. System Device Identification Register -- High (SDIDH) Table 5-8. SDIDH Register Field Descriptions
Field 7:4 Reserved 3:0 ID[11:8] Description Bits 7:4 are reserved. Reading these bits will result in an indeterminate value; writes have no effect. Part Identification Number -- Each derivative in the HCS08 Family has a unique identification number. The MC9S08AC16 Series is hard coded to the value 0x012. See also ID bits in Table 5-9.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 75
Chapter 5 Resets, Interrupts, and System Configuration
7
6
5
4
3
2
1
0
R W Reset
ID7
ID6
ID5
ID4
ID3
ID2
ID1
ID0
0
0
0
1
0
0
1
0
= Unimplemented or Reserved Figure 5-8. System Device Identification Register -- Low (SDIDL) Table 5-9. SDIDL Register Field Descriptions
Field 7:0 ID[7:0] Description Part Identification Number -- Each derivative in the HCS08 Family has a unique identification number. The MC9S08AC16 Series is hard coded to the value 0x012. See also ID bits in Table 5-8.
5.9.7
System Real-Time Interrupt Status and Control Register (SRTISC)
This register contains one read-only status flag, one write-only acknowledge bit, three read/write delay selects, and three unimplemented bits, which always read 0.
7 6 5 4 3 2 1 0
R W Reset
RTIF
0 RTICLKS RTIACK RTIE 0
0 RTIS2 0 0 RTIS1 0 RTIS0 0
0
0
0
= Unimplemented or Reserved
Figure 5-9. System RTI Status and Control Register (SRTISC) Table 5-10. SRTISC Register Field Descriptions
Field 7 RTIF 6 RTIACK 5 RTICLKS 4 RTIE 2:0 RTIS[2:0] Description Real-Time Interrupt Flag -- This read-only status bit indicates the periodic wakeup timer has timed out. 0 Periodic wakeup timer not timed out. 1 Periodic wakeup timer timed out. Real-Time Interrupt Acknowledge -- This write-only bit is used to acknowledge real-time interrupt request (write 1 to clear RTIF). Writing 0 has no meaning or effect. Reads always return logic 0. Real-Time Interrupt Clock Select -- This read/write bit selects the clock source for the real-time interrupt. 0 Real-time interrupt request clock source is internal 1-kHz oscillator. 1 Real-time interrupt request clock source is external clock. Real-Time Interrupt Enable -- This read-write bit enables real-time interrupts. 0 Real-time interrupts disabled. 1 Real-time interrupts enabled. Real-Time Interrupt Delay Selects -- These read/write bits select the wakeup delay for the RTI. The clock source for the real-time interrupt is a self-clocked source which oscillates at about 1 kHz, is independent of other MCU clock sources. Using external clock source the delays will be crystal frequency divided by value in RTIS2:RTIS1:RTIS0. See Table 5-11.
MC9S08AC16 Series Data Sheet, Rev. 8 76 Freescale Semiconductor
Chapter 5 Resets, Interrupts, and System Configuration
Table 5-11. Real-Time Interrupt Frequency
RTIS2:RTIS1:RTIS0 0:0:0 0:0:1 0:1:0 0:1:1 1:0:0 1:0:1 1:1:0 1:1:1
1
1-kHz Clock Source Delay1 Disable periodic wakeup timer 8 ms 32 ms 64 ms 128 ms 256 ms 512 ms 1.024 s
Using External Clock Source Delay (Crystal Frequency) Disable periodic wakeup timer divide by 256 divide by 1024 divide by 2048 divide by 4096 divide by 8192 divide by 16384 divide by 32768
Normal values are shown in this column based on fRTI = 1 kHz. See Appendix A, "Electrical Characteristics and Timing Specifications," fRTI for the tolerance on these values.
5.9.8
System Power Management Status and Control 1 Register (SPMSC1)
7 6 5 4 3 2 1 1 0
R W Reset
LVDF
0 LVDIE LVDACK
LVDRE2 1
LVDSE2 1
LVDE2 1 0
BGBE 0
0
0
0
= Unimplemented or Reserved
1 2
Bit 1 is a reserved bit that must always be written to 0. This bit can be written only one time after reset. Additional writes are ignored.
Figure 5-10. System Power Management Status and Control 1 Register (SPMSC1) Table 5-12. SPMSC1 Register Field Descriptions
Field 7 LVDF 6 LVDACK 5 LVDIE 4 LVDRE Description Low-Voltage Detect Flag -- Provided LVDE = 1, this read-only status bit indicates a low-voltage detect event. Low-Voltage Detect Acknowledge -- This write-only bit is used to acknowledge low voltage detection errors (write 1 to clear LVDF). Reads always return 0. Low-Voltage Detect Interrupt Enable -- This read/write bit enables hardware interrupt requests for LVDF. 0 Hardware interrupt disabled (use polling). 1 Request a hardware interrupt when LVDF = 1. Low-Voltage Detect Reset Enable -- This read/write bit enables LVDF events to generate a hardware reset (provided LVDE = 1). 0 LVDF does not generate hardware resets. 1 Force an MCU reset when LVDF = 1.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 77
Chapter 5 Resets, Interrupts, and System Configuration
Table 5-12. SPMSC1 Register Field Descriptions (continued)
Field 3 LVDSE Description Low-Voltage Detect Stop Enable -- Provided LVDE = 1, this read/write bit determines whether the low-voltage detect function operates when the MCU is in stop mode. 0 Low-voltage detect disabled during stop mode. 1 Low-voltage detect enabled during stop mode. Low-Voltage Detect Enable -- This read/write bit enables low-voltage detect logic and qualifies the operation of other bits in this register. 0 LVD logic disabled. 1 LVD logic enabled. Bandgap Buffer Enable -- The BGBE bit is used to enable an internal buffer for the bandgap voltage reference for use by the ADC module on one of its internal channels. 0 Bandgap buffer disabled. 1 Bandgap buffer enabled.
2 LVDE
0 BGBE
MC9S08AC16 Series Data Sheet, Rev. 8 78 Freescale Semiconductor
Chapter 5 Resets, Interrupts, and System Configuration
5.9.9
System Power Management Status and Control 2 Register (SPMSC2)
This register is used to report the status of the low voltage warning function, and to configure the stop mode behavior of the MCU.
7 6 5 4 3 2 1 0
R W
LVWF
0 LVDV LVWACK LVWV
PPDF
0 PPDACK
PPDC1 0 0
Power-on reset: LVD reset: Any other reset:
0(2) 0(2) 0(2)
0
0
0
0
0
0
U
U
0
0
0
0
0
U
U
0
0
0
0
= Unimplemented or Reserved
1 2
U = Unaffected by reset
This bit can be written only one time after reset. Additional writes are ignored. LVWF will be set in the case when VSupply transitions below the trip point or after reset and VSupply is already below VLVW.
Figure 5-11. System Power Management Status and Control 2 Register (SPMSC2) Table 5-13. SPMSC2 Register Field Descriptions
Field 7 LVWF 6 LVWACK 5 LVDV 4 LVWV 3 PPDF 2 PPDACK 0 PPDC Description Low-Voltage Warning Flag -- The LVWF bit indicates the low voltage warning status. 0 Low voltage warning not present. 1 Low voltage warning is present or was present. Low-Voltage Warning Acknowledge -- The LVWACK bit is the low-voltage warning acknowledge. Writing a 1 to LVWACK clears LVWF to a 0 if a low voltage warning is not present. Low-Voltage Detect Voltage Select -- The LVDV bit selects the LVD trip point voltage (VLVD). 0 Low trip point selected (VLVD = VLVDL). 1 High trip point selected (VLVD = VLVDH). Low-Voltage Warning Voltage Select -- The LVWV bit selects the LVW trip point voltage (VLVW). 0 Low trip point selected (VLVW = VLVWL). 1 High trip point selected (VLVW = VLVWH). Partial Power Down Flag -- The PPDF bit indicates that the MCU has exited the stop2 mode. 0 Not stop2 mode recovery. 1 Stop2 mode recovery. Partial Power Down Acknowledge -- Writing a 1 to PPDACK clears the PPDF bit. Partial Power Down Control -- The write-once PPDC bit controls whether stop2 or stop3 mode is selected. 0 Stop3 mode enabled. 1 Stop2, partial power down, mode enabled.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 79
Chapter 5 Resets, Interrupts, and System Configuration
5.9.10
System Options Register 2 (SOPT2)
This high page register contains bits to configure MCU specific features on the MC9S08AC16 Series devices.
7 6 5 4 3 2 1 0
R W Reset:
COPCLKS1 1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
1
This bit can be written only one time after reset. Additional writes are ignored.
Figure 5-12. System Options Register 2 (SOPT2) Table 5-14. SOPT2 Register Field Descriptions
Field 7 COPCLKS Description COP Watchdog Clock Select -- This write-once bit selects the clock source of the COP watchdog. 0 Internal 1-kHz clock is source to COP. 1 Bus clock is source to COP.
MC9S08AC16 Series Data Sheet, Rev. 8 80 Freescale Semiconductor
Chapter 6 Parallel Input/Output
6.1 Introduction
This chapter explains software controls related to parallel input/output (I/O). The MC9S08AC16 has seven I/O ports which include a total of 38 general-purpose I/O pins. See Chapter 2, "Pins and Connections" for more information about the logic and hardware aspects of these pins. Many of these pins are shared with on-chip peripherals such as timer systems, communication systems, or keyboard interrupts. When these other modules are not controlling the port pins, they revert to general-purpose I/O control. NOTE Not all general-purpose I/O pins are available on all packages. To avoid extra current drain from floating input pins, the user's reset initialization routine in the application program should either enable on-chip pullup devices or change the direction of unconnected pins to outputs so the pins do not float.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 81
Chapter 6 Parallel Input/Output
VDDAD VSSAD VREFL VREFH HCS08 CORE BKGD/MS BDC CPU
10-BIT ANALOG-TO-DIGITAL CONVERTER (ADC1) DEBUG MODULE (DBG)
4 AD1P11-AD1P8
PORT A
4 AD1P3-AD1P0
PTA7 PTA2 PTA1 PTA0 PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 PTB0/TPM3CH0/AD1P0 PTC5/RxD2 PTC4 PTC3/TxD2 PTC2/MCLK PTC1/SDA1 PTC0/SCL1 PTD3/KBIP6/AD1P11 PTD2/KBIP5/AD1P10 PTD1/AD1P9 PTD0/AD1P8
SDA1 IIC MODULE (IIC1) SCL1 PORT C PORT D
RESET IRQ/TPMCLK
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION POWER MANAGEMENT RTI IRQ COP LVD
INTERNAL CLOCK GENERATOR (ICG) LOW-POWER OSCILLATOR 7-BIT KEYBOARD INTERRUPT MODULE (KBI)
EXTAL XTAL
2 KBIP6-KBIP5 5 KBIP4-KBIP0 RxD1 TxD1 RxD2 TxD2 SPSCK1 MOSI1 MISO1 SS1 TPM1CH1 TPM1CH0 TPM1CH3 TPM1CH2 TPM2CH1 TPM2CH0 TPM3CH1 TPM3CH0
TPMCLK
SERIAL COMMUNICATIONS INTERFACE MODULE (SCI1) SERIAL COMMUNICATIONS INTERFACE MODULE (SCI2) SERIAL PERIPHERAL INTERFACE MODULE (SPI1)
PORT B
USER FLASH 16,384 BYTES OR 8192 BYTES
PTE7/SPSCK1 PTE6/MOSI1 PTE5/MISO1 PTE4/SS1 PTE3/TPM1CH1 PTE2/TPM1CH0 PTE1/RxD1 PTE0/TxD1
USER RAM 1024 BYTES OR 768 BYTES VDD VSS VOLTAGE REGULATOR
2-CHANNEL TIMER/PWM MODULE (TPM2)
PORT F
4-CHANNEL TIMER/PWM MODULE (TPM1)
PORT E
PTF6 PTF5/TPM2CH1 PTF4/TPM2CH0 PTF1/TPM1CH3 PTF0/TPM1CH2
= Not available on 32-, 42-, or 44-pin packages = Not available on 32- or 42-pin packages = Not available on 32-pin packages
Notes: 1. Port pins are software configurable with pullup device if input port. 2. Pin contains software configurable pullup/pulldown device if IRQ is enabled (IRQPE = 1). Pulldown is enabled if rising edge detect is selected (IRQEDG = 1) 3. IRQ does not have a clamp diode to VDD. IRQ should not be driven above VDD. 4. Pin contains integrated pullup device. 5. PTD3, PTD2, and PTG4 contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is selected (KBEDGn = 1).
Figure 6-1. Block Diagram Highlighting Parallel Input/Output Pins
MC9S08AC16 Series Data Sheet, Rev. 8 82 Freescale Semiconductor
PORT G
2-CHANNEL TIMER/PWM MODULE (TPM3)
PTG6/EXTAL PTG5/XTAL PTG4/KBIP4 PTG3/KBIP3 PTG2/KBIP2 PTG1/KBIP1 PTG0/KBIP0
Chapter 6 Parallel Input/Output
6.2
Features
Parallel I/O and Pin Control features, depending on package choice, include: * A total of 38 general-purpose I/O pins in seven ports * Hysteresis input buffers * Software-controlled pullups on each input pin * Software-controlled slew rate output buffers * Four port A pins * Four port B pins shared with ADC1 and TPM3 * Six port C pins shared with SCI2, IIC1, and MCLK * Four port D pins shared with ADC1, KBI, and TPM1 and TPM2 external clock inputs * Eight port E pins shared with SCI1, TPM1, and SPI1 * Five port F pins shared with TPM1 and TPM2 * Seven port G pins shared with XTAL, EXTAL, and KBI
6.3
Pin Descriptions
The MC9S08AC16 Series has a total of 38 parallel I/O pins in seven ports (PTA-PTG). Not all pins are bonded out in all packages. Consult the pin assignment in Chapter 2, "Pins and Connections," for available parallel I/O pins. All of these pins are available for general-purpose I/O when they are not used by other on-chip peripheral systems. After reset, the shared peripheral functions are disabled so that the pins are controlled by the parallel I/O. All of the parallel I/O are configured as inputs (PTxDDn = 0). The pin control functions for each pin are configured as follows: slew rate control enabled (PTxSEn = 1), low drive strength selected (PTxDSn = 0), and internal pullups disabled (PTxPEn = 0). The following paragraphs discuss each port and the software controls that determine each pin's use.
6.3.1
Port A
Port A
Bit 7 MCU Pin: PTA7 6 R 5 R 4 R 3 R 2 PTA2 1 PTA1 Bit 0 PTA0
Figure 6-2. Port A Pin Names
Port A pins are general-purpose I/O pins. Parallel I/O function is controlled by the port A data (PTAD) and data direction (PTADD) registers which are located in page zero register space. The pin control registers, pullup enable (PTAPE), slew rate control (PTASE), and drive strength select (PTADS) are located in the high page registers. Refer to Section 6.4, "Parallel I/O Control" for more information about general-purpose I/O control and Section 6.5, "Pin Control" for more information about pin control.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 83
Chapter 6 Parallel Input/Output
6.3.2
Port B
Port B
Bit 7 6 5 4 3 2 1 Bit 0
MCU Pin: R R R R
PTB3/ PTB2/ TPM3CH0/ TPM3CH1/ AD1P3 AD1P2
PTB1/ AD1P1
PTB0/ AD1P0
Figure 6-3. Port B Pin Names
Port B pins are general-purpose I/O pins. Parallel I/O function is controlled by the port B data (PTBD) and data direction (PTBDD) registers which are located in page zero register space. The pin control registers, pullup enable (PTBPE), slew rate control (PTBSE), and drive strength select (PTBDS) are located in the high page registers. Refer to Section 6.4, "Parallel I/O Control" for more information about general-purpose I/O control and Section 6.5, "Pin Control" for more information about pin control. Port B general-purpose I/O are shared with the ADC and TPM3 timer channels. Any pin enabled as an ADC input will have the general-purpose I/O function disabled. When any TPM3 function is enabled, the direction (input or output) is controlled by the TPM3 and not by the data direction register of the parallel I/O port. Refer to Chapter 10, "Timer/PWM (S08TPMV3)," for more information about using port B pins as TPM channels. Refer to Chapter 14, "Analog-to-Digital Converter (S08ADC10V1)" for more information about using port B as analog inputs.
6.3.3
Port C
Port C
Bit 7 6 5 3 3 2 1 Bit 0
MCU Pin:
0
R
PTC5/ RxD2
PTC4
PTC3/ TxD2
PTC2/ MCLK
PTC1/ SDA1
PTC0/ SCL1
Figure 6-4. Port C Pin Names
Port C pins are general-purpose I/O pins. Parallel I/O function is controlled by the port C data (PTCD) and data direction (PTCDD) registers which are located in page zero register space. The pin control registers, pullup enable (PTCPE), slew rate control (PTCSE), and drive strength select (PTCDS) are located in the high page registers. Refer to Section 6.4, "Parallel I/O Control" for more information about general-purpose I/O control and Section 6.5, "Pin Control" for more information about pin control. Port C general-purpose I/O is shared with SCI2, IIC, and MCLK. When any shared function is enabled, the direction, input or output, is controlled by the shared function and not by the data direction register of the parallel I/O port. Also, for pins which are configured as outputs by the shared function, the output data is controlled by the shared function and not by the port data register. Refer to Chapter 11, "Serial Communications Interface (S08SCIV4)" for more information about using port C pins as SCI pins. Refer to Chapter 13, "Inter-Integrated Circuit (S08IICV2)" for more information about using port C pins as IIC pins. Refer to Chapter 5, "Resets, Interrupts, and System Configuration" for more information about using PTC2 as the MCLK pin.
MC9S08AC16 Series Data Sheet, Rev. 8 84 Freescale Semiconductor
Chapter 6 Parallel Input/Output
6.3.4
Port D
Port D
Bit 7 6 5 4 3 2 1 Bit 0
MCU Pin: R R R R
PTD3/ PTD2/ AD1P11/ AD1P10/ KBIP6 KBIP5
PTD1/ AD1P9
PTD0/ AD1P8
Figure 6-5. Port D Pin Names
Port D pins are general-purpose I/O pins. Parallel I/O function is controlled by the port D data (PTDD) and data direction (PTDDD) registers which are located in page zero register space. The pin control registers, pullup enable (PTDPE), slew rate control (PTDSE), and drive strength select (PTDDS) are located in the high page registers. Refer to Section 6.4, "Parallel I/O Control" for more information about general-purpose I/O control and Section 6.5, "Pin Control" for more information about pin control. Port D general-purpose I/O are shared with the ADC and KBI. When any of these shared functions is enabled, the direction, input or output, is controlled by the shared function and not by the data direction register of the parallel I/O port. When a pin is shared with both the ADC and a digital peripheral function, the ADC has higher priority. For example, in the case that both the ADC and the KBI are configured to use PTD7 then the pin is controlled by the ADC module. Refer to Chapter 10, "Timer/PWM (S08TPMV3)" for more information about using port D pins as TPM external clock inputs. Refer to Chapter 14, "Analog-to-Digital Converter (S08ADC10V1)" for more information about using port D pins as analog inputs. Refer to Chapter 9, "Keyboard Interrupt (S08KBIV1)" for more information about using port D pins as keyboard inputs.
6.3.5
Port E
Port E
Bit 7 6 5 4 3 2 1 Bit 0
MCU Pin:
PTE7/ SPSCK1
PTE6/ MOSI1
PTE5/ MISO1
PTE4/ SS1
PTE3/ PTE2/ TPM1CH1 TPM1CH0
PTE1/ RxD1
PTE0/ TxD1
Figure 6-6. Port E Pin Names
Port E pins are general-purpose I/O pins. Parallel I/O function is controlled by the port E data (PTED) and data direction (PTEDD) registers which are located in page zero register space. The pin control registers, pullup enable (PTEPE), slew rate control (PTESE), and drive strength select (PTEDS) are located in the high page registers. Refer to Section 6.4, "Parallel I/O Control" for more information about general-purpose I/O control and Section 6.5, "Pin Control" for more information about pin control. Port E general-purpose I/O is shared with SCI1, SPI, and TPM1 timer channels. When any of these shared functions is enabled, the direction, input or output, is controlled by the shared function and not by the data direction register of the parallel I/O port. Also, for pins which are configured as outputs by the shared function, the output data is controlled by the shared function and not by the port data register.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 85
Chapter 6 Parallel Input/Output
Refer to Chapter 11, "Serial Communications Interface (S08SCIV4)" for more information about using port E pins as SCI pins. Refer to Chapter 12, "Serial Peripheral Interface (S08SPIV3)" for more information about using port E pins as SPI pins. Refer to Chapter 10, "Timer/PWM (S08TPMV3)" for more information about using port E pins as TPM channel pins.
6.3.6
Port F
Port F
Bit 7 6 5 4 3 2 1 Bit 0
MCU Pin:
R
PTF6
PTF5/ PTF4/ TPM2CH1 TPM2CH0
R
R
PTF1/ PTF0/ TPM1CH3 TPM1CH2
Figure 6-7. Port F Pin Names
Port F pins are general-purpose I/O pins. Parallel I/O function is controlled by the port F data (PTFD) and data direction (PTFDD) registers which are located in page zero register space. The pin control registers, pullup enable (PTFPE), slew rate control (PTFSE), and drive strength select (PTFDS) are located in the high page registers. Refer to Section 6.4, "Parallel I/O Control" for more information about general-purpose I/O control and Section 6.5, "Pin Control" for more information about pin control. Port F general-purpose I/O is shared with TPM1 and TPM2 timer channels. When any of these shared functions is enabled, the direction, input or output, is controlled by the shared function and not by the data direction register of the parallel I/O port. Also, for pins which are configured as outputs by the shared function, the output data is controlled by the shared function and not by the port data register. Refer to Chapter 10, "Timer/PWM (S08TPMV3)" for more information about using port F pins as TPM channel pins.
6.3.7
Port G
Port G
Bit 7 6 5 4 3 2 1 Bit 0
MCU Pin:
0
PTG6/ EXTAL
PTG5/ XTAL
PTG4/ KBIP4
PTG3/ KBIP3
PTG2/ KBIP2
PTG1/ KBIP1
PTG0/ KBIP0
Figure 6-8. Port G Pin Names
Port G pins are general-purpose I/O pins. Parallel I/O function is controlled by the port G data (PTGD) and data direction (PTGDD) registers which are located in page zero register space. The pin control registers, pullup enable (PTGPE), slew rate control (PTGSE), and drive strength select (PTGDS) are located in the high page registers. Refer to Section 6.4, "Parallel I/O Control" for more information about general-purpose I/O control and Section 6.5, "Pin Control" for more information about pin control. Port G general-purpose I/O is shared with KBI, XTAL, and EXTAL. When a pin is enabled as a KBI input, the pin functions as an input regardless of the state of the associated PTG data direction register bit. When the external oscillator is enabled, PTG5 and PTG6 function as oscillator pins. In this case the associated parallel I/O and pin control registers have no control of the pins.
MC9S08AC16 Series Data Sheet, Rev. 8 86 Freescale Semiconductor
Chapter 6 Parallel Input/Output
Refer to Chapter 8, "Internal Clock Generator (S08ICGV4)" for more information about using port G pins as XTAL and EXTAL pins. Refer to Chapter 9, "Keyboard Interrupt (S08KBIV1)" for more information about using port G pins as keyboard inputs.
6.4
Parallel I/O Control
Reading and writing of parallel I/O is done through the port data registers. The direction, input or output, is controlled through the port data direction registers. The parallel I/O port function for an individual pin is illustrated in the block diagram below.
PTxDDn
D
Q
Output Enable
PTxDn
D
Q
Output Data
1 Port Read Data 0 Synchronizer Input Data
BUSCLK Figure 6-9. Parallel I/O Block Diagram
The data direction control bits determine whether the pin output driver is enabled, and they control what is read for port data register reads. Each port pin has a data direction register bit. When PTxDDn = 0, the corresponding pin is an input and reads of PTxD return the pin value. When PTxDDn = 1, the corresponding pin is an output and reads of PTxD return the last value written to the port data register. When a peripheral module or system function is in control of a port pin, the data direction register bit still controls what is returned for reads of the port data register, even though the peripheral system has overriding control of the actual pin direction. When a shared analog function is enabled for a pin, all digital pin functions are disabled. A read of the port data register returns a value of 0 for any bits which have shared analog functions enabled. In general, whenever a pin is shared with both an alternate digital function and an analog function, the analog function
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 87
Chapter 6 Parallel Input/Output
has priority such that if both the digital and analog functions are enabled, the analog function controls the pin. It is a good programming practice to write to the port data register before changing the direction of a port pin to become an output. This ensures that the pin will not be driven momentarily with an old data value that happened to be in the port data register.
6.5
Pin Control
The pin control registers are located in the high page register block of the memory. These registers are used to control pullups, slew rate, and drive strength for the I/O pins. The pin control registers operate independently of the parallel I/O registers.
6.5.1
Internal Pullup Enable
An internal pullup device can be enabled for each port pin by setting the corresponding bit in one of the pullup enable registers (PTxPEn). The pullup device is disabled if the pin is configured as an output by the parallel I/O control logic or any shared peripheral function regardless of the state of the corresponding pullup enable register bit. The pullup device is also disabled if the pin is controlled by an analog function.
6.5.2
Output Slew Rate Control Enable
Slew rate control can be enabled for each port pin by setting the corresponding bit in one of the slew rate control registers (PTxSEn). When enabled, slew control limits the rate at which an output can transition in order to reduce EMC emissions. Slew rate control has no effect on pins which are configured as inputs.
6.5.3
Output Drive Strength Select
An output pin can be selected to have high output drive strength by setting the corresponding bit in one of the drive strength select registers (PTxDSn). When high drive is selected a pin is capable of sourcing and sinking greater current. Even though every I/O pin can be selected as high drive, the user must ensure that the total current source and sink limits for the chip are not exceeded. Drive strength selection is intended to affect the DC behavior of I/O pins. However, the AC behavior is also affected. High drive allows a pin to drive a greater load with the same switching speed as a low drive enabled pin into a smaller load. Because of this the EMC emissions may be affected by enabling pins as high drive.
MC9S08AC16 Series Data Sheet, Rev. 8 88 Freescale Semiconductor
Chapter 6 Parallel Input/Output
6.6
Pin Behavior in Stop Modes
Depending on the stop mode, I/O functions differently as the result of executing a STOP instruction. An explanation of I/O behavior for the various stop modes follows: * Stop2 mode is a partial power-down mode, whereby I/O latches are maintained in their state as before the STOP instruction was executed. CPU register status and the state of I/O registers should be saved in RAM before the STOP instruction is executed to place the MCU in stop2 mode. Upon recovery from stop2 mode, before accessing any I/O, the user should examine the state of the PPDF bit in the SPMSC2 register. If the PPDF bit is 0, I/O must be initialized as if a power on reset had occurred. If the PPDF bit is 1, I/O data previously stored in RAM, before the STOP instruction was executed, peripherals may require being initialized and restored to their pre-stop condition. The user must then write a 1 to the PPDACK bit in the SPMSC2 register. Access to I/O is now permitted again in the user's application program. * In stop3 mode, all I/O is maintained because internal logic circuity stays powered up. Upon recovery, normal I/O function is available to the user.
6.7
Parallel I/O and Pin Control Registers
This section provides information about the registers associated with the parallel I/O ports and pin control functions. These parallel I/O registers are located in page zero of the memory map and the pin control registers are located in the high page register section of memory. Refer to tables in Chapter 4, "Memory," for the absolute address assignments for all parallel I/O and pin control registers. This section refers to registers and control bits only by their names. A Freescale-provided equate or header file normally is used to translate these names into the appropriate absolute addresses.
6.7.1
Port A I/O Registers (PTAD and PTADD)
Port A parallel I/O function is controlled by the registers listed below.
7 6 5 4 3 2 1 0
R PTAD7 W Reset
1
R 0
R 0
R 0
R 0
PTAD2 0
PTAD1 0
PTAD0 0
0
Figure 6-10. Port A Data Register (PTAD)1
Bits 6 through 3 are reserved bits that must always be written to 0.
Table 6-1. PTAD Register Field Descriptions
Field 7, 2:0 PTADn Description Port A Data Register Bits -- For port A pins that are inputs, reads return the logic level on the pin. For port A pins that are configured as outputs, reads return the last value written to this register. Writes are latched into all bits of this register. For port A pins that are configured as outputs, the logic level is driven out the corresponding MCU pin. Reset forces PTAD to all 0s, but these 0s are not driven out the corresponding pins because reset also configures all port pins as high-impedance inputs with pullups disabled.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 89
Chapter 6 Parallel Input/Output
7
6
5
4
3
2
1
0
R PTADD7 W Reset
1
R 0
R 0
R 0
R 0
PTADD2 0
PTADD1 0
PTADD0 0
0
Figure 6-11. Data Direction for Port A Register (PTADD)1
Bits 6 through 3 are reserved bits that must always be written to 0.
Table 6-2. PTADD Register Field Descriptions
Field 7, 2:0 PTADDn Description Data Direction for Port A Bits -- These read/write bits control the direction of port A pins and what is read for PTAD reads. 0 Input (output driver disabled) and reads return the pin value. 1 Output driver enabled for port A bit n and PTAD reads return the contents of PTADn.
6.7.2
Port A Pin Control Registers (PTAPE, PTASE, PTADS)
In addition to the I/O control, port A pins are controlled by the registers listed below.
7 6 5 4 3 2 1 0
R PTAPE7 W Reset
1
R 0
R 0
R 0
R 0
PTAPE2 0
1
PTAPE1 0
PTAPE0 0
0
Figure 6-12. Internal Pullup Enable for Port A (PTAPE)
Bits 6 through 3 are reserved bits that must always be written to 0.
Table 6-3. PTAPE Register Field Descriptions
Field 7, 2:0 PTAPEn Description Internal Pullup Enable for Port A Bits -- Each of these control bits determines if the internal pullup device is enabled for the associated PTA pin. For port A pins that are configured as outputs, these bits have no effect and the internal pullup devices are disabled. 0 Internal pullup device disabled for port A bit n. 1 Internal pullup device enabled for port A bit n.
MC9S08AC16 Series Data Sheet, Rev. 8 90 Freescale Semiconductor
Chapter 6 Parallel Input/Output
7
6
5
4
3
2
1
0
R PTASE7 W Reset
1
R 0
R 0
R 0
R 0
PTASE2 0
PTASE1 0
PTASE0 0
0
Figure 6-13. Output Slew Rate Control Enable for Port A (PTASE)1
Bits 6 through 3 are reserved bits that must always be written to 0.
Table 6-4. PTASE Register Field Descriptions
Field 7, 2:0 PTASEn Description Output Slew Rate Control Enable for Port A Bits -- Each of these control bits determine whether output slew rate control is enabled for the associated PTA pin. For port A pins that are configured as inputs, these bits have no effect. 0 Output slew rate control disabled for port A bit n. 1 Output slew rate control enabled for port A bit n.
7
6
5
4
3
2
1
0
R PTADS7 W Reset
1
R 0
R 0
R 0
R 0
PTADS2 0
PTADS1 0
1
PTADS0 0
0
Figure 6-14. Output Drive Strength Selection for Port A (PTADS)
Bits 6 through 3 are reserved bits that must always be written to 0.
Table 6-5. PTADS Register Field Descriptions
Field 7, 2:0 PTADSn Description Output Drive Strength Selection for Port A Bits -- Each of these control bits selects between low and high output drive for the associated PTA pin. 0 Low output drive enabled for port A bit n. 1 High output drive enabled for port A bit n.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 91
Chapter 6 Parallel Input/Output
6.7.3
Port B I/O Registers (PTBD and PTBDD)
Port B parallel I/O function is controlled by the registers in this section.
7 6 5 4 3 2 1 0
R R W Reset
1
R 0
R 0
R 0
PTBD3 0
PTBD2 0
PTBD1 0
PTBD0 0
0
Figure 6-15. Port B Data Register (PTBD)1
Bits 7 through 4 are reserved bits that must always be written to 0.
Table 6-6. PTBD Register Field Descriptions
Field 3:0 PTBD[3:0] Description Port B Data Register Bits -- For port B pins that are inputs, reads return the logic level on the pin. For port B pins that are configured as outputs, reads return the last value written to this register. Writes are latched into all bits of this register. For port B pins that are configured as outputs, the logic level is driven out the corresponding MCU pin. Reset forces PTBD to all 0s, but these 0s are not driven out the corresponding pins because reset also configures all port pins as high-impedance inputs with pullups disabled.
7
6
5
4
3
2
1
0
R R W Reset
1
R 0
R 0
R 0
PTBDD3 0
PTBDD2 0
PTBDD1 0
PTBDD0 0
0
Figure 6-16. Data Direction for Port B
Bits 7 through 4 are reserved bits that must always be written to 0.
(PTBDD)1
Table 6-7. PTBDD Register Field Descriptions
Field Description
3:0 Data Direction for Port B Bits -- These read/write bits control the direction of port B pins and what is read for PTBDD[3:0] PTBD reads. 0 Input (output driver disabled) and reads return the pin value. 1 Output driver enabled for port B bit n and PTBD reads return the contents of PTBDn.
MC9S08AC16 Series Data Sheet, Rev. 8 92 Freescale Semiconductor
Chapter 6 Parallel Input/Output
6.7.4
Port B Pin Control Registers (PTBPE, PTBSE, PTBDS)
In addition to the I/O control, port B pins are controlled by the registers listed below.
7 6 5 4 3 2 1 0
R R W Reset
1
R 0
R 0
R 0
PTBPE3 0
PTBPE2 0
PTBPE1 0
PTBPE0 0
0
Figure 6-17. Internal Pullup Enable for Port B (PTBPE)1
Bits 7 through 4 are reserved bits that must always be written to 0.
Table 6-8. PTBPE Register Field Descriptions
Field Description
3:0 Internal Pullup Enable for Port B Bits -- Each of these control bits determines if the internal pullup device is PTBPE[3:0] enabled for the associated PTB pin. For port B pins that are configured as outputs, these bits have no effect and the internal pullup devices are disabled. 0 Internal pullup device disabled for port B bit n. 1 Internal pullup device enabled for port B bit n.
7
6
5
4
3
2
1
0
R R W Reset
1
R 0
R 0
R 0
PTBSE3 0
PTBSE2 0
PTBSE1 0
PTBSE0 0
0
Figure 6-18. Output Slew Rate Control Enable (PTBSE)1
Bits 7 through 4 are reserved bits that must always be written to 0.
Table 6-9. PTBSE Register Field Descriptions
Field Description
3:0 Output Slew Rate Control Enable for Port B Bits-- Each of these control bits determine whether output slew PTBSE[3:0] rate control is enabled for the associated PTB pin. For port B pins that are configured as inputs, these bits have no effect. 0 Output slew rate control disabled for port B bit n. 1 Output slew rate control enabled for port B bit n.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 93
Chapter 6 Parallel Input/Output
7
6
5
4
3
2
1
0
R R W Reset
1
R 0
R 0
R 0
PTBDS3 0
PTBDS2 0
PTBDS1 0
PTBDS0 0
0
Figure 6-19. Output Drive Strength Selection for Port B (PTBDS)1
Bits 7 through 4 are reserved bits that must always be written to 0.
Table 6-10. PTBDS Register Field Descriptions
Field Description
3:0 Output Drive Strength Selection for Port B Bits -- Each of these control bits selects between low and high PTBDS[3:0] output drive for the associated PTB pin. 0 Low output drive enabled for port B bit n. 1 High output drive enabled for port B bit n.
6.7.5
Port C I/O Registers (PTCD and PTCDD)
Port C parallel I/O function is controlled by the registers listed below.
7 6 5 4 3 2 1 0
R W Reset
1
0 R 0 0 PTCD5 0 PTCD4 0 PTCD3 0
1
PTCD2 0
PTCD1 0
PTCD0 0
Figure 6-20. Port C Data Register (PTCD)
Bit 6 is a reserved bit that must always be written to 0.
Table 6-11. PTCD Register Field Descriptions
Field 5:0 PTCD[5:0] Description Port C Data Register Bits -- For port C pins that are inputs, reads return the logic level on the pin. For port C pins that are configured as outputs, reads return the last value written to this register. Writes are latched into all bits of this register. For port C pins that are configured as outputs, the logic level is driven out the corresponding MCU pin. Reset forces PTCD to all 0s, but these 0s are not driven out the corresponding pins because reset also configures all port pins as high-impedance inputs with pullups disabled.
MC9S08AC16 Series Data Sheet, Rev. 8 94 Freescale Semiconductor
Chapter 6 Parallel Input/Output
7
6
5
4
3
2
1
0
R W Reset
1
0 R 0 0 PTCDD5 0 PTCDD4 0 PTCDD3 0 PTCDD2 0 PTCDD1 0 PTCDD0 0
Figure 6-21. Data Direction for Port C (PTCDD)1
Bit 6 is a reserved bit that must always be written to 0.
Table 6-12. PTCDD Register Field Descriptions
Field Description
5:0 Data Direction for Port C Bits -- These read/write bits control the direction of port C pins and what is read for PTCDD[5:0] PTCD reads. 0 Input (output driver disabled) and reads return the pin value. 1 Output driver enabled for port C bit n and PTCD reads return the contents of PTCDn.
6.7.6
Port C Pin Control Registers (PTCPE, PTCSE, PTCDS)
In addition to the I/O control, port C pins are controlled by the registers listed below.
7 6 5 4 3 2 1 0
R W Reset
1
0 R 0 0 PTCPE5 0 PTCPE4 0 PTCPE3 0 PTCPE2 0
1
PTCPE1 0
PTCPE0 0
Figure 6-22. Internal Pullup Enable for Port C (PTCPE)
Bit 6 is a reserved bit that must always be written to 0.
Table 6-13. PTCPE Register Field Descriptions
Field Description
5:0 Internal Pullup Enable for Port C Bits -- Each of these control bits determines if the internal pullup device is PTCPE[5:0] enabled for the associated PTC pin. For port C pins that are configured as outputs, these bits have no effect and the internal pullup devices are disabled. 0 Internal pullup device disabled for port C bit n. 1 Internal pullup device enabled for port C bit n.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 95
Chapter 6 Parallel Input/Output
7
6
5
4
3
2
1
0
R W Reset
1
0 R 0 0 PTCSE5 0 PTCSE4 0 PTCSE3 0 PTCSE2 0 PTCSE1 0 PTCSE0 0
Figure 6-23. Output Slew Rate Control Enable for Port C (PTCSE)1
Bit 6 is a reserved bit that must always be written to 0.
Table 6-14. PTCSE Register Field Descriptions
Field Description
5:0 Output Slew Rate Control Enable for Port C Bits -- Each of these control bits determine whether output slew PTCSE[5:0] rate control is enabled for the associated PTC pin. For port C pins that are configured as inputs, these bits have no effect. 0 Output slew rate control disabled for port C bit n. 1 Output slew rate control enabled for port C bit n.
7
6
5
4
3
2
1
0
R W Reset
1
0 R 0 0 PTCDS5 0 PTCDS4 0 PTCDS3 0 PTCDS2 0
1
PTCDS1 0
PTCDS0 0
Figure 6-24. Output Drive Strength Selection for Port C (PTCDS)
Bit 6 is a reserved bit that must always be written to 0.
Table 6-15. PTCDS Register Field Descriptions
Field Description
5:0 Output Drive Strength Selection for Port C Bits -- Each of these control bits selects between low and high PTCDS[5:0] output drive for the associated PTC pin. 0 Low output drive enabled for port C bit n. 1 High output drive enabled for port C bit n.
MC9S08AC16 Series Data Sheet, Rev. 8 96 Freescale Semiconductor
Chapter 6 Parallel Input/Output
6.7.7
Port D I/O Registers (PTDD and PTDDD)
Port D parallel I/O function is controlled by the registers listed below.
7 6 5 4 3 2 1 0
R R W Reset
1
R 0
R 0
R 0
PTDD3 0
PTDD2 0
PTDD1 0
PTDD0 0
0
Figure 6-25. Port D Data Register (PTDD)1
Bits 7 through 4 are reserved bits that must always be written to 0.
Table 6-16. PTDD Register Field Descriptions
Field 3:0 PTDD[3:0] Description Port D Data Register Bits -- For port D pins that are inputs, reads return the logic level on the pin. For port D pins that are configured as outputs, reads return the last value written to this register. Writes are latched into all bits of this register. For port D pins that are configured as outputs, the logic level is driven out the corresponding MCU pin. Reset forces PTDD to all 0s, but these 0s are not driven out the corresponding pins because reset also configures all port pins as high-impedance inputs with pullups disabled.
7
6
5
4
3
2
1
0
R R W Reset
1
R 0
R 0
R 0
PTDDD3 0
PTDDD2 0
PTDDD1 0
PTDDD0 0
0
Figure 6-26. Data Direction for Port D
Bits 7 through 4 are reserved bits that must always be written to 0.
(PTDDD)1
Table 6-17. PTDDD Register Field Descriptions
Field Description
3:0 Data Direction for Port D Bits -- These read/write bits control the direction of port D pins and what is read for PTDDD[3:0] PTDD reads. 0 Input (output driver disabled) and reads return the pin value. 1 Output driver enabled for port D bit n and PTDD reads return the contents of PTDDn.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 97
Chapter 6 Parallel Input/Output
6.7.8
Port D Pin Control Registers (PTDPE, PTDSE, PTDDS)
In addition to the I/O control, port D pins are controlled by the registers listed below.
7 6 5 4 3 2 1 0
R R W Reset
1
R 0
R 0
R 0
PTDPE3 0
PTDPE2 0
PTDPE1 0
PTDPE0 0
0
Figure 6-27. Internal Pullup Enable for Port D (PTDPE)1
Bits 7 through 4 are reserved bits that must always be written to 0.
Table 6-18. PTDPE Register Field Descriptions
Field Description
3:0 Internal Pullup Enable for Port D Bits -- Each of these control bits determines if the internal pullup device is PTDPE[3:0] enabled for the associated PTD pin. For port D pins that are configured as outputs, these bits have no effect and the internal pullup devices are disabled. 0 Internal pullup device disabled for port D bit n. 1 Internal pullup device enabled for port D bit n.
7
6
5
4
3
2
1
0
R R W Reset
1
R 0
R 0
R 0
PTDSE3 0
PTDSE2 0
PTDSE1 0
PTDSE0 0
0
Figure 6-28. Output Slew Rate Control Enable for Port D (PTDSE)1
Bits 7 through 4 are reserved bits that must always be written to 0.
Table 6-19. PTDSE Register Field Descriptions
Field Description
3:0 Output Slew Rate Control Enable for Port D Bits -- Each of these control bits determine whether output slew PTDSE[3:0] rate control is enabled for the associated PTD pin. For port D pins that are configured as inputs, these bits have no effect. 0 Output slew rate control disabled for port D bit n. 1 Output slew rate control enabled for port D bit n.
MC9S08AC16 Series Data Sheet, Rev. 8 98 Freescale Semiconductor
Chapter 6 Parallel Input/Output
7
6
5
4
3
2
1
0
R R W Reset
1
R 0
R 0
R 0
PTDDS3 0
PTDDS2 0
PTDDS1 0
PTDDS0 0
0
Figure 6-29. Output Drive Strength Selection for Port D (PTDDS)1
Bits 7 through 4 are reserved bits that must always be written to 0.
Table 6-20. PTDDS Register Field Descriptions
Field Description
3:0 Output Drive Strength Selection for Port D Bits -- Each of these control bits selects between low and high PTDDS[3:0] output drive for the associated PTD pin. 0 Low output drive enabled for port D bit n. 1 High output drive enabled for port D bit n.
6.7.9
Port E I/O Registers (PTED and PTEDD)
Port E parallel I/O function is controlled by the registers listed below.
7 6 5 4 3 2 1 0
R PTED7 W Reset 0 0 0 0 0 0 0 0 PTED6 PTED5 PTED4 PTED3 PTED2 PTED1 PTED0
Figure 6-30. Port E Data Register (PTED) Table 6-21. PTED Register Field Descriptions
Field 7:0 PTED[7:0] Description Port E Data Register Bits -- For port E pins that are inputs, reads return the logic level on the pin. For port E pins that are configured as outputs, reads return the last value written to this register. Writes are latched into all bits of this register. For port E pins that are configured as outputs, the logic level is driven out the corresponding MCU pin. Reset forces PTED to all 0s, but these 0s are not driven out the corresponding pins because reset also configures all port pins as high-impedance inputs with pullups disabled.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 99
Chapter 6 Parallel Input/Output
7
6
5
4
3
2
1
0
R PTEDD7 W Reset 0 0 0 0 0 0 0 0 PTEDD6 PTEDD5 PTEDD4 PTEDD3 PTEDD2 PTEDD1 PTEDD0
Figure 6-31. Data Direction for Port E (PTEDD) Table 6-22. PTEDD Register Field Descriptions
Field Description
7:0 Data Direction for Port E Bits -- These read/write bits control the direction of port E pins and what is read for PTEDD[7:0] PTED reads. 0 Input (output driver disabled) and reads return the pin value. 1 Output driver enabled for port E bit n and PTED reads return the contents of PTEDn.
6.7.10
Port E Pin Control Registers (PTEPE, PTESE, PTEDS)
In addition to the I/O control, port E pins are controlled by the registers listed below.
7 6 5 4 3 2 1 0
R PTEPE7 W Reset 0 0 0 0 0 0 0 0 PTEPE6 PTEPE5 PTEPE4 PTEPE3 PTEPE2 PTEPE1 PTEPE0
Figure 6-32. Internal Pullup Enable for Port E (PTEPE) Table 6-23. PTEPE Register Field Descriptions
Field Description
7:0 Internal Pullup Enable for Port E Bits-- Each of these control bits determines if the internal pullup device is PTEPE[7:0] enabled for the associated PTE pin. For port E pins that are configured as outputs, these bits have no effect and the internal pullup devices are disabled. 0 Internal pullup device disabled for port E bit n. 1 Internal pullup device enabled for port E bit n.
MC9S08AC16 Series Data Sheet, Rev. 8 100 Freescale Semiconductor
Chapter 6 Parallel Input/Output
7
6
5
4
3
2
1
0
R PTESE7 W Reset 0 0 0 0 0 0 0 0 PTESE6 PTESE5 PTESE4 PTESE3 PTESE2 PTESE1 PTESE0
Figure 6-33. Output Slew Rate Control Enable for Port E (PTESE) Table 6-24. PTESE Register Field Descriptions
Field Description
7:0 Output Slew Rate Control Enable for Port E Bits -- Each of these control bits determine whether output slew PTESE[7:0] rate control is enabled for the associated PTE pin. For port E pins that are configured as inputs, these bits have no effect. 0 Output slew rate control disabled for port E bit n. 1 Output slew rate control enabled for port E bit n.
7
6
5
4
3
2
1
0
R PTEDS7 W Reset 0 0 0 0 0 0 0 0 PTEDS6 PTEDS5 PTEDS4 PTEDS3 PTEDS2 PTEDS1 PTEDS0
Figure 6-34. Output Drive Strength Selection for Port E (PTEDS) Table 6-25. PTEDS Register Field Descriptions
Field Description
7:0 Output Drive Strength Selection for Port E Bits -- Each of these control bits selects between low and high PTEDS[7:0] output drive for the associated PTE pin. 0 Low output drive enabled for port E bit n. 1 High output drive enabled for port E bit n.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 101
Chapter 6 Parallel Input/Output
6.7.11
Port F I/O Registers (PTFD and PTFDD)
Port F parallel I/O function is controlled by the registers listed below.
7 6 5 4 3 2 1 0
R R W Reset
1
PTFD6 0
PTFD5 0
PTFD4 0
R 0
R 0
PTFD1 0
PTFD0 0
0
Figure 6-35. Port F Data Register (PTFD)1
Bits 7, 3 and 2 are reserved bits that must always be written to 0.
Table 6-26. PTFD Register Field Descriptions
Field 6:4, 1:0 PTFDn Description Port F Data Register Bits-- For port F pins that are inputs, reads return the logic level on the pin. For port F pins that are configured as outputs, reads return the last value written to this register. Writes are latched into all bits of this register. For port F pins that are configured as outputs, the logic level is driven out the corresponding MCU pin. Reset forces PTFD to all 0s, but these 0s are not driven out the corresponding pins because reset also configures all port pins as high-impedance inputs with pullups disabled.
7
6
5
4
3
2
1
0
R R W Reset
1
PTFDD6 0
PTFDD5 0
PTFDD4 0
R 0
R 0
PTFDD1 0
PTFDD0 0
0
Figure 6-36. Data Direction for Port F
Bits 7, 3 and 2 are reserved bits that must always be written to 0.
(PTFDD)1
Table 6-27. PTFDD Register Field Descriptions
Field 6:4, 1:0 PTFDDn Description Data Direction for Port F Bits -- These read/write bits control the direction of port F pins and what is read for PTFD reads. 0 Input (output driver disabled) and reads return the pin value. 1 Output driver enabled for port F bit n and PTFD reads return the contents of PTFDn.
MC9S08AC16 Series Data Sheet, Rev. 8 102 Freescale Semiconductor
Chapter 6 Parallel Input/Output
6.7.12
Port F Pin Control Registers (PTFPE, PTFSE, PTFDS)
In addition to the I/O control, port F pins are controlled by the registers listed below.
7 6 5 4 3 2 1 0
R R W Reset
1
PTFPE6 0
PTFPE5 0
PTFPE4 0
R 0
R 0
PTFPE1 0
PTFPE0 0
0
Figure 6-37. Internal Pullup Enable for Port F (PTFPE)1
Bits 7, 3 and 2 are reserved bits that must always be written to 0.
Table 6-28. PTFPE Register Field Descriptions
Field 6:4, 1:0 PTFPEn Description Internal Pullup Enable for Port F Bits -- Each of these control bits determines if the internal pullup device is enabled for the associated PTF pin. For port F pins that are configured as outputs, these bits have no effect and the internal pullup devices are disabled. 0 Internal pullup device disabled for port F bit n. 1 Internal pullup device enabled for port F bit n.
7
6
5
4
3
2
1
0
R R W Reset
1
PTFSE6 0
PTFSE5 0
PTFSE4 0
R 0
R 0
PTFSE1 0
PTFSE0 0
0
Figure 6-38. Output Slew Rate Control Enable for Port F (PTFSE)1
Bits 7, 3 and 2 are reserved bits that must always be written to 0.
Table 6-29. PTFSE Register Field Descriptions
Field 6:4, 1:0 PTFSEn Description Output Slew Rate Control Enable for Port F Bits -- Each of these control bits determine whether output slew rate control is enabled for the associated PTF pin. For port F pins that are configured as inputs, these bits have no effect. 0 Output slew rate control disabled for port F bit n. 1 Output slew rate control enabled for port F bit n.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 103
Chapter 6 Parallel Input/Output
7
6
5
4
3
2
1
0
R R W Reset
1
PTFDS6 0
PTFDS5 0
PTFDS4 0
R 0
R 0
PTFDS1 0
PTFDS0 0
0
Figure 6-39. Output Drive Strength Selection for Port F (PTFDS)1
Bits 7, 3 and 2 are reserved bits that must always be written to 0.
Table 6-30. PTFDS Register Field Descriptions
Field 6:4, 1:0 PTFDSn Description Output Drive Strength Selection for Port F Bits -- Each of these control bits selects between low and high output drive for the associated PTF pin. 0 Low output drive enabled for port F bit n. 1 High output drive enabled for port F bit n.
6.7.13
Port G I/O Registers (PTGD and PTGDD)
Port G parallel I/O function is controlled by the registers listed below.
7 6 5 4 3 2 1 0
R W Reset
0 PTGD6 0 0 PTGD5 0 PTGD4 0 PTGD3 0 PTGD2 0 PTGD1 0 PTGD0 0
Figure 6-40. Port G Data Register (PTGD) Table 6-31. PTGD Register Field Descriptions
Field 6:0 PTGD[6:0] Description Port G Data Register Bits -- For port G pins that are inputs, reads return the logic level on the pin. For port G pins that are configured as outputs, reads return the last value written to this register. Writes are latched into all bits of this register. For port G pins that are configured as outputs, the logic level is driven out the corresponding MCU pin. Reset forces PTGD to all 0s, but these 0s are not driven out the corresponding pins because reset also configures all port pins as high-impedance inputs with pullups disabled.
MC9S08AC16 Series Data Sheet, Rev. 8 104 Freescale Semiconductor
Chapter 6 Parallel Input/Output
7
6
5
4
3
2
1
0
R W Reset
0 PTGDD6 0 0 PTGDD5 0 PTGDD4 0 PTGDD3 0 PTGDD2 0 PTGDD1 0 PTGDD0 0
Figure 6-41. Data Direction for Port G (PTGDD) Table 6-32. PTGDD Register Field Descriptions
Field Description
6:0 Data Direction for Port G Bits -- These read/write bits control the direction of port G pins and what is read for PTGDD[6:0] PTGD reads. 0 Input (output driver disabled) and reads return the pin value. 1 Output driver enabled for port G bit n and PTGD reads return the contents of PTGDn.
6.7.14
Port G Pin Control Registers (PTGPE, PTGSE, PTGDS)
In addition to the I/O control, port G pins are controlled by the registers listed below.
7 6 5 4 3 2 1 0
R W Reset
0 PTGPE6 0 0 PTGPE5 0 PTGPE4 0 PTGPE3 0 PTGPE2 0 PTGPE1 0 PTGPE0 0
Figure 6-42. Internal Pullup Enable for Port G Bits (PTGPE) Table 6-33. PTGPE Register Field Descriptions
Field Description
6:0 Internal Pullup Enable for Port G Bits -- Each of these control bits determines if the internal pullup device is PTGPE[6:0] enabled for the associated PTG pin. For port G pins that are configured as outputs, these bits have no effect and the internal pullup devices are disabled. 0 Internal pullup device disabled for port G bit n. 1 Internal pullup device enabled for port G bit n.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 105
Chapter 6 Parallel Input/Output
7
6
5
4
3
2
1
0
R W Reset
0 PTGSE6 0 0 PTGSE5 0 PTGSE4 0 PTGSE3 0 PTGSE2 0 PTGSE1 0 PTGSE0 0
Figure 6-43. Output Slew Rate Control Enable for Port G Bits (PTGSE) Table 6-34. PTGSE Register Field Descriptions
Field Description
6:0 Output Slew Rate Control Enable for Port G Bits-- Each of these control bits determine whether output slew PTGSE[6:0] rate control is enabled for the associated PTG pin. For port G pins that are configured as inputs, these bits have no effect. 0 Output slew rate control disabled for port G bit n. 1 Output slew rate control enabled for port G bit n.
7
6
5
4
3
2
1
0
R W Reset
0 PTGDS6 0 0 PTGDS5 0 PTGDS4 0 PTGDS3 0 PTGDS2 0 PTGDS1 0 PTGDS0 0
Figure 6-44. Output Drive Strength Selection for Port G (PTGDS) Table 6-35. PTGDS Register Field Descriptions
Field Description
6:0 Output Drive Strength Selection for Port G Bits -- Each of these control bits selects between low and high PTGDS[6:0] output drive for the associated PTG pin. 0 Low output drive enabled for port G bit n. 1 High output drive enabled for port G bit n.
MC9S08AC16 Series Data Sheet, Rev. 8 106 Freescale Semiconductor
Chapter 7 Central Processor Unit (S08CPUV2)
7.1 Introduction
This section provides summary information about the registers, addressing modes, and instruction set of the CPU of the HCS08 Family. For a more detailed discussion, refer to the HCS08 Family Reference Manual, volume 1. The HCS08 CPU is fully source- and object-code-compatible with the M68HC08 CPU. Several instructions and enhanced addressing modes were added to improve C compiler efficiency and to support a new background debug system which replaces the monitor mode of earlier M68HC08 microcontrollers (MCU).
7.1.1
Features
Features of the HCS08 CPU include: * Object code fully upward-compatible with M68HC05 and M68HC08 Families * All registers and memory are mapped to a single 64-Kbyte address space * 16-bit stack pointer (any size stack anywhere in 64-Kbyte address space) * 16-bit index register (H:X) with powerful indexed addressing modes * 8-bit accumulator (A) * Many instructions treat X as a second general-purpose 8-bit register * Seven addressing modes: -- Inherent -- Operands in internal registers -- Relative -- 8-bit signed offset to branch destination -- Immediate -- Operand in next object code byte(s) -- Direct -- Operand in memory at 0x0000-0x00FF -- Extended -- Operand anywhere in 64-Kbyte address space -- Indexed relative to H:X -- Five submodes including auto increment -- Indexed relative to SP -- Improves C efficiency dramatically * Memory-to-memory data move instructions with four address mode combinations * Overflow, half-carry, negative, zero, and carry condition codes support conditional branching on the results of signed, unsigned, and binary-coded decimal (BCD) operations * Efficient bit manipulation instructions * Fast 8-bit by 8-bit multiply and 16-bit by 8-bit divide instructions * STOP and WAIT instructions to invoke low-power operating modes
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7.2
Programmer's Model and CPU Registers
7 ACCUMULATOR 16-BIT INDEX REGISTER H:X H INDEX REGISTER (HIGH) 15 15 PROGRAM COUNTER 7 0 CONDITION CODE REGISTER V 1 1 H I N Z C 8 INDEX REGISTER (LOW) 7 0 SP 0 PC CCR X 0 A
Figure 7-1 shows the five CPU registers. CPU registers are not part of the memory map.
STACK POINTER
CARRY ZERO NEGATIVE INTERRUPT MASK HALF-CARRY (FROM BIT 3) TWO'S COMPLEMENT OVERFLOW
Figure 7-1. CPU Registers
7.2.1
Accumulator (A)
The A accumulator is a general-purpose 8-bit register. One operand input to the arithmetic logic unit (ALU) is connected to the accumulator and the ALU results are often stored into the A accumulator after arithmetic and logical operations. The accumulator can be loaded from memory using various addressing modes to specify the address where the loaded data comes from, or the contents of A can be stored to memory using various addressing modes to specify the address where data from A will be stored. Reset has no effect on the contents of the A accumulator.
7.2.2
Index Register (H:X)
This 16-bit register is actually two separate 8-bit registers (H and X), which often work together as a 16-bit address pointer where H holds the upper byte of an address and X holds the lower byte of the address. All indexed addressing mode instructions use the full 16-bit value in H:X as an index reference pointer; however, for compatibility with the earlier M68HC05 Family, some instructions operate only on the low-order 8-bit half (X). Many instructions treat X as a second general-purpose 8-bit register that can be used to hold 8-bit data values. X can be cleared, incremented, decremented, complemented, negated, shifted, or rotated. Transfer instructions allow data to be transferred from A or transferred to A where arithmetic and logical operations can then be performed. For compatibility with the earlier M68HC05 Family, H is forced to 0x00 during reset. Reset has no effect on the contents of X.
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7.2.3
Stack Pointer (SP)
This 16-bit address pointer register points at the next available location on the automatic last-in-first-out (LIFO) stack. The stack may be located anywhere in the 64-Kbyte address space that has RAM and can be any size up to the amount of available RAM. The stack is used to automatically save the return address for subroutine calls, the return address and CPU registers during interrupts, and for local variables. The AIS (add immediate to stack pointer) instruction adds an 8-bit signed immediate value to SP. This is most often used to allocate or deallocate space for local variables on the stack. SP is forced to 0x00FF at reset for compatibility with the earlier M68HC05 Family. HCS08 programs normally change the value in SP to the address of the last location (highest address) in on-chip RAM during reset initialization to free up direct page RAM (from the end of the on-chip registers to 0x00FF). The RSP (reset stack pointer) instruction was included for compatibility with the M68HC05 Family and is seldom used in new HCS08 programs because it only affects the low-order half of the stack pointer.
7.2.4
Program Counter (PC)
The program counter is a 16-bit register that contains the address of the next instruction or operand to be fetched. During normal program execution, the program counter automatically increments to the next sequential memory location every time an instruction or operand is fetched. Jump, branch, interrupt, and return operations load the program counter with an address other than that of the next sequential location. This is called a change-of-flow. During reset, the program counter is loaded with the reset vector that is located at 0xFFFE and 0xFFFF. The vector stored there is the address of the first instruction that will be executed after exiting the reset state.
7.2.5
Condition Code Register (CCR)
The 8-bit condition code register contains the interrupt mask (I) and five flags that indicate the results of the instruction just executed. Bits 6 and 5 are set permanently to 1. The following paragraphs describe the functions of the condition code bits in general terms. For a more detailed explanation of how each instruction sets the CCR bits, refer to the HCS08 Family Reference Manual, volume 1.
7 0 CONDITION CODE REGISTER V 1 1 H I N Z C CCR
CARRY ZERO NEGATIVE INTERRUPT MASK HALF-CARRY (FROM BIT 3) TWO'S COMPLEMENT OVERFLOW
Figure 7-2. Condition Code Register
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Chapter 7 Central Processor Unit (S08CPUV2)
Table 7-1. CCR Register Field Descriptions
Field 7 V Description Two's Complement Overflow Flag -- The CPU sets the overflow flag when a two's complement overflow occurs. The signed branch instructions BGT, BGE, BLE, and BLT use the overflow flag. 0 No overflow 1 Overflow Half-Carry Flag -- The CPU sets the half-carry flag when a carry occurs between accumulator bits 3 and 4 during an add-without-carry (ADD) or add-with-carry (ADC) operation. The half-carry flag is required for binary-coded decimal (BCD) arithmetic operations. The DAA instruction uses the states of the H and C condition code bits to automatically add a correction value to the result from a previous ADD or ADC on BCD operands to correct the result to a valid BCD value. 0 No carry between bits 3 and 4 1 Carry between bits 3 and 4 Interrupt Mask Bit -- When the interrupt mask is set, all maskable CPU interrupts are disabled. CPU interrupts are enabled when the interrupt mask is cleared. When a CPU interrupt occurs, the interrupt mask is set automatically after the CPU registers are saved on the stack, but before the first instruction of the interrupt service routine is executed. Interrupts are not recognized at the instruction boundary after any instruction that clears I (CLI or TAP). This ensures that the next instruction after a CLI or TAP will always be executed without the possibility of an intervening interrupt, provided I was set. 0 Interrupts enabled 1 Interrupts disabled Negative Flag -- The CPU sets the negative flag when an arithmetic operation, logic operation, or data manipulation produces a negative result, setting bit 7 of the result. Simply loading or storing an 8-bit or 16-bit value causes N to be set if the most significant bit of the loaded or stored value was 1. 0 Non-negative result 1 Negative result Zero Flag -- The CPU sets the zero flag when an arithmetic operation, logic operation, or data manipulation produces a result of 0x00 or 0x0000. Simply loading or storing an 8-bit or 16-bit value causes Z to be set if the loaded or stored value was all 0s. 0 Non-zero result 1 Zero result Carry/Borrow Flag -- The CPU sets the carry/borrow flag when an addition operation produces a carry out of bit 7 of the accumulator or when a subtraction operation requires a borrow. Some instructions -- such as bit test and branch, shift, and rotate -- also clear or set the carry/borrow flag. 0 No carry out of bit 7 1 Carry out of bit 7
4 H
3 I
2 N
1 Z
0 C
7.3
Addressing Modes
Addressing modes define the way the CPU accesses operands and data. In the HCS08, all memory, status and control registers, and input/output (I/O) ports share a single 64-Kbyte linear address space so a 16-bit binary address can uniquely identify any memory location. This arrangement means that the same instructions that access variables in RAM can also be used to access I/O and control registers or nonvolatile program space. Some instructions use more than one addressing mode. For instance, move instructions use one addressing mode to specify the source operand and a second addressing mode to specify the destination address. Instructions such as BRCLR, BRSET, CBEQ, and DBNZ use one addressing mode to specify the location
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of an operand for a test and then use relative addressing mode to specify the branch destination address when the tested condition is true. For BRCLR, BRSET, CBEQ, and DBNZ, the addressing mode listed in the instruction set tables is the addressing mode needed to access the operand to be tested, and relative addressing mode is implied for the branch destination.
7.3.1
Inherent Addressing Mode (INH)
In this addressing mode, operands needed to complete the instruction (if any) are located within CPU registers so the CPU does not need to access memory to get any operands.
7.3.2
Relative Addressing Mode (REL)
Relative addressing mode is used to specify the destination location for branch instructions. A signed 8-bit offset value is located in the memory location immediately following the opcode. During execution, if the branch condition is true, the signed offset is sign-extended to a 16-bit value and is added to the current contents of the program counter, which causes program execution to continue at the branch destination address.
7.3.3
Immediate Addressing Mode (IMM)
In immediate addressing mode, the operand needed to complete the instruction is included in the object code immediately following the instruction opcode in memory. In the case of a 16-bit immediate operand, the high-order byte is located in the next memory location after the opcode, and the low-order byte is located in the next memory location after that.
7.3.4
Direct Addressing Mode (DIR)
In direct addressing mode, the instruction includes the low-order eight bits of an address in the direct page (0x0000-0x00FF). During execution a 16-bit address is formed by concatenating an implied 0x00 for the high-order half of the address and the direct address from the instruction to get the 16-bit address where the desired operand is located. This is faster and more memory efficient than specifying a complete 16-bit address for the operand.
7.3.5
Extended Addressing Mode (EXT)
In extended addressing mode, the full 16-bit address of the operand is located in the next two bytes of program memory after the opcode (high byte first).
7.3.6
Indexed Addressing Mode
Indexed addressing mode has seven variations including five that use the 16-bit H:X index register pair and two that use the stack pointer as the base reference.
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7.3.6.1
Indexed, No Offset (IX)
This variation of indexed addressing uses the 16-bit value in the H:X index register pair as the address of the operand needed to complete the instruction.
7.3.6.2
Indexed, No Offset with Post Increment (IX+)
This variation of indexed addressing uses the 16-bit value in the H:X index register pair as the address of the operand needed to complete the instruction. The index register pair is then incremented (H:X = H:X + 0x0001) after the operand has been fetched. This addressing mode is only used for MOV and CBEQ instructions.
7.3.6.3
Indexed, 8-Bit Offset (IX1)
This variation of indexed addressing uses the 16-bit value in the H:X index register pair plus an unsigned 8-bit offset included in the instruction as the address of the operand needed to complete the instruction.
7.3.6.4
Indexed, 8-Bit Offset with Post Increment (IX1+)
This variation of indexed addressing uses the 16-bit value in the H:X index register pair plus an unsigned 8-bit offset included in the instruction as the address of the operand needed to complete the instruction. The index register pair is then incremented (H:X = H:X + 0x0001) after the operand has been fetched. This addressing mode is used only for the CBEQ instruction.
7.3.6.5
Indexed, 16-Bit Offset (IX2)
This variation of indexed addressing uses the 16-bit value in the H:X index register pair plus a 16-bit offset included in the instruction as the address of the operand needed to complete the instruction.
7.3.6.6
SP-Relative, 8-Bit Offset (SP1)
This variation of indexed addressing uses the 16-bit value in the stack pointer (SP) plus an unsigned 8-bit offset included in the instruction as the address of the operand needed to complete the instruction.
7.3.6.7
SP-Relative, 16-Bit Offset (SP2)
This variation of indexed addressing uses the 16-bit value in the stack pointer (SP) plus a 16-bit offset included in the instruction as the address of the operand needed to complete the instruction.
7.4
Special Operations
The CPU performs a few special operations that are similar to instructions but do not have opcodes like other CPU instructions. In addition, a few instructions such as STOP and WAIT directly affect other MCU circuitry. This section provides additional information about these operations.
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7.4.1
Reset Sequence
Reset can be caused by a power-on-reset (POR) event, internal conditions such as the COP (computer operating properly) watchdog, or by assertion of an external active-low reset pin. When a reset event occurs, the CPU immediately stops whatever it is doing (the MCU does not wait for an instruction boundary before responding to a reset event). For a more detailed discussion about how the MCU recognizes resets and determines the source, refer to the Resets, Interrupts, and System Configuration chapter. The reset event is considered concluded when the sequence to determine whether the reset came from an internal source is done and when the reset pin is no longer asserted. At the conclusion of a reset event, the CPU performs a 6-cycle sequence to fetch the reset vector from 0xFFFE and 0xFFFF and to fill the instruction queue in preparation for execution of the first program instruction.
7.4.2
Interrupt Sequence
When an interrupt is requested, the CPU completes the current instruction before responding to the interrupt. At this point, the program counter is pointing at the start of the next instruction, which is where the CPU should return after servicing the interrupt. The CPU responds to an interrupt by performing the same sequence of operations as for a software interrupt (SWI) instruction, except the address used for the vector fetch is determined by the highest priority interrupt that is pending when the interrupt sequence started. The CPU sequence for an interrupt is: 1. Store the contents of PCL, PCH, X, A, and CCR on the stack, in that order. 2. Set the I bit in the CCR. 3. Fetch the high-order half of the interrupt vector. 4. Fetch the low-order half of the interrupt vector. 5. Delay for one free bus cycle. 6. Fetch three bytes of program information starting at the address indicated by the interrupt vector to fill the instruction queue in preparation for execution of the first instruction in the interrupt service routine. After the CCR contents are pushed onto the stack, the I bit in the CCR is set to prevent other interrupts while in the interrupt service routine. Although it is possible to clear the I bit with an instruction in the interrupt service routine, this would allow nesting of interrupts (which is not recommended because it leads to programs that are difficult to debug and maintain). For compatibility with the earlier M68HC05 MCUs, the high-order half of the H:X index register pair (H) is not saved on the stack as part of the interrupt sequence. The user must use a PSHH instruction at the beginning of the service routine to save H and then use a PULH instruction just before the RTI that ends the interrupt service routine. It is not necessary to save H if you are certain that the interrupt service routine does not use any instructions or auto-increment addressing modes that might change the value of H. The software interrupt (SWI) instruction is like a hardware interrupt except that it is not masked by the global I bit in the CCR and it is associated with an instruction opcode within the program so it is not asynchronous to program execution.
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7.4.3
Wait Mode Operation
The WAIT instruction enables interrupts by clearing the I bit in the CCR. It then halts the clocks to the CPU to reduce overall power consumption while the CPU is waiting for the interrupt or reset event that will wake the CPU from wait mode. When an interrupt or reset event occurs, the CPU clocks will resume and the interrupt or reset event will be processed normally. If a serial BACKGROUND command is issued to the MCU through the background debug interface while the CPU is in wait mode, CPU clocks will resume and the CPU will enter active background mode where other serial background commands can be processed. This ensures that a host development system can still gain access to a target MCU even if it is in wait mode.
7.4.4
Stop Mode Operation
Usually, all system clocks, including the crystal oscillator (when used), are halted during stop mode to minimize power consumption. In such systems, external circuitry is needed to control the time spent in stop mode and to issue a signal to wake up the target MCU when it is time to resume processing. Unlike the earlier M68HC05 and M68HC08 MCUs, the HCS08 can be configured to keep a minimum set of clocks running in stop mode. This optionally allows an internal periodic signal to wake the target MCU from stop mode. When a host debug system is connected to the background debug pin (BKGD) and the ENBDM control bit has been set by a serial command through the background interface (or because the MCU was reset into active background mode), the oscillator is forced to remain active when the MCU enters stop mode. In this case, if a serial BACKGROUND command is issued to the MCU through the background debug interface while the CPU is in stop mode, CPU clocks will resume and the CPU will enter active background mode where other serial background commands can be processed. This ensures that a host development system can still gain access to a target MCU even if it is in stop mode. Recovery from stop mode depends on the particular HCS08 and whether the oscillator was stopped in stop mode. Refer to the Modes of Operation chapter for more details.
7.4.5
BGND Instruction
The BGND instruction is new to the HCS08 compared to the M68HC08. BGND would not be used in normal user programs because it forces the CPU to stop processing user instructions and enter the active background mode. The only way to resume execution of the user program is through reset or by a host debug system issuing a GO, TRACE1, or TAGGO serial command through the background debug interface. Software-based breakpoints can be set by replacing an opcode at the desired breakpoint address with the BGND opcode. When the program reaches this breakpoint address, the CPU is forced to active background mode rather than continuing the user program.
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7.5
HCS08 Instruction Set Summary
Table 7-2 provides a summary of the HCS08 instruction set in all possible addressing modes. The table shows operand construction, execution time in internal bus clock cycles, and cycle-by-cycle details for each addressing mode variation of each instruction.
Table 7-2. . Instruction Set Summary (Sheet 1 of 9)
Address Mode Source Form
ADC ADC ADC ADC ADC ADC ADC ADC ADD ADD ADD ADD ADD ADD ADD ADD #opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP #opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP
Cycles
Operation
Object Code
Cyc-by-Cyc Details
pp rpp prpp prpp rpp rfp pprpp prpp pp rpp prpp prpp rpp rfp pprpp prpp pp
Affect on CCR V11H INZC
Add with Carry A (A) + (M) + (C)
IMM DIR EXT IX2 IX1 IX SP2 SP1 IMM DIR EXT IX2 IX1 IX SP2 SP1 IMM
A9 B9 C9 D9 E9 F9 9E D9 9E E9 AB BB CB DB EB FB 9E DB 9E EB
ii dd hh ll ee ff ff ee ff ff ii dd hh ll ee ff ff ee ff ff
2 3 4 4 3 3 5 4 2 3 4 4 3 3 5 4 2
11
-
Add without Carry A (A) + (M)
11
-
AIS #opr8i
Add Immediate Value (Signed) to Stack Pointer SP (SP) + (M) Add Immediate Value (Signed) to Index Register (H:X) H:X (H:X) + (M)
A7 ii
-11-----
AIX #opr8i AND AND AND AND AND AND AND AND #opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP
IMM IMM DIR EXT IX2 IX1 IX SP2 SP1 DIR INH INH IX1 IX SP1 DIR INH INH IX1 IX SP1
AF ii A4 B4 C4 D4 E4 F4 9E D4 9E E4 ii dd hh ll ee ff ff ee ff ff
2 2 3 4 4 3 3 5 4 5 1 1 5 4 6 5 1 1 5 4 6
pp pp rpp prpp prpp rpp rfp pprpp prpp rfwpp p p rfwpp rfwp prfwpp rfwpp p p rfwpp rfwp prfwpp
-11-----
Logical AND A (A) & (M)
011- -
-
ASL opr8a ASLA ASLX ASL oprx8,X ASL ,X ASL oprx8,SP ASR opr8a ASRA ASRX ASR oprx8,X ASR ,X ASR oprx8,SP
Arithmetic Shift Left
C b7 b0 0
(Same as LSL) Arithmetic Shift Right
C b7 b0
38 dd 48 58 68 ff 78 9E 68 ff 37 dd 47 57 67 ff 77 9E 67 ff
11-
-
11-
-
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Table 7-2. . Instruction Set Summary (Sheet 2 of 9)
Address Mode Source Form Cycles Cyc-by-Cyc Details Affect on CCR V11H INZC
ppp rfwpp rfwpp rfwpp rfwpp rfwpp rfwpp rfwpp rfwpp ppp ppp ppp -11-----
Operation
Object Code
BCC rel
Branch if Carry Bit Clear (if C = 0)
REL DIR (b0) DIR (b1) DIR (b2) DIR (b3) DIR (b4) DIR (b5) DIR (b6) DIR (b7) REL REL REL
24 rr 11 13 15 17 19 1B 1D 1F dd dd dd dd dd dd dd dd
3 5 5 5 5 5 5 5 5 3 3 3
BCLR n,opr8a
Clear Bit n in Memory (Mn 0)
-11-----
BCS rel BEQ rel BGE rel
Branch if Carry Bit Set (if C = 1) (Same as BLO) Branch if Equal (if Z = 1) Branch if Greater Than or Equal To (if N V = 0) (Signed) Enter active background if ENBDM=1 Waits for and processes BDM commands until GO, TRACE1, or TAGGO Branch if Greater Than (if Z | (N V) = 0) (Signed) Branch if Half Carry Bit Clear (if H = 0) Branch if Half Carry Bit Set (if H = 1) Branch if Higher (if C | Z = 0) Branch if Higher or Same (if C = 0) (Same as BCC) Branch if IRQ Pin High (if IRQ pin = 1) Branch if IRQ Pin Low (if IRQ pin = 0)
25 rr 27 rr 90 rr
-11----- -11----- -11-----
BGND
INH
82
5+
fp...ppp
-11-----
BGT rel BHCC rel BHCS rel BHI rel BHS rel BIH rel BIL rel BIT BIT BIT BIT BIT BIT BIT BIT #opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP
REL REL REL REL REL REL REL IMM DIR EXT IX2 IX1 IX SP2 SP1 REL REL REL REL REL REL REL REL
92 rr 28 rr 29 rr 22 rr 24 rr 2F rr 2E rr A5 B5 C5 D5 E5 F5 9E D5 9E E5 ii dd hh ll ee ff ff ee ff ff
3 3 3 3 3 3 3 2 3 4 4 3 3 5 4 3 3 3 3 3 3 3 3
ppp ppp ppp ppp ppp ppp ppp pp rpp prpp prpp rpp rfp pprpp prpp ppp ppp ppp ppp ppp ppp ppp ppp
-11----- -11----- -11----- -11----- -11----- -11----- -11-----
Bit Test (A) & (M) (CCR Updated but Operands Not Changed)
011- -
-
BLE rel BLO rel BLS rel BLT rel BMC rel BMI rel BMS rel BNE rel
Branch if Less Than or Equal To (if Z | (N V) = 1) (Signed) Branch if Lower (if C = 1) (Same as BCS) Branch if Lower or Same (if C | Z = 1) Branch if Less Than (if N V = 1) (Signed) Branch if Interrupt Mask Clear (if I = 0) Branch if Minus (if N = 1) Branch if Interrupt Mask Set (if I = 1) Branch if Not Equal (if Z = 0)
93 rr 25 rr 23 rr 91 rr 2C rr 2B rr 2D rr 26 rr
-11----- -11----- -11----- -11----- -11----- -11----- -11----- -11-----
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Chapter 7 Central Processor Unit (S08CPUV2)
Table 7-2. . Instruction Set Summary (Sheet 3 of 9)
Address Mode Source Form
BPL rel BRA rel
Cycles
Operation
Object Code
Cyc-by-Cyc Details
ppp ppp rpppp rpppp rpppp rpppp rpppp rpppp rpppp rpppp ppp rpppp rpppp rpppp rpppp rpppp rpppp rpppp rpppp rfwpp rfwpp rfwpp rfwpp rfwpp rfwpp rfwpp rfwpp
Affect on CCR V11H INZC
-11----- -11-----
Branch if Plus (if N = 0) Branch Always (if I = 1)
REL REL
2A rr 20 rr 01 03 05 07 09 0B 0D 0F dd dd dd dd dd dd dd dd rr rr rr rr rr rr rr rr
3 3 5 5 5 5 5 5 5 5 3 rr rr rr rr rr rr rr rr 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
BRCLR n,opr8a,rel
DIR (b0) DIR (b1) DIR (b2) DIR (b3) Branch if Bit n in Memory Clear (if (Mn) = 0) DIR (b4) DIR (b5) DIR (b6) DIR (b7) Branch Never (if I = 0) REL DIR (b0) DIR (b1) DIR (b2) DIR (b3) DIR (b4) DIR (b5) DIR (b6) DIR (b7) DIR (b0) DIR (b1) DIR (b2) DIR (b3) DIR (b4) DIR (b5) DIR (b6) DIR (b7)
-11----
BRN rel
21 rr 00 02 04 06 08 0A 0C 0E 10 12 14 16 18 1A 1C 1E dd dd dd dd dd dd dd dd dd dd dd dd dd dd dd dd
-11-----
BRSET n,opr8a,rel
Branch if Bit n in Memory Set (if (Mn) = 1)
-11----
BSET n,opr8a
Set Bit n in Memory (Mn 1)
-11-----
BSR rel
Branch to Subroutine PC (PC) + $0002 push (PCL); SP (SP) - $0001 push (PCH); SP (SP) - $0001 PC (PC) + rel Compare and... Branch if (A) = (M) Branch if (A) = (M) Branch if (X) = (M) Branch if (A) = (M) Branch if (A) = (M) Branch if (A) = (M)
REL
AD rr
5
ssppp
-11-----
CBEQ opr8a,rel CBEQA #opr8i,rel CBEQX #opr8i,rel CBEQ oprx8,X+,rel CBEQ ,X+,rel CBEQ oprx8,SP,rel CLC CLI CLR opr8a CLRA CLRX CLRH CLR oprx8,X CLR ,X CLR oprx8,SP
DIR IMM IMM IX1+ IX+ SP1 INH INH DIR INH INH INH IX1 IX SP1
31 41 51 61 71 9E 61 98 9A
dd ii ii ff rr ff
rr rr rr rr rr
5 4 4 5 5 6 1 1 5 1 1 1 5 4 6
rpppp pppp pppp rpppp rfppp prpppp p p rfwpp p p p rfwpp rfwp prfwpp
-11-----
Clear Carry Bit (C 0) Clear Interrupt Mask Bit (I 0) Clear M $00 A $00 X $00 H $00 M $00 M $00 M $00
-11----0 -11-0---
3F dd 4F 5F 8C 6F ff 7F 9E 6F ff
011--01-
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Table 7-2. . Instruction Set Summary (Sheet 4 of 9)
Address Mode Source Form
CMP CMP CMP CMP CMP CMP CMP CMP #opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP
Cycles
Operation
Object Code
Cyc-by-Cyc Details
pp rpp prpp prpp rpp rfp pprpp prpp rfwpp p p rfwpp rfwp prfwpp prrfpp ppp rrfpp prrfpp pp rpp prpp prpp rpp rfp pprpp prpp p rfwpppp fppp fppp rfwpppp rfwppp prfwpppp rfwpp p p rfwpp rfwp prfwpp fffffp pp rpp prpp prpp rpp rfp pprpp prpp
Affect on CCR V11H INZC
Compare Accumulator with Memory A-M (CCR Updated But Operands Not Changed)
IMM DIR EXT IX2 IX1 IX SP2 SP1 DIR INH INH IX1 IX SP1 EXT IMM DIR SP1 IMM DIR EXT IX2 IX1 IX SP2 SP1 INH
A1 B1 C1 D1 E1 F1 9E D1 9E E1
ii dd hh ll ee ff ff ee ff ff
2 3 4 4 3 3 5 4 5 1 1 5 4 6 6 3 5 6 2 3 4 4 3 3 5 4 1
11-
-
COM opr8a COMA COMX COM oprx8,X COM ,X COM oprx8,SP CPHX opr16a CPHX #opr16i CPHX opr8a CPHX oprx8,SP CPX CPX CPX CPX CPX CPX CPX CPX DAA DBNZ opr8a,rel DBNZA rel DBNZX rel DBNZ oprx8,X,rel DBNZ ,X,rel DBNZ oprx8,SP,rel DEC opr8a DECA DECX DEC oprx8,X DEC ,X DEC oprx8,SP DIV EOR EOR EOR EOR EOR EOR EOR EOR #opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP #opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP
Complement M (M)= $FF - (M) (One's Complement) A (A) = $FF - (A) X (X) = $FF - (X) M (M) = $FF - (M) M (M) = $FF - (M) M (M) = $FF - (M) Compare Index Register (H:X) with Memory (H:X) - (M:M + $0001) (CCR Updated But Operands Not Changed)
33 dd 43 53 63 ff 73 9E 63 ff 3E 65 75 9E F3 A3 B3 C3 D3 E3 F3 9E D3 9E E3 72 3B 4B 5B 6B 7B 9E 6B dd rr rr rr ff rr rr ff rr hh ll jj kk dd ff ii dd hh ll ee ff ff ee ff ff
011- -
1
11-
-
Compare X (Index Register Low) with Memory X-M (CCR Updated But Operands Not Changed)
11-
-
Decimal Adjust Accumulator After ADD or ADC of BCD Values
U11-
-
DIR INH Decrement A, X, or M and Branch if Not Zero INH (if (result) 0) IX1 DBNZX Affects X Not H IX SP1 Decrement M (M) - $01 A (A) - $01 X (X) - $01 M (M) - $01 M (M) - $01 M (M) - $01 DIR INH INH IX1 IX SP1 INH IMM DIR EXT IX2 IX1 IX SP2 SP1
7 4 4 7 6 8 5 1 1 5 4 6 6
-11-----
3A dd 4A 5A 6A ff 7A 9E 6A ff 52 A8 B8 C8 D8 E8 F8 9E D8 9E E8 ii dd hh ll ee ff ff ee ff ff
11-
-
-
Divide A (H:A)/(X); H Remainder Exclusive OR Memory with Accumulator A (A M)
-11- --
2 3 4 4 3 3 5 4
011- -
-
MC9S08AC16 Series Data Sheet, Rev. 8 118 Freescale Semiconductor
Chapter 7 Central Processor Unit (S08CPUV2)
Table 7-2. . Instruction Set Summary (Sheet 5 of 9)
Address Mode Source Form
INC opr8a INCA INCX INC oprx8,X INC ,X INC oprx8,SP JMP JMP JMP JMP JMP JSR JSR JSR JSR JSR LDA LDA LDA LDA LDA LDA LDA LDA opr8a opr16a oprx16,X oprx8,X ,X opr8a opr16a oprx16,X oprx8,X ,X #opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP #opr16i opr8a opr16a ,X oprx16,X oprx8,X oprx8,SP Increment
Cycles
Operation
M (M) + $01 A (A) + $01 X (X) + $01 M (M) + $01 M (M) + $01 M (M) + $01
Object Code
Cyc-by-Cyc Details
rfwpp p p rfwpp rfwp prfwpp ppp pppp pppp ppp ppp ssppp pssppp pssppp ssppp ssppp pp rpp prpp prpp rpp rfp pprpp prpp ppp rrpp prrpp prrfp pprrpp prrpp prrpp pp rpp prpp prpp rpp rfp pprpp prpp rfwpp p p rfwpp rfwp prfwpp rfwpp p p rfwpp rfwp prfwpp
Affect on CCR V11H INZC
DIR INH INH IX1 IX SP1 DIR EXT IX2 IX1 IX DIR EXT IX2 IX1 IX IMM DIR EXT IX2 IX1 IX SP2 SP1 IMM DIR EXT IX IX2 IX1 SP1 IMM DIR EXT IX2 IX1 IX SP2 SP1 DIR INH INH IX1 IX SP1 DIR INH INH IX1 IX SP1
3C dd 4C 5C 6C ff 7C 9E 6C ff BC CC DC EC FC BD CD DD ED FD A6 B6 C6 D6 E6 F6 9E D6 9E E6 45 55 32 AE BE CE FE dd hh ll ee ff ff dd hh ll ee ff ff ii dd hh ll ee ff ff ee ff ff jj kk dd hh ll ee ff ff ff ii dd hh ll ee ff ff ee ff ff
5 1 1 5 4 6 3 4 4 3 3 5 6 6 5 5 2 3 4 4 3 3 5 4 3 4 5 5 6 5 5 2 3 4 4 3 3 5 4 5 1 1 5 4 6 5 1 1 5 4 6
11-
-
-
Jump PC Jump Address
-11-----
Jump to Subroutine PC (PC) + n (n = 1, 2, or 3) Push (PCL); SP (SP) - $0001 Push (PCH); SP (SP) - $0001 PC Unconditional Address
-11-----
Load Accumulator from Memory A (M)
011- -
-
LDHX LDHX LDHX LDHX LDHX LDHX LDHX LDX LDX LDX LDX LDX LDX LDX LDX
Load Index Register (H:X) H:X (M:M + $0001)
9E 9E 9E 9E
011- -
-
#opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP
Load X (Index Register Low) from Memory X (M)
AE BE CE DE EE FE 9E DE 9E EE
011- -
-
LSL opr8a LSLA LSLX LSL oprx8,X LSL ,X LSL oprx8,SP LSR opr8a LSRA LSRX LSR oprx8,X LSR ,X LSR oprx8,SP
Logical Shift Left
C b7 b0 0
(Same as ASL) Logical Shift Right
0 b7 b0 C
38 dd 48 58 68 ff 78 9E 68 ff 34 dd 44 54 64 ff 74 9E 64 ff
11-
-
11- -0
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 119
Chapter 7 Central Processor Unit (S08CPUV2)
Table 7-2. . Instruction Set Summary (Sheet 6 of 9)
Address Mode Source Form
MOV opr8a,opr8a MOV opr8a,X+ MOV #opr8i,opr8a MOV ,X+,opr8a MUL NEG opr8a NEGA NEGX NEG oprx8,X NEG ,X NEG oprx8,SP NOP NSA ORA ORA ORA ORA ORA ORA ORA ORA #opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP
Cycles
Operation
Object Code
Cyc-by-Cyc Details
rpwpp rfwpp pwpp rfwpp ffffp rfwpp p p rfwpp rfwp prfwpp p p pp rpp prpp prpp rpp rfp pprpp prpp sp sp sp ufp ufp ufp rfwpp p p rfwpp rfwp prfwpp rfwpp p p rfwpp rfwp prfwpp
Affect on CCR V11H INZC
Move (M)destination (M)source In IX+/DIR and DIR/IX+ Modes, H:X (H:X) + $0001 Unsigned multiply X:A (X) x (A) Negate M - (M) = $00 - (M) (Two's Complement) A - (A) = $00 - (A) X - (X) = $00 - (X) M - (M) = $00 - (M) M - (M) = $00 - (M) M - (M) = $00 - (M) No Operation -- Uses 1 Bus Cycle Nibble Swap Accumulator A (A[3:0]:A[7:4])
DIR/DIR DIR/IX+ IMM/DIR IX+/DIR INH DIR INH INH IX1 IX SP1 INH INH IMM DIR EXT IX2 IX1 IX SP2 SP1 INH INH INH INH INH INH DIR INH INH IX1 IX SP1 DIR INH INH IX1 IX SP1
4E 5E 6E 7E 42
dd dd dd ii dd dd
5 5 4 5 5 5 1 1 5 4 6 1 1
011- -
-
-110---0
30 dd 40 50 60 ff 70 9E 60 ff 9D 62 AA BA CA DA EA FA 9E DA 9E EA 87 8B 89 86 8A 88 39 dd 49 59 69 ff 79 9E 69 ff 36 dd 46 56 66 ff 76 9E 66 ff ii dd hh ll ee ff ff ee ff ff
11-
-
-11----- -11-----
Inclusive OR Accumulator and Memory A (A) | (M)
2 3 4 4 3 3 5 4 2 2 2 3 3 3 5 1 1 5 4 6 5 1 1 5 4 6
011- -
-
PSHA PSHH PSHX PULA PULH PULX ROL opr8a ROLA ROLX ROL oprx8,X ROL ,X ROL oprx8,SP ROR opr8a RORA RORX ROR oprx8,X ROR ,X ROR oprx8,SP
Push Accumulator onto Stack Push (A); SP (SP) - $0001 Push H (Index Register High) onto Stack Push (H); SP (SP) - $0001 Push X (Index Register Low) onto Stack Push (X); SP (SP) - $0001 Pull Accumulator from Stack SP (SP + $0001); Pull (A) Pull H (Index Register High) from Stack SP (SP + $0001); Pull (H) Pull X (Index Register Low) from Stack SP (SP + $0001); Pull (X) Rotate Left through Carry
C b7 b0
-11----- -11----- -11----- -11----- -11----- -11-----
11-
-
Rotate Right through Carry
C b7 b0
11-
-
MC9S08AC16 Series Data Sheet, Rev. 8 120 Freescale Semiconductor
Chapter 7 Central Processor Unit (S08CPUV2)
Table 7-2. . Instruction Set Summary (Sheet 7 of 9)
Address Mode Source Form Cycles Cyc-by-Cyc Details Affect on CCR V11H INZC
p -11-----
Operation
Object Code
RSP
Reset Stack Pointer (Low Byte) SPL $FF (High Byte Not Affected) Return from Interrupt SP (SP) + $0001; SP (SP) + $0001; SP (SP) + $0001; SP (SP) + $0001; SP (SP) + $0001; Pull (CCR) Pull (A) Pull (X) Pull (PCH) Pull (PCL)
INH
9C
1
RTI
INH
80
9
uuuuufppp
11
RTS SBC SBC SBC SBC SBC SBC SBC SBC SEC SEI STA STA STA STA STA STA STA opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP #opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP
Return from Subroutine SP SP + $0001; Pull (PCH) SP SP + $0001; Pull (PCL)
INH IMM DIR EXT IX2 IX1 IX SP2 SP1 INH INH DIR EXT IX2 IX1 IX SP2 SP1 DIR EXT SP1 INH DIR EXT IX2 IX1 IX SP2 SP1
81 A2 B2 C2 D2 E2 F2 9E D2 9E E2 99 9B B7 C7 D7 E7 F7 9E D7 9E E7 dd hh ll ee ff ff ee ff ff ii dd hh ll ee ff ff ee ff ff
5 2 3 4 4 3 3 5 4 1 1 3 4 4 3 2 5 4 4 5 5 2 dd hh ll ee ff ff ee ff ff 3 4 4 3 2 5 4
ufppp pp rpp prpp prpp rpp rfp pprpp prpp p p wpp pwpp pwpp wpp wp ppwpp pwpp wwpp pwwpp pwwpp fp... wpp pwpp pwpp wpp wp ppwpp pwpp
-11-----
Subtract with Carry A (A) - (M) - (C)
11-
-
Set Carry Bit (C 1) Set Interrupt Mask Bit (I 1)
-11----1 -11-1---
Store Accumulator in Memory M (A)
011- -
-
STHX opr8a STHX opr16a STHX oprx8,SP STOP STX STX STX STX STX STX STX opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP
Store H:X (Index Reg.) (M:M + $0001) (H:X) Enable Interrupts: Stop Processing Refer to MCU Documentation I bit 0; Stop Processing
35 dd 96 hh ll 9E FF ff 8E BF CF DF EF FF 9E DF 9E EF
011- -
-
-11-0---
Store X (Low 8 Bits of Index Register) in Memory M (X)
011- -
-
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 121
Chapter 7 Central Processor Unit (S08CPUV2)
Table 7-2. . Instruction Set Summary (Sheet 8 of 9)
Address Mode Source Form
SUB SUB SUB SUB SUB SUB SUB SUB #opr8i opr8a opr16a oprx16,X oprx8,X ,X oprx16,SP oprx8,SP
Cycles
Operation
Object Code
Cyc-by-Cyc Details
pp rpp prpp prpp rpp rfp pprpp prpp
Affect on CCR V11H INZC
Subtract A (A) - (M)
IMM DIR EXT IX2 IX1 IX SP2 SP1
A0 B0 C0 D0 E0 F0 9E D0 9E E0
ii dd hh ll ee ff ff ee ff ff
2 3 4 4 3 3 5 4
11- -
SWI
Software Interrupt PC (PC) + $0001 Push (PCL); SP (SP) - $0001 Push (PCH); SP (SP) - $0001 Push (X); SP (SP) - $0001 Push (A); SP (SP) - $0001 Push (CCR); SP (SP) - $0001 I 1; PCH Interrupt Vector High Byte PCL Interrupt Vector Low Byte Transfer Accumulator to CCR CCR (A) Transfer Accumulator to X (Index Register Low) X (A) Transfer CCR to Accumulator A (CCR) Test for Negative or Zero (M) - $00 (A) - $00 (X) - $00 (M) - $00 (M) - $00 (M) - $00
INH
83
11
sssssvvfppp
-11-1---
TAP
INH
84
1
p
11
TAX
INH
97
1
p
-11-----
TPA TST opr8a TSTA TSTX TST oprx8,X TST ,X TST oprx8,SP TSX TXA
INH DIR INH INH IX1 IX SP1 INH INH
85 3D dd 4D 5D 6D ff 7D 9E 6D ff 95 9F
1 4 1 1 4 3 5 2 1
p rfpp p p rfpp rfp prfpp fp p
-11-----
011- -
-
Transfer SP to Index Reg. H:X (SP) + $0001 Transfer X (Index Reg. Low) to Accumulator A (X)
-11----- -11-----
MC9S08AC16 Series Data Sheet, Rev. 8 122 Freescale Semiconductor
Chapter 7 Central Processor Unit (S08CPUV2)
Table 7-2. . Instruction Set Summary (Sheet 9 of 9)
Address Mode Source Form Cycles Cyc-by-Cyc Details Affect on CCR V11H INZC
fp fp... -11----- -11-0---
Operation
Object Code
TXS WAIT
Transfer Index Reg. to SP SP (H:X) - $0001 Enable Interrupts; Wait for Interrupt I bit 0; Halt CPU
INH INH
94 8F
2 2+
Source Form: Everything in the source forms columns, except expressions in italic characters, is literal information which must appear in the assembly source file exactly as shown. The initial 3- to 5-letter mnemonic and the characters (# , ( ) and +) are always a literal characters. n Any label or expression that evaluates to a single integer in the range 0-7. opr8i Any label or expression that evaluates to an 8-bit immediate value. opr16i Any label or expression that evaluates to a 16-bit immediate value. opr8a Any label or expression that evaluates to an 8-bit direct-page address ($00xx). opr16a Any label or expression that evaluates to a 16-bit address. oprx8 Any label or expression that evaluates to an unsigned 8-bit value, used for indexed addressing. oprx16 Any label or expression that evaluates to a 16-bit value, used for indexed addressing. rel Any label or expression that refers to an address that is within -128 to +127 locations from the start of the next instruction. Operation Symbols: A Accumulator CCR Condition code register H Index register high byte M Memory location n Any bit opr Operand (one or two bytes) PC Program counter PCH Program counter high byte PCL Program counter low byte rel Relative program counter offset byte SP Stack pointer SPL Stack pointer low byte X Index register low byte & Logical AND | Logical OR Logical EXCLUSIVE OR () Contents of + Add - Subtract, Negation (two's complement) x Multiply / Divide # Immediate value Loaded with : Concatenated with CCR Bits: V Overflow bit H Half-carry bit I Interrupt mask N Negative bit Z Zero bit C Carry/borrow bit Addressing Modes: DIR Direct addressing mode EXT Extended addressing mode IMM Immediate addressing mode INH Inherent addressing mode IX Indexed, no offset addressing mode IX1 Indexed, 8-bit offset addressing mode IX2 Indexed, 16-bit offset addressing mode IX+ Indexed, no offset, post increment addressing mode IX1+ Indexed, 8-bit offset, post increment addressing mode REL Relative addressing mode SP1 Stack pointer, 8-bit offset addressing mode SP2 Stack pointer 16-bit offset addressing mode Cycle-by-Cycle Codes: f Free cycle. This indicates a cycle where the CPU does not require use of the system buses. An f cycle is always one cycle of the system bus clock and is always a read cycle. p Progryam fetch; read from next consecutive location in program memory r Read 8-bit operand s Push (write) one byte onto stack u Pop (read) one byte from stack v Read vector from $FFxx (high byte first) w Write 8-bit operand CCR Effects: Set or cleared - Not affected U Undefined
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 123
Chapter 7 Central Processor Unit (S08CPUV2)
Table 7-3. Opcode Map (Sheet 1 of 2)
Bit-Manipulation Branch 00 5 10 5 20 3 30 5 40 DIR 1 5 41 DIR 3 5 42 EXT 1 5 43 DIR 1 5 44 Read-Modify-Write 1 50 1 60 5 70 4 80 Control 9 90 3 A0 2 B0 Register/Memory 3 C0 4 D0 4 E0 3 F0 3 IX 3 IX 3 IX 3 IX 3 IX 3
BRSET0
3 01 3 02 3 03 3 04 3 05 3 06 3 07 3 08 3 09 3 0A 3 0B 3 0C 3 0D 3 0E 3 0F 3 INH IMM DIR EXT DD IX+D
BSET0
DIR 2 5 21 DIR 2 5 22 DIR 2 5 23 DIR 2 5 24 DIR 2 5 25 DIR 2 5 26 DIR 2 5 27 DIR 2 5 28 DIR 2 5 29
BRA BRN BHI BLS BCC
NEG CBEQ LDHX COM LSR STHX ROR ASR LSL ROL DEC DBNZ INC TST CPHX CLR
DIR 1
NEGA CBEQA MUL
NEGX CBEQX DIV
NEG CBEQ NSA
NEG
IX 1 5 81 IX+ 1 1 82
RTI
INH 2 6 91
BGE BLT BGT BLE TXS TSX
SUB CMP SBC CPX AND BIT
SUB CMP SBC CPX AND BIT
SUB CMP SBC CPX AND BIT
SUB CMP SBC CPX AND BIT
SUB CMP SBC CPX AND BIT
SUB CMP SBC CPX AND BIT
IX 3
DIR 2 5 11 DIR 2 5 12 DIR 2 5 13 DIR 2 5 14 DIR 2 5 15 DIR 2 5 16 DIR 2 5 17 DIR 2 5 18 DIR 2 5 19 DIR 2 5 1A DIR 2 5 1B DIR 2 5 1C DIR 2 5 1D DIR 2 5 1E DIR 2 5 1F DIR 2
REL 2 3 31 REL 3 3 32 REL 3 3 33 REL 2 3 34 REL 2 3 35
INH 1 4 51 IMM 3 5 52 INH 1 1 53 INH 1 1 54 INH 1 3 55 IMM 2 1 56 INH 1 1 57 INH 1 1 58 INH 1 1 59 INH 1 1 5A INH 1 4 5B INH 2 1 5C INH 1 1 5D INH 1 5 5E
INH 2 4 61 IMM 3 6 62 INH 1 1 63 INH 2 1 64 INH 2 4 65 DIR 3 1 66 INH 2 1 67 INH 2 1 68 INH 2 1 69 INH 2 1 6A INH 2 4 6B INH 3 1 6C INH 2 1 6D INH 2 5 6E
IX1 1 5 71 IX1+ 2 1 72 INH 1 5 73 IX1 1 5 74
REL 2 3 A1 REL 2 3 A2 REL 2 3 A3 REL 2 2 A4 INH 2 2 A5 INH 2 5 A6 EXT 2 1 A7
IMM 2 2 B1 IMM 2 2 B2 IMM 2 2 B3 IMM 2 2 B4 IMM 2 2 B5 IMM 2 2 B6
DIR 3 3 C1 DIR 3 3 C2 DIR 3 3 C3 DIR 3 3 C4 DIR 3 3 C5 DIR 3 3 C6
EXT 3 4 D1 EXT 3 4 D2 EXT 3 4 D3 EXT 3 4 D4 EXT 3 4 D5 EXT 3 4 D6 EXT 3 4 D7
IX2 2 4 E1 IX2 2 4 E2 IX2 2 4 E3 IX2 2 4 E4 IX2 2 4 E5 IX2 2 4 E6 IX2 2 4 E7
IX1 1 3 F1 IX1 1 3 F2 IX1 1 3 F3 IX1 1 3 F4 IX1 1 3 F5 IX1 1 3 F6
BRCLR0 BRSET1 BRCLR1 BRSET2 BRCLR2 BRSET3 BRCLR3 BRSET4 BRCLR4 BRSET5 BRCLR5 BRSET6 BRCLR6 BRSET7 BRCLR7
BCLR0 BSET1 BCLR1 BSET2 BCLR2 BSET3 BCLR3 BSET4 BCLR4 BSET5
CBEQ DAA COM
IX 1 4 84
RTS
INH 2 5+ 92 INH 2 11 93
BGND SWI
INH 2 1 94
INH 1 4 83
COMA LSRA LDHX RORA ASRA LSLA ROLA DECA DBNZA INCA TSTA MOV CLRA
INH 1
COMX LSRX LDHX RORX ASRX LSLX ROLX DECX DBNZX INCX TSTX MOV CLRX
INH 2 SP1 SP2 IX+ IX1+
COM LSR
LSR
IX 1 5 85 DIR 1 4 86 IX 1 4 87
TAP
INH 1 1 95
DIR 1 4 45 DIR 3 5 46 DIR 1 5 47 DIR 1 5 48 DIR 1 5 49 DIR 1 5 4A DIR 1 7 4B DIR 2 5 4C DIR 1 4 4D DIR 1 6 4E EXT 3 5 4F
IX1 1 3 75 IMM 2 5 76 IX1 1 5 77
BCS BNE BEQ
CPHX ROR ASR
CPHX ROR ASR LSL ROL DEC DBNZ INC
IX 1 3 IX 5 8E
TPA
INH 1 3 96 INH 3 2 97 INH 1 3 98 INH 1 2 99 INH 1 3 9A INH 1 2 9B
REL 2 3 36 REL 2 3 37 REL 2 3 38 REL 2 3 39 REL 2 3 3A
PULA PSHA PULX
STHX TAX
INH 2 1 A8
LDA
IMM 2 2 B7
LDA STA
LDA STA
LDA STA
IX2 2 4 E8 IX2 2 4 E9
LDA
IX1 1 3 F7
LDA
IX 2
DIR 3 3 C7 DIR 3 3 C8 DIR 3 3 C9 DIR 3 3 CA DIR 3 3 CB DIR 3 3 CC DIR 3 5 CD DIR 3 3 CE DIR 3 3 CF DIR 3
AIS
IMM 2 2 B8 IMM 2 2 B9
STA
IX1 1 3 F8 IX1 1 3 F9 IX1 1 3 FA IX1 1 3 FB
STA
IX 3 IX 3 IX 3 IX 3 IX 3 IX 5 IX 3 IX 2
IX1 1 5 78
IX 1 4 88 IX 1 4 89 IX 1 4 8A IX 1 6 8B IX 1 4 8C
EXT 3 4 D8 EXT 3 4 D9 EXT 3 4 DA EXT 3 4 DB EXT 3 4 DC EXT 3 6 DD EXT 3 4 DE EXT 3 4 DF EXT 3
BHCC BHCS BPL BMI BMC
REL 2 3 3D REL 2 3 3E
LSL
IX1 1 5 79
CLC SEC CLI SEI
INH 2 1
EOR ADC ORA ADD
EOR ADC ORA ADD JMP
2 5 BD
EOR ADC ORA ADD JMP JSR LDX STX
EOR ADC ORA ADD JMP JSR LDX STX
IX2 2
EOR ADC ORA ADD JMP JSR LDX
EOR ADC ORA ADD JMP JSR LDX STX
IX
INH 2 1 A9 INH 2 1 AA INH 2 1 AB
ROL DEC DBNZ INC
PSHX PULH PSHH
DIR 2 5 2A DIR 2 5 2B DIR 2 5 2C DIR 2 5 2D DIR 2 5 2E DIR 2 5 2F DIR 2
IX1 1 5 7A IX1 1 7 7B IX1 2 5 7C IX1 1 4 7D IX1 1 4 7E
IMM 2 2 BA IMM 2 2 BB IMM 2 BC
IX2 2 4 EA IX2 2 4 EB IX2 2 4 EC IX2 2 6 ED IX2 2 4 EE IX2 2 4 EF
REL 2 3 3B REL 3 3 3C
BCLR5 BSET6 BCLR6 BSET7 BCLR7
INH 1 1 9C INH 1 9D 1 2+ 9E INH 2+ 9F
IX1 1 3 FC IX1 1 5 FD IX1 1 3 FE IX1 1 3 FF IX1 1
CLRH
RSP
INH 1 AD
BMS BIL BIH
REL 2 REL IX IX1 IX2 IMD DIX+
TST MOV CLR
IX1 1
TST MOV CLR
IX 1
NOP STOP WAIT
INH 1
BSR LDX AIX
IMM 2
JSR LDX STX
INH 2 AE 2 1 AF
REL 2 2 BE IMM 2 2 BF
Page 2 TXA
INH 2
REL 3 3 3F
DD 2 DIX+ 3 1 5F 1 6F
IMD 2 IX+D 1 5 7F 4 8F
STX
Inherent Immediate Direct Extended DIR to DIR IX+ to DIR
Relative Indexed, No Offset Indexed, 8-Bit Offset Indexed, 16-Bit Offset IMM to DIR DIR to IX+
Stack Pointer, 8-Bit Offset Stack Pointer, 16-Bit Offset Indexed, No Offset with Post Increment Indexed, 1-Byte Offset with Post Increment
Opcode in Hexadecimal F0 Number of Bytes 1
SUB
3 HCS08 Cycles Instruction Mnemonic IX Addressing Mode
MC9S08AC16 Series Data Sheet, Rev. 8 124 Freescale Semiconductor
Chapter 7 Central Processor Unit (S08CPUV2)
Table 7-3. Opcode Map (Sheet 2 of 2)
Bit-Manipulation Branch Read-Modify-Write 9E60 Control 6 Register/Memory 9ED0 5 9EE0 4
NEG
3 SP1 9E61 6
SUB CMP SBC
SUB CMP SBC
6 SP1
4 SP2 3 SP1 9ED1 5 9EE1 4 4 SP2 3 SP1 9ED2 5 9EE2 4 4 SP2 3 SP1 9ED3 5 9EE3 4 9EF3
CBEQ
4 SP1
9E63
6
COM
3 SP1 9E64 6
CPX AND BIT
CPX AND BIT LDA STA EOR ADC ORA ADD
SP1
CPHX
4 SP2 3 SP1 3 9ED4 5 9EE4 4 4 SP2 3 SP1 9ED5 5 9EE5 4 4 SP2 3 SP1 9ED6 5 9EE6 4
LSR
3 SP1
9E66
6
ROR
3 SP1 9E67 6
LDA STA EOR ADC ORA ADD
4 SP2 3
4 SP2 3 SP1 9ED7 5 9EE7 4 4 SP2 3 SP1 9ED8 5 9EE8 4 4 SP2 3 SP1 9ED9 5 9EE9 4 4 SP2 3 SP1 9EDA 5 9EEA 4 4 SP2 3 SP1 9EDB 5 9EEB 4
ASR
3 SP1 9E68 6
LSL
3 SP1 9E69 6
ROL
3 SP1 9E6A 6
DEC
3 SP1 9E6B 8
DBNZ
4 SP1 9E6C 6
INC
3 SP1 9E6D 5
TST
3 SP1 9EAE 2 9E6F 6 SP1 5 9EBE IX 4 6 9ECE IX2 3 5 9EDE 5 9EEE 4 9EFE 5
LDHX CLR
3 INH IMM DIR EXT DD IX+D Inherent Immediate Direct Extended DIR to DIR IX+ to DIR REL IX IX1 IX2 IMD DIX+ Relative Indexed, No Offset Indexed, 8-Bit Offset Indexed, 16-Bit Offset IMM to DIR DIR to IX+ SP1 SP2 IX+ IX1+
LDHX
LDHX
LDX STX
4 SP2 3
LDX STX
SP1 3
LDHX STHX
SP1
IX1 4 SP2 3 SP1 3 SP1 9EDF 5 9EEF 4 9EFF 5
Stack Pointer, 8-Bit Offset Stack Pointer, 16-Bit Offset Indexed, No Offset with Post Increment Indexed, 1-Byte Offset with Post Increment Prebyte (9E) and Opcode in Hexadecimal 9E60 Number of Bytes 3 6 HCS08 Cycles Instruction Mnemonic SP1 Addressing Mode
Note: All Sheet 2 Opcodes are Preceded by the Page 2 Prebyte (9E)
NEG
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 125
Chapter 7 Central Processor Unit (S08CPUV2)
MC9S08AC16 Series Data Sheet, Rev. 8 126 Freescale Semiconductor
Chapter 8 Internal Clock Generator (S08ICGV4)
The internal clock generation (ICG) module is used to generate the system clocks for the MC9S08AC16 Series MCU. The analog supply lines VDDA and VSSA are internally derived from the MCU's VDD and VSS pins. Electrical parametric data for the ICG may be found in Appendix A, "Electrical Characteristics and Timing Specifications."
SYSTEM CONTROL LOGIC RTI TPMCLK
ICGERCLK FFE
TPM1
TPM2
IIC1
SCI1
SCI2
SPI1
/2
ICG XCLK* COP ICGOUT ICGLCLK* 1 kHz
/2
BUSCLK
CPU
BDC
TPM3
ADC1
RAM
FLASH FLASH has frequency requirements for program and erase operation. See the Electricals appendix.
* ICGLCLK is the alternate BDC clock source for the MC9S08AC16 Series. * XCLK is the fixed-frequency clock.
ADC has min and max frequency requirements. See the Electricals appendix and the ADC chapter.
Figure 8-1. System Clock Distribution Diagram
NOTE Freescale Semiconductor recommends that FLASH location 0xFFBE be reserved to store a nonvolatile version of ICGTRM. This will allow debugger and programmer vendors to perform a manual trim operation and store the resultant ICGTRM value for users to access at a later time.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 127
Chapter 8 Internal Clock Generator (S08ICGV4)
VDDAD VSSAD VREFL VREFH HCS08 CORE BKGD/MS BDC CPU
10-BIT ANALOG-TO-DIGITAL CONVERTER (ADC1) DEBUG MODULE (DBG)
4 AD1P11-AD1P8
PORT A
4 AD1P3-AD1P0
PTA7 PTA2 PTA1 PTA0 PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 PTB0/TPM3CH0/AD1P0 PTC5/RxD2 PTC4 PTC3/TxD2 PTC2/MCLK PTC1/SDA1 PTC0/SCL1 PTD3/KBIP6/AD1P11 PTD2/KBIP5/AD1P10 PTD1/AD1P9 PTD0/AD1P8
SDA1 IIC MODULE (IIC1) SCL1 PORT C PORT D
RESET IRQ/TPMCLK
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION POWER MANAGEMENT RTI IRQ COP LVD
INTERNAL CLOCK GENERATOR (ICG) LOW-POWER OSCILLATOR 7-BIT KEYBOARD INTERRUPT MODULE (KBI)
EXTAL XTAL
2 KBIP6-KBIP5 5 KBIP4-KBIP0 RxD1 TxD1 RxD2 TxD2 SPSCK1 MOSI1 MISO1 SS1 TPM1CH1 TPM1CH0 TPM1CH3 TPM1CH2 TPM2CH1 TPM2CH0 TPM3CH1 TPM3CH0
TPMCLK
SERIAL COMMUNICATIONS INTERFACE MODULE (SCI1) SERIAL COMMUNICATIONS INTERFACE MODULE (SCI2) SERIAL PERIPHERAL INTERFACE MODULE (SPI1)
PORT B
USER FLASH 16,384 BYTES OR 8192 BYTES
PTE7/SPSCK1 PTE6/MOSI1 PTE5/MISO1 PTE4/SS1 PTE3/TPM1CH1 PTE2/TPM1CH0 PTE1/RxD1 PTE0/TxD1
USER RAM 1024 BYTES OR 768 BYTES VDD VSS VOLTAGE REGULATOR
2-CHANNEL TIMER/PWM MODULE (TPM2)
PORT F
4-CHANNEL TIMER/PWM MODULE (TPM1)
PORT E
PTF6 PTF5/TPM2CH1 PTF4/TPM2CH0 PTF1/TPM1CH3 PTF0/TPM1CH2
= Not available on 32-, 42-, or 44-pin packages = Not available on 32- or 42-pin packages = Not available on 32-pin packages
Notes: 1. Port pins are software configurable with pullup device if input port. 2. Pin contains software configurable pullup/pulldown device if IRQ is enabled (IRQPE = 1). Pulldown is enabled if rising edge detect is selected (IRQEDG = 1) 3. IRQ does not have a clamp diode to VDD. IRQ should not be driven above VDD. 4. Pin contains integrated pullup device. 5. PTD3, PTD2, and PTG4 contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is selected (KBEDGn = 1).
Figure 8-2. MC9S08AC16 Block Diagram Highlighting the ICG
MC9S08AC16 Series Data Sheet, Rev. 8 128 Freescale Semiconductor
PORT G
2-CHANNEL TIMER/PWM MODULE (TPM3)
PTG6/EXTAL PTG5/XTAL PTG4/KBIP4 PTG3/KBIP3 PTG2/KBIP2 PTG1/KBIP1 PTG0/KBIP0
Internal Clock Generator (S08ICGV4)
8.1
Introduction
The ICG provides multiple options for clock sources. This offers a user great flexibility when making choices between cost, precision, current draw, and performance. As seen in Figure 8-3, the ICG consists of four functional blocks. Each of these is briefly described here and then in more detail in a later section. * Oscillator block -- The oscillator block provides means for connecting an external crystal or resonator. Two frequency ranges are software selectable to allow optimal startup and stability. Alternatively, the oscillator block can be used to route an external square wave to the system clock. External sources can provide a very precise clock source. The oscillator is capable of being configured for low power mode or high amplitude mode as selected by HGO. * Internal reference generator -- The internal reference generator consists of two controlled clock sources. One is designed to be approximately 8 MHz and can be selected as a local clock for the background debug controller. The other internal reference clock source is typically 243 kHz and can be trimmed for finer accuracy via software when a precise timed event is input to the MCU. This provides a highly reliable, low-cost clock source. * Frequency-locked loop -- A frequency-locked loop (FLL) stage takes either the internal or external clock source and multiplies it to a higher frequency. Status bits provide information when the circuit has achieved lock and when it falls out of lock. Additionally, this block can monitor the external reference clock and signals whether the clock is valid or not. * Clock select block -- The clock select block provides several switch options for connecting different clock sources to the system clock tree. ICGDCLK is the multiplied clock frequency out of the FLL, ICGERCLK is the reference clock frequency from the crystal or external clock source, and FFE (fixed frequency enable) is a control signal used to control the system fixed frequency clock (XCLK). ICGLCLK is the clock source for the background debug controller (BDC).
8.1.1
Features
The module is intended to be very user friendly with many of the features occurring automatically without user intervention. To quickly configure the module, go to Section 8.5, "Initialization/Application Information" and pick an example that best suits the application needs. Features of the ICG and clock distribution system: * Several options for the primary clock source allow a wide range of cost, frequency, and precision choices: -- 32 kHz-100 kHz crystal or resonator -- 1 MHz-16 MHz crystal or resonator -- External clock -- Internal reference generator * Defaults to self-clocked mode to minimize startup delays * Frequency-locked loop (FLL) generates 8 MHz to 40 MHz (for bus rates up to 20 MHz) -- Uses external or internal clock as reference frequency * Automatic lockout of non-running clock sources * Reset or interrupt on loss of clock or loss of FLL lock
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 129
Internal Clock Generator (S08ICGV4)
* * * * * * *
Digitally-controlled oscillator (DCO) preserves previous frequency settings, allowing fast frequency lock when recovering from stop3 mode DCO will maintain operating frequency during a loss or removal of reference clock Post-FLL divider selects 1 of 8 bus rate divisors (/1 through /128) Separate self-clocked source for real-time interrupt Trimmable internal clock source supports SCI communications without additional external components Automatic FLL engagement after lock is acquired External oscillator selectable for low power or high gain
8.1.2
Modes of Operation
This is a high-level description only. Detailed descriptions of operating modes are contained in Section 8.4, "Functional Description." * Mode 1 -- Off The output clock, ICGOUT, is static. This mode may be entered when the STOP instruction is executed. * Mode 2 -- Self-clocked (SCM) Default mode of operation that is entered immediately after reset. The ICG's FLL is open loop and the digitally controlled oscillator (DCO) is free running at a frequency set by the filter bits. * Mode 3 -- FLL engaged internal (FEI) In this mode, the ICG's FLL is used to create frequencies that are programmable multiples of the internal reference clock. -- FLL engaged internal unlocked is a transition state that occurs while the FLL is attempting to lock. The FLL DCO frequency is off target and the FLL is adjusting the DCO to match the target frequency. -- FLL engaged internal locked is a state that occurs when the FLL detects that the DCO is locked to a multiple of the internal reference. * Mode 4 -- FLL bypassed external (FBE) In this mode, the ICG is configured to bypass the FLL and use an external clock as the clock source. * Mode 5 -- FLL engaged external (FEE) The ICG's FLL is used to generate frequencies that are programmable multiples of the external clock reference. -- FLL engaged external unlocked is a transition state that occurs while the FLL is attempting to lock. The FLL DCO frequency is off target and the FLL is adjusting the DCO to match the target frequency. -- FLL engaged external locked is a state which occurs when the FLL detects that the DCO is locked to a multiple of the external reference.
MC9S08AC16 Series Data Sheet, Rev. 8 130 Freescale Semiconductor
Internal Clock Generator (S08ICGV4)
8.1.3
Block Diagram
Figure 8-3 is a top-level diagram that shows the functional organization of the internal clock generation (ICG) module. This section includes a general description and a feature list.
EXTAL OSCILLATOR (OSC) WITH EXTERNAL REF SELECT XTAL FREQUENCY LOCKED LOOP (FLL) DCO ICG CLOCK SELECT ICGERCLK ICGDCLK REF SELECT OUTPUT CLOCK SELECT /R
ICGOUT
VDDA (SEE NOTE 2) VSSA (SEE NOTE 2)
LOSS OF LOCK AND CLOCK DETECTOR FIXED CLOCK SELECT IRG INTERNAL TYP 243 kHz REFERENCE 8 MHz GENERATORS RG ICGIRCLK
FFE
LOCAL CLOCK FOR OPTIONAL USE WITH BDC ICGLCLK
1
NOTES:
Not all HCS08 microcontrollers have unique supply pins for the ICG. See the device pin assignments.
Figure 8-3. ICG Block Diagram
8.2
External Signal Description
The oscillator pins are used to provide an external clock source for the MCU. The oscillator pins are gain controlled in low-power mode (default). Oscillator amplitudes in low-power mode are limited to approximately 1 V, peak-to-peak.
8.2.1
EXTAL -- External Reference Clock / Oscillator Input
If upon the first write to ICGC1, either the FEE mode or FBE mode is selected, this pin functions as either the external clock input or the input of the oscillator circuit as determined by REFS. If upon the first write to ICGC1, either the FEI mode or SCM mode is selected, this pin is not used by the ICG.
8.2.2
XTAL -- Oscillator Output
If upon the first write to ICGC1, either the FEE mode or FBE mode is selected, this pin functions as the output of the oscillator circuit. If upon the first write to ICGC1, either the FEI mode or SCM mode is selected, this pin is not used by the ICG. The oscillator is capable of being configured to provide a higher amplitude output for improved noise immunity. This mode of operation is selected by HGO = 1.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 131
Internal Clock Generator (S08ICGV4)
8.2.3
External Clock Connections
If an external clock is used, then the pins are connected as shown Figure 8-4.
ICG
EXTAL
VSS
XTAL NOT CONNECTED
CLOCK INPUT
Figure 8-4. External Clock Connections
8.2.4
External Crystal/Resonator Connections
If an external crystal/resonator frequency reference is used, then the pins are connected as shown in Figure 8-5. Recommended component values are listed in the Electrical Characteristics chapter.
ICG
EXTAL
VSS
XTAL
RS C1 C2
RF
CRYSTAL OR RESONATOR
Figure 8-5. External Frequency Reference Connection
8.3
Register Definition
Refer to the direct-page register summary in the Memory chapter of this data sheet for the absolute address assignments for all ICG registers. This section refers to registers and control bits only by their names.
MC9S08AC16 Series Data Sheet, Rev. 8 132 Freescale Semiconductor
Internal Clock Generator (S08ICGV4)
8.3.1
ICG Control Register 1 (ICGC1)
7 6 5 4 3 2 1 0
R W Reset
HGO1 0
0 RANGE 1 REFS 0 0 CLKS 0 OSCSTEN 1 LOCD 0 0
= Unimplemented or Reserved Figure 8-6. ICG Control Register 1 (ICGC1)
1
This bit can be written only once after reset. Additional writes are ignored.
Table 8-1. ICGC1 Register Field Descriptions
Field 7 HGO Description High Gain Oscillator Select -- The HGO bit is used to select between low power operation and high gain operation for improved noise immunity. This bit is write-once after reset. 0 Oscillator configured for low power operation. 1 Oscillator configured for high gain operation. Frequency Range Select -- The RANGE bit controls the oscillator, reference divider, and FLL loop prescaler multiplication factor (P). It selects one of two reference frequency ranges for the ICG. The RANGE bit is write-once after a reset. The RANGE bit only has an effect in FLL engaged external and FLL bypassed external modes. 0 Oscillator configured for low frequency range. FLL loop prescale factor P is 64. 1 Oscillator configured for high frequency range. FLL loop prescale factor P is 1. External Reference Select -- The REFS bit controls the external reference clock source for ICGERCLK. The REFS bit is write-once after a reset. 0 External clock requested. 1 Oscillator using crystal or resonator requested. Clock Mode Select -- The CLKS bits control the clock mode as described below. If FLL bypassed external is requested, it will not be selected until ERCS = 1. If the ICG enters off mode, the CLKS bits will remain unchanged. Writes to the CLKS bits will not take effect if a previous write is not complete. 00 Self-clocked 01 FLL engaged, internal reference 10 FLL bypassed, external reference 11 FLL engaged, external reference The CLKS bits are writable at any time, unless the first write after a reset was CLKS = 0X, the CLKS bits cannot be written to 1X until after the next reset (because the EXTAL pin was not reserved). Enable Oscillator in Off Mode -- The OSCSTEN bit controls whether or not the oscillator circuit remains enabled when the ICG enters off mode. This bit has no effect if HGO = 1 and RANGE = 1. 0 Oscillator disabled when ICG is in off mode unless ENABLE is high, CLKS = 10, and REFST = 1. 1 Oscillator enabled when ICG is in off mode, CLKS = 1X and REFST = 1. Loss of Clock Disable 0 Loss of clock detection enabled. 1 Loss of clock detection disabled.
6 RANGE
5 REFS
4:3 CLKS
2 OSCSTEN
1 LOCD
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 133
Internal Clock Generator (S08ICGV4)
8.3.2
ICG Control Register 2 (ICGC2)
7 6 5 4 3 2 1 0
R LOLRE W Reset 0 0 0 0 0 0 0 0 MFD LOCRE RFD
Figure 8-7. ICG Control Register 2 (ICGC2) Table 8-2. ICGC2 Register Field Descriptions
Field 7 LOLRE Description Loss of Lock Reset Enable -- The LOLRE bit determines what type of request is made by the ICG following a loss of lock indication. The LOLRE bit only has an effect when LOLS is set. 0 Generate an interrupt request on loss of lock. 1 Generate a reset request on loss of lock. Multiplication Factor -- The MFD bits control the programmable multiplication factor in the FLL loop. The value specified by the MFD bits establishes the multiplication factor (N) applied to the reference frequency. Writes to the MFD bits will not take effect if a previous write is not complete. Select a low enough value for N such that fICGDCLK does not exceed its maximum specified value. 000 Multiplication factor = 4 001 Multiplication factor = 6 010 Multiplication factor = 8 011 Multiplication factor = 10 100 Multiplication factor = 12 101 Multiplication factor = 14 110 Multiplication factor = 16 111 Multiplication factor = 18 Loss of Clock Reset Enable -- The LOCRE bit determines how the system manages a loss of clock condition. 0 Generate an interrupt request on loss of clock. 1 Generate a reset request on loss of clock. Reduced Frequency Divider -- The RFD bits control the value of the divider following the clock select circuitry. The value specified by the RFD bits establishes the division factor (R) applied to the selected output clock source. Writes to the RFD bits will not take effect if a previous write is not complete. 000 Division factor = 1 001 Division factor = 2 010 Division factor = 4 011 Division factor = 8 100 Division factor = 16 101 Division factor = 32 110 Division factor = 64 111 Division factor = 128
6:4 MFD
3 LOCRE 2:0 RFD
MC9S08AC16 Series Data Sheet, Rev. 8 134 Freescale Semiconductor
Internal Clock Generator (S08ICGV4)
8.3.3
ICG Status Register 1 (ICGS1)
7 6 5 4 3 2 1 0
R W Reset 0
CLKST
REFST
LOLS
LOCK
LOCS
ERCS
ICGIF 1
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 8-8. ICG Status Register 1 (ICGS1) Table 8-3. ICGS1 Register Field Descriptions
Field 7:6 CLKST Description Clock Mode Status -- The CLKST bits indicate the current clock mode. The CLKST bits don't update immediately after a write to the CLKS bits due to internal synchronization between clock domains. 00 Self-clocked 01 FLL engaged, internal reference 10 FLL bypassed, external reference 11 FLL engaged, external reference Reference Clock Status -- The REFST bit indicates which clock reference is currently selected by the Reference Select circuit. 0 External Clock selected. 1 Crystal/Resonator selected. FLL Loss of Lock Status -- The LOLS bit is a sticky indication of FLL lock status. 0 FLL has not unexpectedly lost lock since LOLS was last cleared. 1 FLL has unexpectedly lost lock since LOLS was last cleared, LOLRE determines action taken.FLL has unexpectedly lost lock since LOLS was last cleared, LOLRE determines action taken. FLL Lock Status -- The LOCK bit indicates whether the FLL has acquired lock. The LOCK bit is cleared in off, self-clocked, and FLL bypassed modes. 0 FLL is currently unlocked. 1 FLL is currently locked. Loss Of Clock Status -- The LOCS bit is an indication of ICG loss of clock status. 0 ICG has not lost clock since LOCS was last cleared. 1 ICG has lost clock since LOCS was last cleared, LOCRE determines action taken. External Reference Clock Status -- The ERCS bit is an indication of whether or not the external reference clock (ICGERCLK) meets the minimum frequency requirement. 0 External reference clock is not stable, frequency requirement is not met. 1 External reference clock is stable, frequency requirement is met. ICG Interrupt Flag -- The ICGIF read/write flag is set when an ICG interrupt request is pending. It is cleared by a reset or by reading the ICG status register when ICGIF is set and then writing a logic 1 to ICGIF. If another ICG interrupt occurs before the clearing sequence is complete, the sequence is reset so ICGIF would remain set after the clear sequence was completed for the earlier interrupt. Writing a logic 0 to ICGIF has no effect. 0 No ICG interrupt request is pending. 1 An ICG interrupt request is pending.
5 REFST
4 LOLS
3 LOCK
2 LOCS 1 ERCS
0 ICGIF
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 135
Internal Clock Generator (S08ICGV4)
8.3.4
ICG Status Register 2 (ICGS2)
7 6 5 4 3 2 1 0
R W Reset
0
0
0
0
0
0
0
DCOS
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 8-9. ICG Status Register 2 (ICGS2) Table 8-4. ICGS2 Register Field Descriptions
Field 0 DCOS Description DCO Clock Stable -- The DCOS bit is set when the DCO clock (ICG2DCLK) is stable, meaning the count error has not changed by more than nunlock for two consecutive samples and the DCO clock is not static. This bit is used when exiting off state if CLKS = X1 to determine when to switch to the requested clock mode. It is also used in self-clocked mode to determine when to start monitoring the DCO clock. This bit is cleared upon entering the off state. 0 DCO clock is unstable. 1 DCO clock is stable.
8.3.5
ICG Filter Registers (ICGFLTU, ICGFLTL)
7 6 5 4 3 2 1 0
R W Reset
0
0
0
0 FLT
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 8-10. ICG Upper Filter Register (ICGFLTU) Table 8-5. ICGFLTU Register Field Descriptions
Field 3:0 FLT Description Filter Value -- The FLT bits indicate the current filter value, which controls the DCO frequency. The FLT bits are read only except when the CLKS bits are programmed to self-clocked mode (CLKS = 00). In self-clocked mode, any write to ICGFLTU updates the current 12-bit filter value. Writes to the ICGFLTU register will not affect FLT if a previous latch sequence is not complete.
MC9S08AC16 Series Data Sheet, Rev. 8 136 Freescale Semiconductor
Internal Clock Generator (S08ICGV4)
7
6
5
4
3
2
1
0
R FLT W Reset 1 1 0 0 0 0 0 0
Figure 8-11. ICG Lower Filter Register (ICGFLTL) Table 8-6. ICGFLTL Register Field Descriptions
Field 7:0 FLT Description Filter Value -- The FLT bits indicate the current filter value, which controls the DCO frequency. The FLT bits are read only except when the CLKS bits are programmed to self-clocked mode (CLKS = 00). In self-clocked mode, any write to ICGFLTU updates the current 12-bit filter value. Writes to the ICGFLTU register will not affect FLT if a previous latch sequence is not complete. The filter registers show the filter value (FLT).
8.3.6
ICG Trim Register (ICGTRM)
7 6 5 4 3 2 1 0
R TRIM W
POR Reset:
1
0
0
0
0
0
0
0
U
U
U
U
U
U
U
U
U = Unaffected by MCU reset Figure 8-12. ICG Trim Register (ICGTRM) Table 8-7. ICGTRM Register Field Descriptions
Field 7 TRIM Description ICG Trim Setting -- The TRIM bits control the internal reference generator frequency. They allow a 25% adjustment of the nominal (POR) period. The bit's effect on period is binary weighted (i.e., bit 1 will adjust twice as much as changing bit 0). Increasing the binary value in TRIM will increase the period and decreasing the value will decrease the period.
8.4
Functional Description
This section provides a functional description of each of the five operating modes of the ICG. Also discussed are the loss of clock and loss of lock errors and requirements for entry into each mode. The ICG is very flexible, and in some configurations, it is possible to exceed certain clock specifications. When using the FLL, configure the ICG so that the frequency of ICGDCLK does not exceed its maximum value to ensure proper MCU operation.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 137
Internal Clock Generator (S08ICGV4)
8.4.1
Off Mode (Off)
Normally when the CPU enters stop mode, the ICG will cease all clock activity and is in the off state. However there are two cases to consider when clock activity continues while the CPU is in stop mode,
8.4.1.1
BDM Active
When the BDM is enabled, the ICG continues activity as originally programmed. This allows access to memory and control registers via the BDC controller.
8.4.1.2
OSCSTEN Bit Set
When the oscillator is enabled in stop mode (OSCSTEN = 1), the individual clock generators are enabled but the clock feed to the rest of the MCU is turned off. This option is provided to avoid long oscillator startup times if necessary, or to run the RTI from the oscillator during stop3.
8.4.1.3
Stop/Off Mode Recovery
Upon the CPU exiting stop mode due to an interrupt, the previously set control bits are valid and the system clock feed resumes. If FEE is selected, the ICG will source the internal reference until the external clock is stable. If FBE is selected, the ICG will wait for the external clock to stabilize before enabling ICGOUT. Upon the CPU exiting stop mode due to a reset, the previously set ICG control bits are ignored and the default reset values applied. Therefore the ICG will exit stop in SCM mode configured for an approximately 8 MHz DCO output (4 MHz bus clock) with trim value maintained. If using a crystal, 4096 clocks are detected prior to engaging ICGERCLK. This is incorporated in crystal start-up time.
8.4.2
Self-Clocked Mode (SCM)
Self-clocked mode (SCM) is the default mode of operation and is entered when any of the following conditions occur: * After any reset. * Exiting from off mode when CLKS does not equal 10. If CLKS = X1, the ICG enters this state temporarily until the DCO is stable (DCOS = 1). * CLKS bits are written from X1 to 00. * CLKS = 1X and ICGERCLK is not detected (both ERCS = 0 and LOCS = 1). In this state, the FLL loop is open. The DCO is on, and the output clock signal ICGOUT frequency is given by fICGDCLK / R. The ICGDCLK frequency can be varied from 8 MHz to 40 MHz by writing a new value into the filter registers (ICGFLTH and ICGFLTL). This is the only mode in which the filter registers can be written. If this mode is entered due to a reset, fICGDCLK will default to fSelf_reset which is nominally 8 MHz. If this mode is entered from FLL engaged internal, fICGDCLK will maintain the previous frequency.If this mode is entered from FLL engaged external (either by programming CLKS or due to a loss of external reference clock), fICGDCLK will maintain the previous frequency, but ICGOUT will double if the FLL was unlocked. If this mode is entered from off mode, fICGDCLK will be equal to the frequency of ICGDCLK before
MC9S08AC16 Series Data Sheet, Rev. 8 138 Freescale Semiconductor
Internal Clock Generator (S08ICGV4)
entering off mode. If CLKS bits are set to 01 or 11 coming out of the Off state, the ICG enters this mode until ICGDCLK is stable as determined by the DCOS bit. After ICGDCLK is considered stable, the ICG automatically closes the loop by switching to FLL engaged (internal or external) as selected by the CLKS bits.
CLKST
CLKS
RFD
REFERENCE DIVIDER (/7)
ICGIRCLK
CLOCK SELECT CIRCUIT
REDUCED FREQUENCY DIVIDER (R)
ICGOUT
RANGE FLT MFD
ICGDCLK
SUBTRACTOR
DIGITAL LOOP FILTER
1x DIGITALLY CONTROLLED OSCILLATOR 2x FLL ANALOG FREQUENCYLOCKED LOOP (FLL)
ICGERCLK
CLKST
OVERFLOW COUNTER ENABLE RANGE
PULSE COUNTER
ICG2DCLK
LOCK AND LOSS OF CLOCK DETECTOR
RESET AND INTERRUPT CONTROL
IRQ RESET
DCOS LOCK
LOLS
LOCS ERCS
LOCD
ICGIF LOLRE LOCRE
Figure 8-13. Detailed Frequency-Locked Loop Block Diagram
8.4.3
FLL Engaged, Internal Clock (FEI) Mode
FLL engaged internal (FEI) is entered when any of the following conditions occur: * CLKS bits are written to 01 * The DCO clock stabilizes (DCOS = 1) while in SCM upon exiting the off state with CLKS = 01 In FLL engaged internal mode, the reference clock is derived from the internal reference clock ICGIRCLK, and the FLL loop will attempt to lock the ICGDCLK frequency to the desired value, as selected by the MFD bits.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 139
Internal Clock Generator (S08ICGV4)
8.4.4
FLL Engaged Internal Unlocked
FEI unlocked is a temporary state that is entered when FEI is entered and the count error (n) output from the subtractor is greater than the maximum nunlock or less than the minimum nunlock, as required by the lock detector to detect the unlock condition. The ICG will remain in this state while the count error (n) is greater than the maximum nlock or less than the minimum nlock, as required by the lock detector to detect the lock condition. In this state the output clock signal ICGOUT frequency is given by fICGDCLK / R.
8.4.5
FLL Engaged Internal Locked
FLL engaged internal locked is entered from FEI unlocked when the count error (n), which comes from the subtractor, is less than nlock (max) and greater than nlock (min) for a given number of samples, as required by the lock detector to detect the lock condition. The output clock signal ICGOUT frequency is given by fICGDCLK / R. In FEI locked, the filter value is updated only once every four comparison cycles. The update made is an average of the error measurements taken in the four previous comparisons.
8.4.6
FLL Bypassed, External Clock (FBE) Mode
FLL bypassed external (FBE) is entered when any of the following conditions occur: * From SCM when CLKS = 10 and ERCS is high * When CLKS = 10, ERCS = 1 upon entering off mode, and off is then exited * From FLL engaged external mode if a loss of DCO clock occurs and the external reference remains valid (both LOCS = 1 and ERCS = 1) In this state, the DCO and IRG are off and the reference clock is derived from the external reference clock, ICGERCLK. The output clock signal ICGOUT frequency is given by fICGERCLK / R. If an external clock source is used (REFS = 0), then the input frequency on the EXTAL pin can be anywhere in the range 0 MHz to 40 MHz. If a crystal or resonator is used (REFS = 1), then frequency range is either low for RANGE = 0 or high for RANGE = 1.
8.4.7
FLL Engaged, External Clock (FEE) Mode
The FLL engaged external (FEE) mode is entered when any of the following conditions occur: * CLKS = 11 and ERCS and DCOS are both high. * The DCO stabilizes (DCOS = 1) while in SCM upon exiting the off state with CLKS = 11. In FEE mode, the reference clock is derived from the external reference clock ICGERCLK, and the FLL loop will attempt to lock the ICGDCLK frequency to the desired value, as selected by the MFD bits. To run in FEE mode, there must be a working 32 kHz-100 kHz or 2 MHz-10 MHz external clock source. The maximum external clock frequency is limited to 10 MHz in FEE mode to prevent over-clocking the DCO. The minimum multiplier for the FLL, from Table 8-12 is 4. Because 4 X 10 MHz is 40MHz, which is the operational limit of the DCO, the reference clock cannot be any faster than 10 MHz.
MC9S08AC16 Series Data Sheet, Rev. 8 140 Freescale Semiconductor
Internal Clock Generator (S08ICGV4)
8.4.7.1
FLL Engaged External Unlocked
FEE unlocked is entered when FEE is entered and the count error (n) output from the subtractor is greater than the maximum nunlock or less than the minimum nunlock, as required by the lock detector to detect the unlock condition. The ICG will remain in this state while the count error (n) is greater than the maximum nlock or less than the minimum nlock, as required by the lock detector to detect the lock condition. In this state, the pulse counter, subtractor, digital loop filter, and DCO form a closed loop and attempt to lock it according to their operational descriptions later in this section. Upon entering this state and until the FLL becomes locked, the output clock signal ICGOUT frequency is given by fICGDCLK / (2xR) This extra divide by two prevents frequency overshoots during the initial locking process from exceeding chip-level maximum frequency specifications. After the FLL has locked, if an unexpected loss of lock causes it to re-enter the unlocked state while the ICG remains in FEE mode, the output clock signal ICGOUT frequency is given by fICGDCLK / R.
8.4.7.2
FLL Engaged External Locked
FEE locked is entered from FEE unlocked when the count error (n) is less than nlock (max) and greater than nlock (min) for a given number of samples, as required by the lock detector to detect the lock condition. The output clock signal ICGOUT frequency is given by fICGDCLK/R. In FLL engaged external locked, the filter value is updated only once every four comparison cycles. The update made is an average of the error measurements taken in the four previous comparisons.
8.4.8
FLL Lock and Loss-of-Lock Detection
To determine the FLL locked and loss-of-lock conditions, the pulse counter counts the pulses of the DCO for one comparison cycle (see Table 8-9 for explanation of a comparison cycle) and passes this number to the subtractor. The subtractor compares this value to the value in MFD and produces a count error, n. To achieve locked status, n must be between nlock (min) and nlock (max). After the FLL has locked, n must stay between nunlock (min) and nunlock (max) to remain locked. If n goes outside this range unexpectedly, the LOLS status bit is set and remains set until cleared by software or until the MCU is reset. LOLS is cleared by reading ICGS1 then writing 1 to ICGIF (LOLRE = 0), or by a loss-of-lock induced reset (LOLRE = 1), or by any MCU reset. If the ICG enters the off state due to stop mode when ENBDM = OSCSTEN = 0, the FLL loses locked status (LOCK is cleared), but LOLS remains unchanged because this is not an unexpected loss-of-lock condition. Though it would be unusual, if ENBDM is cleared to 0 while the MCU is in stop, the ICG enters the off state. Because this is an unexpected stopping of clocks, LOLS will be set when the MCU wakes up from stop. Expected loss of lock occurs when the MFD or CLKS bits are changed or in FEI mode only, when the TRIM bits are changed. In these cases, the LOCK bit will be cleared until the FLL regains lock, but the LOLS will not be set.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 141
Internal Clock Generator (S08ICGV4)
8.4.9
FLL Loss-of-Clock Detection
The reference clock and the DCO clock are monitored under different conditions (see Table 8-8). Provided the reference frequency is being monitored, ERCS = 1 indicates that the reference clock meets minimum frequency requirements. When the reference and/or DCO clock(s) are being monitored, if either one falls below a certain frequency, fLOR and fLOD, respectively, the LOCS status bit will be set to indicate the error. LOCS will remain set until it is acknowledged or until the MCU is reset. LOCS is cleared by reading ICGS1 then writing 1 to ICGIF (LOCRE = 0), or by a loss-of-clock induced reset (LOCRE = 1), or by any MCU reset. If the ICG is in FEE, a loss of reference clock causes the ICG to enter SCM, and a loss of DCO clock causes the ICG to enter FBE mode. If the ICG is in FBE mode, a loss of reference clock will cause the ICG to enter SCM. In each case, the CLKST and CLKS bits will be automatically changed to reflect the new state. If the ICG is in FEE mode when a loss of clock occurs and the ERCS is still set to 1, then the CLKST bits are set to 10 and the ICG reverts to FBE mode. A loss of clock will also cause a loss of lock when in FEE or FEI modes. Because the method of clearing the LOCS and LOLS bits is the same, this would only be an issue in the unlikely case that LOLRE = 1 and LOCRE = 0. In this case, the interrupt would be overridden by the reset for the loss of lock.
Table 8-8. Clock Monitoring (When LOCD = 0)
Mode Off CLKS 0X or 11 10 10 SCM (CLKST = 00) 0X 10 10 11 FEI (CLKST = 01) FBE (CLKST = 10) FEE (CLKST = 11)
1 2
REFST X 0 1 X 0 1 X X X 0 1 X
ERCS Forced Low Forced Low Real-Time1 Forced Low Forced High Real-Time Real-Time Forced Low Real-Time Forced High Real-Time Real-Time
External Reference Clock Monitored? No No Yes(1) No No Yes Yes No Yes No Yes Yes
DCO Clock Monitored? No No No Yes2 Yes(2) Yes(2) Yes(2) Yes Yes No No Yes
0X 11 10 10 11
If ENABLE is high (waiting for external crystal start-up after exiting stop). DCO clock will not be monitored until DCOS = 1 upon entering SCM from off or FLL bypassed external mode.
MC9S08AC16 Series Data Sheet, Rev. 8 142 Freescale Semiconductor
Internal Clock Generator (S08ICGV4)
8.4.10
Clock Mode Requirements
A clock mode is requested by writing to CLKS1:CLKS0 and the actual clock mode is indicated by CLKST1:CLKST0. Provided minimum conditions are met, the status shown in CLKST1:CLKST0 should be the same as the requested mode in CLKS1:CLKS0. Table 8-9 shows the relationship between CLKS, CLKST, and ICGOUT. It also shows the conditions for CLKS = CLKST or the reason CLKS CLKST. NOTE If a crystal will be used before the next reset, then be sure to set REFS = 1 and CLKS = 1x on the first write to the ICGC1 register. Failure to do so will result in "locking" REFS = 0 which will prevent the oscillator amplifier from being enabled until the next reset occurs.
Table 8-9. ICG State Table
Actual Mode (CLKST) Off (XX) Desired Mode (CLKS) Off (XX) FBE (10) SCM (00) SCM (00) FEI (01) FBE (10) FEE (11) FEI (01) FEI (01) FEE (11) FBE (10) FEE (11) FEE (11) Range Reference Frequency (fREFERENCE) 0 0 fICGIRCLK/72 fICGIRCLK/7(1) fICGIRCLK/7(1) fICGIRCLK/7(1) fICGIRCLK/7 fICGIRCLK/7 0 0 fICGERCLK fICGERCLK Comparison Cycle Time -- -- 8/fICGIRCLK 8/fICGIRCLK 8/fICGIRCLK 8/fICGIRCLK 8/fICGIRCLK 8/fICGIRCLK -- -- 2/fICGERCLK 128/fICGERCLK ICGOUT Conditions1 for CLKS = CLKST -- -- Not switching from FBE to SCM -- -- -- DCOS = 1 -- ERCS = 1 -- ERCS = 1 and DCOS = 1 ERCS = 1 and DCOS = 1 Reason CLKS1 CLKST -- ERCS = 0
X X
0 0
X
ICGDCLK/R
--
0 X X 0 X X X 0 1
ICGDCLK/R ICGDCLK/R ICGDCLK/R ICGDCLK/R ICGDCLK/R ICGERCLK/R ICGERCLK/R ICGDCLK/R3 ICGDCLK/R(2)
DCOS = 0 ERCS = 0 DCOS = 0 or ERCS = 0 -- ERCS = 0 -- LOCS = 1 & ERCS = 1 -- --
FBE (10)
FEE (11)
1
CLKST will not update immediately after a write to CLKS. Several bus cycles are required before CLKST updates to the new value. 2 The reference frequency has no effect on ICGOUT in SCM, but the reference frequency is still used in making the comparisons that determine the DCOS bit 3 After initial LOCK; will be ICGDCLK/2R during initial locking process and while FLL is re-locking after the MFD bits are changed.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 143
Internal Clock Generator (S08ICGV4)
8.4.11
Fixed Frequency Clock
The ICG provides a fixed frequency clock output, XCLK, for use by on-chip peripherals. This output is equal to the internal bus clock, BUSCLK, in all modes except FEE. In FEE mode, XCLK is equal to ICGERCLK / 2 when the following conditions are met: * (P x N) / R 4 where P is determined by RANGE (see Table 8-11), N and R are determined by MFD and RFD respectively (see Table 8-12). * LOCK = 1. If the above conditions are not true, then XCLK is equal to BUSCLK. When the ICG is in either FEI or SCM mode, XCLK is turned off. Any peripherals which can use XCLK as a clock source must not do so when the ICG is in FEI or SCM mode.
8.4.12
High Gain Oscillator
The oscillator has the option of running in a high gain oscillator (HGO) mode, which improves the oscillator's resistance to EMC noise when running in FBE or FEE modes. This option is selected by writing a 1 to the HGO bit in the ICGC1 register. HGO is used with both the high and low range oscillators but is only valid when REFS = 1 in the ICGC1 register. When HGO = 0, the standard low-power oscillator is selected. This bit is writable only once after any reset.
8.5
8.5.1
Initialization/Application Information
Introduction
The section is intended to give some basic direction on which configuration a user would want to select when initializing the ICG. For some applications, the serial communication link may dictate the accuracy of the clock reference. For other applications, lowest power consumption may be the chief clock consideration. Still others may have lowest cost as the primary goal. The ICG allows great flexibility in choosing which is best for any application.
MC9S08AC16 Series Data Sheet, Rev. 8 144 Freescale Semiconductor
Internal Clock Generator (S08ICGV4)
Table 8-10. ICG Configuration Consideration
Clock Reference Source = Internal FEI 4 MHz < fBus < 20 MHz. Medium power (will be less than FEE if oscillator range = high) Good clock accuracy (After IRG is trimmed) Lowest system cost (no external components required) IRG is on. DCO is on. 1 SCM This mode is mainly provided for quick and reliable system startup. 3 MHz < fBus < 5 MHz (default). 3 MHz < fBus < 20 MHz (via filter bits). Medium power Poor accuracy. IRG is off. DCO is on and open loop. Clock Reference Source = External FEE 4 MHz < fBus < 20 MHz Medium power (will be less than FEI if oscillator range = low) High clock accuracy Medium/High system cost (crystal, resonator or external clock source required) IRG is off. DCO is on. FBE fBus range 8 MHz when crystal or resonator is used. Lowest power Highest clock accuracy Medium/High system cost (Crystal, resonator or external clock source required) IRG is off. DCO is off.
FLL Engaged
FLL Bypassed
1
The IRG typically consumes 100 A. The FLL and DCO typically consumes 0.5 to 2.5 mA, depending upon output frequency. For minimum power consumption and minimum jitter, choose N and R to be as small as possible.
The following sections contain initialization examples for various configurations. NOTE Hexadecimal values designated by a preceding $, binary values designated by a preceding %, and decimal values have no preceding character. Important configuration information is repeated here for reference.
Table 8-11. ICGOUT Frequency Calculation Options
Clock Scheme SCM -- self-clocked mode (FLL bypassed internal) FBE -- FLL bypassed external FEI -- FLL engaged internal FEE -- FLL engaged external
1
fICGOUT1 fICGDCLK / R fext / R (fIRG / 7)* 64 * N / R fext * P * N / R
P NA NA 64 Range = 0 ; P = 64 Range = 1; P = 1
Note Typical fICGOUT = 8 MHz immediately after reset Typical fIRG = 243 kHz
Ensure that fICGDCLK, which is equal to fICGOUT * R, does not exceed fICGDCLKmax.
Table 8-12. MFD and RFD Decode Table
MFD Value 000 001 010 011 100 Multiplication Factor (N) 4 6 8 10 12 RFD 000 001 010 011 100 Division Factor (R) /1 /2 /4 /8 /16
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 145
Internal Clock Generator (S08ICGV4)
Table 8-12. MFD and RFD Decode Table
101 110 111 14 16 18 101 110 111 /32 /64 /128
8.5.2
Example #1: External Crystal = 32 kHz, Bus Frequency = 4.19 MHz
In this example, the FLL will be used (in FEE mode) to multiply the external 32 kHz oscillator up to 8.38 MHz to achieve 4.19 MHz bus frequency. After the MCU is released from reset, the ICG is in self-clocked mode (SCM) and supplies approximately 8 MHz on ICGOUT, which corresponds to a 4 MHz bus frequency (fBus). The clock scheme will be FLL engaged, external (FEE). So
fICGOUT = fext * P * N / R ; P = 64, fext = 32 kHz Eqn. 8-1
Solving for N / R gives:
N / R = 8.38 MHz /(32 kHz * 64) = 4 ; we can choose N = 4 and R =1 Eqn. 8-2
The values needed in each register to set up the desired operation are: ICGC1 = $38 (%00111000) Bit 7 Bit 6 Bit 5 Bits 4:3 Bit 2 Bit 1 Bit 0 HGO RANGE REFS CLKS OSCSTEN LOCD 0 0 1 11 0 0 0 Configures oscillator for low power Configures oscillator for low-frequency range; FLL prescale factor is 64 Oscillator using crystal or resonator is requested FLL engaged, external reference clock mode Oscillator disabled Loss-of-clock detection enabled Unimplemented or reserved, always reads zero
ICGC2 = $00 (%00000000) Bit 7 Bits 6:4 Bit 3 Bits 2:0 LOLRE MFD LOCRE RFD 0 Generates an interrupt request on loss of lock 000 Sets the MFD multiplication factor to 4 0 Generates an interrupt request on loss of clock 000 Sets the RFD division factor to /1
ICGS1 = $xx This is read only except for clearing interrupt flag ICGS2 = $xx This is read only; should read DCOS = 1 before performing any time critical tasks ICGFLTLU/L = $xx Only needed in self-clocked mode; FLT will be adjusted by loop to give 8.38 MHz DCO clock Bits 15:12 unused 0000
MC9S08AC16 Series Data Sheet, Rev. 8 146 Freescale Semiconductor
Internal Clock Generator (S08ICGV4)
Bits 11:0 FLT ICGTRM = $xx Bits 7:0 TRIM
No need for user initialization
Only need to write when trimming internal oscillator; not used when external crystal is clock source
Figure 8-14 shows flow charts for three conditions requiring ICG initialization.
RESET QUICK RECOVERY FROM STOP RECOVERY FROM STOP OSCSTEN = 1 INITIALIZE ICG ICGC1 = $38 ICGC2 = $00 MINIMUM CURRENT DRAW IN STOP RECOVERY FROM STOP OSCSTEN = 0
CHECK FLL LOCK STATUS. LOCK = 1? YES NO CONTINUE
NO
CHECK FLL LOCK STATUS. LOCK = 1? YES
NO
CHECK FLL LOCK STATUS. LOCK = 1? YES
CONTINUE
CONTINUE NOTE: THIS WILL REQUIRE THE OSCILLATOR TO START AND STABILIZE. ACTUAL TIME IS DEPENDENT ON CRYSTAL /RESONATOR AND EXTERNAL CIRCUITRY.
Figure 8-14. ICG Initialization for FEE in Example #1
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 147
Internal Clock Generator (S08ICGV4)
8.5.3
Example #2: External Crystal = 4 MHz, Bus Frequency = 20 MHz
In this example, the FLL will be used (in FEE mode) to multiply the external 4 MHz oscillator up to 40-MHz to achieve 20 MHz bus frequency. After the MCU is released from reset, the ICG is in self-clocked mode (SCM) and supplies approximately 8 MHz on ICGOUT which corresponds to a 4 MHz bus frequency (fBus). During reset initialization software, the clock scheme will be set to FLL engaged, external (FEE). So
fICGOUT = fext * P * N / R ; P = 1, fext = 4.00 MHz Eqn. 8-3
Solving for N / R gives:
N / R = 40 MHz /(4 MHz * 1) = 10 ; We can choose N = 10 and R = 1 Eqn. 8-4
The values needed in each register to set up the desired operation are: ICGC1 = $78 (%01111000) Bit 7 Bit 6 Bit 5 Bits 4:3 Bit 2 Bit 1 Bit 0 HGO RANGE REFS CLKS OSCSTEN LOCD 0 1 1 11 0 0 0 Configures oscillator for low power Configures oscillator for high-frequency range; FLL prescale factor is 1 Requests an oscillator FLL engaged, external reference clock mode Disables the oscillator Loss-of-clock detection enabled Unimplemented or reserved, always reads zero
ICGC2 = $30 (%00110000) Bit 7 Bit 6:4 Bit 3 Bit 2:0 LOLRE MFD LOCRE RFD 0 Generates an interrupt request on loss of lock 011 Sets the MFD multiplication factor to 10 0 Generates an interrupt request on loss of clock 000 Sets the RFD division factor to /1
ICGS1 = $xx This is read only except for clearing interrupt flag ICGS2 = $xx This is read only. Should read DCOS before performing any time critical tasks ICGFLTLU/L = $xx Not used in this example ICGTRM Not used in this example
MC9S08AC16 Series Data Sheet, Rev. 8 148 Freescale Semiconductor
Internal Clock Generator (S08ICGV4)
RESET
RECOVERY FROM STOP
INITIALIZE ICG ICGC1 = $7A ICGC2 = $30
SERVICE INTERRUPT SOURCE (fBus = 4 MHz)
CHECK FLL LOCK STATUS LOCK = 1? YES
NO
CHECK FLL LOCK STATUS LOCK = 1? YES
NO
CONTINUE CONTINUE
Figure 8-15. ICG Initialization and Stop Recovery for Example #2
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 149
Internal Clock Generator (S08ICGV4)
8.5.4
Example #3: No External Crystal Connection, 5.4 MHz Bus Frequency
In this example, the FLL will be used (in FEI mode) to multiply the internal 243 kHz (approximate) reference clock up to 10.8 MHz to achieve 5.4 MHz bus frequency. This system will also use the trim function to fine tune the frequency based on an external reference signal. After the MCU is released from reset, the ICG is in self-clocked mode (SCM) and supplies approximately 8 MHz on ICGOUT which corresponds to a 4 MHz bus frequency (fBus). The clock scheme will be FLL engaged, internal (FEI). So
fICGOUT = (fIRG / 7) * P * N / R ; P = 64, fIRG = 243 kHz Eqn. 8-5
Solving for N / R gives:
N / R = 10.8 MHz /(243/7 kHz * 64) = 4.86 ; We can choose N = 10 and R = 2. Eqn. 8-6
A trim procedure will be required to hone the frequency to exactly 5.4 MHz. An example of the trim procedure is shown in example #4. The values needed in each register to set up the desired operation are: ICGC1 = $28 (%00101000) Bit 7 HGO 0 Bit 6 RANGE 0 Bit 5 REFS 1 Bits 4:3 CLKS 01 Bit 2 OSCSTEN 0 Bit 1 LOCD 0 Bit 0 0 Configures oscillator for low power Configures oscillator for low-frequency range; FLL prescale factor is 64 Oscillator using crystal or resonator requested (bit is really a don't care) FLL engaged, internal reference clock mode Disables the oscillator Loss-of-clock enabled Unimplemented or reserved, always reads zero
ICGC2 = $31 (%00110001) Bit 7 LOLRE 0 Generates an interrupt request on loss of lock Bit 6:4 MFD 011 Sets the MFD multiplication factor to 10 Bit 3 LOCRE 0 Generates an interrupt request on loss of clock Bit 2:0 RFD 001 Sets the RFD division factor to /2 ICGS1 = $xx This is read only except for clearing interrupt flag ICGS2 = $xx This is read only; good idea to read this before performing time critical operations ICGFLTLU/L = $xx Not used in this example
MC9S08AC16 Series Data Sheet, Rev. 8 150 Freescale Semiconductor
Internal Clock Generator (S08ICGV4)
ICGTRM = $xx Bit 7:0 TRIM
Only need to write when trimming internal oscillator; done in separate operation (see example #4)
RESET RECOVERY FROM STOP
INITIALIZE ICG ICGC1 = $28 ICGC2 = $31
CHECK FLL LOCK STATUS. LOCK = 1? YES NO CONTINUE
NO
CHECK FLL LOCK STATUS. LOCK = 1? YES
CONTINUE NOTE: THIS WILL REQUIRE THE INTERAL REFERENCE CLOCK TO START AND STABILIZE.
Figure 8-16. ICG Initialization and Stop Recovery for Example #3
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 151
Internal Clock Generator (S08ICGV4)
8.5.5
Example #4: Internal Clock Generator Trim
The internally generated clock source is guaranteed to have a period 25% of the nominal value. In some cases, this may be sufficient accuracy. For other applications that require a tight frequency tolerance, a trimming procedure is provided that will allow a very accurate source. This section outlines one example of trimming the internal oscillator. Many other possible trimming procedures are valid and can be used.
Initial conditions: 1) Clock supplied from ATE has 500 sec duty period 2) ICG configured for internal reference with 4 MHz bus START TRIM PROCEDURE ICGTRM = $80, n = 1
MEASURE INCOMING CLOCK WIDTH (COUNT = # OF BUS CLOCKS / 4)
COUNT < EXPECTED = 500 (RUNNING TOO SLOW) . CASE STATEMENT
COUNT = EXPECTED = 500
COUNT > EXPECTED = 500 (RUNNING TOO FAST) ICGTRM = ICGTRM - 128 / (2**n) (DECREASING ICGTRM INCREASES THE FREQUENCY) ICGTRM = ICGTRM + 128 / (2**n) (INCREASING ICGTRM DECREASES THE FREQUENCY) STORE ICGTRM VALUE IN NON-VOLATILE MEMORY
CONTINUE n = n+1
IS n > 8? NO
YES
Figure 8-17. Trim Procedure
In this particular case, the MCU has been attached to a PCB and the entire assembly is undergoing final test with automated test equipment. A separate signal or message is provided to the MCU operating under user provided software control. The MCU initiates a trim procedure as outlined in Figure 8-17 while the tester supplies a precision reference signal. If the intended bus frequency is near the maximum allowed for the device, it is recommended to trim using a reduction divisor (R) twice the final value. After the trim procedure is complete, the reduction divisor can be restored. This will prevent accidental overshoot of the maximum clock frequency.
MC9S08AC16 Series Data Sheet, Rev. 8 152 Freescale Semiconductor
Chapter 9 Keyboard Interrupt (S08KBIV1)
9.1 Introduction
The MC9S08AC16 Series has one KBI module with seven keyboard interrupt inputs that are shared with port D and port G pins. See Chapter 2, "Pins and Connections," for more information about the logic and hardware aspects of these pins. NOTE Bit 7 of KBISC and KBIPE is reserved and reads 0. Neglect the correlative information in Section 9.4.1, "KBI Status and Control Register (KBISC)," and Section 9.4.2, "KBI Pin Enable Register (KBIPE)."
9.2
Keyboard Pin Sharing
The KBI input KBIP6 shares a common pin with PTD3 and AD11, and KBI input KBIP5 shares a common pin with PTD2 and AD10. The KBI inputs KBIP4-KBIP0 are shared on common pins with PTG4-PTG0. KBIP3-KBIP0 are always falling-edge/low-level sensitive. KBIP6-KBIP4 can be configured for rising-edge/high-level or for falling-edge/low-level sensitivity. When any of the inputs KBIP6-KBIP0 are enabled and configured to detect rising edges/high levels, and the pin pullup is enabled through the corresponding port pullup enable bit for that pin, a pulldown resistor rather than a pullup resistor is enabled on the pin.
9.3
Features
The keyboard interrupt (KBI) module features include: * Four falling edge/low level sensitive * Three falling edge/low level or rising edge/high level sensitive * Choice of edge-only or edge-and-level sensitivity * Common interrupt flag and interrupt enable control * Capable of waking up the MCU from stop3, stop2, or wait mode
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 153
Chapter 9 Keyboard Interrupt (S08KBIV1)
VDDAD VSSAD VREFL VREFH HCS08 CORE BKGD/MS BDC CPU
10-BIT ANALOG-TO-DIGITAL CONVERTER (ADC1) DEBUG MODULE (DBG)
4 AD1P11-AD1P8
PORT A
4 AD1P3-AD1P0
PTA7 PTA2 PTA1 PTA0 PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 PTB0/TPM3CH0/AD1P0 PTC5/RxD2 PTC4 PTC3/TxD2 PTC2/MCLK PTC1/SDA1 PTC0/SCL1 PTD3/KBIP6/AD1P11 PTD2/KBIP5/AD1P10 PTD1/AD1P9 PTD0/AD1P8
SDA1 IIC MODULE (IIC1) SCL1 PORT C PORT D
RESET IRQ/TPMCLK
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION POWER MANAGEMENT RTI IRQ COP LVD
INTERNAL CLOCK GENERATOR (ICG) LOW-POWER OSCILLATOR 7-BIT KEYBOARD INTERRUPT MODULE (KBI)
EXTAL XTAL
2 KBIP6-KBIP5 5 KBIP4-KBIP0 RxD1 TxD1 RxD2 TxD2 SPSCK1 MOSI1 MISO1 SS1 TPM1CH1 TPM1CH0 TPM1CH3 TPM1CH2 TPM2CH1 TPM2CH0 TPM3CH1 TPM3CH0
TPMCLK
SERIAL COMMUNICATIONS INTERFACE MODULE (SCI1) SERIAL COMMUNICATIONS INTERFACE MODULE (SCI2) SERIAL PERIPHERAL INTERFACE MODULE (SPI1)
PORT B
USER FLASH 16,384 BYTES OR 8192 BYTES
PTE7/SPSCK1 PTE6/MOSI1 PTE5/MISO1 PTE4/SS1 PTE3/TPM1CH1 PTE2/TPM1CH0 PTE1/RxD1 PTE0/TxD1
USER RAM 1024 BYTES OR 768 BYTES VDD VSS VOLTAGE REGULATOR
2-CHANNEL TIMER/PWM MODULE (TPM2)
PORT F
4-CHANNEL TIMER/PWM MODULE (TPM1)
PORT E
PTF6 PTF5/TPM2CH1 PTF4/TPM2CH0 PTF1/TPM1CH3 PTF0/TPM1CH2
= Not available on 32-, 42-, or 44-pin packages = Not available on 32- or 42-pin packages = Not available on 32-pin packages
Notes: 1. Port pins are software configurable with pullup device if input port. 2. Pin contains software configurable pullup/pulldown device if IRQ is enabled (IRQPE = 1). Pulldown is enabled if rising edge detect is selected (IRQEDG = 1) 3. IRQ does not have a clamp diode to VDD. IRQ should not be driven above VDD. 4. Pin contains integrated pullup device. 5. PTD3, PTD2, and PTG4 contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is selected (KBEDGn = 1).
Figure 9-1. MC9S08AC16 Block Diagram Highlighting the KBI
MC9S08AC16 Series Data Sheet, Rev. 8 154 Freescale Semiconductor
PORT G
2-CHANNEL TIMER/PWM MODULE (TPM3)
PTG6/EXTAL PTG5/XTAL PTG4/KBIP4 PTG3/KBIP3 PTG2/KBIP2 PTG1/KBIP1 PTG0/KBIP0
Keyboard Interrupt (S08KBIV1)
9.3.1
KBIP0
KBI Block Diagram
Figure 9-2 shows the block diagram for a KBI module.
KBIPE0 KBIP3 KBIPE3 1 KBIP4 0 S KBIPE4 KEYBOARD INTERRUPT FF 1 KBIPn 0 S KBIPEn KBIMOD KBIE STOP STOP BYPASS KEYBOARD INTERRUPT REQUEST VDD D CLR Q CK KBACK RESET SYNCHRONIZER BUSCLK KBF
KBEDG4
KBEDGn
Figure 9-2. KBI Block Diagram
9.4
Register Definition
This section provides information about all registers and control bits associated with the KBI module. Refer to the direct-page register summary in the Memory chapter of this data sheet for the absolute address assignments for all KBI registers. This section refers to registers and control bits only by their names. A Freescale-provided equate or header file is used to translate these names into the appropriate absolute addresses.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 155
Keyboard Interrupt (S08KBIV1)
9.4.1
R
KBI Status and Control Register (KBISC)
7 6 5 4 3 2 1 0
KBF KBEDG7 KBEDG6 0 KBEDG5 0 KBEDG4
0 KBIE KBACK KBIMOD 0
W Reset 0 0 0
0
0
= Unimplemented or Reserved
Figure 9-3. KBI Status and Control Register (KBISC) Table 9-1. KBISC Register Field Descriptions
Field Description
7:4 Keyboard Edge Select for KBI Port Bits -- Each of these read/write bits selects the polarity of the edges and/or KBEDG[7:4] levels that are recognized as trigger events on the corresponding KBI port pin when it is configured as a keyboard interrupt input (KBIPEn = 1). Also see the KBIMOD control bit, which determines whether the pin is sensitive to edges-only or edges and levels. 0 Falling edges/low levels 1 Rising edges/high levels 3 KBF Keyboard Interrupt Flag -- This read-only status flag is set whenever the selected edge event has been detected on any of the enabled KBI port pins. This flag is cleared by writing a 1 to the KBACK control bit. The flag will remain set if KBIMOD = 1 to select edge-and-level operation and any enabled KBI port pin remains at the asserted level. KBF can be used as a software pollable flag (KBIE = 0) or it can generate a hardware interrupt request to the CPU (KBIE = 1). 0 No KBI interrupt pending 1 KBI interrupt pending Keyboard Interrupt Acknowledge -- This write-only bit (reads always return 0) is used to clear the KBF status flag by writing a 1 to KBACK. When KBIMOD = 1 to select edge-and-level operation and any enabled KBI port pin remains at the asserted level, KBF is being continuously set so writing 1 to KBACK does not clear the KBF flag. Keyboard Interrupt Enable -- This read/write control bit determines whether hardware interrupts are generated when the KBF status flag equals 1. When KBIE = 0, no hardware interrupts are generated, but KBF can still be used for software polling. 0 KBF does not generate hardware interrupts (use polling) 1 KBI hardware interrupt requested when KBF = 1 Keyboard Detection Mode -- This read/write control bit selects either edge-only detection or edge-and-level detection. KBI port bits 3 through 0 can detect falling edges-only or falling edges and low levels. KBI port bits 7 through 4 can be configured to detect either: * Rising edges-only or rising edges and high levels (KBEDGn = 1) * Falling edges-only or falling edges and low levels (KBEDGn = 0) 0 Edge-only detection 1 Edge-and-level detection
2 KBACK
1 KBIE
KBIMOD
MC9S08AC16 Series Data Sheet, Rev. 8 156 Freescale Semiconductor
Keyboard Interrupt (S08KBIV1)
9.4.2
R
KBI Pin Enable Register (KBIPE)
7 6 5 4 3 2 1 0
KBIPE7 W Reset 0
KBIPE6 0
KBIPE5 0
KBIPE4 0
KBIPE3 0
KBIPE2 0
KBIPE1 0
KBIPE0 0
= Unimplemented or Reserved
Figure 9-4. KBI Pin Enable Register (KBIPE) Table 9-2. KBIPE Register Field Descriptions
Field 7:0 KBIPE[7:0] Description Keyboard Pin Enable for KBI Port Bits -- Each of these read/write bits selects whether the associated KBI port pin is enabled as a keyboard interrupt input or functions as a general-purpose I/O pin. 0 Bit n of KBI port is a general-purpose I/O pin not associated with the KBI 1 Bit n of KBI port enabled as a keyboard interrupt input
9.5
9.5.1
Functional Description
Pin Enables
The KBIPEn control bits in the KBIPE register allow a user to enable (KBIPEn = 1) any combination of KBI-related port pins to be connected to the KBI module. Pins corresponding to 0s in KBIPE are general-purpose I/O pins that are not associated with the KBI module.
9.5.2
Edge and Level Sensitivity
Synchronous logic is used to detect edges. Prior to detecting an edge, enabled keyboard inputs in a KBI module must be at the deasserted logic level. A falling edge is detected when an enabled keyboard input signal is seen as a logic 1 (the deasserted level) during one bus cycle and then a logic 0 (the asserted level) during the next cycle. A rising edge is detected when the input signal is seen as a logic 0 during one bus cycle and then a logic 1 during the next cycle. The KBIMOD control bit can be set to reconfigure the detection logic so that it detects edges and levels. In KBIMOD = 1 mode, the KBF status flag becomes set when an edge is detected (when one or more enabled pins change from the deasserted to the asserted level while all other enabled pins remain at their deasserted levels), but the flag is continuously set (and cannot be cleared) as long as any enabled keyboard input pin remains at the asserted level. When the MCU enters stop mode, the synchronous edge-detection logic is bypassed (because clocks are stopped). In stop mode, KBI inputs act as asynchronous level-sensitive inputs so they can wake the MCU from stop mode.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 157
Keyboard Interrupt (S08KBIV1)
9.5.3
KBI Interrupt Controls
The KBF status flag becomes set (1) when an edge event has been detected on any KBI input pin. If KBIE = 1 in the KBISC register, a hardware interrupt will be requested whenever KBF = 1. The KBF flag is cleared by writing a 1 to the keyboard acknowledge (KBACK) bit. When KBIMOD = 0 (selecting edge-only operation), KBF is always cleared by writing 1 to KBACK. When KBIMOD = 1 (selecting edge-and-level operation), KBF cannot be cleared as long as any keyboard input is at its asserted level.
MC9S08AC16 Series Data Sheet, Rev. 8 158 Freescale Semiconductor
Chapter 10 Timer/PWM (S08TPMV3)
10.1 Introduction
The MC9S08AC16 Series includes three independent timer/PWM (TPM) modules which support traditional input capture, output compare, or buffered edge-aligned pulse-width modulation (PWM) on each channel. A control bit in each TPM configures all channels in that timer to operate as center-aligned PWM functions. In each TPM, timing functions are based on a separate 16-bit counter with prescaler and modulo features to control frequency and range (period between overflows) of the time reference. This timing system is ideally suited for a wide range of control applications, and the center-aligned PWM capability on the TPM extends the field of applications to motor control in small appliances. The use of the fixed system clock, XCLK, as the clock source for any of the TPM modules allows the TPM prescaler to run using the oscillator rate divided by two (ICGERCLK/2). This option is only available if the ICG is configured in FEE mode and the proper conditions are met (see Section 8.4.11, "Fixed Frequency Clock"). In all other ICG modes this selection is redundant because XCLK is the same as BUSCLK. An external clock source can be connected to the TPMCLK pin. The maximum frequency for TPMCLK is the bus clock frequency divided by 4. All three TPM modules can independently select TPMCLK as the clock source.
10.2
Features
The timer system in the MC9S08AC16 Series includes a 4-channel TPM1 (2-channel TPM1 on 32-bit package option), a separate 2-channel TPM2 and a separate 2-channel TPM3. Timer system features include: * A total of up to eight channels: -- Each channel may be input capture, output compare, or buffered edge-aligned PWM -- Rising-edge, falling-edge, or any-edge input capture trigger -- Set, clear, or toggle output compare action -- Selectable polarity on PWM outputs * Each TPM may be configured for buffered, center-aligned pulse-width modulation (CPWM) on all channels * Clock source to prescaler for each TPM is independently selectable as bus clock, fixed system clock, or an external pin: -- Prescale taps for divide by 1, 2, 4, 8, 16, 32, 64, or 128 -- External clock input: TPMCLK for use by TPM1, TPM2, and/or TPM3 * 16-bit free-running or up/down (CPWM) count operation * 16-bit modulus register to control counter range * Timer system enable
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 159
Chapter 10 Timer/PWM (S08TPMV3)
*
One interrupt per channel plus a terminal count interrupt for each TPM module
VDDAD VSSAD VREFL VREFH HCS08 CORE BKGD/MS BDC CPU IIC MODULE (IIC1) RESET HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
10-BIT ANALOG-TO-DIGITAL CONVERTER (ADC1) DEBUG MODULE (DBG)
4 AD1P11-AD1P8
PORT A
4 AD1P3-AD1P0
PTA7 PTA2 PTA1 PTA0 PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 PTB0/TPM3CH0/AD1P0 PTC5/RxD2 PTC4 PTC3/TxD2 PTC2/MCLK PTC1/SDA1 PTC0/SCL1 PTD3/KBIP6/AD1P11 PTD2/KBIP5/AD1P10 PTD1/AD1P9 PTD0/AD1P8
SDA1 SCL1 PORT C PORT D
IRQ/TPMCLK
MODES OF OPERATION POWER MANAGEMENT RTI IRQ COP LVD
INTERNAL CLOCK GENERATOR (ICG) LOW-POWER OSCILLATOR 7-BIT KEYBOARD INTERRUPT MODULE (KBI)
EXTAL XTAL
2 KBIP6-KBIP5 5 KBIP4-KBIP0 RxD1 TxD1 RxD2 TxD2 SPSCK1 MOSI1 MISO1 SS1 TPM1CH1 TPM1CH0 TPM1CH3 TPM1CH2 TPM2CH1 TPM2CH0 TPM3CH1 TPM3CH0
TPMCLK
SERIAL COMMUNICATIONS INTERFACE MODULE (SCI1) SERIAL COMMUNICATIONS INTERFACE MODULE (SCI2) SERIAL PERIPHERAL INTERFACE MODULE (SPI1)
PORT B
USER FLASH 16,384 BYTES OR 8192 BYTES
PTE7/SPSCK1 PTE6/MOSI1 PTE5/MISO1 PTE4/SS1 PTE3/TPM1CH1 PTE2/TPM1CH0 PTE1/RxD1 PTE0/TxD1
USER RAM 1024 BYTES OR 768 BYTES VDD VSS VOLTAGE REGULATOR
2-CHANNEL TIMER/PWM MODULE (TPM2)
PORT F
4-CHANNEL TIMER/PWM MODULE (TPM1)
PORT E
PTF6 PTF5/TPM2CH1 PTF4/TPM2CH0 PTF1/TPM1CH3 PTF0/TPM1CH2
= Not available on 32-, 42-, or 44-pin packages = Not available on 32- or 42-pin packages = Not available on 32-pin packages
Notes: 1. Port pins are software configurable with pullup device if input port. 2. Pin contains software configurable pullup/pulldown device if IRQ is enabled (IRQPE = 1). Pulldown is enabled if rising edge detect is selected (IRQEDG = 1) 3. IRQ does not have a clamp diode to VDD. IRQ should not be driven above VDD. 4. Pin contains integrated pullup device. 5. PTD3, PTD2, and PTG4 contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is selected (KBEDGn = 1).
Figure 10-1. MC9S08AC16 Block Diagram Highlighting the TPM
MC9S08AC16 Series Data Sheet, Rev. 8 160 Freescale Semiconductor
PORT G
2-CHANNEL TIMER/PWM MODULE (TPM3)
PTG6/EXTAL PTG5/XTAL PTG4/KBIP4 PTG3/KBIP3 PTG2/KBIP2 PTG1/KBIP1 PTG0/KBIP0
Chapter 10 Timer/PWM (S08TPMV3)
10.3
TPMV3 Differences from Previous Versions
The TPMV3 is the latest version of the Timer/PWM module that addresses errata found in previous versions. The following section outlines the differences between TPMV3 and TPMV2 modules, and any considerations that should be taken when porting code.
Table 10-1. TPMV2 and TPMV3 Porting Considerations
Action Write to TPMxCnTH:L registers1 Any write to TPMxCNTH or TPMxCNTL registers Clears the TPM counter (TPMxCNTH:L) and the prescaler counter. Clears the TPM counter (TPMxCNTH:L) only. TPMV3 TPMV2
Read of TPMxCNTH:L registers1 In BDM mode, any read of TPMxCNTH:L registers Returns the value of the TPM If only one byte of the counter that is frozen. TPMxCNTH:L registers was read before the BDM mode became active, returns the latched value of TPMxCNTH:L from the read buffer (instead of the frozen TPM counter value). Does not clear this read coherency mechanism.
In BDM mode, a write to TPMxSC, TPMxCNTH or TPMxCNTL Clears this read coherency mechanism. Read of TPMxCnVH:L registers2 In BDM mode, any read of TPMxCnVH:L registers Returns the value of the TPMxCnVH:L register.
If only one byte of the TPMxCnVH:L registers was read before the BDM mode became active, returns the latched value of TPMxCNTH:L from the read buffer (instead of the value in the TPMxCnVH:L registers). Does not clear this read coherency mechanism.
In BDM mode, a write to TPMxCnSC Write to TPMxCnVH:L registers In Input Capture mode, writes to TPMxCnVH:L registers3 In Output Compare mode, when (CLKSB:CLKSA not = 0:0), writes to TPMxCnVH:L registers3
Clears this read coherency mechanism.
Not allowed. Update the TPMxCnVH:L registers with the value of their write buffer at the next change of the TPM counter (end of the prescaler counting) after the second byte is written.
Allowed. Always update these registers when their second byte is written.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 161
Chapter 10 Timer/PWM (S08TPMV3)
Table 10-1. TPMV2 and TPMV3 Porting Considerations (continued)
Action TPMV3 TPMV2 Update after both bytes are written and when the TPM counter changes from TPMxMODH:L to $0000.
In Edge-Aligned PWM mode when (CLKSB:CLKSA not = 00), Update the TPMxCnVH:L writes to TPMxCnVH:L registers registers with the value of their write buffer after both bytes were written and when the TPM counter changes from (TPMxMODH:L - 1) to (TPMxMODH:L). Note: If the TPM counter is a free-running counter, then this update is made when the TPM counter changes from $FFFE to $FFFF. In Center-Aligned PWM mode when (CLKSB:CLKSA not = 00), writes to TPMxCnVH:L registers4 Update the TPMxCnVH:L registers with the value of their write buffer after both bytes are written and when the TPM counter changes from (TPMxMODH:L - 1) to (TPMxMODH:L). Note: If the TPM counter is a free-running counter, then this update is made when the TPM counter changes from $FFFE to $FFFF.
Update after both bytes are written and when the TPM counter changes from TPMxMODH:L to (TPMxMODH:L - 1).
Center-Aligned PWM When TPMxCnVH:L = TPMxMODH:L5 When TPMxCnVH:L = (TPMxMODH:L 1)6 Produces 100% duty cycle. Produces a near 100% duty cycle. Waits for the start of a new PWM period to begin using the new duty cycle setting. Finishes the current PWM period using the old duty cycle setting. Produces 0% duty cycle. Produces 0% duty cycle. Changes the channel output at the middle of the current PWM period (when the count reaches 0x0000). Finishes the current PWM period using the new duty cycle setting.
TPMxCnVH:L is changed from 0x0000 to a non-zero value7
TPMxCnVH:L is changed from a non-zero value to 0x00008
Write to TPMxMODH:L registers in BDM mode In BDM mode, a write to TPMxSC register Clears the write coherency Does not clear the write mechanism of TPMxMODH:L coherency mechanism. registers.
1 2 3 4 5 6 7
For more information, refer to Section 10.5.2, "TPM-Counter Registers (TPMxCNTH:TPMxCNTL)." [SE110-TPM case 7] For more information, refer to Section 10.5.5, "TPM Channel Value Registers (TPMxCnVH:TPMxCnVL)." For more information, refer to Section 10.6.2.1, "Input Capture Mode." For more information, refer to Section 10.6.2.4, "Center-Aligned PWM Mode." For more information, refer to Section 10.6.2.4, "Center-Aligned PWM Mode." [SE110-TPM case 1] For more information, refer to Section 10.6.2.4, "Center-Aligned PWM Mode." [SE110-TPM case 2] For more information, refer to Section 10.6.2.4, "Center-Aligned PWM Mode." [SE110-TPM case 3 and 5]
MC9S08AC16 Series Data Sheet, Rev. 8 162 Freescale Semiconductor
Chapter 10 Timer/PWM (S08TPMV3)
8
For more information, refer to Section 10.6.2.4, "Center-Aligned PWM Mode." [SE110-TPM case 4]
10.3.1
Migrating from TPMV1
In addition to Section 10.3, "TPMV3 Differences from Previous Versions," keep in mind the following considerations when migrating from a device that uses TPMV1. * You can write to the Channel Value register (TPMxCnV) when the timer is not in input capture mode for TPMV2, not TPMV3. * In edge- or center- aligned modes, the Channel Value register (TPMxCnV) registers only update when the timer changes from TPMMOD-1 to TPMMOD, or in the case of a free running timer from 0xFFFE to 0xFFFF. * Also, when configuring the TPM modules, it is best to write to TPMxSC before TPMxCnV as a write to TPMxSC resets the coherency mechanism on the TPMxCnV registers.
Table 10-2. Migrating to TPMV3 Considerations
When... Writing to the Channel Value Register (TPMxCnV) register... Action / Best Practice Timer must be in Input Capture mode.
Updating the Channel Value Register (TPMxCnV) Only occurs when the timer changes from register in edge-aligned or center-aligned modes... TPMMOD-1 to TPMMOD (or in the case of a free running timer, from 0xFFFE to 0xFFFF). Reseting the coherency mechanism for the Channel Value Register (TPMxCnV) register... Configuring the TPM modules... Write to TPMxSC. Write first to TPMxSC and then to TPMxCnV register.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 163
Timer/PWM Module (S08TPMV3)
10.3.2
Features
The TPM includes these distinctive features: * One to eight channels: -- Each channel may be input capture, output compare, or edge-aligned PWM -- Rising-Edge, falling-edge, or any-edge input capture trigger -- Set, clear, or toggle output compare action -- Selectable polarity on PWM outputs * Module may be configured for buffered, center-aligned pulse-width-modulation (CPWM) on all channels * Timer clock source selectable as prescaled bus clock, fixed system clock, or an external clock pin -- Prescale taps for divide-by 1, 2, 4, 8, 16, 32, 64, or 128 -- Fixed system clock source are synchronized to the bus clock by an on-chip synchronization circuit -- External clock pin may be shared with any timer channel pin or a separated input pin * 16-bit free-running or modulo up/down count operation * Timer system enable * One interrupt per channel plus terminal count interrupt
10.3.3
Modes of Operation
In general, TPM channels may be independently configured to operate in input capture, output compare, or edge-aligned PWM modes. A control bit allows the whole TPM (all channels) to switch to center-aligned PWM mode. When center-aligned PWM mode is selected, input capture, output compare, and edge-aligned PWM functions are not available on any channels of this TPM module. When the microcontroller is in active BDM background or BDM foreground mode, the TPM temporarily suspends all counting until the microcontroller returns to normal user operating mode. During stop mode, all system clocks, including the main oscillator, are stopped; therefore, the TPM is effectively disabled until clocks resume. During wait mode, the TPM continues to operate normally. Provided the TPM does not need to produce a real time reference or provide the interrupt source(s) needed to wake the MCU from wait mode, the user can save power by disabling TPM functions before entering wait mode. * Input capture mode When a selected edge event occurs on the associated MCU pin, the current value of the 16-bit timer counter is captured into the channel value register and an interrupt flag bit is set. Rising edges, falling edges, any edge, or no edge (disable channel) may be selected as the active edge which triggers the input capture. * Output compare mode When the value in the timer counter register matches the channel value register, an interrupt flag bit is set, and a selected output action is forced on the associated MCU pin. The output compare action may be selected to force the pin to zero, force the pin to one, toggle the pin, or ignore the pin (used for software timing functions).
MC9S08AC16 Series Data Sheet, Rev. 8 164 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
*
*
Edge-aligned PWM mode The value of a 16-bit modulo register plus 1 sets the period of the PWM output signal. The channel value register sets the duty cycle of the PWM output signal. The user may also choose the polarity of the PWM output signal. Interrupts are available at the end of the period and at the duty-cycle transition point. This type of PWM signal is called edge-aligned because the leading edges of all PWM signals are aligned with the beginning of the period, which is the same for all channels within a TPM. Center-aligned PWM mode Twice the value of a 16-bit modulo register sets the period of the PWM output, and the channel-value register sets the half-duty-cycle duration. The timer counter counts up until it reaches the modulo value and then counts down until it reaches zero. As the count matches the channel value register while counting down, the PWM output becomes active. When the count matches the channel value register while counting up, the PWM output becomes inactive. This type of PWM signal is called center-aligned because the centers of the active duty cycle periods for all channels are aligned with a count value of zero. This type of PWM is required for types of motors used in small appliances.
This is a high-level description only. Detailed descriptions of operating modes are in later sections.
10.3.4
Block Diagram
The TPM uses one input/output (I/O) pin per channel, TPMxCHn (timer channel n) where n is the channel number (1-8). The TPM shares its I/O pins with general purpose I/O port pins (refer to I/O pin descriptions in full-chip specification for the specific chip implementation). Figure 10-2 shows the TPM structure. The central component of the TPM is the 16-bit counter that can operate as a free-running counter or a modulo up/down counter. The TPM counter (when operating in normal up-counting mode) provides the timing reference for the input capture, output compare, and edge-aligned PWM functions. The timer counter modulo registers, TPMxMODH:TPMxMODL, control the modulo value of the counter (the values 0x0000 or 0xFFFF effectively make the counter free running). Software can read the counter value at any time without affecting the counting sequence. Any write to either half of the TPMxCNT counter resets the counter, regardless of the data value written.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 165
Timer/PWM Module (S08TPMV3)
BUS CLOCK FIXED SYSTEM CLOCK EXTERNAL CLOCK
SYNC
CLOCK SOURCE SELECT OFF, BUS, FIXED SYSTEM CLOCK, EXT
PRESCALE AND SELECT 1, 2, 4, 8, 16, 32, 64, or 128
CLKSB:CLKSA CPWMS 16-BIT COUNTER COUNTER RESET 16-BIT COMPARATOR TPMxMODH:TPMxMODL ELS0B ELS0A
PS2:PS1:PS0
TOF TOIE
INTERRUPT LOGIC
CHANNEL 0 16-BIT COMPARATOR TPMxC0VH:TPMxC0VL 16-BIT LATCH
PORT LOGIC CH0F INTERRUPT LOGIC
TPMxCH0
MS0B
MS0A
CH0IE
INTERNAL BUS
CHANNEL 1 16-BIT COMPARATOR TPMxC1VH:TPMxC1VL 16-BIT LATCH
ELS1B
ELS1A
PORT LOGIC CH1F INTERRUPT LOGIC
TPMxCH1
MS1B
MS1A
CH1IE
Up to 8 channels
CHANNEL 7 16-BIT COMPARATOR TPMxC7VH:TPMxC7VL 16-BIT LATCH
ELS7B
ELS7A
PORT LOGIC CH7F INTERRUPT LOGIC
TPMxCH7
MS7B
MS7A
CH7IE
Figure 10-2. TPM Block Diagram
MC9S08AC16 Series Data Sheet, Rev. 8 166 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
The TPM channels are programmable independently as input capture, output compare, or edge-aligned PWM channels. Alternately, the TPM can be configured to produce CPWM outputs on all channels. When the TPM is configured for CPWMs, the counter operates as an up/down counter; input capture, output compare, and EPWM functions are not practical. If a channel is configured as input capture, an internal pullup device may be enabled for that channel. The details of how a module interacts with pin controls depends upon the chip implementation because the I/O pins and associated general purpose I/O controls are not part of the module. Refer to the discussion of the I/O port logic in a full-chip specification. Because center-aligned PWMs are usually used to drive 3-phase AC-induction motors and brushless DC motors, they are typically used in sets of three or six channels.
10.4
Signal Description
Table 10-3 shows the user-accessible signals for the TPM. The number of channels may be varied from one to eight. When an external clock is included, it can be shared with the same pin as any TPM channel; however, it could be connected to a separate input pin. Refer to the I/O pin descriptions in full-chip specification for the specific chip implementation.
Table 10-3. Signal Properties
Name EXTCLK1 TPMxCHn
1 2
Function External clock source which may be selected to drive the TPM counter. I/O pin associated with TPM channel n
When preset, this signal can share any channel pin; however depending upon full-chip implementation, this signal could be connected to a separate external pin. 2 n=channel number (1 to 8)
Refer to documentation for the full-chip for details about reset states, port connections, and whether there is any pullup device on these pins. TPM channel pins can be associated with general purpose I/O pins and have passive pullup devices which can be enabled with a control bit when the TPM or general purpose I/O controls have configured the associated pin as an input. When no TPM function is enabled to use a corresponding pin, the pin reverts to being controlled by general purpose I/O controls, including the port-data and data-direction registers. Immediately after reset, no TPM functions are enabled, so all associated pins revert to general purpose I/O control.
10.4.1
Detailed Signal Descriptions
This section describes each user-accessible pin signal in detail. Although Table 10-3 grouped all channel pins together, any TPM pin can be shared with the external clock source signal. Since I/O pin logic is not part of the TPM, refer to full-chip documentation for a specific derivative for more details about the interaction of TPM pin functions and general purpose I/O controls including port data, data direction, and pullup controls.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 167
Timer/PWM Module (S08TPMV3)
10.4.1.1
EXTCLK -- External Clock Source
Control bits in the timer status and control register allow the user to select nothing (timer disable), the bus-rate clock (the normal default source), a crystal-related clock, or an external clock as the clock which drives the TPM prescaler and subsequently the 16-bit TPM counter. The external clock source is synchronized in the TPM. The bus clock clocks the synchronizer; the frequency of the external source must be no more than one-fourth the frequency of the bus-rate clock, to meet Nyquist criteria and allowing for jitter. The external clock signal shares the same pin as a channel I/O pin, so the channel pin will not be usable for channel I/O function when selected as the external clock source. It is the user's responsibility to avoid such settings. If this pin is used as an external clock source (CLKSB:CLKSA = 1:1), the channel can still be used in output compare mode as a software timer (ELSnB:ELSnA = 0:0).
10.4.1.2
TPMxCHn -- TPM Channel n I/O Pin(s)
Each TPM channel is associated with an I/O pin on the MCU. The function of this pin depends on the channel configuration. The TPM pins share with general purpose I/O pins, where each pin has a port data register bit, and a data direction control bit, and the port has optional passive pullups which may be enabled whenever a port pin is acting as an input. The TPM channel does not control the I/O pin when (ELSnB:ELSnA = 0:0) or when (CLKSB:CLKSA = 0:0) so it normally reverts to general purpose I/O control. When CPWMS = 1 (and ELSnB:ELSnA not = 0:0), all channels within the TPM are configured for center-aligned PWM and the TPMxCHn pins are all controlled by the TPM system. When CPWMS=0, the MSnB:MSnA control bits determine whether the channel is configured for input capture, output compare, or edge-aligned PWM. When a channel is configured for input capture (CPWMS=0, MSnB:MSnA = 0:0 and ELSnB:ELSnA not = 0:0), the TPMxCHn pin is forced to act as an edge-sensitive input to the TPM. ELSnB:ELSnA control bits determine what polarity edge or edges will trigger input-capture events. A synchronizer based on the bus clock is used to synchronize input edges to the bus clock. This implies the minimum pulse width--that can be reliably detected--on an input capture pin is four bus clock periods (with ideal clock pulses as near as two bus clocks can be detected). TPM uses this pin as an input capture input to override the port data and data direction controls for the same pin. When a channel is configured for output compare (CPWMS=0, MSnB:MSnA = 0:1 and ELSnB:ELSnA not = 0:0), the associated data direction control is overridden, the TPMxCHn pin is considered an output controlled by the TPM, and the ELSnB:ELSnA control bits determine how the pin is controlled. The remaining three combinations of ELSnB:ELSnA determine whether the TPMxCHn pin is toggled, cleared, or set each time the 16-bit channel value register matches the timer counter. When the output compare toggle mode is initially selected, the previous value on the pin is driven out until the next output compare event--then the pin is toggled.
MC9S08AC16 Series Data Sheet, Rev. 8 168 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
When a channel is configured for edge-aligned PWM (CPWMS=0, MSnB=1 and ELSnB:ELSnA not = 0:0), the data direction is overridden, the TPMxCHn pin is forced to be an output controlled by the TPM, and ELSnA controls the polarity of the PWM output signal on the pin. When ELSnB:ELSnA=1:0, the TPMxCHn pin is forced high at the start of each new period (TPMxCNT=0x0000), and the pin is forced low when the channel value register matches the timer counter. When ELSnA=1, the TPMxCHn pin is forced low at the start of each new period (TPMxCNT=0x0000), and the pin is forced high when the channel value register matches the timer counter.
TPMxMODH:TPMxMODL = 0x0008 TPMxCnVH:TPMxCnVL = 0x0005
TPMxCNTH:TPMxCNTL TPMxCHn CHnF BIT TOF BIT
...
0
1
2
3
4
5
6
7
8
0
1
2
...
Figure 10-3. High-True Pulse of an Edge-Aligned PWM
TPMxMODH:TPMxMODL = 0x0008 TPMxCnVH:TPMxCnVL = 0x0005
TPMxCNTH:TPMxCNTL TPMxCHn CHnF BIT TOF BIT
...
0
1
2
3
4
5
6
7
8
0
1
2
...
Figure 10-4. Low-True Pulse of an Edge-Aligned PWM
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 169
Timer/PWM Module (S08TPMV3)
When the TPM is configured for center-aligned PWM (and ELSnB:ELSnA not = 0:0), the data direction for all channels in this TPM are overridden, the TPMxCHn pins are forced to be outputs controlled by the TPM, and the ELSnA bits control the polarity of each TPMxCHn output. If ELSnB:ELSnA=1:0, the corresponding TPMxCHn pin is cleared when the timer counter is counting up, and the channel value register matches the timer counter; the TPMxCHn pin is set when the timer counter is counting down, and the channel value register matches the timer counter. If ELSnA=1, the corresponding TPMxCHn pin is set when the timer counter is counting up and the channel value register matches the timer counter; the TPMxCHn pin is cleared when the timer counter is counting down and the channel value register matches the timer counter.
TPMxMODH:TPMxMODL = 0x0008 TPMxCnVH:TPMxCnVL = 0x0005
TPMxCNTH:TPMxCNTL TPMxCHn CHnF BIT TOF BIT
...
7
8
7
6
5
4
3
2
1
0
1
2
3
4
5
6
7
8
7
6
5
...
Figure 10-5. High-True Pulse of a Center-Aligned PWM
TPMxMODH:TPMxMODL = 0x0008 TPMxCnVH:TPMxCnVL = 0x0005
TPMxCNTH:TPMxCNTL TPMxCHn CHnF BIT TOF BIT
...
7
8
7
6
5
4
3
2
1
0
1
2
3
4
5
6
7
8
7
6
5
...
Figure 10-6. Low-True Pulse of a Center-Aligned PWM
MC9S08AC16 Series Data Sheet, Rev. 8 170 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
10.5
Register Definition
This section consists of register descriptions in address order. A typical MCU system may contain multiple TPMs, and each TPM may have one to eight channels, so register names include placeholder characters to identify which TPM and which channel is being referenced. For example, TPMxCnSC refers to timer (TPM) x, channel n. TPM1C2SC would be the status and control register for channel 2 of timer 1.
10.5.1
TPM Status and Control Register (TPMxSC)
TPMxSC contains the overflow status flag and control bits used to configure the interrupt enable, TPM configuration, clock source, and prescale factor. These controls relate to all channels within this timer module.
7 6 5 4 3 2 1 0
R W Reset
TOF TOIE 0 0 0 0 0 0 0 0 0 CPWMS CLKSB CLKSA PS2 PS1 PS0
Figure 10-7. TPM Status and Control Register (TPMxSC) Table 10-4. TPMxSC Field Descriptions
Field 7 TOF Description Timer overflow flag. This read/write flag is set when the TPM counter resets to 0x0000 after reaching the modulo value programmed in the TPM counter modulo registers. Clear TOF by reading the TPM status and control register when TOF is set and then writing a logic 0 to TOF. If another TPM overflow occurs before the clearing sequence is complete, the sequence is reset so TOF would remain set after the clear sequence was completed for the earlier TOF. This is done so a TOF interrupt request cannot be lost during the clearing sequence for a previous TOF. Reset clears TOF. Writing a logic 1 to TOF has no effect. 0 TPM counter has not reached modulo value or overflow 1 TPM counter has overflowed Timer overflow interrupt enable. This read/write bit enables TPM overflow interrupts. If TOIE is set, an interrupt is generated when TOF equals one. Reset clears TOIE. 0 TOF interrupts inhibited (use for software polling) 1 TOF interrupts enabled Center-aligned PWM select. When present, this read/write bit selects CPWM operating mode. By default, the TPM operates in up-counting mode for input capture, output compare, and edge-aligned PWM functions. Setting CPWMS reconfigures the TPM to operate in up/down counting mode for CPWM functions. Reset clears CPWMS. 0 All channels operate as input capture, output compare, or edge-aligned PWM mode as selected by the MSnB:MSnA control bits in each channel's status and control register. 1 All channels operate in center-aligned PWM mode.
6 TOIE
5 CPWMS
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 171
Timer/PWM Module (S08TPMV3)
Table 10-4. TPMxSC Field Descriptions (continued)
Field Description
4-3 Clock source selects. As shown in Table 10-5, this 2-bit field is used to disable the TPM system or select one of CLKS[B:A] three clock sources to drive the counter prescaler. The fixed system clock source is only meaningful in systems with a PLL-based or FLL-based system clock. When there is no PLL or FLL, the fixed-system clock source is the same as the bus rate clock. The external source is synchronized to the bus clock by TPM module, and the fixed system clock source (when a PLL or FLL is present) is synchronized to the bus clock by an on-chip synchronization circuit. When a PLL or FLL is present but not enabled, the fixed-system clock source is the same as the bus-rate clock. 2-0 PS[2:0] Prescale factor select. This 3-bit field selects one of 8 division factors for the TPM clock input as shown in Table 10-6. This prescaler is located after any clock source synchronization or clock source selection so it affects the clock source selected to drive the TPM system. The new prescale factor will affect the clock source on the next system clock cycle after the new value is updated into the register bits.
Table 10-5. TPM-Clock-Source Selection
CLKSB:CLKSA 00 01 10 11 TPM Clock Source to Prescaler Input No clock selected (TPM counter disable) Bus rate clock Fixed system clock External source
Table 10-6. Prescale Factor Selection
PS2:PS1:PS0 000 001 010 011 100 101 110 111 TPM Clock Source Divided-by 1 2 4 8 16 32 64 128
10.5.2
TPM-Counter Registers (TPMxCNTH:TPMxCNTL)
The two read-only TPM counter registers contain the high and low bytes of the value in the TPM counter. Reading either byte (TPMxCNTH or TPMxCNTL) latches the contents of both bytes into a buffer where they remain latched until the other half is read. This allows coherent 16-bit reads in either big-endian or little-endian order which makes this more friendly to various compiler implementations. The coherency mechanism is automatically restarted by an MCU reset or any write to the timer status/control register (TPMxSC).
MC9S08AC16 Series Data Sheet, Rev. 8 172 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
Reset clears the TPM counter registers. Writing any value to TPMxCNTH or TPMxCNTL also clears the TPM counter (TPMxCNTH:TPMxCNTL) and resets the coherency mechanism, regardless of the data involved in the write.
7 6 5 4 3 2 1 0
R W Reset
Bit 15
14
13
12
11
10
9
Bit 8
Any write to TPMxCNTH clears the 16-bit counter 0 0 0 0 0 0 0 0
Figure 10-8. TPM Counter Register High (TPMxCNTH)
7 6 5 4 3 2 1 0
R W Reset
Bit 7
6
5
4
3
2
1
Bit 0
Any write to TPMxCNTL clears the 16-bit counter 0 0 0 0 0 0 0 0
Figure 10-9. TPM Counter Register Low (TPMxCNTL)
When BDM is active, the timer counter is frozen (this is the value that will be read by user); the coherency mechanism is frozen such that the buffer latches remain in the state they were in when the BDM became active, even if one or both counter halves are read while BDM is active. This assures that if the user was in the middle of reading a 16-bit register when BDM became active, it will read the appropriate value from the other half of the 16-bit value after returning to normal execution. In BDM mode, writing any value to TPMxSC, TPMxCNTH or TPMxCNTL registers resets the read coherency mechanism of the TPMxCNTH:L registers, regardless of the data involved in the write.
10.5.3
TPM Counter Modulo Registers (TPMxMODH:TPMxMODL)
The read/write TPM modulo registers contain the modulo value for the TPM counter. After the TPM counter reaches the modulo value, the TPM counter resumes counting from 0x0000 at the next clock, and the overflow flag (TOF) becomes set. Writing to TPMxMODH or TPMxMODL inhibits the TOF bit and overflow interrupts until the other byte is written. Reset sets the TPM counter modulo registers to 0x0000 which results in a free running timer counter (modulo disabled). Writing to either byte (TPMxMODH or TPMxMODL) latches the value into a buffer and the registers are updated with the value of their write buffer according to the value of CLKSB:CLKSA bits, so: * If (CLKSB:CLKSA = 0:0), then the registers are updated when the second byte is written * If (CLKSB:CLKSA not = 0:0), then the registers are updated after both bytes were written, and the TPM counter changes from (TPMxMODH:TPMxMODL - 1) to (TPMxMODH:TPMxMODL). If the TPM counter is a free-running counter, the update is made when the TPM counter changes from 0xFFFE to 0xFFFF The latching mechanism may be manually reset by writing to the TPMxSC address (whether BDM is active or not).
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 173
Timer/PWM Module (S08TPMV3)
When BDM is active, the coherency mechanism is frozen (unless reset by writing to TPMxSC register) such that the buffer latches remain in the state they were in when the BDM became active, even if one or both halves of the modulo register are written while BDM is active. Any write to the modulo registers bypasses the buffer latches and directly writes to the modulo register while BDM is active.
7 6 5 4 3 2 1 0
R Bit 15 W Reset 0 0 0 0 0 0 0 0 14 13 12 11 10 9 Bit 8
Figure 10-10. TPM Counter Modulo Register High (TPMxMODH)
7 6 5 4 3 2 1 0
R Bit 7 W Reset 0 0 0 0 0 0 0 0 6 5 4 3 2 1 Bit 0
Figure 10-11. TPM Counter Modulo Register Low (TPMxMODL)
Reset the TPM counter before writing to the TPM modulo registers to avoid confusion about when the first counter overflow will occur.
10.5.4
TPM Channel n Status and Control Register (TPMxCnSC)
TPMxCnSC contains the channel-interrupt-status flag and control bits used to configure the interrupt enable, channel configuration, and pin function.
7 6 5 4 3 2 1 0
R W Reset
CHnF CHnIE 0 0 0 0 0 0 0 MSnB MSnA ELSnB ELSnA
0
0
0
0
= Unimplemented or Reserved
Figure 10-12. TPM Channel n Status and Control Register (TPMxCnSC)
MC9S08AC16 Series Data Sheet, Rev. 8 174 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
Table 10-7. TPMxCnSC Field Descriptions
Field 7 CHnF Description Channel n flag. When channel n is an input-capture channel, this read/write bit is set when an active edge occurs on the channel n pin. When channel n is an output compare or edge-aligned/center-aligned PWM channel, CHnF is set when the value in the TPM counter registers matches the value in the TPM channel n value registers. When channel n is an edge-aligned/center-aligned PWM channel and the duty cycle is set to 0% or 100%, CHnF will not be set even when the value in the TPM counter registers matches the value in the TPM channel n value registers. A corresponding interrupt is requested when CHnF is set and interrupts are enabled (CHnIE = 1). Clear CHnF by reading TPMxCnSC while CHnF is set and then writing a logic 0 to CHnF. If another interrupt request occurs before the clearing sequence is complete, the sequence is reset so CHnF remains set after the clear sequence completed for the earlier CHnF. This is done so a CHnF interrupt request cannot be lost due to clearing a previous CHnF. Reset clears the CHnF bit. Writing a logic 1 to CHnF has no effect. 0 No input capture or output compare event occurred on channel n 1 Input capture or output compare event on channel n Channel n interrupt enable. This read/write bit enables interrupts from channel n. Reset clears CHnIE. 0 Channel n interrupt requests disabled (use for software polling) 1 Channel n interrupt requests enabled Mode select B for TPM channel n. When CPWMS=0, MSnB=1 configures TPM channel n for edge-aligned PWM mode. Refer to the summary of channel mode and setup controls in Table 10-8. Mode select A for TPM channel n. When CPWMS=0 and MSnB=0, MSnA configures TPM channel n for input-capture mode or output compare mode. Refer to Table 10-8 for a summary of channel mode and setup controls. Note: If the associated port pin is not stable for at least two bus clock cycles before changing to input capture mode, it is possible to get an unexpected indication of an edge trigger. Edge/level select bits. Depending upon the operating mode for the timer channel as set by CPWMS:MSnB:MSnA and shown in Table 10-8, these bits select the polarity of the input edge that triggers an input capture event, select the level that will be driven in response to an output compare match, or select the polarity of the PWM output. Setting ELSnB:ELSnA to 0:0 configures the related timer pin as a general purpose I/O pin not related to any timer functions. This function is typically used to temporarily disable an input capture channel or to make the timer pin available as a general purpose I/O pin when the associated timer channel is set up as a software timer that does not require the use of a pin.
6 CHnIE 5 MSnB 4 MSnA
3-2 ELSnB ELSnA
Table 10-8. Mode, Edge, and Level Selection
CPWMS X MSnB:MSnA XX ELSnB:ELSnA 00 Mode Configuration
Pin not used for TPM - revert to general purpose I/O or other peripheral control
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 175
Timer/PWM Module (S08TPMV3)
Table 10-8. Mode, Edge, and Level Selection
CPWMS 0 MSnB:MSnA 00 ELSnB:ELSnA 01 10 11 01 00 01 10 11 1X 10 X1 1 XX 10 X1 Center-aligned PWM Edge-aligned PWM Output compare Mode Input capture Configuration Capture on rising edge only Capture on falling edge only Capture on rising or falling edge Software compare only Toggle output on compare Clear output on compare Set output on compare High-true pulses (clear output on compare) Low-true pulses (set output on compare) High-true pulses (clear output on compare-up) Low-true pulses (set output on compare-up)
10.5.5
TPM Channel Value Registers (TPMxCnVH:TPMxCnVL)
These read/write registers contain the captured TPM counter value of the input capture function or the output compare value for the output compare or PWM functions. The channel registers are cleared by reset.
7 6 5 4 3 2 1 0
R Bit 15 W Reset 0 0 0 0 0 0 0 0 14 13 12 11 10 9 Bit 8
Figure 10-13. TPM Channel Value Register High (TPMxCnVH)
7 6 5 4 3 2 1 0
R Bit 7 W Reset 0 0 0 0 0 0 0 0 6 5 4 3 2 1 Bit 0
Figure 10-14. TPM Channel Value Register Low (TPMxCnVL)
In input capture mode, reading either byte (TPMxCnVH or TPMxCnVL) latches the contents of both bytes into a buffer where they remain latched until the other half is read. This latching mechanism also resets
MC9S08AC16 Series Data Sheet, Rev. 8 176 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
(becomes unlatched) when the TPMxCnSC register is written (whether BDM mode is active or not). Any write to the channel registers will be ignored during the input capture mode. When BDM is active, the coherency mechanism is frozen (unless reset by writing to TPMxCnSC register) such that the buffer latches remain in the state they were in when the BDM became active, even if one or both halves of the channel register are read while BDM is active. This assures that if the user was in the middle of reading a 16-bit register when BDM became active, it will read the appropriate value from the other half of the 16-bit value after returning to normal execution. The value read from the TPMxCnVH and TPMxCnVL registers in BDM mode is the value of these registers and not the value of their read buffer. In output compare or PWM modes, writing to either byte (TPMxCnVH or TPMxCnVL) latches the value into a buffer. After both bytes are written, they are transferred as a coherent 16-bit value into the timer-channel registers according to the value of CLKSB:CLKSA bits and the selected mode, so: * If (CLKSB:CLKSA = 0:0), then the registers are updated when the second byte is written. * If (CLKSB:CLKSA not = 0:0 and in output compare mode) then the registers are updated after the second byte is written and on the next change of the TPM counter (end of the prescaler counting). * If (CLKSB:CLKSA not = 0:0 and in EPWM or CPWM modes), then the registers are updated after the both bytes were written, and the TPM counter changes from (TPMxMODH:TPMxMODL - 1) to (TPMxMODH:TPMxMODL). If the TPM counter is a free-running counter then the update is made when the TPM counter changes from 0xFFFE to 0xFFFF. The latching mechanism may be manually reset by writing to the TPMxCnSC register (whether BDM mode is active or not). This latching mechanism allows coherent 16-bit writes in either big-endian or little-endian order which is friendly to various compiler implementations. When BDM is active, the coherency mechanism is frozen such that the buffer latches remain in the state they were in when the BDM became active even if one or both halves of the channel register are written while BDM is active. Any write to the channel registers bypasses the buffer latches and directly write to the channel register while BDM is active. The values written to the channel register while BDM is active are used for PWM & output compare operation once normal execution resumes. Writes to the channel registers while BDM is active do not interfere with partial completion of a coherency sequence. After the coherency mechanism has been fully exercised, the channel registers are updated using the buffered values written (while BDM was not active) by the user.
10.6
Functional Description
All TPM functions are associated with a central 16-bit counter which allows flexible selection of the clock source and prescale factor. There is also a 16-bit modulo register associated with the main counter. The CPWMS control bit chooses between center-aligned PWM operation for all channels in the TPM (CPWMS=1) or general purpose timing functions (CPWMS=0) where each channel can independently be configured to operate in input capture, output compare, or edge-aligned PWM mode. The CPWMS control bit is located in the main TPM status and control register because it affects all channels within the TPM and influences the way the main counter operates. (In CPWM mode, the counter changes to an up/down mode rather than the up-counting mode used for general purpose timer functions.)
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 177
Timer/PWM Module (S08TPMV3)
The following sections describe the main counter and each of the timer operating modes (input capture, output compare, edge-aligned PWM, and center-aligned PWM). Because details of pin operation and interrupt activity depend upon the operating mode, these topics will be covered in the associated mode explanation sections.
10.6.1
Counter
All timer functions are based on the main 16-bit counter (TPMxCNTH:TPMxCNTL). This section discusses selection of the clock source, end-of-count overflow, up-counting vs. up/down counting, and manual counter reset.
10.6.1.1
Counter Clock Source
The 2-bit field, CLKSB:CLKSA, in the timer status and control register (TPMxSC) selects one of three possible clock sources or OFF (which effectively disables the TPM). See Table 10-5. After any MCU reset, CLKSB:CLKSA=0:0 so no clock source is selected, and the TPM is in a very low power state. These control bits may be read or written at any time and disabling the timer (writing 00 to the CLKSB:CLKSA field) does not affect the values in the counter or other timer registers.
Table 10-9. TPM Clock Source Selection
CLKSB:CLKSA 00 01 10 11 TPM Clock Source to Prescaler Input No clock selected (TPM counter disabled) Bus rate clock Fixed system clock External source
The bus rate clock is the main system bus clock for the MCU. This clock source requires no synchronization because it is the clock that is used for all internal MCU activities including operation of the CPU and buses. In MCUs that have no PLL and FLL or the PLL and FLL are not engaged, the fixed system clock source is the same as the bus-rate-clock source, and it does not go through a synchronizer. When a PLL or FLL is present and engaged, a synchronizer is required between the crystal divided-by two clock source and the timer counter so counter transitions will be properly aligned to bus-clock transitions. A synchronizer will be used at chip level to synchronize the crystal-related source clock to the bus clock. The external clock source may be connected to any TPM channel pin. This clock source always has to pass through a synchronizer to assure that counter transitions are properly aligned to bus clock transitions. The bus-rate clock drives the synchronizer; therefore, to meet Nyquist criteria even with jitter, the frequency of the external clock source must not be faster than the bus rate divided-by four. With ideal clocks the external clock can be as fast as bus clock divided by four. When the external clock source shares the TPM channel pin, this pin should not be used for other channel timing functions. For example, it would be ambiguous to configure channel 0 for input capture when the TPM channel 0 pin was also being used as the timer external clock source. (It is the user's responsibility
MC9S08AC16 Series Data Sheet, Rev. 8 178 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
to avoid such settings.) The TPM channel could still be used in output compare mode for software timing functions (pin controls set not to affect the TPM channel pin).
10.6.1.2
Counter Overflow and Modulo Reset
An interrupt flag and enable are associated with the 16-bit main counter. The flag (TOF) is a software-accessible indication that the timer counter has overflowed. The enable signal selects between software polling (TOIE=0) where no hardware interrupt is generated, or interrupt-driven operation (TOIE=1) where a static hardware interrupt is generated whenever the TOF flag is equal to one. The conditions causing TOF to become set depend on whether the TPM is configured for center-aligned PWM (CPWMS=1). In the simplest mode, there is no modulus limit and the TPM is not in CPWMS=1 mode. In this case, the 16-bit timer counter counts from 0x0000 through 0xFFFF and overflows to 0x0000 on the next counting clock. TOF becomes set at the transition from 0xFFFF to 0x0000. When a modulus limit is set, TOF becomes set at the transition from the value set in the modulus register to 0x0000. When the TPM is in center-aligned PWM mode (CPWMS=1), the TOF flag gets set as the counter changes direction at the end of the count value set in the modulus register (that is, at the transition from the value set in the modulus register to the next lower count value). This corresponds to the end of a PWM period (the 0x0000 count value corresponds to the center of a period).
10.6.1.3
Counting Modes
The main timer counter has two counting modes. When center-aligned PWM is selected (CPWMS=1), the counter operates in up/down counting mode. Otherwise, the counter operates as a simple up counter. As an up counter, the timer counter counts from 0x0000 through its terminal count and then continues with 0x0000. The terminal count is 0xFFFF or a modulus value in TPMxMODH:TPMxMODL. When center-aligned PWM operation is specified, the counter counts up from 0x0000 through its terminal count and then down to 0x0000 where it changes back to up counting. Both 0x0000 and the terminal count value are normal length counts (one timer clock period long). In this mode, the timer overflow flag (TOF) becomes set at the end of the terminal-count period (as the count changes to the next lower count value).
10.6.1.4
Manual Counter Reset
The main timer counter can be manually reset at any time by writing any value to either half of TPMxCNTH or TPMxCNTL. Resetting the counter in this manner also resets the coherency mechanism in case only half of the counter was read before resetting the count.
10.6.2
Channel Mode Selection
Provided CPWMS=0, the MSnB and MSnA control bits in the channel n status and control registers determine the basic mode of operation for the corresponding channel. Choices include input capture, output compare, and edge-aligned PWM.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 179
Timer/PWM Module (S08TPMV3)
10.6.2.1
Input Capture Mode
With the input-capture function, the TPM can capture the time at which an external event occurs. When an active edge occurs on the pin of an input-capture channel, the TPM latches the contents of the TPM counter into the channel-value registers (TPMxCnVH:TPMxCnVL). Rising edges, falling edges, or any edge may be chosen as the active edge that triggers an input capture. In input capture mode, the TPMxCnVH and TPMxCnVL registers are read only. When either half of the 16-bit capture register is read, the other half is latched into a buffer to support coherent 16-bit accesses in big-endian or little-endian order. The coherency sequence can be manually reset by writing to the channel status/control register (TPMxCnSC). An input capture event sets a flag bit (CHnF) which may optionally generate a CPU interrupt request. While in BDM, the input capture function works as configured by the user. When an external event occurs, the TPM latches the contents of the TPM counter (which is frozen because of the BDM mode) into the channel value registers and sets the flag bit.
10.6.2.2
Output Compare Mode
With the output-compare function, the TPM can generate timed pulses with programmable position, polarity, duration, and frequency. When the counter reaches the value in the channel-value registers of an output-compare channel, the TPM can set, clear, or toggle the channel pin. In output compare mode, values are transferred to the corresponding timer channel registers only after both 8-bit halves of a 16-bit register have been written and according to the value of CLKSB:CLKSA bits, so: * If (CLKSB:CLKSA = 0:0), the registers are updated when the second byte is written * If (CLKSB:CLKSA not = 0:0), the registers are updated at the next change of the TPM counter (end of the prescaler counting) after the second byte is written. The coherency sequence can be manually reset by writing to the channel status/control register (TPMxCnSC). An output compare event sets a flag bit (CHnF) which may optionally generate a CPU-interrupt request.
10.6.2.3
Edge-Aligned PWM Mode
This type of PWM output uses the normal up-counting mode of the timer counter (CPWMS=0) and can be used when other channels in the same TPM are configured for input capture or output compare functions. The period of this PWM signal is determined by the value of the modulus register (TPMxMODH:TPMxMODL) plus 1. The duty cycle is determined by the setting in the timer channel register (TPMxCnVH:TPMxCnVL). The polarity of this PWM signal is determined by the setting in the ELSnA control bit. 0% and 100% duty cycle cases are possible. The output compare value in the TPM channel registers determines the pulse width (duty cycle) of the PWM signal (Figure 10-15). The time between the modulus overflow and the output compare is the pulse width. If ELSnA=0, the counter overflow forces the PWM signal high, and the output compare forces the PWM signal low. If ELSnA=1, the counter overflow forces the PWM signal low, and the output compare forces the PWM signal high.
MC9S08AC16 Series Data Sheet, Rev. 8 180 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
OVERFLOW PERIOD PULSE WIDTH TPMxCHn
OVERFLOW
OVERFLOW
OUTPUT COMPARE
OUTPUT COMPARE
OUTPUT COMPARE
Figure 10-15. PWM Period and Pulse Width (ELSnA=0)
When the channel value register is set to 0x0000, the duty cycle is 0%. 100% duty cycle can be achieved by setting the timer-channel register (TPMxCnVH:TPMxCnVL) to a value greater than the modulus setting. This implies that the modulus setting must be less than 0xFFFF in order to get 100% duty cycle. Because the TPM may be used in an 8-bit MCU, the settings in the timer channel registers are buffered to ensure coherent 16-bit updates and to avoid unexpected PWM pulse widths. Writes to any of the registers TPMxCnVH and TPMxCnVL, actually write to buffer registers. In edge-aligned PWM mode, values are transferred to the corresponding timer-channel registers according to the value of CLKSB:CLKSA bits, so: * If (CLKSB:CLKSA = 0:0), the registers are updated when the second byte is written * If (CLKSB:CLKSA not = 0:0), the registers are updated after the both bytes were written, and the TPM counter changes from (TPMxMODH:TPMxMODL - 1) to (TPMxMODH:TPMxMODL). If the TPM counter is a free-running counter then the update is made when the TPM counter changes from 0xFFFE to 0xFFFF.
10.6.2.4
Center-Aligned PWM Mode
This type of PWM output uses the up/down counting mode of the timer counter (CPWMS=1). The output compare value in TPMxCnVH:TPMxCnVL determines the pulse width (duty cycle) of the PWM signal while the period is determined by the value in TPMxMODH:TPMxMODL. TPMxMODH:TPMxMODL should be kept in the range of 0x0001 to 0x7FFF because values outside this range can produce ambiguous results. ELSnA will determine the polarity of the CPWM output. pulse width = 2 x (TPMxCnVH:TPMxCnVL) period = 2 x (TPMxMODH:TPMxMODL); TPMxMODH:TPMxMODL=0x0001-0x7FFF If the channel-value register TPMxCnVH:TPMxCnVL is zero or negative (bit 15 set), the duty cycle will be 0%. If TPMxCnVH:TPMxCnVL is a positive value (bit 15 clear) and is greater than the (non-zero) modulus setting, the duty cycle will be 100% because the duty cycle compare will never occur. This implies the usable range of periods set by the modulus register is 0x0001 through 0x7FFE (0x7FFF if you do not need to generate 100% duty cycle). This is not a significant limitation. The resulting period would be much longer than required for normal applications. TPMxMODH:TPMxMODL=0x0000 is a special case that should not be used with center-aligned PWM mode. When CPWMS=0, this case corresponds to the counter running free from 0x0000 through 0xFFFF, but when CPWMS=1 the counter needs a valid match to the modulus register somewhere other than at 0x0000 in order to change directions from up-counting to down-counting.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 181
Timer/PWM Module (S08TPMV3)
The output compare value in the TPM channel registers (times 2) determines the pulse width (duty cycle) of the CPWM signal (Figure 10-16). If ELSnA=0, a compare occurred while counting up forces the CPWM output signal low and a compare occurred while counting down forces the output high. The counter counts up until it reaches the modulo setting in TPMxMODH:TPMxMODL, then counts down until it reaches zero. This sets the period equal to two times TPMxMODH:TPMxMODL.
COUNT= 0 OUTPUT COUNT= COMPARE TPMxMODH:TPMxMODL (COUNT DOWN) OUTPUT COMPARE (COUNT UP) COUNT= TPMxMODH:TPMxMODL
TPMxCHn PULSE WIDTH 2 x TPMxCnVH:TPMxCnVL PERIOD 2 x TPMxMODH:TPMxMODL
Figure 10-16. CPWM Period and Pulse Width (ELSnA=0)
Center-aligned PWM outputs typically produce less noise than edge-aligned PWMs because fewer I/O pin transitions are lined up at the same system clock edge. This type of PWM is also required for some types of motor drives. Input capture, output compare, and edge-aligned PWM functions do not make sense when the counter is operating in up/down counting mode so this implies that all active channels within a TPM must be used in CPWM mode when CPWMS=1. The TPM may be used in an 8-bit MCU. The settings in the timer channel registers are buffered to ensure coherent 16-bit updates and to avoid unexpected PWM pulse widths. Writes to any of the registers TPMxMODH, TPMxMODL, TPMxCnVH, and TPMxCnVL, actually write to buffer registers. In center-aligned PWM mode, the TPMxCnVH:L registers are updated with the value of their write buffer according to the value of CLKSB:CLKSA bits, so: * If (CLKSB:CLKSA = 0:0), the registers are updated when the second byte is written * If (CLKSB:CLKSA not = 0:0), the registers are updated after the both bytes were written, and the TPM counter changes from (TPMxMODH:TPMxMODL - 1) to (TPMxMODH:TPMxMODL). If the TPM counter is a free-running counter, the update is made when the TPM counter changes from 0xFFFE to 0xFFFF. When TPMxCNTH:TPMxCNTL=TPMxMODH:TPMxMODL, the TPM can optionally generate a TOF interrupt (at the end of this count). Writing to TPMxSC cancels any values written to TPMxMODH and/or TPMxMODL and resets the coherency mechanism for the modulo registers. Writing to TPMxCnSC cancels any values written to the channel value registers and resets the coherency mechanism for TPMxCnVH:TPMxCnVL.
MC9S08AC16 Series Data Sheet, Rev. 8 182 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
10.7
10.7.1
Reset Overview
General
The TPM is reset whenever any MCU reset occurs.
10.7.2
Description of Reset Operation
Reset clears the TPMxSC register which disables clocks to the TPM and disables timer overflow interrupts (TOIE=0). CPWMS, MSnB, MSnA, ELSnB, and ELSnA are all cleared which configures all TPM channels for input-capture operation with the associated pins disconnected from I/O pin logic (so all MCU pins related to the TPM revert to general purpose I/O pins).
10.8
10.8.1
Interrupts
General
The TPM generates an optional interrupt for the main counter overflow and an interrupt for each channel. The meaning of channel interrupts depends on each channel's mode of operation. If the channel is configured for input capture, the interrupt flag is set each time the selected input capture edge is recognized. If the channel is configured for output compare or PWM modes, the interrupt flag is set each time the main timer counter matches the value in the 16-bit channel value register. All TPM interrupts are listed in Table 10-10 which shows the interrupt name, the name of any local enable that can block the interrupt request from leaving the TPM and getting recognized by the separate interrupt processing logic.
Table 10-10. Interrupt Summary
Interrupt TOF Local Enable TOIE Source Counter overflow Description Set each time the timer counter reaches its terminal count (at transition to next count value which is usually 0x0000) An input capture or output compare event took place on channel n
CHnF
CHnIE
Channel event
The TPM module will provide a high-true interrupt signal. Vectors and priorities are determined at chip integration time in the interrupt module so refer to the user's guide for the interrupt module or to the chip's complete documentation for details.
10.8.2
Description of Interrupt Operation
For each interrupt source in the TPM, a flag bit is set upon recognition of the interrupt condition such as timer overflow, channel-input capture, or output-compare events. This flag may be read (polled) by software to determine that the action has occurred, or an associated enable bit (TOIE or CHnIE) can be set
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 183
Timer/PWM Module (S08TPMV3)
to enable hardware interrupt generation. While the interrupt enable bit is set, a static interrupt will generate whenever the associated interrupt flag equals one. The user's software must perform a sequence of steps to clear the interrupt flag before returning from the interrupt-service routine. TPM interrupt flags are cleared by a two-step process including a read of the flag bit while it is set (1) followed by a write of zero (0) to the bit. If a new event is detected between these two steps, the sequence is reset and the interrupt flag remains set after the second step to avoid the possibility of missing the new event.
10.8.2.1
Timer Overflow Interrupt (TOF) Description
The meaning and details of operation for TOF interrupts varies slightly depending upon the mode of operation of the TPM system (general purpose timing functions versus center-aligned PWM operation). The flag is cleared by the two step sequence described above. 10.8.2.1.1 Normal Case
Normally TOF is set when the timer counter changes from 0xFFFF to 0x0000. When the TPM is not configured for center-aligned PWM (CPWMS=0), TOF gets set when the timer counter changes from the terminal count (the value in the modulo register) to 0x0000. This case corresponds to the normal meaning of counter overflow. 10.8.2.1.2 Center-Aligned PWM Case
When CPWMS=1, TOF gets set when the timer counter changes direction from up-counting to down-counting at the end of the terminal count (the value in the modulo register). In this case the TOF corresponds to the end of a PWM period.
10.8.2.2
Channel Event Interrupt Description
The meaning of channel interrupts depends on the channel's current mode (input-capture, output-compare, edge-aligned PWM, or center-aligned PWM). 10.8.2.2.1 Input Capture Events
When a channel is configured as an input capture channel, the ELSnB:ELSnA control bits select no edge (off), rising edges, falling edges or any edge as the edge which triggers an input capture event. When the selected edge is detected, the interrupt flag is set. The flag is cleared by the two-step sequence described in Section 10.8.2, "Description of Interrupt Operation." 10.8.2.2.2 Output Compare Events
When a channel is configured as an output compare channel, the interrupt flag is set each time the main timer counter matches the 16-bit value in the channel value register. The flag is cleared by the two-step sequence described Section 10.8.2, "Description of Interrupt Operation."
MC9S08AC16 Series Data Sheet, Rev. 8 184 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
10.8.2.2.3
PWM End-of-Duty-Cycle Events
For channels configured for PWM operation there are two possibilities. When the channel is configured for edge-aligned PWM, the channel flag gets set when the timer counter matches the channel value register which marks the end of the active duty cycle period. When the channel is configured for center-aligned PWM, the timer count matches the channel value register twice during each PWM cycle. In this CPWM case, the channel flag is set at the start and at the end of the active duty cycle period which are the times when the timer counter matches the channel value register. The flag is cleared by the two-step sequence described Section 10.8.2, "Description of Interrupt Operation."
10.9
The Differences from TPM v2 to TPM v3
1. Write to TPMxCNTH:L registers (Section 10.5.2, "TPM-Counter Registers (TPMxCNTH:TPMxCNTL)) [SE110-TPM case 7] Any write to TPMxCNTH or TPMxCNTL registers in TPM v3 clears the TPM counter (TPMxCNTH:L) and the prescaler counter. Instead, in the TPM v2 only the TPM counter is cleared in this case. 2. Read of TPMxCNTH:L registers (Section 10.5.2, "TPM-Counter Registers (TPMxCNTH:TPMxCNTL)) -- In TPM v3, any read of TPMxCNTH:L registers during BDM mode returns the value of the TPM counter that is frozen. In TPM v2, if only one byte of the TPMxCNTH:L registers was read before the BDM mode became active, then any read of TPMxCNTH:L registers during BDM mode returns the latched value of TPMxCNTH:L from the read buffer instead of the frozen TPM counter value. -- This read coherency mechanism is cleared in TPM v3 in BDM mode if there is a write to TPMxSC, TPMxCNTH or TPMxCNTL. Instead, in these conditions the TPM v2 does not clear this read coherency mechanism. 3. Read of TPMxCnVH:L registers (Section 10.5.5, "TPM Channel Value Registers (TPMxCnVH:TPMxCnVL)) -- In TPM v3, any read of TPMxCnVH:L registers during BDM mode returns the value of the TPMxCnVH:L register. In TPM v2, if only one byte of the TPMxCnVH:L registers was read before the BDM mode became active, then any read of TPMxCnVH:L registers during BDM mode returns the latched value of TPMxCNTH:L from the read buffer instead of the value in the TPMxCnVH:L registers. -- This read coherency mechanism is cleared in TPM v3 in BDM mode if there is a write to TPMxCnSC. Instead, in this condition the TPM v2 does not clear this read coherency mechanism. 4. Write to TPMxCnVH:L registers -- Input Capture Mode (Section 10.6.2.1, "Input Capture Mode) In this mode the TPM v3 does not allow the writes to TPMxCnVH:L registers. Instead, the TPM v2 allows these writes. -- Output Compare Mode (Section 10.6.2.2, "Output Compare Mode) In this mode and if (CLKSB:CLKSA not = 0:0), the TPM v3 updates the TPMxCnVH:L registers with the value of their write buffer at the next change of the TPM counter (end of the
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 185
Timer/PWM Module (S08TPMV3)
prescaler counting) after the second byte is written. Instead, the TPM v2 always updates these registers when their second byte is written. The following procedure can be used in the TPM v3 to verify if the TPMxCnVH:L registers were updated with the new value that was written to these registers (value in their write buffer). ... write the new value to TPMxCnVH:L; read TPMxCnVH and TPMxCnVL registers; while (the read value of TPMxCnVH:L is different from the new value written to TPMxCnVH:L) begin read again TPMxCnVH and TPMxCnVL; end ... In this point, the TPMxCnVH:L registers were updated, so the program can continue and, for example, write to TPMxC0SC without cancelling the previous write to TPMxCnVH:L registers. -- Edge-Aligned PWM (Section 10.6.2.3, "Edge-Aligned PWM Mode) In this mode and if (CLKSB:CLKSA not = 00), the TPM v3 updates the TPMxCnVH:L registers with the value of their write buffer after that the both bytes were written and when the TPM counter changes from (TPMxMODH:L - 1) to (TPMxMODH:L). If the TPM counter is a free-running counter, then this update is made when the TPM counter changes from $FFFE to $FFFF. Instead, the TPM v2 makes this update after that the both bytes were written and when the TPM counter changes from TPMxMODH:L to $0000. -- Center-Aligned PWM (Section 10.6.2.4, "Center-Aligned PWM Mode) In this mode and if (CLKSB:CLKSA not = 00), the TPM v3 updates the TPMxCnVH:L registers with the value of their write buffer after that the both bytes were written and when the TPM counter changes from (TPMxMODH:L - 1) to (TPMxMODH:L). If the TPM counter is a free-running counter, then this update is made when the TPM counter changes from $FFFE to $FFFF. Instead, the TPM v2 makes this update after that the both bytes were written and when the TPM counter changes from TPMxMODH:L to (TPMxMODH:L - 1). 5. Center-Aligned PWM (Section 10.6.2.4, "Center-Aligned PWM Mode) -- TPMxCnVH:L = TPMxMODH:L [SE110-TPM case 1] In this case, the TPM v3 produces 100% duty cycle. Instead, the TPM v2 produces 0% duty cycle. -- TPMxCnVH:L = (TPMxMODH:L - 1) [SE110-TPM case 2] In this case, the TPM v3 produces almost 100% duty cycle. Instead, the TPM v2 produces 0% duty cycle. -- TPMxCnVH:L is changed from 0x0000 to a non-zero value [SE110-TPM case 3 and 5] In this case, the TPM v3 waits for the start of a new PWM period to begin using the new duty cycle setting. Instead, the TPM v2 changes the channel output at the middle of the current PWM period (when the count reaches 0x0000).
MC9S08AC16 Series Data Sheet, Rev. 8 186 Freescale Semiconductor
Timer/PWM Module (S08TPMV3)
-- TPMxCnVH:L is changed from a non-zero value to 0x0000 [SE110-TPM case 4] In this case, the TPM v3 finishes the current PWM period using the old duty cycle setting. Instead, the TPM v2 finishes the current PWM period using the new duty cycle setting. 6. Write to TPMxMODH:L registers in BDM mode (Section 10.5.3, "TPM Counter Modulo Registers (TPMxMODH:TPMxMODL)) In the TPM v3 a write to TPMxSC register in BDM mode clears the write coherency mechanism of TPMxMODH:L registers. Instead, in the TPM v2 this coherency mechanism is not cleared when there is a write to TPMxSC register. 7. Update of EPWM signal when CLKSB:CLKSA = 00 In the TPM v3 if CLKSB:CLKSA = 00, then the EPWM signal in the channel output is not update (it is frozen while CLKSB:CLKSA = 00). Instead, in the TPM v2 the EPWM signal is updated at the next rising edge of bus clock after a write to TPMxCnSC register. The Figure 10-17 and Figure 10-18 show when the EPWM signals generated by TPM v2 and TPM v3 after the reset (CLKSB:CLKSA = 00) and if there is a write to TPMxCnSC register.
EPWM mode TPMxMODH:TPMxMODL = 0x0007 TPMxCnVH:TPMxCnVL = 0x0005
RESET (active low) BUS CLOCK TPMxCNTH:TPMxCNTL 00 00 00 10 10 0 1 2 34 5 6 01 7 01 2 ...
CLKSB:CLKSA BITS MSnB:MSnA BITS ELSnB:ELSnA BITS TPMv2 TPMxCHn TPMv3 TPMxCHn CHnF BIT (in TPMv2 and TPMv3)
Figure 10-17. Generation of high-true EPWM signal by TPM v2 and v3 after the reset
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 187
Timer/PWM Module (S08TPMV3)
EPWM mode TPMxMODH:TPMxMODL = 0x0007 TPMxCnVH:TPMxCnVL = 0x0005
RESET (active low) BUS CLOCK TPMxCNTH:TPMxCNTL 00 00 00 10 01 0 1 2 34 5 6 01 7 01 2 ...
CLKSB:CLKSA BITS MSnB:MSnA BITS ELSnB:ELSnA BITS TPMv2 TPMxCHn TPMv3 TPMxCHn CHnF BIT (in TPMv2 and TPMv3)
Figure 10-18. Generation of low-true EPWM signal by TPM v2 and v3 after the reset
The following procedure can be used in TPM v3 (when the channel pin is also a port pin) to emulate the high-true EPWM generated by TPM v2 after the reset. ... configure the channel pin as output port pin and set the output pin; configure the channel to generate the EPWM signal but keep ELSnB:ELSnA as 00; configure the other registers (TPMxMODH, TPMxMODL, TPMxCnVH, TPMxCnVL, ...); configure CLKSB:CLKSA bits (TPM v3 starts to generate the high-true EPWM signal, however TPM does not control the channel pin, so the EPWM signal is not available); wait until the TOF is set (or use the TOF interrupt); enable the channel output by configuring ELSnB:ELSnA bits (now EPWM signal is available); ...
MC9S08AC16 Series Data Sheet, Rev. 8 188 Freescale Semiconductor
Chapter 11 Serial Communications Interface (S08SCIV4)
11.1 Introduction
The MC9S08AC16 Series includes two independent serial communications interface (SCI) modules which are sometimes called universal asynchronous receiver/transmitters (UARTs). Typically, these systems are used to connect to the RS232 serial input/output (I/O) port of a personal computer or workstation, but they can also be used to communicate with other embedded controllers. A flexible, 13-bit, modulo-based baud rate generator supports a broad range of standard baud rates beyond 115.2 kbaud. Transmit and receive within the same SCI use a common baud rate, and each SCI module has a separate baud rate generator. This SCI system offers many advanced features not commonly found on other asynchronous serial I/O peripherals on other embedded controllers. The receiver employs an advanced data sampling technique that ensures reliable communication and noise detection. Hardware parity, receiver wakeup, and double buffering on transmit and receive are also included. NOTE Ignore any references to stop1 low-power mode in this chapter, because the MC9S08AC16 Series does not support it.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 189
Chapter 11 Serial Communications Interface (S08SCIV4) VDDAD VSSAD VREFL VREFH HCS08 CORE BKGD/MS BDC CPU IIC MODULE (IIC1) RESET IRQ/TPMCLK HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
10-BIT ANALOG-TO-DIGITAL CONVERTER (ADC1) DEBUG MODULE (DBG)
4 AD1P11-AD1P8
PORT A
4 AD1P3-AD1P0
PTA7 PTA2 PTA1 PTA0 PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 PTB0/TPM3CH0/AD1P0 PTC5/RxD2 PTC4 PTC3/TxD2 PTC2/MCLK PTC1/SDA1 PTC0/SCL1 PTD3/KBIP6/AD1P11 PTD2/KBIP5/AD1P10 PTD1/AD1P9 PTD0/AD1P8
SDA1 SCL1 PORT C PORT D
MODES OF OPERATION POWER MANAGEMENT RTI IRQ COP LVD
INTERNAL CLOCK GENERATOR (ICG) LOW-POWER OSCILLATOR 7-BIT KEYBOARD INTERRUPT MODULE (KBI)
EXTAL XTAL
2 KBIP6-KBIP5 5 KBIP4-KBIP0 RxD1 TxD1 RxD2 TxD2 SPSCK1 MOSI1 MISO1 SS1 TPM1CH1 TPM1CH0 TPM1CH3 TPM1CH2 TPM2CH1 TPM2CH0 TPM3CH1 TPM3CH0
TPMCLK
SERIAL COMMUNICATIONS INTERFACE MODULE (SCI1) SERIAL COMMUNICATIONS INTERFACE MODULE (SCI2) SERIAL PERIPHERAL INTERFACE MODULE (SPI1)
PORT B
USER FLASH 16,384 BYTES OR 8192 BYTES
PTE7/SPSCK1 PTE6/MOSI1 PTE5/MISO1 PTE4/SS1 PTE3/TPM1CH1 PTE2/TPM1CH0 PTE1/RxD1 PTE0/TxD1
USER RAM 1024 BYTES OR 768 BYTES VDD VSS VOLTAGE REGULATOR
2-CHANNEL TIMER/PWM MODULE (TPM2)
PORT F
4-CHANNEL TIMER/PWM MODULE (TPM1)
PORT E
PTF6 PTF5/TPM2CH1 PTF4/TPM2CH0 PTF1/TPM1CH3 PTF0/TPM1CH2
= Not available on 32-, 42-, or 44-pin packages = Not available on 32- or 42-pin packages = Not available on 32-pin packages
Notes: 1. Port pins are software configurable with pullup device if input port. 2. Pin contains software configurable pullup/pulldown device if IRQ is enabled (IRQPE = 1). Pulldown is enabled if rising edge detect is selected (IRQEDG = 1) 3. IRQ does not have a clamp diode to VDD. IRQ should not be driven above VDD. 4. Pin contains integrated pullup device. 5. PTD3, PTD2, and PTG4 contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is selected (KBEDGn = 1).
Figure 11-1. MC9S08AC16 Block Diagram Highlighting the SCI
MC9S08AC16 Series Data Sheet, Rev. 8 190 Freescale Semiconductor
PORT G
2-CHANNEL TIMER/PWM MODULE (TPM3)
PTG6/EXTAL PTG5/XTAL PTG4/KBIP4 PTG3/KBIP3 PTG2/KBIP2 PTG1/KBIP1 PTG0/KBIP0
Serial Communications Interface (S08SCIV4)
11.1.1
Features
Features of SCI module include: * Full-duplex, standard non-return-to-zero (NRZ) format * Double-buffered transmitter and receiver with separate enables * Programmable baud rates (13-bit modulo divider) * Interrupt-driven or polled operation: -- Transmit data register empty and transmission complete -- Receive data register full -- Receive overrun, parity error, framing error, and noise error -- Idle receiver detect -- Active edge on receive pin -- Break detect supporting LIN * Hardware parity generation and checking * Programmable 8-bit or 9-bit character length * Receiver wakeup by idle-line or address-mark * Optional 13-bit break character generation / 11-bit break character detection * Selectable transmitter output polarity
11.1.2
Modes of Operation
See Section 11.3, "Functional Description," For details concerning SCI operation in these modes: * 8- and 9-bit data modes * Stop mode operation * Loop mode * Single-wire mode
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 191
Serial Communications Interface (S08SCIV4)
11.1.3
Block Diagram
INTERNAL BUS (WRITE-ONLY) LOOPS SCID - Tx BUFFER RSRC LOOP CONTROL
Figure 11-2 shows the transmitter portion of the SCI.
START
STOP
M
11-BIT TRANSMIT SHIFT REGISTER
TO RECEIVE DATA IN TO TxD PIN
SHIFT DIRECTION
LSB
1 x BAUD RATE CLOCK
H
8
7
6
5
4
3
2
1
0
L
TXINV PREAMBLE (ALL 1s)
LOAD FROM SCIxD
T8 PE PT TE SBK TXDIR BRK13
PARITY GENERATION
BREAK (ALL 0s) SCI CONTROLS TxD
SHIFT ENABLE
TRANSMIT CONTROL
TxD DIRECTION
TO TxD PIN LOGIC
TDRE TIE TC TCIE Tx INTERRUPT REQUEST
Figure 11-2. SCI Transmitter Block Diagram
MC9S08AC16 Series Data Sheet, Rev. 8 192 Freescale Semiconductor
Serial Communications Interface (S08SCIV4)
Figure 11-3 shows the receiver portion of the SCI.
INTERNAL BUS (READ-ONLY) 16 x BAUD RATE CLOCK FROM TRANSMITTER SINGLE-WIRE LOOP CONTROL LSB 8 7 6 5 4 3 2 1 0 SHIFT DIRECTION RWU RWUID RDRF RIE IDLE ILIE LBKDIF LBKDIE RXEDGIF RXEDGIE OR ORIE FE FEIE NF NEIE PE PT PARITY CHECKING PF PEIE ERROR INTERRUPT REQUEST Rx INTERRUPT REQUEST M LBKDE ALL 1s DATA RECOVERY MSB STOP LOOPS RSRC FROM RxD PIN RXINV START L 11-BIT RECEIVE SHIFT REGISTER DIVIDE BY 16 SCID - Rx BUFFER
H
WAKE ILT ACTIVE EDGE DETECT
WAKEUP LOGIC
Figure 11-3. SCI Receiver Block Diagram
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 193
Serial Communications Interface (S08SCIV4)
11.2
Register Definition
The SCI has eight 8-bit registers to control baud rate, select SCI options, report SCI status, and for transmit/receive data. Refer to the direct-page register summary in the Memory chapter of this data sheet for the absolute address assignments for all SCI registers. This section refers to registers and control bits only by their names.
11.2.1
SCI Baud Rate Registers (SCIxBDH, SCIxBDL)
This pair of registers controls the prescale divisor for SCI baud rate generation. To update the 13-bit baud rate setting [SBR12:SBR0], first write to SCIxBDH to buffer the high half of the new value and then write to SCIxBDL. The working value in SCIxBDH does not change until SCIxBDL is written. SCIxBDL is reset to a non-zero value, so after reset the baud rate generator remains disabled until the first time the receiver or transmitter is enabled (RE or TE bits in SCIxC2 are written to 1).
7 6 5 4 3 2 1 0
R LBKDIE W Reset 0 0 RXEDGIE
0 SBR12 0 0 SBR11 0 SBR10 0 SBR9 0 SBR8 0
= Unimplemented or Reserved
Figure 11-4. SCI Baud Rate Register (SCIxBDH) Table 11-1. SCIxBDH Field Descriptions
Field 7 LBKDIE 6 RXEDGIE 4:0 SBR[12:8] Description LIN Break Detect Interrupt Enable (for LBKDIF) 0 Hardware interrupts from LBKDIF disabled (use polling). 1 Hardware interrupt requested when LBKDIF flag is 1. RxD Input Active Edge Interrupt Enable (for RXEDGIF) 0 Hardware interrupts from RXEDGIF disabled (use polling). 1 Hardware interrupt requested when RXEDGIF flag is 1. Baud Rate Modulo Divisor -- The 13 bits in SBR[12:0] are referred to collectively as BR, and they set the modulo divide rate for the SCI baud rate generator. When BR = 0, the SCI baud rate generator is disabled to reduce supply current. When BR = 1 to 8191, the SCI baud rate = BUSCLK/(16xBR). See also BR bits in Table 11-2.
7
6
5
4
3
2
1
0
R SBR7 W Reset 0 0 0 0 0 1 0 0 SBR6 SBR5 SBR4 SBR3 SBR2 SBR1 SBR0
Figure 11-5. SCI Baud Rate Register (SCIxBDL)
MC9S08AC16 Series Data Sheet, Rev. 8 194 Freescale Semiconductor
Serial Communications Interface (S08SCIV4)
Table 11-2. SCIxBDL Field Descriptions
Field 7:0 SBR[7:0] Description Baud Rate Modulo Divisor -- These 13 bits in SBR[12:0] are referred to collectively as BR, and they set the modulo divide rate for the SCI baud rate generator. When BR = 0, the SCI baud rate generator is disabled to reduce supply current. When BR = 1 to 8191, the SCI baud rate = BUSCLK/(16xBR). See also BR bits in Table 11-1.
11.2.2
SCI Control Register 1 (SCIxC1)
This read/write register is used to control various optional features of the SCI system.
7
6
5
4
3
2
1
0
R LOOPS W Reset 0 0 0 0 0 0 0 0 SCISWAI RSRC M WAKE ILT PE PT
Figure 11-6. SCI Control Register 1 (SCIxC1) Table 11-3. SCIxC1 Field Descriptions
Field 7 LOOPS Description Loop Mode Select -- Selects between loop back modes and normal 2-pin full-duplex modes. When LOOPS = 1, the transmitter output is internally connected to the receiver input. 0 Normal operation -- RxD and TxD use separate pins. 1 Loop mode or single-wire mode where transmitter outputs are internally connected to receiver input. (See RSRC bit.) RxD pin is not used by SCI. SCI Stops in Wait Mode 0 SCI clocks continue to run in wait mode so the SCI can be the source of an interrupt that wakes up the CPU. 1 SCI clocks freeze while CPU is in wait mode. Receiver Source Select -- This bit has no meaning or effect unless the LOOPS bit is set to 1. When LOOPS = 1, the receiver input is internally connected to the TxD pin and RSRC determines whether this connection is also connected to the transmitter output. 0 Provided LOOPS = 1, RSRC = 0 selects internal loop back mode and the SCI does not use the RxD pins. 1 Single-wire SCI mode where the TxD pin is connected to the transmitter output and receiver input. 9-Bit or 8-Bit Mode Select 0 Normal -- start + 8 data bits (LSB first) + stop. 1 Receiver and transmitter use 9-bit data characters start + 8 data bits (LSB first) + 9th data bit + stop. Receiver Wakeup Method Select -- Refer to Section 11.3.3.2, "Receiver Wakeup Operation" for more information. 0 Idle-line wakeup. 1 Address-mark wakeup. Idle Line Type Select -- Setting this bit to 1 ensures that the stop bit and logic 1 bits at the end of a character do not count toward the 10 or 11 bit times of logic high level needed by the idle line detection logic. Refer to Section 11.3.3.2.1, "Idle-Line Wakeup" for more information. 0 Idle character bit count starts after start bit. 1 Idle character bit count starts after stop bit.
6 SCISWAI 5 RSRC
4 M
3 WAKE
2 ILT
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Table 11-3. SCIxC1 Field Descriptions (continued)
Field 1 PE Description Parity Enable -- Enables hardware parity generation and checking. When parity is enabled, the most significant bit (MSB) of the data character (eighth or ninth data bit) is treated as the parity bit. 0 No hardware parity generation or checking. 1 Parity enabled. Parity Type -- Provided parity is enabled (PE = 1), this bit selects even or odd parity. Odd parity means the total number of 1s in the data character, including the parity bit, is odd. Even parity means the total number of 1s in the data character, including the parity bit, is even. 0 Even parity. 1 Odd parity.
0 PT
11.2.3
SCI Control Register 2 (SCIxC2)
This register can be read or written at any time.
7 6 5 4 3 2 1 0
R TIE W Reset 0 0 0 0 0 0 0 0 TCIE RIE ILIE TE RE RWU SBK
Figure 11-7. SCI Control Register 2 (SCIxC2) Table 11-4. SCIxC2 Field Descriptions
Field 7 TIE 6 TCIE 5 RIE 4 ILIE 3 TE Description Transmit Interrupt Enable (for TDRE) 0 Hardware interrupts from TDRE disabled (use polling). 1 Hardware interrupt requested when TDRE flag is 1. Transmission Complete Interrupt Enable (for TC) 0 Hardware interrupts from TC disabled (use polling). 1 Hardware interrupt requested when TC flag is 1. Receiver Interrupt Enable (for RDRF) 0 Hardware interrupts from RDRF disabled (use polling). 1 Hardware interrupt requested when RDRF flag is 1. Idle Line Interrupt Enable (for IDLE) 0 Hardware interrupts from IDLE disabled (use polling). 1 Hardware interrupt requested when IDLE flag is 1. Transmitter Enable 0 Transmitter off. 1 Transmitter on. TE must be 1 in order to use the SCI transmitter. When TE = 1, the SCI forces the TxD pin to act as an output for the SCI system. When the SCI is configured for single-wire operation (LOOPS = RSRC = 1), TXDIR controls the direction of traffic on the single SCI communication line (TxD pin). TE also can be used to queue an idle character by writing TE = 0 then TE = 1 while a transmission is in progress. Refer to Section 11.3.2.1, "Send Break and Queued Idle" for more details. When TE is written to 0, the transmitter keeps control of the port TxD pin until any data, queued idle, or queued break character finishes transmitting before allowing the pin to revert to a general-purpose I/O pin.
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Table 11-4. SCIxC2 Field Descriptions (continued)
Field 2 RE Description Receiver Enable -- When the SCI receiver is off, the RxD pin reverts to being a general-purpose port I/O pin. If LOOPS = 1 the RxD pin reverts to being a general-purpose I/O pin even if RE = 1. 0 Receiver off. 1 Receiver on. Receiver Wakeup Control -- This bit can be written to 1 to place the SCI receiver in a standby state where it waits for automatic hardware detection of a selected wakeup condition. The wakeup condition is either an idle line between messages (WAKE = 0, idle-line wakeup), or a logic 1 in the most significant data bit in a character (WAKE = 1, address-mark wakeup). Application software sets RWU and (normally) a selected hardware condition automatically clears RWU. Refer to Section 11.3.3.2, "Receiver Wakeup Operation" for more details. 0 Normal SCI receiver operation. 1 SCI receiver in standby waiting for wakeup condition. Send Break -- Writing a 1 and then a 0 to SBK queues a break character in the transmit data stream. Additional break characters of 10 or 11 (13 or 14 if BRK13 = 1) bit times of logic 0 are queued as long as SBK = 1. Depending on the timing of the set and clear of SBK relative to the information currently being transmitted, a second break character may be queued before software clears SBK. Refer to Section 11.3.2.1, "Send Break and Queued Idle" for more details. 0 Normal transmitter operation. 1 Queue break character(s) to be sent.
1 RWU
0 SBK
11.2.4
SCI Status Register 1 (SCIxS1)
This register has eight read-only status flags. Writes have no effect. Special software sequences (which do not involve writing to this register) are used to clear these status flags.
7
6
5
4
3
2
1
0
R W Reset
TDRE
TC
RDRF
IDLE
OR
NF
FE
PF
1
1
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 11-8. SCI Status Register 1 (SCIxS1)
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 197
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Table 11-5. SCIxS1 Field Descriptions
Field 7 TDRE Description Transmit Data Register Empty Flag -- TDRE is set out of reset and when a transmit data value transfers from the transmit data buffer to the transmit shifter, leaving room for a new character in the buffer. To clear TDRE, read SCIxS1 with TDRE = 1 and then write to the SCI data register (SCIxD). 0 Transmit data register (buffer) full. 1 Transmit data register (buffer) empty. Transmission Complete Flag -- TC is set out of reset and when TDRE = 1 and no data, preamble, or break character is being transmitted. 0 Transmitter active (sending data, a preamble, or a break). 1 Transmitter idle (transmission activity complete). TC is cleared automatically by reading SCIxS1 with TC = 1 and then doing one of the following three things: * Write to the SCI data register (SCIxD) to transmit new data * Queue a preamble by changing TE from 0 to 1 * Queue a break character by writing 1 to SBK in SCIxC2 Receive Data Register Full Flag -- RDRF becomes set when a character transfers from the receive shifter into the receive data register (SCIxD). To clear RDRF, read SCIxS1 with RDRF = 1 and then read the SCI data register (SCIxD). 0 Receive data register empty. 1 Receive data register full. Idle Line Flag -- IDLE is set when the SCI receive line becomes idle for a full character time after a period of activity. When ILT = 0, the receiver starts counting idle bit times after the start bit. So if the receive character is all 1s, these bit times and the stop bit time count toward the full character time of logic high (10 or 11 bit times depending on the M control bit) needed for the receiver to detect an idle line. When ILT = 1, the receiver doesn't start counting idle bit times until after the stop bit. So the stop bit and any logic high bit times at the end of the previous character do not count toward the full character time of logic high needed for the receiver to detect an idle line. To clear IDLE, read SCIxS1 with IDLE = 1 and then read the SCI data register (SCIxD). After IDLE has been cleared, it cannot become set again until after a new character has been received and RDRF has been set. IDLE will get set only once even if the receive line remains idle for an extended period. 0 No idle line detected. 1 Idle line was detected. Receiver Overrun Flag -- OR is set when a new serial character is ready to be transferred to the receive data register (buffer), but the previously received character has not been read from SCIxD yet. In this case, the new character (and all associated error information) is lost because there is no room to move it into SCIxD. To clear OR, read SCIxS1 with OR = 1 and then read the SCI data register (SCIxD). 0 No overrun. 1 Receive overrun (new SCI data lost). Noise Flag -- The advanced sampling technique used in the receiver takes seven samples during the start bit and three samples in each data bit and the stop bit. If any of these samples disagrees with the rest of the samples within any bit time in the frame, the flag NF will be set at the same time as the flag RDRF gets set for the character. To clear NF, read SCIxS1 and then read the SCI data register (SCIxD). 0 No noise detected. 1 Noise detected in the received character in SCIxD.
6 TC
5 RDRF
4 IDLE
3 OR
2 NF
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Table 11-5. SCIxS1 Field Descriptions (continued)
Field 1 FE Description Framing Error Flag -- FE is set at the same time as RDRF when the receiver detects a logic 0 where the stop bit was expected. This suggests the receiver was not properly aligned to a character frame. To clear FE, read SCIxS1 with FE = 1 and then read the SCI data register (SCIxD). 0 No framing error detected. This does not guarantee the framing is correct. 1 Framing error. Parity Error Flag -- PF is set at the same time as RDRF when parity is enabled (PE = 1) and the parity bit in the received character does not agree with the expected parity value. To clear PF, read SCIxS1 and then read the SCI data register (SCIxD). 0 No parity error. 1 Parity error.
0 PF
11.2.5
SCI Status Register 2 (SCIxS2)
This register has one read-only status flag.
7 6 5 4 3 2 1 0
R LBKDIF W Reset 0 0 RXEDGIF
0 RXINV 0 0 RWUID 0 BRK13 0 LBKDE 0
RAF
0
= Unimplemented or Reserved
Figure 11-9. SCI Status Register 2 (SCIxS2) Table 11-6. SCIxS2 Field Descriptions
Field 7 LBKDIF Description LIN Break Detect Interrupt Flag -- LBKDIF is set when the LIN break detect circuitry is enabled and a LIN break character is detected. LBKDIF is cleared by writing a "1" to it. 0 No LIN break character has been detected. 1 LIN break character has been detected. RxD Pin Active Edge Interrupt Flag -- RXEDGIF is set when an active edge (falling if RXINV = 0, rising if RXINV=1) on the RxD pin occurs. RXEDGIF is cleared by writing a "1" to it. 0 No active edge on the receive pin has occurred. 1 An active edge on the receive pin has occurred. Receive Data Inversion -- Setting this bit reverses the polarity of the received data input. 0 Receive data not inverted 1 Receive data inverted Receive Wake Up Idle Detect-- RWUID controls whether the idle character that wakes up the receiver sets the IDLE bit. 0 During receive standby state (RWU = 1), the IDLE bit does not get set upon detection of an idle character. 1 During receive standby state (RWU = 1), the IDLE bit gets set upon detection of an idle character. Break Character Generation Length -- BRK13 is used to select a longer transmitted break character length. Detection of a framing error is not affected by the state of this bit. 0 Break character is transmitted with length of 10 bit times (11 if M = 1) 1 Break character is transmitted with length of 13 bit times (14 if M = 1)
6 RXEDGIF
4 RXINV1 3 RWUID
2 BRK13
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Table 11-6. SCIxS2 Field Descriptions (continued)
Field 1 LBKDE Description LIN Break Detection Enable-- LBKDE is used to select a longer break character detection length. While LBKDE is set, framing error (FE) and receive data register full (RDRF) flags are prevented from setting. 0 Break character is detected at length of 10 bit times (11 if M = 1). 1 Break character is detected at length of 11 bit times (12 if M = 1). Receiver Active Flag -- RAF is set when the SCI receiver detects the beginning of a valid start bit, and RAF is cleared automatically when the receiver detects an idle line. This status flag can be used to check whether an SCI character is being received before instructing the MCU to go to stop mode. 0 SCI receiver idle waiting for a start bit. 1 SCI receiver active (RxD input not idle).
0 RAF
1
Setting RXINV inverts the RxD input for all cases: data bits, start and stop bits, break, and idle.
When using an internal oscillator in a LIN system, it is necessary to raise the break detection threshold by one bit time. Under the worst case timing conditions allowed in LIN, it is possible that a 0x00 data character can appear to be 10.26 bit times long at a slave which is running 14% faster than the master. This would trigger normal break detection circuitry which is designed to detect a 10 bit break symbol. When the LBKDE bit is set, framing errors are inhibited and the break detection threshold changes from 10 bits to 11 bits, preventing false detection of a 0x00 data character as a LIN break symbol.
11.2.6
SCI Control Register 3 (SCIxC3)
7 6 5 4 3 2 1 0
R W Reset
R8 T8 0 0 TXDIR 0 TXINV 0 ORIE 0 NEIE 0 FEIE 0 PEIE 0
= Unimplemented or Reserved
Figure 11-10. SCI Control Register 3 (SCIxC3) Table 11-7. SCIxC3 Field Descriptions
Field 7 R8 Description Ninth Data Bit for Receiver -- When the SCI is configured for 9-bit data (M = 1), R8 can be thought of as a ninth receive data bit to the left of the MSB of the buffered data in the SCIxD register. When reading 9-bit data, read R8 before reading SCIxD because reading SCIxD completes automatic flag clearing sequences which could allow R8 and SCIxD to be overwritten with new data. Ninth Data Bit for Transmitter -- When the SCI is configured for 9-bit data (M = 1), T8 may be thought of as a ninth transmit data bit to the left of the MSB of the data in the SCIxD register. When writing 9-bit data, the entire 9-bit value is transferred to the SCI shift register after SCIxD is written so T8 should be written (if it needs to change from its previous value) before SCIxD is written. If T8 does not need to change in the new value (such as when it is used to generate mark or space parity), it need not be written each time SCIxD is written. TxD Pin Direction in Single-Wire Mode -- When the SCI is configured for single-wire half-duplex operation (LOOPS = RSRC = 1), this bit determines the direction of data at the TxD pin. 0 TxD pin is an input in single-wire mode. 1 TxD pin is an output in single-wire mode.
6 T8
5 TXDIR
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Table 11-7. SCIxC3 Field Descriptions (continued)
Field 4 TXINV1 3 ORIE 2 NEIE 1 FEIE Description Transmit Data Inversion -- Setting this bit reverses the polarity of the transmitted data output. 0 Transmit data not inverted 1 Transmit data inverted Overrun Interrupt Enable -- This bit enables the overrun flag (OR) to generate hardware interrupt requests. 0 OR interrupts disabled (use polling). 1 Hardware interrupt requested when OR = 1. Noise Error Interrupt Enable -- This bit enables the noise flag (NF) to generate hardware interrupt requests. 0 NF interrupts disabled (use polling). 1 Hardware interrupt requested when NF = 1. Framing Error Interrupt Enable -- This bit enables the framing error flag (FE) to generate hardware interrupt requests. 0 FE interrupts disabled (use polling). 1 Hardware interrupt requested when FE = 1. Parity Error Interrupt Enable -- This bit enables the parity error flag (PF) to generate hardware interrupt requests. 0 PF interrupts disabled (use polling). 1 Hardware interrupt requested when PF = 1.
0 PEIE
1
Setting TXINV inverts the TxD output for all cases: data bits, start and stop bits, break, and idle.
11.2.7
SCI Data Register (SCIxD)
This register is actually two separate registers. Reads return the contents of the read-only receive data buffer and writes go to the write-only transmit data buffer. Reads and writes of this register are also involved in the automatic flag clearing mechanisms for the SCI status flags.
7 6 5 4 3 2 1 0
R W Reset
R7 T7 0
R6 T6 0
R5 T5 0
R4 T4 0
R3 T3 0
R2 T2 0
R1 T1 0
R0 T0 0
Figure 11-11. SCI Data Register (SCIxD)
11.3
Functional Description
The SCI allows full-duplex, asynchronous, NRZ serial communication among the MCU and remote devices, including other MCUs. The SCI comprises a baud rate generator, transmitter, and receiver block. The transmitter and receiver operate independently, although they use the same baud rate generator. During normal operation, the MCU monitors the status of the SCI, writes the data to be transmitted, and processes received data. The following describes each of the blocks of the SCI.
11.3.1
Baud Rate Generation
As shown in Figure 11-12, the clock source for the SCI baud rate generator is the bus-rate clock.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 201
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MODULO DIVIDE BY (1 THROUGH 8191) DIVIDE BY 16 Tx BAUD RATE
BUSCLK
SBR12:SBR0 BAUD RATE GENERATOR OFF IF [SBR12:SBR0] = 0
Rx SAMPLING CLOCK (16 x BAUD RATE) BAUD RATE = BUSCLK [SBR12:SBR0] x 16
Figure 11-12. SCI Baud Rate Generation
SCI communications require the transmitter and receiver (which typically derive baud rates from independent clock sources) to use the same baud rate. Allowed tolerance on this baud frequency depends on the details of how the receiver synchronizes to the leading edge of the start bit and how bit sampling is performed. The MCU resynchronizes to bit boundaries on every high-to-low transition, but in the worst case, there are no such transitions in the full 10- or 11-bit time character frame so any mismatch in baud rate is accumulated for the whole character time. For a SCI system whose bus frequency is driven by a crystal, the allowed baud rate mismatch is about 4.5 percent for 8-bit data format and about 4 percent for 9-bit data format. Although baud rate modulo divider settings do not always produce baud rates that exactly match standard rates, it is normally possible to get within a few percent, which is acceptable for reliable communications.
11.3.2
Transmitter Functional Description
This section describes the overall block diagram for the SCI transmitter, as well as specialized functions for sending break and idle characters. The transmitter block diagram is shown in Figure 11-2. The transmitter output (TxD) idle state defaults to logic high (TXINV = 0 following reset). The transmitter output is inverted by setting TXINV = 1. The transmitter is enabled by setting the TE bit in SCIxC2. This queues a preamble character that is one full character frame of the idle state. The transmitter then remains idle until data is available in the transmit data buffer. Programs store data into the transmit data buffer by writing to the SCI data register (SCIxD). The central element of the SCI transmitter is the transmit shift register that is either 10 or 11 bits long depending on the setting in the M control bit. For the remainder of this section, we will assume M = 0, selecting the normal 8-bit data mode. In 8-bit data mode, the shift register holds a start bit, eight data bits, and a stop bit. When the transmit shift register is available for a new SCI character, the value waiting in the transmit data register is transferred to the shift register (synchronized with the baud rate clock) and the transmit data register empty (TDRE) status flag is set to indicate another character may be written to the transmit data buffer at SCIxD. If no new character is waiting in the transmit data buffer after a stop bit is shifted out the TxD pin, the transmitter sets the transmit complete flag and enters an idle mode, with TxD high, waiting for more characters to transmit.
MC9S08AC16 Series Data Sheet, Rev. 8 202 Freescale Semiconductor
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Writing 0 to TE does not immediately release the pin to be a general-purpose I/O pin. Any transmit activity that is in progress must first be completed. This includes data characters in progress, queued idle characters, and queued break characters.
11.3.2.1
Send Break and Queued Idle
The SBK control bit in SCIxC2 is used to send break characters which were originally used to gain the attention of old teletype receivers. Break characters are a full character time of logic 0 (10 bit times including the start and stop bits). A longer break of 13 bit times can be enabled by setting BRK13 = 1. Normally, a program would wait for TDRE to become set to indicate the last character of a message has moved to the transmit shifter, then write 1 and then write 0 to the SBK bit. This action queues a break character to be sent as soon as the shifter is available. If SBK is still 1 when the queued break moves into the shifter (synchronized to the baud rate clock), an additional break character is queued. If the receiving device is another SCI, the break characters will be received as 0s in all eight data bits and a framing error (FE = 1) occurs. When idle-line wakeup is used, a full character time of idle (logic 1) is needed between messages to wake up any sleeping receivers. Normally, a program would wait for TDRE to become set to indicate the last character of a message has moved to the transmit shifter, then write 0 and then write 1 to the TE bit. This action queues an idle character to be sent as soon as the shifter is available. As long as the character in the shifter does not finish while TE = 0, the SCI transmitter never actually releases control of the TxD pin. If there is a possibility of the shifter finishing while TE = 0, set the general-purpose I/O controls so the pin that is shared with TxD is an output driving a logic 1. This ensures that the TxD line will look like a normal idle line even if the SCI loses control of the port pin between writing 0 and then 1 to TE. The length of the break character is affected by the BRK13 and M bits as shown below.
Table 11-8. Break Character Length
BRK13 0 0 1 1 M 0 1 0 1 Break Character Length 10 bit times 11 bit times 13 bit times 14 bit times
11.3.3
Receiver Functional Description
In this section, the receiver block diagram (Figure 11-3) is used as a guide for the overall receiver functional description. Next, the data sampling technique used to reconstruct receiver data is described in more detail. Finally, two variations of the receiver wakeup function are explained. The receiver input is inverted by setting RXINV = 1. The receiver is enabled by setting the RE bit in SCIxC2. Character frames consist of a start bit of logic 0, eight (or nine) data bits (LSB first), and a stop bit of logic 1. For information about 9-bit data mode, refer to Section 11.3.5.1, "8- and 9-Bit Data Modes." For the remainder of this discussion, we assume the SCI is configured for normal 8-bit data mode. After receiving the stop bit into the receive shifter, and provided the receive data register is not already full, the data character is transferred to the receive data register and the receive data register full (RDRF)
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status flag is set. If RDRF was already set indicating the receive data register (buffer) was already full, the overrun (OR) status flag is set and the new data is lost. Because the SCI receiver is double-buffered, the program has one full character time after RDRF is set before the data in the receive data buffer must be read to avoid a receiver overrun. When a program detects that the receive data register is full (RDRF = 1), it gets the data from the receive data register by reading SCIxD. The RDRF flag is cleared automatically by a 2-step sequence which is normally satisfied in the course of the user's program that handles receive data. Refer to Section 11.3.4, "Interrupts and Status Flags" for more details about flag clearing.
11.3.3.1
Data Sampling Technique
The SCI receiver uses a 16x baud rate clock for sampling. The receiver starts by taking logic level samples at 16 times the baud rate to search for a falling edge on the RxD serial data input pin. A falling edge is defined as a logic 0 sample after three consecutive logic 1 samples. The 16x baud rate clock is used to divide the bit time into 16 segments labeled RT1 through RT16. When a falling edge is located, three more samples are taken at RT3, RT5, and RT7 to make sure this was a real start bit and not merely noise. If at least two of these three samples are 0, the receiver assumes it is synchronized to a receive character. The receiver then samples each bit time, including the start and stop bits, at RT8, RT9, and RT10 to determine the logic level for that bit. The logic level is interpreted to be that of the majority of the samples taken during the bit time. In the case of the start bit, the bit is assumed to be 0 if at least two of the samples at RT3, RT5, and RT7 are 0 even if one or all of the samples taken at RT8, RT9, and RT10 are 1s. If any sample in any bit time (including the start and stop bits) in a character frame fails to agree with the logic level for that bit, the noise flag (NF) will be set when the received character is transferred to the receive data buffer. The falling edge detection logic continuously looks for falling edges, and if an edge is detected, the sample clock is resynchronized to bit times. This improves the reliability of the receiver in the presence of noise or mismatched baud rates. It does not improve worst case analysis because some characters do not have any extra falling edges anywhere in the character frame. In the case of a framing error, provided the received character was not a break character, the sampling logic that searches for a falling edge is filled with three logic 1 samples so that a new start bit can be detected almost immediately. In the case of a framing error, the receiver is inhibited from receiving any new characters until the framing error flag is cleared. The receive shift register continues to function, but a complete character cannot transfer to the receive data buffer if FE is still set.
11.3.3.2
Receiver Wakeup Operation
Receiver wakeup is a hardware mechanism that allows an SCI receiver to ignore the characters in a message that is intended for a different SCI receiver. In such a system, all receivers evaluate the first character(s) of each message, and as soon as they determine the message is intended for a different receiver, they write logic 1 to the receiver wake up (RWU) control bit in SCIxC2. When RWU bit is set, the status flags associated with the receiver (with the exception of the idle bit, IDLE, when RWUID bit is set) are inhibited from setting, thus eliminating the software overhead for handling the unimportant
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message characters. At the end of a message, or at the beginning of the next message, all receivers automatically force RWU to 0 so all receivers wake up in time to look at the first character(s) of the next message. 11.3.3.2.1 Idle-Line Wakeup
When WAKE = 0, the receiver is configured for idle-line wakeup. In this mode, RWU is cleared automatically when the receiver detects a full character time of the idle-line level. The M control bit selects 8-bit or 9-bit data mode that determines how many bit times of idle are needed to constitute a full character time (10 or 11 bit times because of the start and stop bits). When RWU is one and RWUID is zero, the idle condition that wakes up the receiver does not set the IDLE flag. The receiver wakes up and waits for the first data character of the next message which will set the RDRF flag and generate an interrupt if enabled. When RWUID is one, any idle condition sets the IDLE flag and generates an interrupt if enabled, regardless of whether RWU is zero or one. The idle-line type (ILT) control bit selects one of two ways to detect an idle line. When ILT = 0, the idle bit counter starts after the start bit so the stop bit and any logic 1s at the end of a character count toward the full character time of idle. When ILT = 1, the idle bit counter does not start until after a stop bit time, so the idle detection is not affected by the data in the last character of the previous message. 11.3.3.2.2 Address-Mark Wakeup
When WAKE = 1, the receiver is configured for address-mark wakeup. In this mode, RWU is cleared automatically when the receiver detects a logic 1 in the most significant bit of a received character (eighth bit in M = 0 mode and ninth bit in M = 1 mode). Address-mark wakeup allows messages to contain idle characters but requires that the MSB be reserved for use in address frames. The logic 1 MSB of an address frame clears the RWU bit before the stop bit is received and sets the RDRF flag. In this case the character with the MSB set is received even though the receiver was sleeping during most of this character time.
11.3.4
Interrupts and Status Flags
The SCI system has three separate interrupt vectors to reduce the amount of software needed to isolate the cause of the interrupt. One interrupt vector is associated with the transmitter for TDRE and TC events. Another interrupt vector is associated with the receiver for RDRF, IDLE, RXEDGIF and LBKDIF events, and a third vector is used for OR, NF, FE, and PF error conditions. Each of these ten interrupt sources can be separately masked by local interrupt enable masks. The flags can still be polled by software when the local masks are cleared to disable generation of hardware interrupt requests. The SCI transmitter has two status flags that optionally can generate hardware interrupt requests. Transmit data register empty (TDRE) indicates when there is room in the transmit data buffer to write another transmit character to SCIxD. If the transmit interrupt enable (TIE) bit is set, a hardware interrupt will be requested whenever TDRE = 1. Transmit complete (TC) indicates that the transmitter is finished transmitting all data, preamble, and break characters and is idle with TxD at the inactive level. This flag is often used in systems with modems to determine when it is safe to turn off the modem. If the transmit complete interrupt enable (TCIE) bit is set, a hardware interrupt will be requested whenever TC = 1.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 205
Serial Communications Interface (S08SCIV4)
Instead of hardware interrupts, software polling may be used to monitor the TDRE and TC status flags if the corresponding TIE or TCIE local interrupt masks are 0s. When a program detects that the receive data register is full (RDRF = 1), it gets the data from the receive data register by reading SCIxD. The RDRF flag is cleared by reading SCIxS1 while RDRF = 1 and then reading SCIxD. When polling is used, this sequence is naturally satisfied in the normal course of the user program. If hardware interrupts are used, SCIxS1 must be read in the interrupt service routine (ISR). Normally, this is done in the ISR anyway to check for receive errors, so the sequence is automatically satisfied. The IDLE status flag includes logic that prevents it from getting set repeatedly when the RxD line remains idle for an extended period of time. IDLE is cleared by reading SCIxS1 while IDLE = 1 and then reading SCIxD. After IDLE has been cleared, it cannot become set again until the receiver has received at least one new character and has set RDRF. If the associated error was detected in the received character that caused RDRF to be set, the error flags -- noise flag (NF), framing error (FE), and parity error flag (PF) -- get set at the same time as RDRF. These flags are not set in overrun cases. If RDRF was already set when a new character is ready to be transferred from the receive shifter to the receive data buffer, the overrun (OR) flag gets set instead the data along with any associated NF, FE, or PF condition is lost. At any time, an active edge on the RxD serial data input pin causes the RXEDGIF flag to set. The RXEDGIF flag is cleared by writing a "1" to it. This function does depend on the receiver being enabled (RE = 1).
11.3.5
Additional SCI Functions
The following sections describe additional SCI functions.
11.3.5.1
8- and 9-Bit Data Modes
The SCI system (transmitter and receiver) can be configured to operate in 9-bit data mode by setting the M control bit in SCIxC1. In 9-bit mode, there is a ninth data bit to the left of the MSB of the SCI data register. For the transmit data buffer, this bit is stored in T8 in SCIxC3. For the receiver, the ninth bit is held in R8 in SCIxC3. For coherent writes to the transmit data buffer, write to the T8 bit before writing to SCIxD. If the bit value to be transmitted as the ninth bit of a new character is the same as for the previous character, it is not necessary to write to T8 again. When data is transferred from the transmit data buffer to the transmit shifter, the value in T8 is copied at the same time data is transferred from SCIxD to the shifter. 9-bit data mode typically is used in conjunction with parity to allow eight bits of data plus the parity in the ninth bit. Or it is used with address-mark wakeup so the ninth data bit can serve as the wakeup bit. In custom protocols, the ninth bit can also serve as a software-controlled marker.
MC9S08AC16 Series Data Sheet, Rev. 8 206 Freescale Semiconductor
Serial Communications Interface (S08SCIV4)
11.3.5.2
Stop Mode Operation
During all stop modes, clocks to the SCI module are halted. In stop1 and stop2 modes, all SCI register data is lost and must be re-initialized upon recovery from these two stop modes. No SCI module registers are affected in stop3 mode. The receive input active edge detect circuit is still active in stop3 mode, but not in stop2.. An active edge on the receive input brings the CPU out of stop3 mode if the interrupt is not masked (RXEDGIE = 1). Note, because the clocks are halted, the SCI module will resume operation upon exit from stop (only in stop3 mode). Software should ensure stop mode is not entered while there is a character being transmitted out of or received into the SCI module.
11.3.5.3
Loop Mode
When LOOPS = 1, the RSRC bit in the same register chooses between loop mode (RSRC = 0) or single-wire mode (RSRC = 1). Loop mode is sometimes used to check software, independent of connections in the external system, to help isolate system problems. In this mode, the transmitter output is internally connected to the receiver input and the RxD pin is not used by the SCI, so it reverts to a general-purpose port I/O pin.
11.3.5.4
Single-Wire Operation
When LOOPS = 1, the RSRC bit in the same register chooses between loop mode (RSRC = 0) or single-wire mode (RSRC = 1). Single-wire mode is used to implement a half-duplex serial connection. The receiver is internally connected to the transmitter output and to the TxD pin. The RxD pin is not used and reverts to a general-purpose port I/O pin. In single-wire mode, the TXDIR bit in SCIxC3 controls the direction of serial data on the TxD pin. When TXDIR = 0, the TxD pin is an input to the SCI receiver and the transmitter is temporarily disconnected from the TxD pin so an external device can send serial data to the receiver. When TXDIR = 1, the TxD pin is an output driven by the transmitter. In single-wire mode, the internal loop back connection from the transmitter to the receiver causes the receiver to receive characters that are sent out by the transmitter.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 207
Serial Communications Interface (S08SCIV4)
MC9S08AC16 Series Data Sheet, Rev. 8 208 Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S08SPIV3)
12.1 Introduction
The MC9S08AC16 Series has one serial peripheral interface (SPI) module. The four pins associated with SPI functionality are shared with port E pins 4-7. See Appendix A, "Electrical Characteristics and Timing Specifications," for SPI electrical parametric information. NOTE Ignore any references to stop1 low-power mode in this chapter, because the MC9S08AC16 Series does not support it.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 209
Chapter 12 Serial Peripheral Interface (S08SPIV3) VDDAD VSSAD VREFL VREFH HCS08 CORE BKGD/MS BDC CPU IIC MODULE (IIC1) RESET IRQ/TPMCLK HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
10-BIT ANALOG-TO-DIGITAL CONVERTER (ADC1) DEBUG MODULE (DBG)
4 AD1P11-AD1P8
PORT A
4 AD1P3-AD1P0
PTA7 PTA2 PTA1 PTA0 PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 PTB0/TPM3CH0/AD1P0 PTC5/RxD2 PTC4 PTC3/TxD2 PTC2/MCLK PTC1/SDA1 PTC0/SCL1 PTD3/KBIP6/AD1P11 PTD2/KBIP5/AD1P10 PTD1/AD1P9 PTD0/AD1P8
SDA1 SCL1 PORT C PORT D
MODES OF OPERATION POWER MANAGEMENT RTI IRQ COP LVD
INTERNAL CLOCK GENERATOR (ICG) LOW-POWER OSCILLATOR 7-BIT KEYBOARD INTERRUPT MODULE (KBI)
EXTAL XTAL
2 KBIP6-KBIP5 5 KBIP4-KBIP0 RxD1 TxD1 RxD2 TxD2 SPSCK1 MOSI1 MISO1 SS1 TPM1CH1 TPM1CH0 TPM1CH3 TPM1CH2 TPM2CH1 TPM2CH0 TPM3CH1 TPM3CH0
TPMCLK
SERIAL COMMUNICATIONS INTERFACE MODULE (SCI1) SERIAL COMMUNICATIONS INTERFACE MODULE (SCI2) SERIAL PERIPHERAL INTERFACE MODULE (SPI1)
PORT B
USER FLASH 16,384 BYTES OR 8192 BYTES
PTE7/SPSCK1 PTE6/MOSI1 PTE5/MISO1 PTE4/SS1 PTE3/TPM1CH1 PTE2/TPM1CH0 PTE1/RxD1 PTE0/TxD1
USER RAM 1024 BYTES OR 768 BYTES VDD VSS VOLTAGE REGULATOR
2-CHANNEL TIMER/PWM MODULE (TPM2)
PORT F
4-CHANNEL TIMER/PWM MODULE (TPM1)
PORT E
PTF6 PTF5/TPM2CH1 PTF4/TPM2CH0 PTF1/TPM1CH3 PTF0/TPM1CH2
= Not available on 32-, 42-, or 44-pin packages = Not available on 32- or 42-pin packages = Not available on 32-pin packages
Notes: 1. Port pins are software configurable with pullup device if input port. 2. Pin contains software configurable pullup/pulldown device if IRQ is enabled (IRQPE = 1). Pulldown is enabled if rising edge detect is selected (IRQEDG = 1) 3. IRQ does not have a clamp diode to VDD. IRQ should not be driven above VDD. 4. Pin contains integrated pullup device. 5. PTD3, PTD2, and PTG4 contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is selected (KBEDGn = 1).
Figure 12-1. MC9S08AC16 Block Diagram Highlighting the SPI
MC9S08AC16 Series Data Sheet, Rev. 8 210 Freescale Semiconductor
PORT G
2-CHANNEL TIMER/PWM MODULE (TPM3)
PTG6/EXTAL PTG5/XTAL PTG4/KBIP4 PTG3/KBIP3 PTG2/KBIP2 PTG1/KBIP1 PTG0/KBIP0
Serial Peripheral Interface (S08SPIV3)
12.1.1
Features
Features of the SPI module include: * Master or slave mode operation * Full-duplex or single-wire bidirectional option * Programmable transmit bit rate * Double-buffered transmit and receive * Serial clock phase and polarity options * Slave select output * Selectable MSB-first or LSB-first shifting
12.1.2
Block Diagrams
This section includes block diagrams showing SPI system connections, the internal organization of the SPI module, and the SPI clock dividers that control the master mode bit rate.
12.1.2.1
SPI System Block Diagram
Figure 12-2 shows the SPI modules of two MCUs connected in a master-slave arrangement. The master device initiates all SPI data transfers. During a transfer, the master shifts data out (on the MOSI pin) to the slave while simultaneously shifting data in (on the MISO pin) from the slave. The transfer effectively exchanges the data that was in the SPI shift registers of the two SPI systems. The SPSCK signal is a clock output from the master and an input to the slave. The slave device must be selected by a low level on the slave select input (SS pin). In this system, the master device has configured its SS pin as an optional slave select output.
MASTER MOSI SPI SHIFTER 7 6 5 4 3 2 1 0 MISO MISO 7 6 MOSI SPI SHIFTER 5 4 3 2 1 0 SLAVE
SPSCK CLOCK GENERATOR
SPSCK
SS
SS
Figure 12-2. SPI System Connections
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 211
Serial Peripheral Interface (S08SPIV3)
The most common uses of the SPI system include connecting simple shift registers for adding input or output ports or connecting small peripheral devices such as serial A/D or D/A converters. Although Figure 12-2 shows a system where data is exchanged between two MCUs, many practical systems involve simpler connections where data is unidirectionally transferred from the master MCU to a slave or from a slave to the master MCU.
12.1.2.2
SPI Module Block Diagram
Figure 12-3 is a block diagram of the SPI module. The central element of the SPI is the SPI shift register. Data is written to the double-buffered transmitter (write to SPI1D) and gets transferred to the SPI shift register at the start of a data transfer. After shifting in a byte of data, the data is transferred into the double-buffered receiver where it can be read (read from SPI1D). Pin multiplexing logic controls connections between MCU pins and the SPI module. When the SPI is configured as a master, the clock output is routed to the SPSCK pin, the shifter output is routed to MOSI, and the shifter input is routed from the MISO pin. When the SPI is configured as a slave, the SPSCK pin is routed to the clock input of the SPI, the shifter output is routed to MISO, and the shifter input is routed from the MOSI pin. In the external SPI system, simply connect all SPSCK pins to each other, all MISO pins together, and all MOSI pins together. Peripheral devices often use slightly different names for these pins.
MC9S08AC16 Series Data Sheet, Rev. 8 212 Freescale Semiconductor
Serial Peripheral Interface (S08SPIV3) PIN CONTROL M SPE Tx BUFFER (WRITE SPI1D) ENABLE SPI SYSTEM SHIFT OUT SPI SHIFT REGISTER SHIFT IN SPC0 BIDIROE LSBFE SHIFT DIRECTION SHIFT CLOCK Rx BUFFER FULL Tx BUFFER EMPTY M S MISO (SISO) S
MOSI (MOMI)
Rx BUFFER (READ SPI1D)
MASTER CLOCK BUS RATE CLOCK MSTR SPIBR CLOCK GENERATOR MASTER/SLAVE MODE SELECT MODFEN MODE FAULT DETECTION SSOE CLOCK LOGIC SLAVE CLOCK
M S MASTER/ SLAVE SPSCK
SS
SPRF
SPTEF SPTIE SPI INTERRUPT REQUEST
MODF SPIE
Figure 12-3. SPI Module Block Diagram
12.1.3
SPI Baud Rate Generation
As shown in Figure 12-4, the clock source for the SPI baud rate generator is the bus clock. The three prescale bits (SPPR2:SPPR1:SPPR0) choose a prescale divisor of 1, 2, 3, 4, 5, 6, 7, or 8. The three rate select bits (SPR2:SPR1:SPR0) divide the output of the prescaler stage by 2, 4, 8, 16, 32, 64, 128, or 256 to get the internal SPI master mode bit-rate clock.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 213
Serial Peripheral Interface (S08SPIV3) PRESCALER BUS CLOCK DIVIDE BY 1, 2, 3, 4, 5, 6, 7, or 8 CLOCK RATE DIVIDER DIVIDE BY 2, 4, 8, 16, 32, 64, 128, or 256 MASTER SPI BIT RATE
SPPR2:SPPR1:SPPR0
SPR2:SPR1:SPR0
Figure 12-4. SPI Baud Rate Generation
12.2
External Signal Description
The SPI optionally shares four port pins. The function of these pins depends on the settings of SPI control bits. When the SPI is disabled (SPE = 0), these four pins revert to being general-purpose port I/O pins that are not controlled by the SPI.
12.2.1
SPSCK -- SPI Serial Clock
When the SPI is enabled as a slave, this pin is the serial clock input. When the SPI is enabled as a master, this pin is the serial clock output.
12.2.2
MOSI -- Master Data Out, Slave Data In
When the SPI is enabled as a master and SPI pin control zero (SPC0) is 0 (not bidirectional mode), this pin is the serial data output. When the SPI is enabled as a slave and SPC0 = 0, this pin is the serial data input. If SPC0 = 1 to select single-wire bidirectional mode, and master mode is selected, this pin becomes the bidirectional data I/O pin (MOMI). Also, the bidirectional mode output enable bit determines whether the pin acts as an input (BIDIROE = 0) or an output (BIDIROE = 1). If SPC0 = 1 and slave mode is selected, this pin is not used by the SPI and reverts to being a general-purpose port I/O pin.
12.2.3
MISO -- Master Data In, Slave Data Out
When the SPI is enabled as a master and SPI pin control zero (SPC0) is 0 (not bidirectional mode), this pin is the serial data input. When the SPI is enabled as a slave and SPC0 = 0, this pin is the serial data output. If SPC0 = 1 to select single-wire bidirectional mode, and slave mode is selected, this pin becomes the bidirectional data I/O pin (SISO) and the bidirectional mode output enable bit determines whether the pin acts as an input (BIDIROE = 0) or an output (BIDIROE = 1). If SPC0 = 1 and master mode is selected, this pin is not used by the SPI and reverts to being a general-purpose port I/O pin.
12.2.4
SS -- Slave Select
When the SPI is enabled as a slave, this pin is the low-true slave select input. When the SPI is enabled as a master and mode fault enable is off (MODFEN = 0), this pin is not used by the SPI and reverts to being a general-purpose port I/O pin. When the SPI is enabled as a master and MODFEN = 1, the slave select output enable bit determines whether this pin acts as the mode fault input (SSOE = 0) or as the slave select output (SSOE = 1).
MC9S08AC16 Series Data Sheet, Rev. 8 214 Freescale Semiconductor
Serial Peripheral Interface (S08SPIV3)
12.3
12.3.1
Modes of Operation
SPI in Stop Modes
The SPI is disabled in all stop modes, regardless of the settings before executing the STOP instruction. During either stop1 or stop2 mode, the SPI module will be fully powered down. Upon wake-up from stop1 or stop2 mode, the SPI module will be in the reset state. During stop3 mode, clocks to the SPI module are halted. No registers are affected. If stop3 is exited with a reset, the SPI will be put into its reset state. If stop3 is exited with an interrupt, the SPI continues from the state it was in when stop3 was entered.
12.4
Register Definition
The SPI has five 8-bit registers to select SPI options, control baud rate, report SPI status, and for transmit/receive data. Refer to the direct-page register summary in the Memory chapter of this data sheet for the absolute address assignments for all SPI registers. This section refers to registers and control bits only by their names, and a Freescale-provided equate or header file is used to translate these names into the appropriate absolute addresses.
12.4.1
SPI Control Register 1 (SPI1C1)
This read/write register includes the SPI enable control, interrupt enables, and configuration options.
7 6 5 4 3 2 1 0
R SPIE W Reset 0 0 0 0 0 1 0 0 SPE SPTIE MSTR CPOL CPHA SSOE LSBFE
Figure 12-5. SPI Control Register 1 (SPI1C1) Table 12-1. SPI1C1 Field Descriptions
Field 7 SPIE Description SPI Interrupt Enable (for SPRF and MODF) -- This is the interrupt enable for SPI receive buffer full (SPRF) and mode fault (MODF) events. 0 Interrupts from SPRF and MODF inhibited (use polling) 1 When SPRF or MODF is 1, request a hardware interrupt SPI System Enable -- Disabling the SPI halts any transfer that is in progress, clears data buffers, and initializes internal state machines. SPRF is cleared and SPTEF is set to indicate the SPI transmit data buffer is empty. 0 SPI system inactive 1 SPI system enabled SPI Transmit Interrupt Enable -- This is the interrupt enable bit for SPI transmit buffer empty (SPTEF). 0 Interrupts from SPTEF inhibited (use polling) 1 When SPTEF is 1, hardware interrupt requested
6 SPE
5 SPTIE
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 215
Serial Peripheral Interface (S08SPIV3)
Table 12-1. SPI1C1 Field Descriptions (continued)
Field 4 MSTR 3 CPOL Description Master/Slave Mode Select 0 SPI module configured as a slave SPI device 1 SPI module configured as a master SPI device Clock Polarity -- This bit effectively places an inverter in series with the clock signal from a master SPI or to a slave SPI device. Refer to Section 12.5.1, "SPI Clock Formats" for more details. 0 Active-high SPI clock (idles low) 1 Active-low SPI clock (idles high) Clock Phase -- This bit selects one of two clock formats for different kinds of synchronous serial peripheral devices. Refer to Section 12.5.1, "SPI Clock Formats" for more details. 0 First edge on SPSCK occurs at the middle of the first cycle of an 8-cycle data transfer 1 First edge on SPSCK occurs at the start of the first cycle of an 8-cycle data transfer Slave Select Output Enable -- This bit is used in combination with the mode fault enable (MODFEN) bit in SPCR2 and the master/slave (MSTR) control bit to determine the function of the SS pin as shown in Table 12-2. LSB First (Shifter Direction) 0 SPI serial data transfers start with most significant bit 1 SPI serial data transfers start with least significant bit
2 CPHA
1 SSOE 0 LSBFE
Table 12-2. SS Pin Function
MODFEN 0 0 1 1 SSOE 0 1 0 1 Master Mode General-purpose I/O (not SPI) General-purpose I/O (not SPI) SS input for mode fault Automatic SS output Slave Mode Slave select input Slave select input Slave select input Slave select input
NOTE Ensure that the SPI should not be disabled (SPE=0) at the same time as a bit change to the CPHA bit. These changes should be performed as separate operations or unexpected behavior may occur.
12.4.2
SPI Control Register 2 (SPI1C2)
This read/write register is used to control optional features of the SPI system. Bits 7, 6, 5, and 2 are not implemented and always read 0.
7 6 5 4 3 2 1 0
R W Reset
0
0
0 MODFEN BIDIROE 0
0 SPISWAI 0 0 SPC0 0
0
0
0
0
= Unimplemented or Reserved
Figure 12-6. SPI Control Register 2 (SPI1C2)
MC9S08AC16 Series Data Sheet, Rev. 8 216 Freescale Semiconductor
Serial Peripheral Interface (S08SPIV3)
Table 12-3. SPI1C2 Register Field Descriptions
Field 4 MODFEN Description Master Mode-Fault Function Enable -- When the SPI is configured for slave mode, this bit has no meaning or effect. (The SS pin is the slave select input.) In master mode, this bit determines how the SS pin is used (refer to Table 12-2 for more details). 0 Mode fault function disabled, master SS pin reverts to general-purpose I/O not controlled by SPI 1 Mode fault function enabled, master SS pin acts as the mode fault input or the slave select output Bidirectional Mode Output Enable -- When bidirectional mode is enabled by SPI pin control 0 (SPC0) = 1, BIDIROE determines whether the SPI data output driver is enabled to the single bidirectional SPI I/O pin. Depending on whether the SPI is configured as a master or a slave, it uses either the MOSI (MOMI) or MISO (SISO) pin, respectively, as the single SPI data I/O pin. When SPC0 = 0, BIDIROE has no meaning or effect. 0 Output driver disabled so SPI data I/O pin acts as an input 1 SPI I/O pin enabled as an output SPI Stop in Wait Mode 0 SPI clocks continue to operate in wait mode 1 SPI clocks stop when the MCU enters wait mode SPI Pin Control 0 -- The SPC0 bit chooses single-wire bidirectional mode. If MSTR = 0 (slave mode), the SPI uses the MISO (SISO) pin for bidirectional SPI data transfers. If MSTR = 1 (master mode), the SPI uses the MOSI (MOMI) pin for bidirectional SPI data transfers. When SPC0 = 1, BIDIROE is used to enable or disable the output driver for the single bidirectional SPI I/O pin. 0 SPI uses separate pins for data input and data output 1 SPI configured for single-wire bidirectional operation
3 BIDIROE
1 SPISWAI 0 SPC0
12.4.3
SPI Baud Rate Register (SPI1BR)
This register is used to set the prescaler and bit rate divisor for an SPI master. This register may be read or written at any time.
7 6 5 4 3 2 1 0
R W Reset
0 SPPR2 0 0 SPPR1 0 SPPR0 0
0 SPR2 0 0 SPR1 0 SPR0 0
= Unimplemented or Reserved
Figure 12-7. SPI Baud Rate Register (SPI1BR) Table 12-4. SPI1BR Register Field Descriptions
Field 6:4 SPPR[2:0] 2:0 SPR[2:0] Description SPI Baud Rate Prescale Divisor -- This 3-bit field selects one of eight divisors for the SPI baud rate prescaler as shown in Table 12-5. The input to this prescaler is the bus rate clock (BUSCLK). The output of this prescaler drives the input of the SPI baud rate divider (see Figure 12-4). SPI Baud Rate Divisor -- This 3-bit field selects one of eight divisors for the SPI baud rate divider as shown in Table 12-6. The input to this divider comes from the SPI baud rate prescaler (see Figure 12-4). The output of this divider is the SPI bit rate clock for master mode.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 217
Serial Peripheral Interface (S08SPIV3)
Table 12-5. SPI Baud Rate Prescaler Divisor
SPPR2:SPPR1:SPPR0 0:0:0 0:0:1 0:1:0 0:1:1 1:0:0 1:0:1 1:1:0 1:1:1 Prescaler Divisor 1 2 3 4 5 6 7 8
Table 12-6. SPI Baud Rate Divisor
SPR2:SPR1:SPR0 0:0:0 0:0:1 0:1:0 0:1:1 1:0:0 1:0:1 1:1:0 1:1:1 Rate Divisor 2 4 8 16 32 64 128 256
12.4.4
SPI Status Register (SPI1S)
This register has three read-only status bits. Bits 6, 3, 2, 1, and 0 are not implemented and always read 0. Writes have no meaning or effect.
7 6 5 4 3 2 1 0
R W Reset
SPRF
0
SPTEF
MODF
0
0
0
0
0
0
1
0
0
0
0
0
= Unimplemented or Reserved
Figure 12-8. SPI Status Register (SPI1S)
MC9S08AC16 Series Data Sheet, Rev. 8 218 Freescale Semiconductor
Serial Peripheral Interface (S08SPIV3)
Table 12-7. SPI1S Register Field Descriptions
Field 7 SPRF Description SPI Read Buffer Full Flag -- SPRF is set at the completion of an SPI transfer to indicate that received data may be read from the SPI data register (SPI1D). SPRF is cleared by reading SPRF while it is set, then reading the SPI data register. 0 No data available in the receive data buffer 1 Data available in the receive data buffer SPI Transmit Buffer Empty Flag -- This bit is set when there is room in the transmit data buffer. It is cleared by reading SPI1S with SPTEF set, followed by writing a data value to the transmit buffer at SPI1D. SPI1S must be read with SPTEF = 1 before writing data to SPI1D or the SPI1D write will be ignored. SPTEF generates an SPTEF CPU interrupt request if the SPTIE bit in the SPI1C1 is also set. SPTEF is automatically set when a data byte transfers from the transmit buffer into the transmit shift register. For an idle SPI (no data in the transmit buffer or the shift register and no transfer in progress), data written to SPI1D is transferred to the shifter almost immediately so SPTEF is set within two bus cycles allowing a second 8-bit data value to be queued into the transmit buffer. After completion of the transfer of the value in the shift register, the queued value from the transmit buffer will automatically move to the shifter and SPTEF will be set to indicate there is room for new data in the transmit buffer. If no new data is waiting in the transmit buffer, SPTEF simply remains set and no data moves from the buffer to the shifter. 0 SPI transmit buffer not empty 1 SPI transmit buffer empty Master Mode Fault Flag -- MODF is set if the SPI is configured as a master and the slave select input goes low, indicating some other SPI device is also configured as a master. The SS pin acts as a mode fault error input only when MSTR = 1, MODFEN = 1, and SSOE = 0; otherwise, MODF will never be set. MODF is cleared by reading MODF while it is 1, then writing to SPI control register 1 (SPI1C1). 0 No mode fault error 1 Mode fault error detected
5 SPTEF
4 MODF
12.4.5
R
SPI Data Register (SPI1D)
7 6 5 4 3 2 1 0
Bit 7 W Reset 0
6 0
5 0
4 0
3 0
2 0
1 0
Bit 0 0
Figure 12-9. SPI Data Register (SPI1D)
Reads of this register return the data read from the receive data buffer. Writes to this register write data to the transmit data buffer. When the SPI is configured as a master, writing data to the transmit data buffer initiates an SPI transfer. Data should not be written to the transmit data buffer unless the SPI transmit buffer empty flag (SPTEF) is set, indicating there is room in the transmit buffer to queue a new transmit byte. Data may be read from SPI1D any time after SPRF is set and before another transfer is finished. Failure to read the data out of the receive data buffer before a new transfer ends causes a receive overrun condition and the data from the new transfer is lost.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 219
Serial Peripheral Interface (S08SPIV3)
12.5
Functional Description
An SPI transfer is initiated by checking for the SPI transmit buffer empty flag (SPTEF = 1) and then writing a byte of data to the SPI data register (SPI1D) in the master SPI device. When the SPI shift register is available, this byte of data is moved from the transmit data buffer to the shifter, SPTEF is set to indicate there is room in the buffer to queue another transmit character if desired, and the SPI serial transfer starts. During the SPI transfer, data is sampled (read) on the MISO pin at one SPSCK edge and shifted, changing the bit value on the MOSI pin, one-half SPSCK cycle later. After eight SPSCK cycles, the data that was in the shift register of the master has been shifted out the MOSI pin to the slave while eight bits of data were shifted in the MISO pin into the master's shift register. At the end of this transfer, the received data byte is moved from the shifter into the receive data buffer and SPRF is set to indicate the data can be read by reading SPI1D. If another byte of data is waiting in the transmit buffer at the end of a transfer, it is moved into the shifter, SPTEF is set, and a new transfer is started. Normally, SPI data is transferred most significant bit (MSB) first. If the least significant bit first enable (LSBFE) bit is set, SPI data is shifted LSB first. When the SPI is configured as a slave, its SS pin must be driven low before a transfer starts and SS must stay low throughout the transfer. If a clock format where CPHA = 0 is selected, SS must be driven to a logic 1 between successive transfers. If CPHA = 1, SS may remain low between successive transfers. See Section 12.5.1, "SPI Clock Formats" for more details. Because the transmitter and receiver are double buffered, a second byte, in addition to the byte currently being shifted out, can be queued into the transmit data buffer, and a previously received character can be in the receive data buffer while a new character is being shifted in. The SPTEF flag indicates when the transmit buffer has room for a new character. The SPRF flag indicates when a received character is available in the receive data buffer. The received character must be read out of the receive buffer (read SPI1D) before the next transfer is finished or a receive overrun error results. In the case of a receive overrun, the new data is lost because the receive buffer still held the previous character and was not ready to accept the new data. There is no indication for such an overrun condition so the application system designer must ensure that previous data has been read from the receive buffer before a new transfer is initiated.
12.5.1
SPI Clock Formats
To accommodate a wide variety of synchronous serial peripherals from different manufacturers, the SPI system has a clock polarity (CPOL) bit and a clock phase (CPHA) control bit to select one of four clock formats for data transfers. CPOL selectively inserts an inverter in series with the clock. CPHA chooses between two different clock phase relationships between the clock and data. Figure 12-10 shows the clock formats when CPHA = 1. At the top of the figure, the eight bit times are shown for reference with bit 1 starting at the first SPSCK edge and bit 8 ending one-half SPSCK cycle after the sixteenth SPSCK edge. The MSB first and LSB first lines show the order of SPI data bits depending on the setting in LSBFE. Both variations of SPSCK polarity are shown, but only one of these waveforms applies for a specific transfer, depending on the value in CPOL. The SAMPLE IN waveform applies to the MOSI input of a slave or the MISO input of a master. The MOSI waveform applies to the
MC9S08AC16 Series Data Sheet, Rev. 8 220 Freescale Semiconductor
Serial Peripheral Interface (S08SPIV3)
MOSI output pin from a master and the MISO waveform applies to the MISO output from a slave. The SS OUT waveform applies to the slave select output from a master (provided MODFEN and SSOE = 1). The master SS output goes to active low one-half SPSCK cycle before the start of the transfer and goes back high at the end of the eighth bit time of the transfer. The SS IN waveform applies to the slave select input of a slave.
BIT TIME # (REFERENCE) 1 2 ... 6 7 8
SPSCK (CPOL = 0)
SPSCK (CPOL = 1)
SAMPLE IN (MISO OR MOSI)
MOSI (MASTER OUT) MSB FIRST LSB FIRST MISO (SLAVE OUT) BIT 7 BIT 0 BIT 6 BIT 1 ... ... BIT 2 BIT 5 BIT 1 BIT 6 BIT 0 BIT 7
SS OUT (MASTER)
SS IN (SLAVE)
Figure 12-10. SPI Clock Formats (CPHA = 1)
When CPHA = 1, the slave begins to drive its MISO output when SS goes to active low, but the data is not defined until the first SPSCK edge. The first SPSCK edge shifts the first bit of data from the shifter onto the MOSI output of the master and the MISO output of the slave. The next SPSCK edge causes both the master and the slave to sample the data bit values on their MISO and MOSI inputs, respectively. At the third SPSCK edge, the SPI shifter shifts one bit position which shifts in the bit value that was just sampled, and shifts the second data bit value out the other end of the shifter to the MOSI and MISO outputs of the master and slave, respectively. When CHPA = 1, the slave's SS input is not required to go to its inactive high level between transfers. Figure 12-11 shows the clock formats when CPHA = 0. At the top of the figure, the eight bit times are shown for reference with bit 1 starting as the slave is selected (SS IN goes low), and bit 8 ends at the last SPSCK edge. The MSB first and LSB first lines show the order of SPI data bits depending on the setting
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 221
Serial Peripheral Interface (S08SPIV3)
in LSBFE. Both variations of SPSCK polarity are shown, but only one of these waveforms applies for a specific transfer, depending on the value in CPOL. The SAMPLE IN waveform applies to the MOSI input of a slave or the MISO input of a master. The MOSI waveform applies to the MOSI output pin from a master and the MISO waveform applies to the MISO output from a slave. The SS OUT waveform applies to the slave select output from a master (provided MODFEN and SSOE = 1). The master SS output goes to active low at the start of the first bit time of the transfer and goes back high one-half SPSCK cycle after the end of the eighth bit time of the transfer. The SS IN waveform applies to the slave select input of a slave.
BIT TIME # (REFERENCE) SPSCK (CPOL = 0) 1 2 ... 6 7 8
SPSCK (CPOL = 1)
SAMPLE IN (MISO OR MOSI)
MOSI (MASTER OUT) MSB FIRST LSB FIRST MISO (SLAVE OUT) BIT 7 BIT 0 BIT 6 BIT 1 ... ... BIT 2 BIT 5 BIT 1 BIT 6 BIT 0 BIT 7
SS OUT (MASTER)
SS IN (SLAVE)
Figure 12-11. SPI Clock Formats (CPHA = 0)
When CPHA = 0, the slave begins to drive its MISO output with the first data bit value (MSB or LSB depending on LSBFE) when SS goes to active low. The first SPSCK edge causes both the master and the slave to sample the data bit values on their MISO and MOSI inputs, respectively. At the second SPSCK edge, the SPI shifter shifts one bit position which shifts in the bit value that was just sampled and shifts the second data bit value out the other end of the shifter to the MOSI and MISO outputs of the master and slave, respectively. When CPHA = 0, the slave's SS input must go to its inactive high level between transfers.
MC9S08AC16 Series Data Sheet, Rev. 8 222 Freescale Semiconductor
Serial Peripheral Interface (S08SPIV3)
12.5.2
SPI Interrupts
There are three flag bits, two interrupt mask bits, and one interrupt vector associated with the SPI system. The SPI interrupt enable mask (SPIE) enables interrupts from the SPI receiver full flag (SPRF) and mode fault flag (MODF). The SPI transmit interrupt enable mask (SPTIE) enables interrupts from the SPI transmit buffer empty flag (SPTEF). When one of the flag bits is set, and the associated interrupt mask bit is set, a hardware interrupt request is sent to the CPU. If the interrupt mask bits are cleared, software can poll the associated flag bits instead of using interrupts. The SPI interrupt service routine (ISR) should check the flag bits to determine what event caused the interrupt. The service routine should also clear the flag bit(s) before returning from the ISR (usually near the beginning of the ISR).
12.5.3
Mode Fault Detection
A mode fault occurs and the mode fault flag (MODF) becomes set when a master SPI device detects an error on the SS pin (provided the SS pin is configured as the mode fault input signal). The SS pin is configured to be the mode fault input signal when MSTR = 1, mode fault enable is set (MODFEN = 1), and slave select output enable is clear (SSOE = 0). The mode fault detection feature can be used in a system where more than one SPI device might become a master at the same time. The error is detected when a master's SS pin is low, indicating that some other SPI device is trying to address this master as if it were a slave. This could indicate a harmful output driver conflict, so the mode fault logic is designed to disable all SPI output drivers when such an error is detected. When a mode fault is detected, MODF is set and MSTR is cleared to change the SPI configuration back to slave mode. The output drivers on the SPSCK, MOSI, and MISO (if not bidirectional mode) are disabled. MODF is cleared by reading it while it is set, then writing to the SPI control register 1 (SPI1C1). User software should verify the error condition has been corrected before changing the SPI back to master mode.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 223
Serial Peripheral Interface (S08SPIV3)
MC9S08AC16 Series Data Sheet, Rev. 8 224 Freescale Semiconductor
Chapter 13 Inter-Integrated Circuit (S08IICV2)
13.1 Introduction
The MC9S08AC16 Series series of microcontrollers has an inter-integrated circuit (IIC) module for communication with other integrated circuits. The two pins associated with this module, SCL and SDA, are shared with port C pins 0 and 1, respectively. NOTE Ignore any references to stop1 low-power mode in this chapter, because the MC9S08AC16 Series does not support it.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 225
Chapter 13 Inter-Integrated Circuit (S08IICV2)
VDDAD VSSAD VREFL VREFH HCS08 CORE BKGD/MS BDC CPU
10-BIT ANALOG-TO-DIGITAL CONVERTER (ADC1) DEBUG MODULE (DBG)
4 AD1P11-AD1P8
PORT A
4 AD1P3-AD1P0
PTA7 PTA2 PTA1 PTA0 PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 PTB0/TPM3CH0/AD1P0 PTC5/RxD2 PTC4 PTC3/TxD2 PTC2/MCLK PTC1/SDA1 PTC0/SCL1 PTD3/KBIP6/AD1P11 PTD2/KBIP5/AD1P10 PTD1/AD1P9 PTD0/AD1P8
SDA1 IIC MODULE (IIC1) SCL1 PORT C PORT D
RESET IRQ/TPMCLK
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION POWER MANAGEMENT RTI IRQ COP LVD
INTERNAL CLOCK GENERATOR (ICG) LOW-POWER OSCILLATOR 7-BIT KEYBOARD INTERRUPT MODULE (KBI)
EXTAL XTAL
2 KBIP6-KBIP5 5 KBIP4-KBIP0 RxD1 TxD1 RxD2 TxD2 SPSCK1 MOSI1 MISO1 SS1 TPM1CH1 TPM1CH0 TPM1CH3 TPM1CH2 TPM2CH1 TPM2CH0 TPM3CH1 TPM3CH0
TPMCLK
SERIAL COMMUNICATIONS INTERFACE MODULE (SCI1) SERIAL COMMUNICATIONS INTERFACE MODULE (SCI2) SERIAL PERIPHERAL INTERFACE MODULE (SPI1)
PORT B
USER FLASH 16,384 BYTES OR 8192 BYTES
PTE7/SPSCK1 PTE6/MOSI1 PTE5/MISO1 PTE4/SS1 PTE3/TPM1CH1 PTE2/TPM1CH0 PTE1/RxD1 PTE0/TxD1
USER RAM 1024 BYTES OR 768 BYTES VDD VSS VOLTAGE REGULATOR
2-CHANNEL TIMER/PWM MODULE (TPM2)
PORT F
4-CHANNEL TIMER/PWM MODULE (TPM1)
PORT E
PTF6 PTF5/TPM2CH1 PTF4/TPM2CH0 PTF1/TPM1CH3 PTF0/TPM1CH2
= Not available on 32-, 42-, or 44-pin packages = Not available on 32- or 42-pin packages = Not available on 32-pin packages
Notes: 1. Port pins are software configurable with pullup device if input port. 2. Pin contains software configurable pullup/pulldown device if IRQ is enabled (IRQPE = 1). Pulldown is enabled if rising edge detect is selected (IRQEDG = 1) 3. IRQ does not have a clamp diode to VDD. IRQ should not be driven above VDD. 4. Pin contains integrated pullup device. 5. PTD3, PTD2, and PTG4 contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is selected (KBEDGn = 1).
Figure 13-1. MC9S08AC16 Block Diagram Highlighting the IIC
MC9S08AC16 Series Data Sheet, Rev. 8 226 Freescale Semiconductor
PORT G
2-CHANNEL TIMER/PWM MODULE (TPM3)
PTG6/EXTAL PTG5/XTAL PTG4/KBIP4 PTG3/KBIP3 PTG2/KBIP2 PTG1/KBIP1 PTG0/KBIP0
Inter-Integrated Circuit (S08IICV2)
13.1.1
Features
The IIC includes these distinctive features: * Compatible with IIC bus standard * Multi-master operation * Software programmable for one of 64 different serial clock frequencies * Software selectable acknowledge bit * Interrupt driven byte-by-byte data transfer * Arbitration lost interrupt with automatic mode switching from master to slave * Calling address identification interrupt * Start and stop signal generation/detection * Repeated start signal generation * Acknowledge bit generation/detection * Bus busy detection * General call recognition * 10-bit address extension
13.1.2
Modes of Operation
A brief description of the IIC in the various MCU modes is given here. * Run mode -- This is the basic mode of operation. To conserve power in this mode, disable the module. * Wait mode -- The module continues to operate while the MCU is in wait mode and can provide a wake-up interrupt. * Stop mode -- The IIC is inactive in stop3 mode for reduced power consumption. The stop instruction does not affect IIC register states. Stop2 resets the register contents.
13.1.3
Block Diagram
Figure 13-2 is a block diagram of the IIC.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 227
Inter-Integrated Circuit (S08IICV2)
Address Interrupt ADDR_DECODE
Data Bus
DATA_MUX
CTRL_REG
FREQ_REG
ADDR_REG
STATUS_REG
DATA_REG
Input Sync Start Stop Arbitration Control Clock Control In/Out Data Shift Register
Address Compare
SCL
SDA
Figure 13-2. IIC Functional Block Diagram
13.2
External Signal Description
This section describes each user-accessible pin signal.
13.2.1
SCL -- Serial Clock Line
The bidirectional SCL is the serial clock line of the IIC system.
13.2.2
SDA -- Serial Data Line
The bidirectional SDA is the serial data line of the IIC system.
13.3
Register Definition
This section consists of the IIC register descriptions in address order. Refer to the direct-page register summary in the memory chapter of this document for the absolute address assignments for all IIC registers. This section refers to registers and control bits only by their names. A
MC9S08AC16 Series Data Sheet, Rev. 8 228 Freescale Semiconductor
Inter-Integrated Circuit (S08IICV2)
Freescale-provided equate or header file is used to translate these names into the appropriate absolute addresses.
13.3.1
IIC Address Register (IIC1A)
7 6 5 4 3 2 1 0
R AD7 W Reset 0 0 0 0 0 0 0 AD6 AD5 AD4 AD3 AD2 AD1
0
0
= Unimplemented or Reserved
Figure 13-3. IIC Address Register (IIC1A) Table 13-1. IIC1A Field Descriptions
Field 7-1 AD[7:1] Description Slave Address. The AD[7:1] field contains the slave address to be used by the IIC module. This field is used on the 7-bit address scheme and the lower seven bits of the 10-bit address scheme.
13.3.2
IIC Frequency Divider Register (IIC1F)
7 6 5 4 3 2 1 0
R MULT W Reset 0 0 0 0 0 0 0 0 ICR
Figure 13-4. IIC Frequency Divider Register (IIC1F)
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 229
Inter-Integrated Circuit (S08IICV2)
Table 13-2. IIC1F Field Descriptions
Field 7-6 MULT Description IIC Multiplier Factor. The MULT bits define the multiplier factor, mul. This factor, along with the SCL divider, generates the IIC baud rate. The multiplier factor mul as defined by the MULT bits is provided below. 00 mul = 01 01 mul = 02 10 mul = 04 11 Reserved IIC Clock Rate. The ICR bits are used to prescale the bus clock for bit rate selection. These bits and the MULT bits determine the IIC baud rate, the SDA hold time, the SCL Start hold time, and the SCL Stop hold time. Table 13-4 provides the SCL divider and hold values for corresponding values of the ICR. The SCL divider multiplied by multiplier factor mul generates IIC baud rate. bus speed (Hz) IIC baud rate = -------------------------------------------mul x SCLdivider
5-0 ICR
Eqn. 13-1
SDA hold time is the delay from the falling edge of SCL (IIC clock) to the changing of SDA (IIC data). SDA hold time = bus period (s) x mul x SDA hold value
Eqn. 13-2
SCL start hold time is the delay from the falling edge of SDA (IIC data) while SCL is high (Start condition) to the falling edge of SCL (IIC clock). SCL Start hold time = bus period (s) x mul x SCL Start hold value SCL stop hold time is the delay from the rising edge of SCL (IIC clock) to the rising edge of SDA SDA (IIC data) while SCL is high (Stop condition). SCL Stop hold time = bus period (s) x mul x SCL Stop hold value
Eqn. 13-3
Eqn. 13-4
For example, if the bus speed is 8 MHz, the table below shows the possible hold time values with different ICR and MULT selections to achieve an IIC baud rate of 100kbps.
Table 13-3. Hold Time Values for 8 MHz Bus Speed
Hold Times (s) MULT ICR SDA 0x2 0x1 0x1 0x0 0x0 0x00 0x07 0x0B 0x14 0x18 3.500 2.500 2.250 2.125 1.125 SCL Start 3.000 4.000 4.000 4.250 4.750 SCL Stop 5.500 5.250 5.250 5.125 5.125
MC9S08AC16 Series Data Sheet, Rev. 8 230 Freescale Semiconductor
Inter-Integrated Circuit (S08IICV2)
Table 13-4. IIC Divider and Hold Values
ICR (hex) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F SCL Divider 20 22 24 26 28 30 34 40 28 32 36 40 44 48 56 68 48 56 64 72 80 88 104 128 80 96 112 128 144 160 192 240 SDA Hold Value 7 7 8 8 9 9 10 10 7 7 9 9 11 11 13 13 9 9 13 13 17 17 21 21 9 9 17 17 25 25 33 33 SCL Hold (Start) Value 6 7 8 9 10 11 13 16 10 12 14 16 18 20 24 30 18 22 26 30 34 38 46 58 38 46 54 62 70 78 94 118 SDA Hold (Stop) Value 11 12 13 14 15 16 18 21 15 17 19 21 23 25 29 35 25 29 33 37 41 45 53 65 41 49 57 65 73 81 97 121 ICR (hex) 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F SCL Divider 160 192 224 256 288 320 384 480 320 384 448 512 576 640 768 960 640 768 896 1024 1152 1280 1536 1920 1280 1536 1792 2048 2304 2560 3072 3840 SDA Hold Value 17 17 33 33 49 49 65 65 33 33 65 65 97 97 129 129 65 65 129 129 193 193 257 257 129 129 257 257 385 385 513 513 SCL Hold (Start) Value 78 94 110 126 142 158 190 238 158 190 222 254 286 318 382 478 318 382 446 510 574 638 766 958 638 766 894 1022 1150 1278 1534 1918 SCL Hold (Stop) Value 81 97 113 129 145 161 193 241 161 193 225 257 289 321 385 481 321 385 449 513 577 641 769 961 641 769 897 1025 1153 1281 1537 1921
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 231
Inter-Integrated Circuit (S08IICV2)
13.3.3
IIC Control Register (IIC1C1)
7 6 5 4 3 2 1 0
R IICEN W Reset 0 0 0 0 0 IICIE MST TX TXAK
0 RSTA 0
0
0
0
0
= Unimplemented or Reserved
Figure 13-5. IIC Control Register (IIC1C1) Table 13-5. IIC1C1 Field Descriptions
Field 7 IICEN 6 IICIE 5 MST Description IIC Enable. The IICEN bit determines whether the IIC module is enabled. 0 IIC is not enabled 1 IIC is enabled IIC Interrupt Enable. The IICIE bit determines whether an IIC interrupt is requested. 0 IIC interrupt request not enabled 1 IIC interrupt request enabled Master Mode Select. The MST bit changes from a 0 to a 1 when a start signal is generated on the bus and master mode is selected. When this bit changes from a 1 to a 0 a stop signal is generated and the mode of operation changes from master to slave. 0 Slave mode 1 Master mode Transmit Mode Select. The TX bit selects the direction of master and slave transfers. In master mode, this bit should be set according to the type of transfer required. Therefore, for address cycles, this bit is always high. When addressed as a slave, this bit should be set by software according to the SRW bit in the status register. 0 Receive 1 Transmit Transmit Acknowledge Enable. This bit specifies the value driven onto the SDA during data acknowledge cycles for master and slave receivers. 0 An acknowledge signal is sent out to the bus after receiving one data byte 1 No acknowledge signal response is sent Repeat start. Writing a 1 to this bit generates a repeated start condition provided it is the current master. This bit is always read as cleared. Attempting a repeat at the wrong time results in loss of arbitration.
4 TX
3 TXAK
2 RSTA
13.3.4
IIC Status Register (IIC1S)
7 6 5 4 3 2 1 0
R W Reset
TCF IAAS 1 0
BUSY ARBL 0 0
0
SRW IICIF
RXAK
0
0
0
0
= Unimplemented or Reserved
Figure 13-6. IIC Status Register (IIC1S)
MC9S08AC16 Series Data Sheet, Rev. 8 232 Freescale Semiconductor
Inter-Integrated Circuit (S08IICV2)
Table 13-6. IIC1S Field Descriptions
Field 7 TCF Description Transfer Complete Flag. This bit is set on the completion of a byte transfer. This bit is only valid during or immediately following a transfer to the IIC module or from the IIC module.The TCF bit is cleared by reading the IIC1D register in receive mode or writing to the IIC1D in transmit mode. 0 Transfer in progress 1 Transfer complete Addressed as a Slave. The IAAS bit is set when the calling address matches the programmed slave address or when the GCAEN bit is set and a general call is received. Writing the IIC1C register clears this bit. 0 Not addressed 1 Addressed as a slave Bus Busy. The BUSY bit indicates the status of the bus regardless of slave or master mode. The BUSY bit is set when a start signal is detected and cleared when a stop signal is detected. 0 Bus is idle 1 Bus is busy Arbitration Lost. This bit is set by hardware when the arbitration procedure is lost. The ARBL bit must be cleared by software by writing a 1 to it. 0 Standard bus operation 1 Loss of arbitration Slave Read/Write. When addressed as a slave, the SRW bit indicates the value of the R/W command bit of the calling address sent to the master. 0 Slave receive, master writing to slave 1 Slave transmit, master reading from slave IIC Interrupt Flag. The IICIF bit is set when an interrupt is pending. This bit must be cleared by software, by writing a 1 to it in the interrupt routine. One of the following events can set the IICIF bit: * One byte transfer completes * Match of slave address to calling address * Arbitration lost 0 No interrupt pending 1 Interrupt pending Receive Acknowledge. When the RXAK bit is low, it indicates an acknowledge signal has been received after the completion of one byte of data transmission on the bus. If the RXAK bit is high it means that no acknowledge signal is detected. 0 Acknowledge received 1 No acknowledge received
6 IAAS
5 BUSY
4 ARBL
2 SRW
1 IICIF
0 RXAK
13.3.5
IIC Data I/O Register (IIC1D)
7 6 5 4 3 2 1 0
R DATA W Reset 0 0 0 0 0 0 0 0
Figure 13-7. IIC Data I/O Register (IIC1D)
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 233
Inter-Integrated Circuit (S08IICV2)
Table 13-7. IIC1D Field Descriptions
Field 7-0 DATA Description Data -- In master transmit mode, when data is written to the IIC1D, a data transfer is initiated. The most significant bit is sent first. In master receive mode, reading this register initiates receiving of the next byte of data.
NOTE When transitioning out of master receive mode, the IIC mode should be switched before reading the IIC1D register to prevent an inadvertent initiation of a master receive data transfer. In slave mode, the same functions are available after an address match has occurred. The TX bit in IIC1C must correctly reflect the desired direction of transfer in master and slave modes for the transmission to begin. For instance, if the IIC is configured for master transmit but a master receive is desired, reading the IIC1D does not initiate the receive. Reading the IIC1D returns the last byte received while the IIC is configured in master receive or slave receive modes. The IIC1D does not reflect every byte transmitted on the IIC bus, nor can software verify that a byte has been written to the IIC1D correctly by reading it back. In master transmit mode, the first byte of data written to IIC1D following assertion of MST is used for the address transfer and should comprise of the calling address (in bit 7 to bit 1) concatenated with the required R/W bit (in position bit 0).
13.3.6
IIC Control Register 2 (IIC1C2)
7 6 5 4 3 2 1 0
R GCAEN W Reset 0 0 ADEXT
0
0
0 AD10 AD9 0 AD8 0
0
0
0
0
= Unimplemented or Reserved Figure 13-8. IIC Control Register (IIC1C2) Table 13-8. IIC1C2 Field Descriptions
Field 7 GCAEN 6 ADEXT 2-0 AD[10:8] Description General Call Address Enable. The GCAEN bit enables or disables general call address. 0 General call address is disabled 1 General call address is enabled Address Extension. The ADEXT bit controls the number of bits used for the slave address. 0 7-bit address scheme 1 10-bit address scheme Slave Address. The AD[10:8] field contains the upper three bits of the slave address in the 10-bit address scheme. This field is only valid when the ADEXT bit is set.
MC9S08AC16 Series Data Sheet, Rev. 8 234 Freescale Semiconductor
Inter-Integrated Circuit (S08IICV2)
13.4
Functional Description
This section provides a complete functional description of the IIC module.
13.4.1
IIC Protocol
The IIC bus system uses a serial data line (SDA) and a serial clock line (SCL) for data transfer. All devices connected to it must have open drain or open collector outputs. A logic AND function is exercised on both lines with external pull-up resistors. The value of these resistors is system dependent. Normally, a standard communication is composed of four parts: * Start signal * Slave address transmission * Data transfer * Stop signal The stop signal should not be confused with the CPU stop instruction. The IIC bus system communication is described briefly in the following sections and illustrated in Figure 13-9.
msb SCL 1 2 3 4 5 6 7 lsb 8 9 msb 1 2 3 4 5 6 7 lsb 8 9
SDA
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
XXX
D7
D6
D5
D4
D3
D2
D1
D0
Start Signal
Calling Address
Read/ Ack Write Bit
Data Byte
No Ack Bit lsb
Stop Signal
msb SCL 1 2 3 4 5 6 7
lsb 8 9
msb 1 2 3 4 5 6 7
8
9
SDA
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
XX
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
Start Signal
Calling Address
Read/ Ack Write Bit
Repeated Start Signal
New Calling Address
Read/ Write
No Ack Bit
Stop Signal
Figure 13-9. IIC Bus Transmission Signals
13.4.1.1
Start Signal
When the bus is free, no master device is engaging the bus (SCL and SDA lines are at logical high), a master may initiate communication by sending a start signal. As shown in Figure 13-9, a start signal is defined as a high-to-low transition of SDA while SCL is high. This signal denotes the beginning of a new data transfer (each data transfer may contain several bytes of data) and brings all slaves out of their idle states.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 235
Inter-Integrated Circuit (S08IICV2)
13.4.1.2
Slave Address Transmission
The first byte of data transferred immediately after the start signal is the slave address transmitted by the master. This is a seven-bit calling address followed by a R/W bit. The R/W bit tells the slave the desired direction of data transfer. 1 = Read transfer, the slave transmits data to the master. 0 = Write transfer, the master transmits data to the slave. Only the slave with a calling address that matches the one transmitted by the master responds by sending back an acknowledge bit. This is done by pulling the SDA low at the ninth clock (see Figure 13-9). No two slaves in the system may have the same address. If the IIC module is the master, it must not transmit an address equal to its own slave address. The IIC cannot be master and slave at the same time. However, if arbitration is lost during an address cycle, the IIC reverts to slave mode and operates correctly even if it is being addressed by another master.
13.4.1.3
Data Transfer
Before successful slave addressing is achieved, the data transfer can proceed byte-by-byte in a direction specified by the R/W bit sent by the calling master. All transfers that come after an address cycle are referred to as data transfers, even if they carry sub-address information for the slave device Each data byte is 8 bits long. Data may be changed only while SCL is low and must be held stable while SCL is high as shown in Figure 13-9. There is one clock pulse on SCL for each data bit, the msb being transferred first. Each data byte is followed by a 9th (acknowledge) bit, which is signalled from the receiving device. An acknowledge is signalled by pulling the SDA low at the ninth clock. In summary, one complete data transfer needs nine clock pulses. If the slave receiver does not acknowledge the master in the ninth bit time, the SDA line must be left high by the slave. The master interprets the failed acknowledge as an unsuccessful data transfer. If the master receiver does not acknowledge the slave transmitter after a data byte transmission, the slave interprets this as an end of data transfer and releases the SDA line. In either case, the data transfer is aborted and the master does one of two things: * Relinquishes the bus by generating a stop signal. * Commences a new calling by generating a repeated start signal.
13.4.1.4
Stop Signal
The master can terminate the communication by generating a stop signal to free the bus. However, the master may generate a start signal followed by a calling command without generating a stop signal first. This is called repeated start. A stop signal is defined as a low-to-high transition of SDA while SCL at logical 1 (see Figure 13-9). The master can generate a stop even if the slave has generated an acknowledge at which point the slave must release the bus.
MC9S08AC16 Series Data Sheet, Rev. 8 236 Freescale Semiconductor
Inter-Integrated Circuit (S08IICV2)
13.4.1.5
Repeated Start Signal
As shown in Figure 13-9, a repeated start signal is a start signal generated without first generating a stop signal to terminate the communication. This is used by the master to communicate with another slave or with the same slave in different mode (transmit/receive mode) without releasing the bus.
13.4.1.6
Arbitration Procedure
The IIC bus is a true multi-master bus that allows more than one master to be connected on it. If two or more masters try to control the bus at the same time, a clock synchronization procedure determines the bus clock, for which the low period is equal to the longest clock low period and the high is equal to the shortest one among the masters. The relative priority of the contending masters is determined by a data arbitration procedure, a bus master loses arbitration if it transmits logic 1 while another master transmits logic 0. The losing masters immediately switch over to slave receive mode and stop driving SDA output. In this case, the transition from master to slave mode does not generate a stop condition. Meanwhile, a status bit is set by hardware to indicate loss of arbitration.
13.4.1.7
Clock Synchronization
Because wire-AND logic is performed on the SCL line, a high-to-low transition on the SCL line affects all the devices connected on the bus. The devices start counting their low period and after a device's clock has gone low, it holds the SCL line low until the clock high state is reached. However, the change of low to high in this device clock may not change the state of the SCL line if another device clock is still within its low period. Therefore, synchronized clock SCL is held low by the device with the longest low period. Devices with shorter low periods enter a high wait state during this time (see Figure 13-10). When all devices concerned have counted off their low period, the synchronized clock SCL line is released and pulled high. There is then no difference between the device clocks and the state of the SCL line and all the devices start counting their high periods. The first device to complete its high period pulls the SCL line low again.
Delay SCL1 Start Counting High Period
SCL2
SCL
Internal Counter Reset
Figure 13-10. IIC Clock Synchronization
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 237
Inter-Integrated Circuit (S08IICV2)
13.4.1.8
Handshaking
The clock synchronization mechanism can be used as a handshake in data transfer. Slave devices may hold the SCL low after completion of one byte transfer (9 bits). In such a case, it halts the bus clock and forces the master clock into wait states until the slave releases the SCL line.
13.4.1.9
Clock Stretching
The clock synchronization mechanism can be used by slaves to slow down the bit rate of a transfer. After the master has driven SCL low the slave can drive SCL low for the required period and then release it. If the slave SCL low period is greater than the master SCL low period then the resulting SCL bus signal low period is stretched.
13.4.2
10-bit Address
For 10-bit addressing, 0x11110 is used for the first 5 bits of the first address byte. Various combinations of read/write formats are possible within a transfer that includes 10-bit addressing.
13.4.2.1
Master-Transmitter Addresses a Slave-Receiver
The transfer direction is not changed (see Table 13-9). When a 10-bit address follows a start condition, each slave compares the first seven bits of the first byte of the slave address (11110XX) with its own address and tests whether the eighth bit (R/W direction bit) is 0. More than one device can find a match and generate an acknowledge (A1). Then, each slave that finds a match compares the eight bits of the second byte of the slave address with its own address. Only one slave finds a match and generates an acknowledge (A2). The matching slave remains addressed by the master until it receives a stop condition (P) or a repeated start condition (Sr) followed by a different slave address.
Slave Address 1st 7 bits S 11110 + AD10 + AD9 0 R/W A1 AD[8:1] Slave Address 2nd byte A2 Data A ... Data A/A P
Table 13-9. Master-Transmitter Addresses Slave-Receiver with a 10-bit Address
After the master-transmitter has sent the first byte of the 10-bit address, the slave-receiver sees an IIC interrupt. Software must ensure the contents of IICD are ignored and not treated as valid data for this interrupt.
13.4.2.2
Master-Receiver Addresses a Slave-Transmitter
The transfer direction is changed after the second R/W bit (see Table 13-10). Up to and including acknowledge bit A2, the procedure is the same as that described for a master-transmitter addressing a slave-receiver. After the repeated start condition (Sr), a matching slave remembers that it was addressed before. This slave then checks whether the first seven bits of the first byte of the slave address following Sr are the same as they were after the start condition (S) and tests whether the eighth (R/W) bit is 1. If there is a match, the slave considers that it has been addressed as a transmitter and generates acknowledge A3. The slave-transmitter remains addressed until it receives a stop condition (P) or a repeated start condition (Sr) followed by a different slave address.
MC9S08AC16 Series Data Sheet, Rev. 8 238 Freescale Semiconductor
Inter-Integrated Circuit (S08IICV2)
After a repeated start condition (Sr), all other slave devices also compare the first seven bits of the first byte of the slave address with their own addresses and test the eighth (R/W) bit. However, none of them are addressed because R/W = 1 (for 10-bit devices) or the 11110XX slave address (for 7-bit devices) does not match.
S Slave Address 1st 7 bits 11110 + AD10 + AD9 R/W A1 0 Slave Address 2nd byte AD[8:1] A2 Sr Slave Address 1st 7 bits 11110 + AD10 + AD9 R/W A3 1 Data A ... Data A P
Table 13-10. Master-Receiver Addresses a Slave-Transmitter with a 10-bit Address
After the master-receiver has sent the first byte of the 10-bit address, the slave-transmitter sees an IIC interrupt. Software must ensure the contents of IICD are ignored and not treated as valid data for this interrupt.
13.4.3
General Call Address
General calls can be requested in 7-bit address or 10-bit address. If the GCAEN bit is set, the IIC matches the general call address as well as its own slave address. When the IIC responds to a general call, it acts as a slave-receiver and the IAAS bit is set after the address cycle. Software must read the IICD register after the first byte transfer to determine whether the address matches is its own slave address or a general call. If the value is 00, the match is a general call. If the GCAEN bit is clear, the IIC ignores any data supplied from a general call address by not issuing an acknowledgement.
13.5
Resets
The IIC is disabled after reset. The IIC cannot cause an MCU reset.
13.6
Interrupts
The IIC generates a single interrupt. An interrupt from the IIC is generated when any of the events in Table 13-11 occur, provided the IICIE bit is set. The interrupt is driven by bit IICIF (of the IIC status register) and masked with bit IICIE (of the IIC control register). The IICIF bit must be cleared by software by writing a 1 to it in the interrupt routine. You can determine the interrupt type by reading the status register.
Table 13-11. Interrupt Summary
Interrupt Source Complete 1-byte transfer Match of received calling address Arbitration Lost Status TCF IAAS ARBL Flag IICIF IICIF IICIF Local Enable IICIE IICIE IICIE
13.6.1
Byte Transfer Interrupt
The TCF (transfer complete flag) bit is set at the falling edge of the ninth clock to indicate the completion of byte transfer.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 239
Inter-Integrated Circuit (S08IICV2)
13.6.2
Address Detect Interrupt
When the calling address matches the programmed slave address (IIC address register) or when the GCAEN bit is set and a general call is received, the IAAS bit in the status register is set. The CPU is interrupted, provided the IICIE is set. The CPU must check the SRW bit and set its Tx mode accordingly.
13.6.3
Arbitration Lost Interrupt
The IIC is a true multi-master bus that allows more than one master to be connected on it. If two or more masters try to control the bus at the same time, the relative priority of the contending masters is determined by a data arbitration procedure. The IIC module asserts this interrupt when it loses the data arbitration process and the ARBL bit in the status register is set. Arbitration is lost in the following circumstances: * SDA sampled as a low when the master drives a high during an address or data transmit cycle. * SDA sampled as a low when the master drives a high during the acknowledge bit of a data receive cycle. * A start cycle is attempted when the bus is busy. * A repeated start cycle is requested in slave mode. * A stop condition is detected when the master did not request it. This bit must be cleared by software writing a 1 to it.
MC9S08AC16 Series Data Sheet, Rev. 8 240 Freescale Semiconductor
Inter-Integrated Circuit (S08IICV2)
13.7
Initialization/Application Information
Module Initialization (Slave)
1. Write: IICC2 -- to enable or disable general call -- to select 10-bit or 7-bit addressing mode 2. Write: IICA -- to set the slave address 3. Write: IICC1 -- to enable IIC and interrupts 4. Initialize RAM variables (IICEN = 1 and IICIE = 1) for transmit data 5. Initialize RAM variables used to achieve the routine shown in Figure 13-12
Module Initialization (Master)
1. Write: IICF -- to set the IIC baud rate (example provided in this chapter) 2. Write: IICC1 -- to enable IIC and interrupts 3. Initialize RAM variables (IICEN = 1 and IICIE = 1) for transmit data 4. Initialize RAM variables used to achieve the routine shown in Figure 13-12 5. Write: IICC1 -- to enable TX
Register Model IICA MULT AD[7:1] 0
When addressed as a slave (in slave mode), the module responds to this address IICF ICR Baud rate = BUSCLK / (2 x MULT x (SCL DIVIDER)) IICC1 IICS IICD IICEN TCF IICIE IAAS MST BUSY TX ARBL DATA Data register; Write to transmit IIC data read to read IIC data IICC2 GCAEN ADEXT Address configuration 0 0 0 AD10 AD9 AD8 TXAK 0 RSTA SRW 0 IICIF 0 RXAK
Module configuration Module status flags
Figure 13-11. IIC Module Quick Start
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 241
Inter-Integrated Circuit (S08IICV2)
Clear IICIF
Y
Master Mode ?
N
TX
Tx/Rx ?
RX
Y
Arbitration Lost ? N
Last Byte Transmitted ? N
Y
Clear ARBL
RXAK=0 ? Y
N
Last Byte to Be Read ? N
N Y
IAAS=1 ? Y
Y
IAAS=1 ? N Data Transfer See Note 2 TX/RX ? TX RX
Address Transfer See Note 1 Y End of Addr Cycle (Master Rx) ? N Y 2nd Last Byte to Be Read ? N Y (Read) SRW=1 ? N (Write)
Write Next Byte to IICD
Set TXACK =1
Generate Stop Signal (MST = 0)
Set TX Mode
Y
ACK from Receiver ? N Read Data from IICD and Store
Write Data to IICD
Tx Next Byte
Switch to Rx Mode
Set RX Mode
Switch to Rx Mode
Dummy Read from IICD
Generate Stop Signal (MST = 0)
Read Data from IICD and Store
Dummy Read from IICD
Dummy Read from IICD
RTI NOTES: 1. If general call is enabled, a check must be done to determine whether the received address was a general call address (0x00). If the received address was a general call address, then the general call must be handled by user software.
2.
When 10-bit addressing is used to address a slave, the slave sees an interrupt following the first byte of the extended address. User software must ensure that for this interrupt, the contents of IICD are ignored and not treated as a valid data transfer.
Figure 13-12. Typical IIC Interrupt Routine
MC9S08AC16 Series Data Sheet, Rev. 8 242 Freescale Semiconductor
Chapter 14 Analog-to-Digital Converter (S08ADC10V1)
14.1 Overview
The 10-bit analog-to-digital converter (ADC) is a successive approximation ADC designed for operation within an integrated microcontroller system-on-chip. The ADC module design supports up to 28 separate analog inputs (AD0-AD27). Only 9 (AD0-AD3, AD8-AD11, and AD27) of the possible inputs are implemented on the MC9S08AC16 Series Family of MCUs. These inputs are selected by the ADCH bits. Some inputs are shared with I/O pins as shown in Figure 14-1. All of the channel assignments of the ADC for the MC9S08AC16 Series devices are summarized in Table 14-1. NOTE Ignore any references to stop1 low-power mode in this chapter, because the MC9S08AC16 Series does not support it.
14.2
Channel Assignments
The ADC channel assignments for the MC9S08AC16 Series devices are shown in the table below. Channels that are unimplemented are internally connected to VREFL. Reserved channels convert to an unknown value. Channels which are connected to an I/O pin have an associated pin control bit as shown.
Table 14-1. ADC Channel Assignment
ADCH 00000 00001 00010 00011 00100 00101 00110 00111 01000 01001 01010 01011 01100 01101 01110 Channel AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7 AD8 AD9 AD10 AD11 AD12 AD13 AD14 Input PTB0/AD1P0 PTB1/AD1P1 PTB2/AD1P2 PTB3/AD1P3 VREFL VREFL VREFL VREFL PTD0/AD1P8 PTD1/AD1P9 PTD2/AD1P10 PTD3/AD1P11 VREFL VREFL VREFL Pin Control ADPC0 ADPC1 ADPC2 ADPC3 N/A N/A N/A N/A ADPC8 ADPC9 ADPC10 ADPC11 N/A N/A N/A ADCH 10000 10001 10010 10011 10100 10101 10110 10111 11000 11001 11010 11011 11100 11101 11110 VREFH VREFL Channel AD16 AD17 AD18 AD19 AD20 AD21 AD22 AD23 AD24 AD25 AD26 AD27 Input VREFL VREFL VREFL VREFL VREFL VREFL Reserved Reserved Reserved Reserved Temp Sensor Internal Bandgap Reserved VREFH VREFL Pin Control N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 243
Chapter 14 Analog-to-Digital Converter (S08ADC10V1)
Table 14-1. ADC Channel Assignment (continued)
ADCH 01111 Channel AD15 Input VREFL Pin Control N/A ADCH 11111 Channel module disabled Input None Pin Control N/A
NOTE Selecting the internal bandgap channel requires BGBE =1 in SPMSC1 see Section 5.9.8, "System Power Management Status and Control 1 Register (SPMSC1)." For value of bandgap voltage reference see Section A.6, "DC Characteristics."
14.2.1
Alternate Clock
The ADC module is capable of performing conversions using the MCU bus clock, the bus clock divided by two, the local asynchronous clock (ADACK) within the module, or the alternate clock, ALTCLK. The alternate clock for the MC9S08AC16 Series MCU devices is the external reference clock (ICGERCLK) from the internal clock generator (ICG) module. Because ICGERCLK is active only while an external clock source is enabled, the ICG must be configured for either FBE or FEE mode (CLKS1 = 1). ICGERCLK must run at a frequency such that the ADC conversion clock (ADCK) runs at a frequency within its specified range (fADCK) after being divided down from the ALTCLK input as determined by the ADIV bits. For example, if the ADIV bits are set up to divide by four, then the minimum frequency for ALTCLK (ICGERCLK) is four times the minimum value for fADCK and the maximum frequency is four times the maximum value for fADCK. Because of the minimum frequency requirement, when an oscillator circuit is used it must be configured for high range operation (RANGE = 1). ALTCLK is active while the MCU is in wait mode provided the conditions described above are met. This allows ALTCLK to be used as the conversion clock source for the ADC while the MCU is in wait mode. ALTCLK cannot be used as the ADC conversion clock source while the MCU is in stop3.
14.2.2
Hardware Trigger
The ADC hardware trigger, ADHWT, is output from the real time interrupt (RTI) counter. The RTI counter can be clocked by either ICGERCLK or a nominal 1 kHz clock source within the RTI block. The 1-kHz clock source can be used with the MCU in run, wait, or stop3. With the ICG configured for either FBE or FEE mode, ICGERCLK can be used with the MCU in run or wait. The period of the RTI is determined by the input clock frequency and the RTIS bits. When the ADC hardware trigger is enabled, a conversion is initiated upon an RTI counter overflow. The RTI counter is a free running counter that generates an overflow at the RTI rate determined by the RTIS bits.
14.2.2.1
Analog Pin Enables
The ADC on MC9S08AC16 Series contains only two analog pin enable registers, APCTL1 and APCTL2.
MC9S08AC16 Series Data Sheet, Rev. 8 244 Freescale Semiconductor
Chapter 14 Analog-to-Digital Converter (S08ADC10V1)
14.2.2.2
Low-Power Mode Operation
The ADC is capable of running in stop3 mode but requires LVDSE and LVDE in SPMSC1 to be set.
14.2.3
Temperature Sensor
The ADC1 module includes a temperature sensor whose output is connected to one of the ADC analog channel inputs. Equation 14-1 provides an approximate transfer function of the temperature sensor.
Temp = 25 - ((VTEMP -VTEMP25) / m) Eqn. 14-1
where: -- VTEMP is the voltage of the temperature sensor channel at the ambient temperature. -- VTEMP25 is the voltage of the temperature sensor channel at 25C. -- m is the hot or cold voltage versus temperature slope in V/C. For temperature calculations, use the VTEMP25 and m values from the ADC Electricals table. In application code, the user reads the temperature sensor channel, calculates VTEMP, and compares to VTEMP25 . If VTEMP is greater than VTEMP25 the cold slope value is applied in Equation 14-1. If VTEMP is less than VTEMP25 the hot slope value is applied in Equation 14-1. To improve accuracy , calibrate the bandgap voltage reference and temperature sensor. Calibrating at 25 C will improve accuracy to 4.5 C. Calibration at 3 points, -40 C, 25 C, and 125 C will improve accuracy to 2.5 C. Once calibration has been completed, the user will need to calculate the slope for both hot and cold. In application code, the user would then calculate the temperature using Equation 14-1 as detailed above and then determine if the temperature is above or below 25 C. Once determined if the temperature is above or below 25 C, the user can recalculate the temperature using the hot or cold slope value obtained during calibration. For more information on using the temperature sensor, consult AN3031.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 245
Chapter 14 Analog-to-Digital Converter (S08ADC10V1)
VDDAD VSSAD VREFL VREFH HCS08 CORE BKGD/MS BDC CPU
10-BIT ANALOG-TO-DIGITAL CONVERTER (ADC1) DEBUG MODULE (DBG)
4 AD1P11-AD1P8
PORT A
4 AD1P3-AD1P0
PTA7 PTA2 PTA1 PTA0 PTB3/AD1P3 PTB2/AD1P2 PTB1/TPM3CH1/AD1P1 PTB0/TPM3CH0/AD1P0 PTC5/RxD2 PTC4 PTC3/TxD2 PTC2/MCLK PTC1/SDA1 PTC0/SCL1 PTD3/KBIP6/AD1P11 PTD2/KBIP5/AD1P10 PTD1/AD1P9 PTD0/AD1P8
SDA1 IIC MODULE (IIC1) SCL1 PORT C PORT D
RESET IRQ/TPMCLK
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION POWER MANAGEMENT RTI IRQ COP LVD
INTERNAL CLOCK GENERATOR (ICG) LOW-POWER OSCILLATOR 7-BIT KEYBOARD INTERRUPT MODULE (KBI)
EXTAL XTAL
2 KBIP6-KBIP5 5 KBIP4-KBIP0 RxD1 TxD1 RxD2 TxD2 SPSCK1 MOSI1 MISO1 SS1 TPM1CH1 TPM1CH0 TPM1CH3 TPM1CH2 TPM2CH1 TPM2CH0 TPM3CH1 TPM3CH0
TPMCLK
SERIAL COMMUNICATIONS INTERFACE MODULE (SCI1) SERIAL COMMUNICATIONS INTERFACE MODULE (SCI2) SERIAL PERIPHERAL INTERFACE MODULE (SPI1)
PORT B
USER FLASH 16,384 BYTES OR 8192 BYTES
PTE7/SPSCK1 PTE6/MOSI1 PTE5/MISO1 PTE4/SS1 PTE3/TPM1CH1 PTE2/TPM1CH0 PTE1/RxD1 PTE0/TxD1
USER RAM 1024 BYTES OR 768 BYTES VDD VSS VOLTAGE REGULATOR
2-CHANNEL TIMER/PWM MODULE (TPM2)
PORT F
4-CHANNEL TIMER/PWM MODULE (TPM1)
PORT E
PTF6 PTF5/TPM2CH1 PTF4/TPM2CH0 PTF1/TPM1CH3 PTF0/TPM1CH2
= Not available on 32-, 42-, or 44-pin packages = Not available on 32- or 42-pin packages = Not available on 32-pin packages
Notes: 1. Port pins are software configurable with pullup device if input port. 2. Pin contains software configurable pullup/pulldown device if IRQ is enabled (IRQPE = 1). Pulldown is enabled if rising edge detect is selected (IRQEDG = 1) 3. IRQ does not have a clamp diode to VDD. IRQ should not be driven above VDD. 4. Pin contains integrated pullup device. 5. PTD3, PTD2, and PTG4 contain both pullup and pulldown devices. Pulldown enabled when KBI is enabled (KBIPEn = 1) and rising edge is selected (KBEDGn = 1).
Figure 14-1. MC9S08AC16 Block Diagram Highlighting the ADC
MC9S08AC16 Series Data Sheet, Rev. 8 246 Freescale Semiconductor
PORT G
2-CHANNEL TIMER/PWM MODULE (TPM3)
PTG6/EXTAL PTG5/XTAL PTG4/KBIP4 PTG3/KBIP3 PTG2/KBIP2 PTG1/KBIP1 PTG0/KBIP0
Analog-to-Digital Converter (S08ADC10V1)
14.2.4
Features
Features of the ADC module include: * Linear successive approximation algorithm with 10 bits resolution. * Up to 28 analog inputs. * Output formatted in 10- or 8-bit right-justified format. * Single or continuous conversion (automatic return to idle after single conversion). * Configurable sample time and conversion speed/power. * Conversion complete flag and interrupt. * Input clock selectable from up to four sources. * Operation in wait or stop3 modes for lower noise operation. * Asynchronous clock source for lower noise operation. * Selectable asynchronous hardware conversion trigger. * Automatic compare with interrupt for less-than, or greater-than or equal-to, programmable value.
14.2.5
Block Diagram
Figure 14-2 provides a block diagram of the ADC module
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 247
Analog-to-Digital Converter (S08ADC10V1)
3
Compare true
ADC1SC1
COCO AIEN
ADC1CFG
ADLSMP
complete
ADTRG
ADICLK
ADLPC
ADCH
MODE
ADCO
ADIV
1
2
Async Clock Gen
ADACK MCU STOP ADHWT ADCK Clock Divide
Bus Clock
/2 ALTCLK
Control Sequencer
initialize transfer sample convert abort
AD0
***
AIEN 1
ADVIN
SAR Converter
COCO 2
Interrupt
AD27
VREFH VREFL
Data Registers Sum
Compare true Compare Logic Value ACFGT
3
Compare Value Registers
ADC1SC2
Figure 14-2. ADC Block Diagram
14.3
External Signal Description
The ADC module supports up to 28 separate analog inputs. It also requires four supply/reference/ground connections.
Table 14-2. Signal Properties
Name AD27-AD0 VREFH VREFL VDDAD VSSAD Function Analog Channel inputs High reference voltage Low reference voltage Analog power supply Analog ground
MC9S08AC16 Series Data Sheet, Rev. 8 248 Freescale Semiconductor
Analog-to-Digital Converter (S08ADC10V1)
14.3.1
Analog Power (VDDAD)
The ADC analog portion uses VDDAD as its power connection. In some packages, VDDAD is connected internally to VDD. If externally available, connect the VDDAD pin to the same voltage potential as VDD. External filtering may be necessary to ensure clean VDDAD for good results.
14.3.2
Analog Ground (VSSAD)
The ADC analog portion uses VSSAD as its ground connection. In some packages, VSSAD is connected internally to VSS. If externally available, connect the VSSAD pin to the same voltage potential as VSS.
14.3.3
Voltage Reference High (VREFH)
VREFH is the high reference voltage for the converter. In some packages, VREFH is connected internally to VDDAD. If externally available, VREFH may be connected to the same potential as VDDAD, or may be driven by an external source that is between the minimum VDDAD spec and the VDDAD potential (VREFH must never exceed VDDAD).
14.3.4
Voltage Reference Low (VREFL)
VREFL is the low reference voltage for the converter. In some packages, VREFL is connected internally to VSSAD. If externally available, connect the VREFL pin to the same voltage potential as VSSAD.
14.3.5
Analog Channel Inputs (ADx)
The ADC module supports up to 28 separate analog inputs. An input is selected for conversion through the ADCH channel select bits.
14.4
* * * * * *
Register Definition
Status and control register, ADC1SC1 Status and control register, ADC1SC2 Data result registers, ADC1RH and ADC1RL Compare value registers, ADC1CVH and ADC1CVL Configuration register, ADC1CFG Pin enable registers, APCTL1, APCTL2, APCTL3
These memory mapped registers control and monitor operation of the ADC:
14.4.1
Status and Control Register 1 (ADC1SC1)
This section describes the function of the ADC status and control register (ADC1SC1). Writing ADC1SC1 aborts the current conversion and initiates a new conversion (if the ADCH bits are equal to a value other than all 1s).
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 249
Analog-to-Digital Converter (S08ADC10V1)
7
6
5
4
3
2
1
0
R W Reset:
COCO AIEN 0 0 ADCO 0 1 1 ADCH 1 1 1
= Unimplemented or Reserved
Figure 14-3. Status and Control Register (ADC1SC1) Table 14-3. ADC1SC1 Register Field Descriptions
Field 7 COCO Description Conversion Complete Flag -- The COCO flag is a read-only bit which is set each time a conversion is completed when the compare function is disabled (ACFE = 0). When the compare function is enabled (ACFE = 1) the COCO flag is set upon completion of a conversion only if the compare result is true. This bit is cleared whenever ADC1SC1 is written or whenever ADC1RL is read. 0 Conversion not completed 1 Conversion completed Interrupt Enable -- AIEN is used to enable conversion complete interrupts. When COCO becomes set while AIEN is high, an interrupt is asserted. 0 Conversion complete interrupt disabled 1 Conversion complete interrupt enabled Continuous Conversion Enable -- ADCO is used to enable continuous conversions. 0 One conversion following a write to the ADC1SC1 when software triggered operation is selected, or one conversion following assertion of ADHWT when hardware triggered operation is selected. 1 Continuous conversions initiated following a write to ADC1SC1 when software triggered operation is selected. Continuous conversions are initiated by an ADHWT event when hardware triggered operation is selected. Input Channel Select -- The ADCH bits form a 5-bit field which is used to select one of the input channels. The input channels are detailed in Figure 14-4. The successive approximation converter subsystem is turned off when the channel select bits are all set to 1. This feature allows for explicit disabling of the ADC and isolation of the input channel from all sources. Terminating continuous conversions this way will prevent an additional, single conversion from being performed. It is not necessary to set the channel select bits to all 1s to place the ADC in a low-power state when continuous conversions are not enabled because the module automatically enters a low-power state when a conversion completes.
6 AIEN
5 ADCO
4:0 ADCH
Figure 14-4. Input Channel Select
ADCH 00000 00001 00010 00011 00100 00101 00110 00111 Input Select AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7 ADCH 10000 10001 10010 10011 10100 10101 10110 10111 Input Select AD16 AD17 AD18 AD19 AD20 AD21 AD22 AD23
MC9S08AC16 Series Data Sheet, Rev. 8 250 Freescale Semiconductor
Analog-to-Digital Converter (S08ADC10V1)
Figure 14-4. Input Channel Select (continued)
ADCH 01000 01001 01010 01011 01100 01101 01110 01111 Input Select AD8 AD9 AD10 AD11 AD12 AD13 AD14 AD15 ADCH 11000 11001 11010 11011 11100 11101 11110 11111 Input Select AD24 AD25 AD26 AD27 Reserved VREFH VREFL Module disabled
14.4.2
Status and Control Register 2 (ADC1SC2)
The ADC1SC2 register is used to control the compare function, conversion trigger and conversion active of the ADC module.
7 6 5 4 3 2 1 0
R W Reset:
ADACT ADTRG 0 0 ACFE 0 ACFGT 0
0
0
R1 0
R1 0
0
0
= Unimplemented or Reserved
1
Bits 1 and 0 are reserved bits that must always be written to 0.
Figure 14-5. Status and Control Register 2 (ADC1SC2) Table 14-4. ADC1SC2 Register Field Descriptions
Field 7 ADACT Description Conversion Active -- ADACT indicates that a conversion is in progress. ADACT is set when a conversion is initiated and cleared when a conversion is completed or aborted. 0 Conversion not in progress 1 Conversion in progress Conversion Trigger Select -- ADTRG is used to select the type of trigger to be used for initiating a conversion. Two types of trigger are selectable: software trigger and hardware trigger. When software trigger is selected, a conversion is initiated following a write to ADC1SC1. When hardware trigger is selected, a conversion is initiated following the assertion of the ADHWT input. 0 Software trigger selected 1 Hardware trigger selected
6 ADTRG
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 251
Analog-to-Digital Converter (S08ADC10V1)
Table 14-4. ADC1SC2 Register Field Descriptions (continued)
Field 5 ACFE 4 ACFGT Description Compare Function Enable -- ACFE is used to enable the compare function. 0 Compare function disabled 1 Compare function enabled Compare Function Greater Than Enable -- ACFGT is used to configure the compare function to trigger when the result of the conversion of the input being monitored is greater than or equal to the compare value. The compare function defaults to triggering when the result of the compare of the input being monitored is less than the compare value. 0 Compare triggers when input is less than compare level 1 Compare triggers when input is greater than or equal to compare level
14.4.3
Data Result High Register (ADC1RH)
ADC1RH contains the upper two bits of the result of a 10-bit conversion. When configured for 8-bit conversions both ADR8 and ADR9 are equal to zero. ADC1RH is updated each time a conversion completes except when automatic compare is enabled and the compare condition is not met. In 10-bit MODE, reading ADC1RH prevents the ADC from transferring subsequent conversion results into the result registers until ADC1RL is read. If ADC1RL is not read until after the next conversion is completed, then the intermediate conversion result will be lost. In 8-bit mode there is no interlocking with ADC1RL. In the case that the MODE bits are changed, any data in ADC1RH becomes invalid.
7 6 5 4 3 2 1 0
R W Reset:
0
0
0
0
0
0
ADR9
ADR8
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 14-6. Data Result High Register (ADC1RH)
14.4.4
Data Result Low Register (ADC1RL)
ADC1RL contains the lower eight bits of the result of a 10-bit conversion, and all eight bits of an 8-bit conversion. This register is updated each time a conversion completes except when automatic compare is enabled and the compare condition is not met. In 10-bit mode, reading ADC1RH prevents the ADC from transferring subsequent conversion results into the result registers until ADC1RL is read. If ADC1RL is not read until the after next conversion is completed, then the intermediate conversion results will be lost. In 8-bit mode, there is no interlocking with ADC1RH. In the case that the MODE bits are changed, any data in ADC1RL becomes invalid.
MC9S08AC16 Series Data Sheet, Rev. 8 252 Freescale Semiconductor
Analog-to-Digital Converter (S08ADC10V1)
7
6
5
4
3
2
1
0
R W Reset:
ADR7
ADR6
ADR5
ADR4
ADR3
ADR2
ADR1
ADR0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 14-7. Data Result Low Register (ADC1RL)
14.4.5
Compare Value High Register (ADC1CVH)
This register holds the upper two bits of the 10-bit compare value. These bits are compared to the upper two bits of the result following a conversion in 10-bit mode when the compare function is enabled.In 8-bit operation, ADC1CVH is not used during compare.
7 6 5 4 3 2 1 0
R W Reset:
0
0
0
0 ADCV9 ADCV8 0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 14-8. Compare Value High Register (ADC1CVH)
14.4.6
Compare Value Low Register (ADC1CVL)
This register holds the lower 8 bits of the 10-bit compare value, or all 8 bits of the 8-bit compare value. Bits ADCV7:ADCV0 are compared to the lower 8 bits of the result following a conversion in either 10-bit or 8-bit mode.
7 6 5 4 3 2 1 0
R ADCV7 W Reset: 0 0 0 0 0 0 0 0 ADCV6 ADCV5 ADCV4 ADCV3 ADCV2 ADCV1 ADCV0
Figure 14-9. Compare Value Low Register(ADC1CVL)
14.4.7
Configuration Register (ADC1CFG)
ADC1CFG is used to select the mode of operation, clock source, clock divide, and configure for low power or long sample time.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 253
Analog-to-Digital Converter (S08ADC10V1)
7
6
5
4
3
2
1
0
R ADLPC W Reset: 0 0 0 0 0 0 0 0 ADIV ADLSMP MODE ADICLK
Figure 14-10. Configuration Register (ADC1CFG) Table 14-5. ADC1CFG Register Field Descriptions
Field 7 ADLPC Description Low Power Configuration -- ADLPC controls the speed and power configuration of the successive approximation converter. This is used to optimize power consumption when higher sample rates are not required. 0 High speed configuration 1 Low power configuration: {FC31}The power is reduced at the expense of maximum clock speed. Clock Divide Select -- ADIV select the divide ratio used by the ADC to generate the internal clock ADCK. Table 14-6 shows the available clock configurations. Long Sample Time Configuration -- ADLSMP selects between long and short sample time. This adjusts the sample period to allow higher impedance inputs to be accurately sampled or to maximize conversion speed for lower impedance inputs. Longer sample times can also be used to lower overall power consumption when continuous conversions are enabled if high conversion rates are not required. 0 Short sample time 1 Long sample time Conversion Mode Selection -- MODE bits are used to select between 10- or 8-bit operation. See Table 14-7. Input Clock Select -- ADICLK bits select the input clock source to generate the internal clock ADCK. See Table 14-8.
6:5 ADIV 4 ADLSMP
3:2 MODE 1:0 ADICLK
Table 14-6. Clock Divide Select
ADIV 00 01 10 11 Divide Ratio 1 2 4 8 Clock Rate Input clock Input clock / 2 Input clock / 4 Input clock / 8
Table 14-7. Conversion Modes
MODE 00 01 10 11 Mode Description 8-bit conversion (N=8) Reserved 10-bit conversion (N=10) Reserved
MC9S08AC16 Series Data Sheet, Rev. 8 254 Freescale Semiconductor
Analog-to-Digital Converter (S08ADC10V1)
Table 14-8. Input Clock Select
ADICLK 00 01 10 11 Bus clock Bus clock divided by 2 Alternate clock (ALTCLK) Asynchronous clock (ADACK) Selected Clock Source
14.4.8
Pin Control 1 Register (APCTL1)
The pin control registers are used to disable the I/O port control of MCU pins used as analog inputs. APCTL1 is used to control the pins associated with channels 0-7 of the ADC module.
7 6 5 4 3 2 1 0
R ADPC7 W Reset: 0 0 0 0 0 0 0 0 ADPC6 ADPC5 ADPC4 ADPC3 ADPC2 ADPC1 ADPC0
Figure 14-11. Pin Control 1 Register (APCTL1) Table 14-9. APCTL1 Register Field Descriptions
Field 7 ADPC7 6 ADPC6 5 ADPC5 4 ADPC4 3 ADPC3 2 ADPC2 Description ADC Pin Control 7 -- ADPC7 is used to control the pin associated with channel AD7. 0 AD7 pin I/O control enabled 1 AD7 pin I/O control disabled ADC Pin Control 6 -- ADPC6 is used to control the pin associated with channel AD6. 0 AD6 pin I/O control enabled 1 AD6 pin I/O control disabled ADC Pin Control 5 -- ADPC5 is used to control the pin associated with channel AD5. 0 AD5 pin I/O control enabled 1 AD5 pin I/O control disabled ADC Pin Control 4 -- ADPC4 is used to control the pin associated with channel AD4. 0 AD4 pin I/O control enabled 1 AD4 pin I/O control disabled ADC Pin Control 3 -- ADPC3 is used to control the pin associated with channel AD3. 0 AD3 pin I/O control enabled 1 AD3 pin I/O control disabled ADC Pin Control 2 -- ADPC2 is used to control the pin associated with channel AD2. 0 AD2 pin I/O control enabled 1 AD2 pin I/O control disabled
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 255
Analog-to-Digital Converter (S08ADC10V1)
Table 14-9. APCTL1 Register Field Descriptions (continued)
Field 1 ADPC1 0 ADPC0 Description ADC Pin Control 1 -- ADPC1 is used to control the pin associated with channel AD1. 0 AD1 pin I/O control enabled 1 AD1 pin I/O control disabled ADC Pin Control 0 -- ADPC0 is used to control the pin associated with channel AD0. 0 AD0 pin I/O control enabled 1 AD0 pin I/O control disabled
14.4.9
Pin Control 2 Register (APCTL2)
APCTL2 is used to control channels 8-15 of the ADC module.
7 6 5 4 3 2 1 0
R ADPC15 W Reset: 0 0 0 0 0 0 0 0 ADPC14 ADPC13 ADPC12 ADPC11 ADPC10 ADPC9 ADPC8
Figure 14-12. Pin Control 2 Register (APCTL2) Table 14-10. APCTL2 Register Field Descriptions
Field 7 ADPC15 6 ADPC14 5 ADPC13 4 ADPC12 3 ADPC11 2 ADPC10 Description ADC Pin Control 15 -- ADPC15 is used to control the pin associated with channel AD15. 0 AD15 pin I/O control enabled 1 AD15 pin I/O control disabled ADC Pin Control 14 -- ADPC14 is used to control the pin associated with channel AD14. 0 AD14 pin I/O control enabled 1 AD14 pin I/O control disabled ADC Pin Control 13 -- ADPC13 is used to control the pin associated with channel AD13. 0 AD13 pin I/O control enabled 1 AD13 pin I/O control disabled ADC Pin Control 12 -- ADPC12 is used to control the pin associated with channel AD12. 0 AD12 pin I/O control enabled 1 AD12 pin I/O control disabled ADC Pin Control 11 -- ADPC11 is used to control the pin associated with channel AD11. 0 AD11 pin I/O control enabled 1 AD11 pin I/O control disabled ADC Pin Control 10 -- ADPC10 is used to control the pin associated with channel AD10. 0 AD10 pin I/O control enabled 1 AD10 pin I/O control disabled
MC9S08AC16 Series Data Sheet, Rev. 8 256 Freescale Semiconductor
Analog-to-Digital Converter (S08ADC10V1)
Table 14-10. APCTL2 Register Field Descriptions (continued)
Field 1 ADPC9 0 ADPC8 Description ADC Pin Control 9 -- ADPC9 is used to control the pin associated with channel AD9. 0 AD9 pin I/O control enabled 1 AD9 pin I/O control disabled ADC Pin Control 8 -- ADPC8 is used to control the pin associated with channel AD8. 0 AD8 pin I/O control enabled 1 AD8 pin I/O control disabled
14.4.10 Pin Control 3 Register (APCTL3)
APCTL3 is used to control channels 16-23 of the ADC module.
7 6 5 4 3 2 1 0
R ADPC23 W Reset: 0 0 0 0 0 0 0 0 ADPC22 ADPC21 ADPC20 ADPC19 ADPC18 ADPC17 ADPC16
Figure 14-13. Pin Control 3 Register (APCTL3) Table 14-11. APCTL3 Register Field Descriptions
Field 7 ADPC23 6 ADPC22 5 ADPC21 4 ADPC20 3 ADPC19 2 ADPC18 Description ADC Pin Control 23 -- ADPC23 is used to control the pin associated with channel AD23. 0 AD23 pin I/O control enabled 1 AD23 pin I/O control disabled ADC Pin Control 22 -- ADPC22 is used to control the pin associated with channel AD22. 0 AD22 pin I/O control enabled 1 AD22 pin I/O control disabled ADC Pin Control 21 -- ADPC21 is used to control the pin associated with channel AD21. 0 AD21 pin I/O control enabled 1 AD21 pin I/O control disabled ADC Pin Control 20 -- ADPC20 is used to control the pin associated with channel AD20. 0 AD20 pin I/O control enabled 1 AD20 pin I/O control disabled ADC Pin Control 19 -- ADPC19 is used to control the pin associated with channel AD19. 0 AD19 pin I/O control enabled 1 AD19 pin I/O control disabled ADC Pin Control 18 -- ADPC18 is used to control the pin associated with channel AD18. 0 AD18 pin I/O control enabled 1 AD18 pin I/O control disabled
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 257
Analog-to-Digital Converter (S08ADC10V1)
Table 14-11. APCTL3 Register Field Descriptions (continued)
Field 1 ADPC17 0 ADPC16 Description ADC Pin Control 17 -- ADPC17 is used to control the pin associated with channel AD17. 0 AD17 pin I/O control enabled 1 AD17 pin I/O control disabled ADC Pin Control 16 -- ADPC16 is used to control the pin associated with channel AD16. 0 AD16 pin I/O control enabled 1 AD16 pin I/O control disabled
14.5
Functional Description
The ADC module is disabled during reset or when the ADCH bits are all high. The module is idle when a conversion has completed and another conversion has not been initiated. When idle, the module is in its lowest power state. The ADC can perform an analog-to-digital conversion on any of the software selectable channels. The selected channel voltage is converted by a successive approximation algorithm into an 11-bit digital result. In 8-bit mode, the selected channel voltage is converted by a successive approximation algorithm into a 9-bit digital result. When the conversion is completed, the result is placed in the data registers (ADC1RH and ADC1RL).In 10-bit mode, the result is rounded to 10 bits and placed in ADC1RH and ADC1RL. In 8-bit mode, the result is rounded to 8 bits and placed in ADC1RL. The conversion complete flag (COCO) is then set and an interrupt is generated if the conversion complete interrupt has been enabled (AIEN = 1). The ADC module has the capability of automatically comparing the result of a conversion with the contents of its compare registers. The compare function is enabled by setting the ACFE bit and operates in conjunction with any of the conversion modes and configurations.
14.5.1
Clock Select and Divide Control
One of four clock sources can be selected as the clock source for the ADC module. This clock source is then divided by a configurable value to generate the input clock to the converter (ADCK). The clock is selected from one of the following sources by means of the ADICLK bits. * * * * The bus clock, which is equal to the frequency at which software is executed. This is the default selection following reset. The bus clock divided by 2. For higher bus clock rates, this allows a maximum divide by 16 of the bus clock. ALTCLK, as defined for this MCU (See module section introduction). The asynchronous clock (ADACK) - This clock is generated from a clock source within the ADC module. When selected as the clock source this clock remains active while the MCU is in wait or stop3 mode and allows conversions in these modes for lower noise operation.
Whichever clock is selected, its frequency must fall within the specified frequency range for ADCK. If the available clocks are too slow, the ADC will not perform according to specifications. If the available clocks
MC9S08AC16 Series Data Sheet, Rev. 8 258 Freescale Semiconductor
Analog-to-Digital Converter (S08ADC10V1)
are too fast, then the clock must be divided to the appropriate frequency. This divider is specified by the ADIV bits and can be divide-by 1, 2, 4, or 8.
14.5.2
Input Select and Pin Control
The pin control registers (APCTL3, APCTL2, and APCTL1) are used to disable the I/O port control of the pins used as analog inputs.When a pin control register bit is set, the following conditions are forced for the associated MCU pin: * The output buffer is forced to its high impedance state. * The input buffer is disabled. A read of the I/O port returns a zero for any pin with its input buffer disabled. * The pullup is disabled.
14.5.3
Hardware Trigger
The ADC module has a selectable asynchronous hardware conversion trigger, ADHWT, that is enabled when the ADTRG bit is set. This source is not available on all MCUs. Consult the module introduction for information on the ADHWT source specific to this MCU. When ADHWT source is available and hardware trigger is enabled (ADTRG=1), a conversion is initiated on the rising edge of ADHWT. If a conversion is in progress when a rising edge occurs, the rising edge is ignored. In continuous convert configuration, only the initial rising edge to launch continuous conversions is observed. The hardware trigger function operates in conjunction with any of the conversion modes and configurations.
14.5.4
Conversion Control
Conversions can be performed in either 10-bit mode or 8-bit mode as determined by the MODE bits. Conversions can be initiated by either a software or hardware trigger. In addition, the ADC module can be configured for low power operation, long sample time, continuous conversion, and automatic compare of the conversion result to a software determined compare value.
14.5.4.1
Initiating Conversions
A conversion is initiated: * Following a write to ADC1SC1 (with ADCH bits not all 1s) if software triggered operation is selected. * Following a hardware trigger (ADHWT) event if hardware triggered operation is selected. * Following the transfer of the result to the data registers when continuous conversion is enabled. If continuous conversions are enabled a new conversion is automatically initiated after the completion of the current conversion. In software triggered operation, continuous conversions begin after ADC1SC1 is written and continue until aborted. In hardware triggered operation, continuous conversions begin after a hardware trigger event and continue until aborted.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 259
Analog-to-Digital Converter (S08ADC10V1)
14.5.4.2
Completing Conversions
A conversion is completed when the result of the conversion is transferred into the data result registers, ADC1RH and ADC1RL. This is indicated by the setting of COCO. An interrupt is generated if AIEN is high at the time that COCO is set. A blocking mechanism prevents a new result from overwriting previous data in ADC1RH and ADC1RL if the previous data is in the process of being read while in 10-bit MODE (the ADC1RH register has been read but the ADC1RL register has not). When blocking is active, the data transfer is blocked, COCO is not set, and the new result is lost. In the case of single conversions with the compare function enabled and the compare condition false, blocking has no effect and ADC operation is terminated. In all other cases of operation, when a data transfer is blocked, another conversion is initiated regardless of the state of ADCO (single or continuous conversions enabled). If single conversions are enabled, the blocking mechanism could result in several discarded conversions and excess power consumption. To avoid this issue, the data registers must not be read after initiating a single conversion until the conversion completes.
14.5.4.3
* * * *
Aborting Conversions
Any conversion in progress will be aborted when: A write to ADC1SC1 occurs (the current conversion will be aborted and a new conversion will be initiated, if ADCH are not all 1s). A write to ADC1SC2, ADC1CFG, ADC1CVH, or ADC1CVL occurs. This indicates a mode of operation change has occurred and the current conversion is therefore invalid. The MCU is reset. The MCU enters stop mode with ADACK not enabled.
When a conversion is aborted, the contents of the data registers, ADC1RH and ADC1RL, are not altered but continue to be the values transferred after the completion of the last successful conversion. In the case that the conversion was aborted by a reset, ADC1RH and ADC1RL return to their reset states.
14.5.4.4
Power Control
The ADC module remains in its idle state until a conversion is initiated. If ADACK is selected as the conversion clock source, the ADACK clock generator is also enabled. Power consumption when active can be reduced by setting ADLPC. This results in a lower maximum value for fADCK (see the electrical specifications).
14.5.4.5
Total Conversion Time
The total conversion time depends on the sample time (as determined by ADLSMP), the MCU bus frequency, the conversion mode (8-bit or 10-bit), and the frequency of the conversion clock (fADCK). After the module becomes active, sampling of the input begins. ADLSMP is used to select between short and long sample times.When sampling is complete, the converter is isolated from the input channel and a successive approximation algorithm is performed to determine the digital value of the analog signal. The
MC9S08AC16 Series Data Sheet, Rev. 8 260 Freescale Semiconductor
Analog-to-Digital Converter (S08ADC10V1)
result of the conversion is transferred to ADC1RH and ADC1RL upon completion of the conversion algorithm. If the bus frequency is less than the fADCK frequency, precise sample time for continuous conversions cannot be guaranteed when short sample is enabled (ADLSMP=0). If the bus frequency is less than 1/11th of the fADCK frequency, precise sample time for continuous conversions cannot be guaranteed when long sample is enabled (ADLSMP=1). The maximum total conversion time for different conditions is summarized in Table 14-12.
Table 14-12. Total Conversion Time vs. Control Conditions
Conversion Type Single or first continuous 8-bit Single or first continuous 10-bit Single or first continuous 8-bit Single or first continuous 10-bit Single or first continuous 8-bit Single or first continuous 10-bit Single or first continuous 8-bit Single or first continuous 10-bit Subsequent continuous 8-bit; fBUS > fADCK Subsequent continuous 10-bit; fBUS > fADCK Subsequent continuous 8-bit; fBUS > fADCK/11 Subsequent continuous 10-bit; fBUS > fADCK/11 ADICLK 0x, 10 0x, 10 0x, 10 0x, 10 11 11 11 11 xx xx xx xx ADLSMP 0 0 1 1 0 0 1 1 0 0 1 1 Max Total Conversion Time 20 ADCK cycles + 5 bus clock cycles 23 ADCK cycles + 5 bus clock cycles 40 ADCK cycles + 5 bus clock cycles 43 ADCK cycles + 5 bus clock cycles 5 s + 20 ADCK + 5 bus clock cycles 5 s + 23 ADCK + 5 bus clock cycles 5 s + 40 ADCK + 5 bus clock cycles 5 s + 43 ADCK + 5 bus clock cycles 17 ADCK cycles 20 ADCK cycles 37 ADCK cycles 40 ADCK cycles
The maximum total conversion time is determined by the clock source chosen and the divide ratio selected. The clock source is selectable by the ADICLK bits, and the divide ratio is specified by the ADIV bits. For example, in 10-bit mode, with the bus clock selected as the input clock source, the input clock divide-by-1 ratio selected, and a bus frequency of 8 MHz, then the conversion time for a single conversion is: Conversion time = 23 ADCK cyc 8 MHz/1 + 5 bus cyc 8 MHz = 3.5 s
Number of bus cycles = 3.5 s x 8 MHz = 28 cycles NOTE The ADCK frequency must be between fADCK minimum and fADCK maximum to meet ADC specifications.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 261
Analog-to-Digital Converter (S08ADC10V1)
14.5.5
Automatic Compare Function
The compare function can be configured to check for either an upper limit or lower limit. After the input is sampled and converted, the result is added to the two's complement of the compare value (ADC1CVH and ADC1CVL). When comparing to an upper limit (ACFGT = 1), if the result is greater-than or equal-to the compare value, COCO is set. When comparing to a lower limit (ACFGT = 0), if the result is less than the compare value, COCO is set. The value generated by the addition of the conversion result and the two's complement of the compare value is transferred to ADC1RH and ADC1RL. Upon completion of a conversion while the compare function is enabled, if the compare condition is not true, COCO is not set and no data is transferred to the result registers. An ADC interrupt is generated upon the setting of COCO if the ADC interrupt is enabled (AIEN = 1). NOTE The compare function can be used to monitor the voltage on a channel while the MCU is in either wait or stop3 mode. The ADC interrupt will wake the MCU when the compare condition is met.
14.5.6
MCU Wait Mode Operation
The WAIT instruction puts the MCU in a lower power-consumption standby mode from which recovery is very fast because the clock sources remain active. If a conversion is in progress when the MCU enters wait mode, it continues until completion. Conversions can be initiated while the MCU is in wait mode by means of the hardware trigger or if continuous conversions are enabled. The bus clock, bus clock divided by two, and ADACK are available as conversion clock sources while in wait mode. The use of ALTCLK as the conversion clock source in wait is dependent on the definition of ALTCLK for this MCU. Consult the module introduction for information on ALTCLK specific to this MCU. A conversion complete event sets the COCO and generates an ADC interrupt to wake the MCU from wait mode if the ADC interrupt is enabled (AIEN = 1).
14.5.7
MCU Stop3 Mode Operation
The STOP instruction is used to put the MCU in a low power-consumption standby mode during which most or all clock sources on the MCU are disabled.
14.5.7.1
Stop3 Mode With ADACK Disabled
If the asynchronous clock, ADACK, is not selected as the conversion clock, executing a STOP instruction aborts the current conversion and places the ADC in its idle state. The contents of ADC1RH and ADC1RL are unaffected by stop3 mode.After exiting from stop3 mode, a software or hardware trigger is required to resume conversions.
MC9S08AC16 Series Data Sheet, Rev. 8 262 Freescale Semiconductor
Analog-to-Digital Converter (S08ADC10V1)
14.5.7.2
Stop3 Mode With ADACK Enabled
If ADACK is selected as the conversion clock, the ADC continues operation during stop3 mode. For guaranteed ADC operation, the MCU's voltage regulator must remain active during stop3 mode. Consult the module introduction for configuration information for this MCU. If a conversion is in progress when the MCU enters stop3 mode, it continues until completion. Conversions can be initiated while the MCU is in stop3 mode by means of the hardware trigger or if continuous conversions are enabled. A conversion complete event sets the COCO and generates an ADC interrupt to wake the MCU from stop3 mode if the ADC interrupt is enabled (AIEN = 1). NOTE It is possible for the ADC module to wake the system from low power stop and cause the MCU to begin consuming run-level currents without generating a system level interrupt. To prevent this scenario, software should ensure that the data transfer blocking mechanism (discussed in Section 14.5.4.2, "Completing Conversions) is cleared when entering stop3 and continuing ADC conversions.
14.5.8
MCU Stop1 and Stop2 Mode Operation
The ADC module is automatically disabled when the MCU enters either stop1 or stop2 mode. All module registers contain their reset values following exit from stop1 or stop2. Therefore the module must be re-enabled and re-configured following exit from stop1 or stop2.
14.6
Initialization Information
This section gives an example which provides some basic direction on how a user would initialize and configure the ADC module. The user has the flexibility of choosing between configuring the module for 8-bit or 10-bit resolution, single or continuous conversion, and a polled or interrupt approach, among many other options. Refer to Table 14-6, Table 14-7, and Table 14-8 for information used in this example. NOTE Hexadecimal values designated by a preceding 0x, binary values designated by a preceding %, and decimal values have no preceding character.
14.6.1
14.6.1.1
ADC Module Initialization Example
Initialization Sequence
Before the ADC module can be used to complete conversions, an initialization procedure must be performed. A typical sequence is as follows: 1. Update the configuration register (ADCCFG) to select the input clock source and the divide ratio used to generate the internal clock, ADCK. This register is also used for selecting sample time and low-power configuration.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 263
Analog-to-Digital Converter (S08ADC10V1)
2. Update status and control register 2 (ADCSC2) to select the conversion trigger (hardware or software) and compare function options, if enabled. 3. Update status and control register 1 (ADCSC1) to select whether conversions will be continuous or completed only once, and to enable or disable conversion complete interrupts. The input channel on which conversions will be performed is also selected here.
14.6.1.2
Pseudo -- Code Example
In this example, the ADC module will be set up with interrupts enabled to perform a single 10-bit conversion at low power with a long sample time on input channel 1, where the internal ADCK clock will be derived from the bus clock divided by 1. ADCCFG = 0x98 (%10011000) Bit 7 ADLPC 1 Configures for low power (lowers maximum clock speed) Bit 6:5 ADIV 00 Sets the ADCK to the input clock / 1 Bit 4 ADLSMP 1 Configures for long sample time Bit 3:2 MODE 10 Sets mode at 10-bit conversions Bit 1:0 ADICLK 00 Selects bus clock as input clock source ADCSC2 = 0x00 (%00000000) Bit 7 ADACT 0 Bit 6 ADTRG 0 Bit 5 ACFE 0 Bit 4 ACFGT 0 Bit 3:2 00 Bit 1:0 00 ADCSC1 = 0x41 (%01000001) Bit 7 COCO 0 Bit 6 AIEN 1 Bit 5 ADCO 0 Bit 4:0 ADCH 00001 Flag indicates if a conversion is in progress Software trigger selected Compare function disabled Not used in this example Unimplemented or reserved, always reads zero Reserved for internal use; always write zero Read-only flag which is set when a conversion completes Conversion complete interrupt enabled One conversion only (continuous conversions disabled) Input channel 1 selected as ADC input channel
ADCRH/L = 0xxx Holds results of conversion. Read high byte (ADCRH) before low byte (ADCRL) so that conversion data cannot be overwritten with data from the next conversion. ADCCVH/L = 0xxx Holds compare value when compare function enabled APCTL1=0x02 AD1 pin I/O control disabled. All other AD pins remain general purpose I/O pins APCTL2=0x00 All other AD pins remain general purpose I/O pins
MC9S08AC16 Series Data Sheet, Rev. 8 264 Freescale Semiconductor
Analog-to-Digital Converter (S08ADC10V1)
RESET
INITIALIZE ADC ADCCFG = $98 ADCSC2 = $00 ADCSC1 = $41
CHECK COCO=1? YES READ ADCRH THEN ADCRL TO CLEAR COCO BIT
NO
CONTINUE
Figure 14-14. Initialization Flowchart for Example
14.7
Application Information
This section contains information for using the ADC module in applications. The ADC has been designed to be integrated into a microcontroller for use in embedded control applications requiring an A/D converter.
14.7.1
External Pins and Routing
The following sections discuss the external pins associated with the ADC module and how they should be used for best results.
14.7.1.1
Analog Supply Pins
The ADC module has analog power and ground supplies (VDDAD and VSSAD) which are available as separate pins on some devices. On other devices, VSSAD is shared on the same pin as the MCU digital VSS, and on others, both VSSAD and VDDAD are shared with the MCU digital supply pins. In these cases, there are separate pads for the analog supplies which are bonded to the same pin as the corresponding digital supply so that some degree of isolation between the supplies is maintained. When available on a separate pin, both VDDAD and VSSAD must be connected to the same voltage potential as their corresponding MCU digital supply (VDD and VSS) and must be routed carefully for maximum noise immunity and bypass capacitors placed as near as possible to the package.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 265
Analog-to-Digital Converter (S08ADC10V1)
In cases where separate power supplies are used for analog and digital power, the ground connection between these supplies must be at the VSSAD pin. This should be the only ground connection between these supplies if possible. The VSSAD pin makes a good single point ground location.
14.7.1.2
Analog Reference Pins
In addition to the analog supplies, the ADC module has connections for two reference voltage inputs. The high reference is VREFH, which may be shared on the same pin as VDDAD on some devices. The low reference is VREFL, which may be shared on the same pin as VSSAD on some devices. When available on a separate pin, VREFH may be connected to the same potential as VDDAD, or may be driven by an external source that is between the minimum VDDAD spec and the VDDAD potential (VREFH must never exceed VDDAD). When available on a separate pin, VREFL must be connected to the same voltage potential as VSSAD. Both VREFH and VREFL must be routed carefully for maximum noise immunity and bypass capacitors placed as near as possible to the package. AC current in the form of current spikes required to supply charge to the capacitor array at each successive approximation step is drawn through the VREFH and VREFL loop. The best external component to meet this current demand is a 0.1 F capacitor with good high frequency characteristics. This capacitor is connected between VREFH and VREFL and must be placed as near as possible to the package pins. Resistance in the path is not recommended because the current will cause a voltage drop which could result in conversion errors. Inductance in this path must be minimum (parasitic only).
14.7.1.3
Analog Input Pins
The external analog inputs are typically shared with digital I/O pins on MCU devices. The pin I/O control is disabled by setting the appropriate control bit in one of the pin control registers. Conversions can be performed on inputs without the associated pin control register bit set. It is recommended that the pin control register bit always be set when using a pin as an analog input. This avoids problems with contention because the output buffer will be in its high impedance state and the pullup is disabled. Also, the input buffer draws dc current when its input is not at either VDD or VSS. Setting the pin control register bits for all pins used as analog inputs should be done to achieve lowest operating current. Empirical data shows that capacitors on the analog inputs improve performance in the presence of noise or when the source impedance is high. Use of 0.01 F capacitors with good high-frequency characteristics is sufficient. These capacitors are not necessary in all cases, but when used they must be placed as near as possible to the package pins and be referenced to VSSA. For proper conversion, the input voltage must fall between VREFH and VREFL. If the input is equal to or exceeds VREFH, the converter circuit converts the signal to $3FF (full scale 10-bit representation) or $FF (full scale 8-bit representation). If the input is equal to or less than VREFL, the converter circuit converts it to $000. Input voltages between VREFH and VREFL are straight-line linear conversions. There will be a brief current associated with VREFL when the sampling capacitor is charging. The input is sampled for 3.5 cycles of the ADCK source when ADLSMP is low, or 23.5 cycles when ADLSMP is high. For minimal loss of accuracy due to current injection, pins adjacent to the analog input pins should not be transitioning during conversions.
MC9S08AC16 Series Data Sheet, Rev. 8 266 Freescale Semiconductor
Analog-to-Digital Converter (S08ADC10V1)
14.7.2
Sources of Error
Several sources of error exist for A/D conversions. These are discussed in the following sections.
14.7.2.1
Sampling Error
For proper conversions, the input must be sampled long enough to achieve the proper accuracy. Given the maximum input resistance of approximately 7k and input capacitance of approximately 5.5 pF, sampling to within 1/4LSB (at 10-bit resolution) can be achieved within the minimum sample window (3.5 cycles @ 8 MHz maximum ADCK frequency) provided the resistance of the external analog source (RAS) is kept below 5 k. Higher source resistances or higher-accuracy sampling is possible by setting ADLSMP (to increase the sample window to 23.5 cycles) or decreasing ADCK frequency to increase sample time.
14.7.2.2
Pin Leakage Error
Leakage on the I/O pins can cause conversion error if the external analog source resistance (RAS) is high. If this error cannot be tolerated by the application, keep RAS lower than VDDAD / (2N*ILEAK) for less than 1/4LSB leakage error (N = 8 in 8-bit mode or 10 in 10-bit mode).
14.7.2.3
Noise-Induced Errors
System noise which occurs during the sample or conversion process can affect the accuracy of the conversion. The ADC accuracy numbers are guaranteed as specified only if the following conditions are met: * There is a 0.1 F low-ESR capacitor from VREFH to VREFL. * There is a 0.1 F low-ESR capacitor from VDDAD to VSSAD. * If inductive isolation is used from the primary supply, an additional 1 F capacitor is placed from VDDAD to VSSAD. * VSSAD (and VREFL, if connected) is connected to VSS at a quiet point in the ground plane. * Operate the MCU in wait or stop3 mode before initiating (hardware triggered conversions) or immediately after initiating (hardware or software triggered conversions) the ADC conversion. -- For software triggered conversions, immediately follow the write to the ADC1SC1 with a WAIT instruction or STOP instruction. -- For stop3 mode operation, select ADACK as the clock source. Operation in stop3 reduces VDD noise but increases effective conversion time due to stop recovery. * There is no I/O switching, input or output, on the MCU during the conversion. There are some situations where external system activity causes radiated or conducted noise emissions or excessive VDD noise is coupled into the ADC. In these situations, or when the MCU cannot be placed in wait or stop3 or I/O activity cannot be halted, these recommended actions may reduce the effect of noise on the accuracy: * Place a 0.01 F capacitor (CAS) on the selected input channel to VREFL or VSSAD (this will improve noise issues but will affect sample rate based on the external analog source resistance).
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* *
Average the result by converting the analog input many times in succession and dividing the sum of the results. Four samples are required to eliminate the effect of a 1LSB, one-time error. Reduce the effect of synchronous noise by operating off the asynchronous clock (ADACK) and averaging. Noise that is synchronous to ADCK cannot be averaged out.
14.7.2.4
Code Width and Quantization Error
The ADC quantizes the ideal straight-line transfer function into 1024 steps (in 10-bit mode). Each step ideally has the same height (1 code) and width. The width is defined as the delta between the transition points to one code and the next. The ideal code width for an N bit converter (in this case N can be 8 or 10), defined as 1LSB, is:
1LSB = (VREFH - VREFL) / 2N Eqn. 14-2
There is an inherent quantization error due to the digitization of the result. For 8-bit or 10-bit conversions the code will transition when the voltage is at the midpoint between the points where the straight line transfer function is exactly represented by the actual transfer function. Therefore, the quantization error will be 1/2LSB in 8- or 10-bit mode. As a consequence, however, the code width of the first ($000) conversion is only 1/2LSB and the code width of the last ($FF or $3FF) is 1.5LSB.
14.7.2.5
Linearity Errors
The ADC may also exhibit non-linearity of several forms. Every effort has been made to reduce these errors but the system should be aware of them because they affect overall accuracy. These errors are: * Zero-scale error (EZS) (sometimes called offset) -- This error is defined as the difference between the actual code width of the first conversion and the ideal code width (1/2LSB). Note, if the first conversion is $001, then the difference between the actual $001 code width and its ideal (1LSB) is used. * Full-scale error (EFS) -- This error is defined as the difference between the actual code width of the last conversion and the ideal code width (1.5LSB). Note, if the last conversion is $3FE, then the difference between the actual $3FE code width and its ideal (1LSB) is used. * Differential non-linearity (DNL) -- This error is defined as the worst-case difference between the actual code width and the ideal code width for all conversions. * Integral non-linearity (INL) -- This error is defined as the highest-value the (absolute value of the) running sum of DNL achieves. More simply, this is the worst-case difference of the actual transition voltage to a given code and its corresponding ideal transition voltage, for all codes. * Total unadjusted error (TUE) -- This error is defined as the difference between the actual transfer function and the ideal straight-line transfer function, and therefore includes all forms of error.
14.7.2.6
Code Jitter, Non-Monotonicity and Missing Codes
Analog-to-digital converters are susceptible to three special forms of error. These are code jitter, non-monotonicity, and missing codes. Code jitter is when, at certain points, a given input voltage converts to one of two values when sampled repeatedly. Ideally, when the input voltage is infinitesimally smaller than the transition voltage, the
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Analog-to-Digital Converter (S08ADC10V1)
converter yields the lower code (and vice-versa). However, even very small amounts of system noise can cause the converter to be indeterminate (between two codes) for a range of input voltages around the transition voltage. This range is normally around 1/2 LSB and will increase with noise. This error may be reduced by repeatedly sampling the input and averaging the result. Additionally the techniques discussed in Section 14.7.2.3 will reduce this error. Non-monotonicity is defined as when, except for code jitter, the converter converts to a lower code for a higher input voltage. Missing codes are those values which are never converted for any input value. In 8-bit or 10-bit mode, the ADC is guaranteed to be monotonic and to have no missing codes.
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Chapter 15 Development Support
15.1 Introduction
Development support systems in the HCS08 include the background debug controller (BDC) and the on-chip debug module (DBG). The BDC provides a single-wire debug interface to the target MCU that provides a convenient interface for programming the on-chip FLASH and other nonvolatile memories. The BDC is also the primary debug interface for development and allows non-intrusive access to memory data and traditional debug features such as CPU register modify, breakpoints, and single instruction trace commands. In the HCS08 Family, address and data bus signals are not available on external pins (not even in test modes). Debug is done through commands fed into the target MCU via the single-wire background debug interface. The debug module provides a means to selectively trigger and capture bus information so an external development system can reconstruct what happened inside the MCU on a cycle-by-cycle basis without having external access to the address and data signals. The alternate BDC clock source for MC9S08AC16 Series is the ICGLCLK. See Chapter 8, "Internal Clock Generator (S08ICGV4)" for more information about ICGCLK and how to select clock sources.
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15.1.1
Features
Features of the BDC module include: * Single pin for mode selection and background communications * BDC registers are not located in the memory map * SYNC command to determine target communications rate * Non-intrusive commands for memory access * Active background mode commands for CPU register access * GO and TRACE1 commands * BACKGROUND command can wake CPU from stop or wait modes * One hardware address breakpoint built into BDC * Oscillator runs in stop mode, if BDC enabled * COP watchdog disabled while in active background mode Features of the ICE system include: * Two trigger comparators: Two address + read/write (R/W) or one full address + data + R/W * Flexible 8-word by 16-bit FIFO (first-in, first-out) buffer for capture information: -- Change-of-flow addresses or -- Event-only data * Two types of breakpoints: -- Tag breakpoints for instruction opcodes -- Force breakpoints for any address access * Nine trigger modes: -- Basic: A-only, A OR B -- Sequence: A then B -- Full: A AND B data, A AND NOT B data -- Event (store data): Event-only B, A then event-only B -- Range: Inside range (A address B), outside range (address < A or address > B)
15.2
Background Debug Controller (BDC)
All MCUs in the HCS08 Family contain a single-wire background debug interface that supports in-circuit programming of on-chip nonvolatile memory and sophisticated non-intrusive debug capabilities. Unlike debug interfaces on earlier 8-bit MCUs, this system does not interfere with normal application resources. It does not use any user memory or locations in the memory map and does not share any on-chip peripherals. BDC commands are divided into two groups: * Active background mode commands require that the target MCU is in active background mode (the user program is not running). Active background mode commands allow the CPU registers to be read or written, and allow the user to trace one user instruction at a time, or GO to the user program from active background mode.
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Development Support
*
Non-intrusive commands can be executed at any time even while the user's program is running. Non-intrusive commands allow a user to read or write MCU memory locations or access status and control registers within the background debug controller.
Typically, a relatively simple interface pod is used to translate commands from a host computer into commands for the custom serial interface to the single-wire background debug system. Depending on the development tool vendor, this interface pod may use a standard RS-232 serial port, a parallel printer port, or some other type of communications such as a universal serial bus (USB) to communicate between the host PC and the pod. The pod typically connects to the target system with ground, the BKGD pin, RESET, and sometimes VDD. An open-drain connection to reset allows the host to force a target system reset, which is useful to regain control of a lost target system or to control startup of a target system before the on-chip nonvolatile memory has been programmed. Sometimes VDD can be used to allow the pod to use power from the target system to avoid the need for a separate power supply. However, if the pod is powered separately, it can be connected to a running target system without forcing a target system reset or otherwise disturbing the running application program.
BKGD 1 NO CONNECT 3 NO CONNECT 5 2 GND 4 RESET 6 VDD
Figure 15-1. BDM Tool Connector
15.2.1
BKGD Pin Description
BKGD is the single-wire background debug interface pin. The primary function of this pin is for bidirectional serial communication of active background mode commands and data. During reset, this pin is used to select between starting in active background mode or starting the user's application program. This pin is also used to request a timed sync response pulse to allow a host development tool to determine the correct clock frequency for background debug serial communications. BDC serial communications use a custom serial protocol first introduced on the M68HC12 Family of microcontrollers. This protocol assumes the host knows the communication clock rate that is determined by the target BDC clock rate. All communication is initiated and controlled by the host that drives a high-to-low edge to signal the beginning of each bit time. Commands and data are sent most significant bit first (MSB first). For a detailed description of the communications protocol, refer to Section 15.2.2, "Communication Details." If a host is attempting to communicate with a target MCU that has an unknown BDC clock rate, a SYNC command may be sent to the target MCU to request a timed sync response signal from which the host can determine the correct communication speed. BKGD is a pseudo-open-drain pin and there is an on-chip pullup so no external pullup resistor is required. Unlike typical open-drain pins, the external RC time constant on this pin, which is influenced by external capacitance, plays almost no role in signal rise time. The custom protocol provides for brief, actively driven speedup pulses to force rapid rise times on this pin without risking harmful drive level conflicts. Refer to Section 15.2.2, "Communication Details," for more detail.
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When no debugger pod is connected to the 6-pin BDM interface connector, the internal pullup on BKGD chooses normal operating mode. When a debug pod is connected to BKGD it is possible to force the MCU into active background mode after reset. The specific conditions for forcing active background depend upon the HCS08 derivative (refer to the introduction to this Development Support section). It is not necessary to reset the target MCU to communicate with it through the background debug interface.
15.2.2
Communication Details
The BDC serial interface requires the external controller to generate a falling edge on the BKGD pin to indicate the start of each bit time. The external controller provides this falling edge whether data is transmitted or received. BKGD is a pseudo-open-drain pin that can be driven either by an external controller or by the MCU. Data is transferred MSB first at 16 BDC clock cycles per bit (nominal speed). The interface times out if 512 BDC clock cycles occur between falling edges from the host. Any BDC command that was in progress when this timeout occurs is aborted without affecting the memory or operating mode of the target MCU system. The custom serial protocol requires the debug pod to know the target BDC communication clock speed. The clock switch (CLKSW) control bit in the BDC status and control register allows the user to select the BDC clock source. The BDC clock source can either be the bus or the alternate BDC clock source. The BKGD pin can receive a high or low level or transmit a high or low level. The following diagrams show timing for each of these cases. Interface timing is synchronous to clocks in the target BDC, but asynchronous to the external host. The internal BDC clock signal is shown for reference in counting cycles.
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Development Support
Figure 15-2 shows an external host transmitting a logic 1 or 0 to the BKGD pin of a target HCS08 MCU. The host is asynchronous to the target so there is a 0-to-1 cycle delay from the host-generated falling edge to where the target perceives the beginning of the bit time. Ten target BDC clock cycles later, the target senses the bit level on the BKGD pin. Typically, the host actively drives the pseudo-open-drain BKGD pin during host-to-target transmissions to speed up rising edges. Because the target does not drive the BKGD pin during the host-to-target transmission period, there is no need to treat the line as an open-drain signal during this period.
BDC CLOCK (TARGET MCU)
HOST TRANSMIT 1
HOST TRANSMIT 0 10 CYCLES SYNCHRONIZATION UNCERTAINTY PERCEIVED START OF BIT TIME TARGET SENSES BIT LEVEL
EARLIEST START OF NEXT BIT
Figure 15-2. BDC Host-to-Target Serial Bit Timing
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Figure 15-3 shows the host receiving a logic 1 from the target HCS08 MCU. Because the host is asynchronous to the target MCU, there is a 0-to-1 cycle delay from the host-generated falling edge on BKGD to the perceived start of the bit time in the target MCU. The host holds the BKGD pin low long enough for the target to recognize it (at least two target BDC cycles). The host must release the low drive before the target MCU drives a brief active-high speedup pulse seven cycles after the perceived start of the bit time. The host should sample the bit level about 10 cycles after it started the bit time.
BDC CLOCK (TARGET MCU)
HOST DRIVE TO BKGD PIN
HIGH-IMPEDANCE
TARGET MCU SPEEDUP PULSE
HIGH-IMPEDANCE
HIGH-IMPEDANCE
PERCEIVED START OF BIT TIME R-C RISE BKGD PIN 10 CYCLES 10 CYCLES HOST SAMPLES BKGD PIN
EARLIEST START OF NEXT BIT
Figure 15-3. BDC Target-to-Host Serial Bit Timing (Logic 1)
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Development Support
Figure 15-4 shows the host receiving a logic 0 from the target HCS08 MCU. Because the host is asynchronous to the target MCU, there is a 0-to-1 cycle delay from the host-generated falling edge on BKGD to the start of the bit time as perceived by the target MCU. The host initiates the bit time but the target HCS08 finishes it. Because the target wants the host to receive a logic 0, it drives the BKGD pin low for 13 BDC clock cycles, then briefly drives it high to speed up the rising edge. The host samples the bit level about 10 cycles after starting the bit time.
BDC CLOCK (TARGET MCU)
HOST DRIVE TO BKGD PIN
HIGH-IMPEDANCE
TARGET MCU DRIVE AND SPEED-UP PULSE PERCEIVED START OF BIT TIME
SPEEDUP PULSE
BKGD PIN 10 CYCLES 10 CYCLES HOST SAMPLES BKGD PIN
EARLIEST START OF NEXT BIT
Figure 15-4. BDM Target-to-Host Serial Bit Timing (Logic 0)
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15.2.3
BDC Commands
BDC commands are sent serially from a host computer to the BKGD pin of the target HCS08 MCU. All commands and data are sent MSB-first using a custom BDC communications protocol. Active background mode commands require that the target MCU is currently in the active background mode while non-intrusive commands may be issued at any time whether the target MCU is in active background mode or running a user application program. Table 15-1 shows all HCS08 BDC commands, a shorthand description of their coding structure, and the meaning of each command. Coding Structure Nomenclature This nomenclature is used in Table 15-1 to describe the coding structure of the BDC commands. Commands begin with an 8-bit hexadecimal command code in the host-to-target direction (most significant bit first) / = separates parts of the command d = delay 16 target BDC clock cycles AAAA = a 16-bit address in the host-to-target direction RD = 8 bits of read data in the target-to-host direction WD = 8 bits of write data in the host-to-target direction RD16 = 16 bits of read data in the target-to-host direction WD16 = 16 bits of write data in the host-to-target direction SS = the contents of BDCSCR in the target-to-host direction (STATUS) CC = 8 bits of write data for BDCSCR in the host-to-target direction (CONTROL) RBKP = 16 bits of read data in the target-to-host direction (from BDCBKPT breakpoint register) WBKP = 16 bits of write data in the host-to-target direction (for BDCBKPT breakpoint register)
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Development Support
Table 15-1. BDC Command Summary
Command Mnemonic SYNC ACK_ENABLE ACK_DISABLE BACKGROUND READ_STATUS WRITE_CONTROL READ_BYTE READ_BYTE_WS READ_LAST WRITE_BYTE WRITE_BYTE_WS READ_BKPT WRITE_BKPT GO TRACE1 TAGGO READ_A READ_CCR READ_PC READ_HX READ_SP READ_NEXT READ_NEXT_WS WRITE_A WRITE_CCR WRITE_PC WRITE_HX WRITE_SP WRITE_NEXT WRITE_NEXT_WS
1
Active BDM/ Non-intrusive Non-intrusive Non-intrusive Non-intrusive Non-intrusive Non-intrusive Non-intrusive Non-intrusive Non-intrusive Non-intrusive Non-intrusive Non-intrusive Non-intrusive Non-intrusive Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM Active BDM n/a1 D5/d D6/d 90/d E4/SS C4/CC
Coding Structure
Description Request a timed reference pulse to determine target BDC communication speed Enable acknowledge protocol. Refer to document order no. HCS08RMv1/D. Disable acknowledge protocol. Refer to document order no. HCS08RMv1/D. Enter active background mode if enabled (ignore if ENBDM bit equals 0) Read BDC status from BDCSCR Write BDC controls in BDCSCR Read a byte from target memory Read a byte and report status Re-read byte from address just read and report status Write a byte to target memory Write a byte and report status Read BDCBKPT breakpoint register Write BDCBKPT breakpoint register Go to execute the user application program starting at the address currently in the PC Trace 1 user instruction at the address in the PC, then return to active background mode Same as GO but enable external tagging (HCS08 devices have no external tagging pin) Read accumulator (A) Read condition code register (CCR) Read program counter (PC) Read H and X register pair (H:X) Read stack pointer (SP) Increment H:X by one then read memory byte located at H:X Increment H:X by one then read memory byte located at H:X. Report status and data. Write accumulator (A) Write condition code register (CCR) Write program counter (PC) Write H and X register pair (H:X) Write stack pointer (SP) Increment H:X by one, then write memory byte located at H:X Increment H:X by one, then write memory byte located at H:X. Also report status.
E0/AAAA/d/RD E1/AAAA/d/SS/RD E8/SS/RD C0/AAAA/WD/d C1/AAAA/WD/d/SS E2/RBKP C2/WBKP 08/d 10/d 18/d 68/d/RD 69/d/RD 6B/d/RD16 6C/d/RD16 6F/d/RD16 70/d/RD 71/d/SS/RD 48/WD/d 49/WD/d 4B/WD16/d 4C/WD16/d 4F/WD16/d 50/WD/d 51/WD/d/SS
The SYNC command is a special operation that does not have a command code.
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The SYNC command is unlike other BDC commands because the host does not necessarily know the correct communications speed to use for BDC communications until after it has analyzed the response to the SYNC command. To issue a SYNC command, the host: * Drives the BKGD pin low for at least 128 cycles of the slowest possible BDC clock (The slowest clock is normally the reference oscillator/64 or the self-clocked rate/64.) * Drives BKGD high for a brief speedup pulse to get a fast rise time (This speedup pulse is typically one cycle of the fastest clock in the system.) * Removes all drive to the BKGD pin so it reverts to high impedance * Monitors the BKGD pin for the sync response pulse The target, upon detecting the SYNC request from the host (which is a much longer low time than would ever occur during normal BDC communications): * Waits for BKGD to return to a logic high * Delays 16 cycles to allow the host to stop driving the high speedup pulse * Drives BKGD low for 128 BDC clock cycles * Drives a 1-cycle high speedup pulse to force a fast rise time on BKGD * Removes all drive to the BKGD pin so it reverts to high impedance The host measures the low time of this 128-cycle sync response pulse and determines the correct speed for subsequent BDC communications. Typically, the host can determine the correct communication speed within a few percent of the actual target speed and the communication protocol can easily tolerate speed errors of several percent.
15.2.4
BDC Hardware Breakpoint
The BDC includes one relatively simple hardware breakpoint that compares the CPU address bus to a 16-bit match value in the BDCBKPT register. This breakpoint can generate a forced breakpoint or a tagged breakpoint. A forced breakpoint causes the CPU to enter active background mode at the first instruction boundary following any access to the breakpoint address. The tagged breakpoint causes the instruction opcode at the breakpoint address to be tagged so that the CPU will enter active background mode rather than executing that instruction if and when it reaches the end of the instruction queue. This implies that tagged breakpoints can only be placed at the address of an instruction opcode while forced breakpoints can be set at any address. The breakpoint enable (BKPTEN) control bit in the BDC status and control register (BDCSCR) is used to enable the breakpoint logic (BKPTEN = 1). When BKPTEN = 0, its default value after reset, the breakpoint logic is disabled and no BDC breakpoints are requested regardless of the values in other BDC breakpoint registers and control bits. The force/tag select (FTS) control bit in BDCSCR is used to select forced (FTS = 1) or tagged (FTS = 0) type breakpoints. The on-chip debug module (DBG) includes circuitry for two additional hardware breakpoints that are more flexible than the simple breakpoint in the BDC module.
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Development Support
15.3
On-Chip Debug System (DBG)
Because HCS08 devices do not have external address and data buses, the most important functions of an in-circuit emulator have been built onto the chip with the MCU. The debug system consists of an 8-stage FIFO that can store address or data bus information, and a flexible trigger system to decide when to capture bus information and what information to capture. The system relies on the single-wire background debug system to access debug control registers and to read results out of the eight stage FIFO. The debug module includes control and status registers that are accessible in the user's memory map. These registers are located in the high register space to avoid using valuable direct page memory space. Most of the debug module's functions are used during development, and user programs rarely access any of the control and status registers for the debug module. The one exception is that the debug system can provide the means to implement a form of ROM patching. This topic is discussed in greater detail in Section 15.3.6, "Hardware Breakpoints."
15.3.1
Comparators A and B
Two 16-bit comparators (A and B) can optionally be qualified with the R/W signal and an opcode tracking circuit. Separate control bits allow you to ignore R/W for each comparator. The opcode tracking circuitry optionally allows you to specify that a trigger will occur only if the opcode at the specified address is actually executed as opposed to only being read from memory into the instruction queue. The comparators are also capable of magnitude comparisons to support the inside range and outside range trigger modes. Comparators are disabled temporarily during all BDC accesses. The A comparator is always associated with the 16-bit CPU address. The B comparator compares to the CPU address or the 8-bit CPU data bus, depending on the trigger mode selected. Because the CPU data bus is separated into a read data bus and a write data bus, the RWAEN and RWA control bits have an additional purpose, in full address plus data comparisons they are used to decide which of these buses to use in the comparator B data bus comparisons. If RWAEN = 1 (enabled) and RWA = 0 (write), the CPU's write data bus is used. Otherwise, the CPU's read data bus is used. The currently selected trigger mode determines what the debugger logic does when a comparator detects a qualified match condition. A match can cause: * Generation of a breakpoint to the CPU * Storage of data bus values into the FIFO * Starting to store change-of-flow addresses into the FIFO (begin type trace) * Stopping the storage of change-of-flow addresses into the FIFO (end type trace)
15.3.2
Bus Capture Information and FIFO Operation
The usual way to use the FIFO is to setup the trigger mode and other control options, then arm the debugger. When the FIFO has filled or the debugger has stopped storing data into the FIFO, you would read the information out of it in the order it was stored into the FIFO. Status bits indicate the number of words of valid information that are in the FIFO as data is stored into it. If a trace run is manually halted by writing 0 to ARM before the FIFO is full (CNT = 1:0:0:0), the information is shifted by one position and
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the host must perform ((8 - CNT) - 1) dummy reads of the FIFO to advance it to the first significant entry in the FIFO. In most trigger modes, the information stored in the FIFO consists of 16-bit change-of-flow addresses. In these cases, read DBGFH then DBGFL to get one coherent word of information out of the FIFO. Reading DBGFL (the low-order byte of the FIFO data port) causes the FIFO to shift so the next word of information is available at the FIFO data port. In the event-only trigger modes (see Section 15.3.5, "Trigger Modes"), 8-bit data information is stored into the FIFO. In these cases, the high-order half of the FIFO (DBGFH) is not used and data is read out of the FIFO by simply reading DBGFL. Each time DBGFL is read, the FIFO is shifted so the next data value is available through the FIFO data port at DBGFL. In trigger modes where the FIFO is storing change-of-flow addresses, there is a delay between CPU addresses and the input side of the FIFO. Because of this delay, if the trigger event itself is a change-of-flow address or a change-of-flow address appears during the next two bus cycles after a trigger event starts the FIFO, it will not be saved into the FIFO. In the case of an end-trace, if the trigger event is a change-of-flow, it will be saved as the last change-of-flow entry for that debug run. The FIFO can also be used to generate a profile of executed instruction addresses when the debugger is not armed. When ARM = 0, reading DBGFL causes the address of the most-recently fetched opcode to be saved in the FIFO. To use the profiling feature, a host debugger would read addresses out of the FIFO by reading DBGFH then DBGFL at regular periodic intervals. The first eight values would be discarded because they correspond to the eight DBGFL reads needed to initially fill the FIFO. Additional periodic reads of DBGFH and DBGFL return delayed information about executed instructions so the host debugger can develop a profile of executed instruction addresses.
15.3.3
Change-of-Flow Information
To minimize the amount of information stored in the FIFO, only information related to instructions that cause a change to the normal sequential execution of instructions is stored. With knowledge of the source and object code program stored in the target system, an external debugger system can reconstruct the path of execution through many instructions from the change-of-flow information stored in the FIFO. For conditional branch instructions where the branch is taken (branch condition was true), the source address is stored (the address of the conditional branch opcode). Because BRA and BRN instructions are not conditional, these events do not cause change-of-flow information to be stored in the FIFO. Indirect JMP and JSR instructions use the current contents of the H:X index register pair to determine the destination address, so the debug system stores the run-time destination address for any indirect JMP or JSR. For interrupts, RTI, or RTS, the destination address is stored in the FIFO as change-of-flow information.
15.3.4
Tag vs. Force Breakpoints and Triggers
Tagging is a term that refers to identifying an instruction opcode as it is fetched into the instruction queue, but not taking any other action until and unless that instruction is actually executed by the CPU. This distinction is important because any change-of-flow from a jump, branch, subroutine call, or interrupt causes some instructions that have been fetched into the instruction queue to be thrown away without being executed.
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A force-type breakpoint waits for the current instruction to finish and then acts upon the breakpoint request. The usual action in response to a breakpoint is to go to active background mode rather than continuing to the next instruction in the user application program. The tag vs. force terminology is used in two contexts within the debug module. The first context refers to breakpoint requests from the debug module to the CPU. The second refers to match signals from the comparators to the debugger control logic. When a tag-type break request is sent to the CPU, a signal is entered into the instruction queue along with the opcode so that if/when this opcode ever executes, the CPU will effectively replace the tagged opcode with a BGND opcode so the CPU goes to active background mode rather than executing the tagged instruction. When the TRGSEL control bit in the DBGT register is set to select tag-type operation, the output from comparator A or B is qualified by a block of logic in the debug module that tracks opcodes and only produces a trigger to the debugger if the opcode at the compare address is actually executed. There is separate opcode tracking logic for each comparator so more than one compare event can be tracked through the instruction queue at a time.
15.3.5
Trigger Modes
The trigger mode controls the overall behavior of a debug run. The 4-bit TRG field in the DBGT register selects one of nine trigger modes. When TRGSEL = 1 in the DBGT register, the output of the comparator must propagate through an opcode tracking circuit before triggering FIFO actions. The BEGIN bit in DBGT chooses whether the FIFO begins storing data when the qualified trigger is detected (begin trace), or the FIFO stores data in a circular fashion from the time it is armed until the qualified trigger is detected (end trigger). A debug run is started by writing a 1 to the ARM bit in the DBGC register, which sets the ARMF flag and clears the AF and BF flags and the CNT bits in DBGS. A begin-trace debug run ends when the FIFO gets full. An end-trace run ends when the selected trigger event occurs. Any debug run can be stopped manually by writing a 0 to ARM or DBGEN in DBGC. In all trigger modes except event-only modes, the FIFO stores change-of-flow addresses. In event-only trigger modes, the FIFO stores data in the low-order eight bits of the FIFO. The BEGIN control bit is ignored in event-only trigger modes and all such debug runs are begin type traces. When TRGSEL = 1 to select opcode fetch triggers, it is not necessary to use R/W in comparisons because opcode tags would only apply to opcode fetches that are always read cycles. It would also be unusual to specify TRGSEL = 1 while using a full mode trigger because the opcode value is normally known at a particular address. The following trigger mode descriptions only state the primary comparator conditions that lead to a trigger. Either comparator can usually be further qualified with R/W by setting RWAEN (RWBEN) and the corresponding RWA (RWB) value to be matched against R/W. The signal from the comparator with optional R/W qualification is used to request a CPU breakpoint if BRKEN = 1 and TAG determines whether the CPU request will be a tag request or a force request.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 283
Development Support
A-Only -- Trigger when the address matches the value in comparator A A OR B -- Trigger when the address matches either the value in comparator A or the value in comparator B A Then B -- Trigger when the address matches the value in comparator B but only after the address for another cycle matched the value in comparator A. There can be any number of cycles after the A match and before the B match. A AND B Data (Full Mode) -- This is called a full mode because address, data, and R/W (optionally) must match within the same bus cycle to cause a trigger event. Comparator A checks address, the low byte of comparator B checks data, and R/W is checked against RWA if RWAEN = 1. The high-order half of comparator B is not used. In full trigger modes it is not useful to specify a tag-type CPU breakpoint (BRKEN = TAG = 1), but if you do, the comparator B data match is ignored for the purpose of issuing the tag request to the CPU and the CPU breakpoint is issued when the comparator A address matches. A AND NOT B Data (Full Mode) -- Address must match comparator A, data must not match the low half of comparator B, and R/W must match RWA if RWAEN = 1. All three conditions must be met within the same bus cycle to cause a trigger. In full trigger modes it is not useful to specify a tag-type CPU breakpoint (BRKEN = TAG = 1), but if you do, the comparator B data match is ignored for the purpose of issuing the tag request to the CPU and the CPU breakpoint is issued when the comparator A address matches. Event-Only B (Store Data) -- Trigger events occur each time the address matches the value in comparator B. Trigger events cause the data to be captured into the FIFO. The debug run ends when the FIFO becomes full. A Then Event-Only B (Store Data) -- After the address has matched the value in comparator A, a trigger event occurs each time the address matches the value in comparator B. Trigger events cause the data to be captured into the FIFO. The debug run ends when the FIFO becomes full. Inside Range (A Address B) -- A trigger occurs when the address is greater than or equal to the value in comparator A and less than or equal to the value in comparator B at the same time. Outside Range (Address < A or Address > B) -- A trigger occurs when the address is either less than the value in comparator A or greater than the value in comparator B.
MC9S08AC16 Series Data Sheet, Rev. 8 284 Freescale Semiconductor
Development Support
15.3.6
Hardware Breakpoints
The BRKEN control bit in the DBGC register may be set to 1 to allow any of the trigger conditions described in Section 15.3.5, "Trigger Modes," to be used to generate a hardware breakpoint request to the CPU. TAG in DBGC controls whether the breakpoint request will be treated as a tag-type breakpoint or a force-type breakpoint. A tag breakpoint causes the current opcode to be marked as it enters the instruction queue. If a tagged opcode reaches the end of the pipe, the CPU executes a BGND instruction to go to active background mode rather than executing the tagged opcode. A force-type breakpoint causes the CPU to finish the current instruction and then go to active background mode. If the background mode has not been enabled (ENBDM = 1) by a serial WRITE_CONTROL command through the BKGD pin, the CPU will execute an SWI instruction instead of going to active background mode.
15.4
Register Definition
This section contains the descriptions of the BDC and DBG registers and control bits. Refer to the high-page register summary in the device overview chapter of this data sheet for the absolute address assignments for all DBG registers. This section refers to registers and control bits only by their names.
15.4.1
BDC Registers and Control Bits
The BDC has two registers: * The BDC status and control register (BDCSCR) is an 8-bit register containing control and status bits for the background debug controller. * The BDC breakpoint match register (BDCBKPT) holds a 16-bit breakpoint match address. These registers are accessed with dedicated serial BDC commands and are not located in the memory space of the target MCU (so they do not have addresses and cannot be accessed by user programs). Some of the bits in the BDCSCR have write limitations; otherwise, these registers may be read or written at any time. For example, the ENBDM control bit may not be written while the MCU is in active background mode. (This prevents the ambiguous condition of the control bit forbidding active background mode while the MCU is already in active background mode.) Also, the four status bits (BDMACT, WS, WSF, and DVF) are read-only status indicators and can never be written by the WRITE_CONTROL serial BDC command. The clock switch (CLKSW) control bit may be read or written at any time.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 285
Development Support
15.4.1.1
BDC Status and Control Register (BDCSCR)
This register can be read or written by serial BDC commands (READ_STATUS and WRITE_CONTROL) but is not accessible to user programs because it is not located in the normal memory map of the MCU.
7 6 5 4 3 2 1 0
R ENBDM W Normal Reset Reset in Active BDM: 0 1
BDMACT BKPTEN 0 1 0 0 FTS 0 0 CLKSW 0 1
WS
WSF
DVF
0 0
0 0
0 0
= Unimplemented or Reserved
Figure 15-5. BDC Status and Control Register (BDCSCR) Table 15-2. BDCSCR Register Field Descriptions
Field 7 ENBDM Description Enable BDM (Permit Active Background Mode) -- Typically, this bit is written to 1 by the debug host shortly after the beginning of a debug session or whenever the debug host resets the target and remains 1 until a normal reset clears it. 0 BDM cannot be made active (non-intrusive commands still allowed) 1 BDM can be made active to allow active background mode commands Background Mode Active Status -- This is a read-only status bit. 0 BDM not active (user application program running) 1 BDM active and waiting for serial commands BDC Breakpoint Enable -- If this bit is clear, the BDC breakpoint is disabled and the FTS (force tag select) control bit and BDCBKPT match register are ignored. 0 BDC breakpoint disabled 1 BDC breakpoint enabled Force/Tag Select -- When FTS = 1, a breakpoint is requested whenever the CPU address bus matches the BDCBKPT match register. When FTS = 0, a match between the CPU address bus and the BDCBKPT register causes the fetched opcode to be tagged. If this tagged opcode ever reaches the end of the instruction queue, the CPU enters active background mode rather than executing the tagged opcode. 0 Tag opcode at breakpoint address and enter active background mode if CPU attempts to execute that instruction 1 Breakpoint match forces active background mode at next instruction boundary (address need not be an opcode) Select Source for BDC Communications Clock -- CLKSW defaults to 0, which selects the alternate BDC clock source. 0 Alternate BDC clock source 1 MCU bus clock
6 BDMACT 5 BKPTEN
4 FTS
3 CLKSW
MC9S08AC16 Series Data Sheet, Rev. 8 286 Freescale Semiconductor
Development Support
Table 15-2. BDCSCR Register Field Descriptions (continued)
Field 2 WS Description Wait or Stop Status -- When the target CPU is in wait or stop mode, most BDC commands cannot function. However, the BACKGROUND command can be used to force the target CPU out of wait or stop and into active background mode where all BDC commands work. Whenever the host forces the target MCU into active background mode, the host should issue a READ_STATUS command to check that BDMACT = 1 before attempting other BDC commands. 0 Target CPU is running user application code or in active background mode (was not in wait or stop mode when background became active) 1 Target CPU is in wait or stop mode, or a BACKGROUND command was used to change from wait or stop to active background mode Wait or Stop Failure Status -- This status bit is set if a memory access command failed due to the target CPU executing a wait or stop instruction at or about the same time. The usual recovery strategy is to issue a BACKGROUND command to get out of wait or stop mode into active background mode, repeat the command that failed, then return to the user program. (Typically, the host would restore CPU registers and stack values and re-execute the wait or stop instruction.) 0 Memory access did not conflict with a wait or stop instruction 1 Memory access command failed because the CPU entered wait or stop mode Data Valid Failure Status -- This status bit is not used in the MC9S08AC16 Series because it does not have any slow access memory. 0 Memory access did not conflict with a slow memory access 1 Memory access command failed because CPU was not finished with a slow memory access
1 WSF
0 DVF
15.4.1.2
BDC Breakpoint Match Register (BDCBKPT)
This 16-bit register holds the address for the hardware breakpoint in the BDC. The BKPTEN and FTS control bits in BDCSCR are used to enable and configure the breakpoint logic. Dedicated serial BDC commands (READ_BKPT and WRITE_BKPT) are used to read and write the BDCBKPT register but is not accessible to user programs because it is not located in the normal memory map of the MCU. Breakpoints are normally set while the target MCU is in active background mode before running the user application program. For additional information about setup and use of the hardware breakpoint logic in the BDC, refer to Section 15.2.4, "BDC Hardware Breakpoint."
15.4.2
System Background Debug Force Reset Register (SBDFR)
This register contains a single write-only control bit. A serial background mode command such as WRITE_BYTE must be used to write to SBDFR. Attempts to write this register from a user program are ignored. Reads always return 0x00.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 287
Development Support
7
6
5
4
3
2
1
0
R W Reset
0
0
0
0
0
0
0
0 BDFR1
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
1
BDFR is writable only through serial background mode debug commands, not from user programs.
Figure 15-6. System Background Debug Force Reset Register (SBDFR) Table 15-3. SBDFR Register Field Description
Field 0 BDFR Description Background Debug Force Reset -- A serial active background mode command such as WRITE_BYTE allows an external debug host to force a target system reset. Writing 1 to this bit forces an MCU reset. This bit cannot be written from a user program.
15.4.3
DBG Registers and Control Bits
The debug module includes nine bytes of register space for three 16-bit registers and three 8-bit control and status registers. These registers are located in the high register space of the normal memory map so they are accessible to normal application programs. These registers are rarely if ever accessed by normal user application programs with the possible exception of a ROM patching mechanism that uses the breakpoint logic.
15.4.3.1
Debug Comparator A High Register (DBGCAH)
This register contains compare value bits for the high-order eight bits of comparator A. This register is forced to 0x00 at reset and can be read at any time or written at any time unless ARM = 1.
15.4.3.2
Debug Comparator A Low Register (DBGCAL)
This register contains compare value bits for the low-order eight bits of comparator A. This register is forced to 0x00 at reset and can be read at any time or written at any time unless ARM = 1.
15.4.3.3
Debug Comparator B High Register (DBGCBH)
This register contains compare value bits for the high-order eight bits of comparator B. This register is forced to 0x00 at reset and can be read at any time or written at any time unless ARM = 1.
15.4.3.4
Debug Comparator B Low Register (DBGCBL)
This register contains compare value bits for the low-order eight bits of comparator B. This register is forced to 0x00 at reset and can be read at any time or written at any time unless ARM = 1.
MC9S08AC16 Series Data Sheet, Rev. 8 288 Freescale Semiconductor
Development Support
15.4.3.5
Debug FIFO High Register (DBGFH)
This register provides read-only access to the high-order eight bits of the FIFO. Writes to this register have no meaning or effect. In the event-only trigger modes, the FIFO only stores data into the low-order byte of each FIFO word, so this register is not used and will read 0x00. Reading DBGFH does not cause the FIFO to shift to the next word. When reading 16-bit words out of the FIFO, read DBGFH before reading DBGFL because reading DBGFL causes the FIFO to advance to the next word of information.
15.4.3.6
Debug FIFO Low Register (DBGFL)
This register provides read-only access to the low-order eight bits of the FIFO. Writes to this register have no meaning or effect. Reading DBGFL causes the FIFO to shift to the next available word of information. When the debug module is operating in event-only modes, only 8-bit data is stored into the FIFO (high-order half of each FIFO word is unused). When reading 8-bit words out of the FIFO, simply read DBGFL repeatedly to get successive bytes of data from the FIFO. It isn't necessary to read DBGFH in this case. Do not attempt to read data from the FIFO while it is still armed (after arming but before the FIFO is filled or ARMF is cleared) because the FIFO is prevented from advancing during reads of DBGFL. This can interfere with normal sequencing of reads from the FIFO. Reading DBGFL while the debugger is not armed causes the address of the most-recently fetched opcode to be stored to the last location in the FIFO. By reading DBGFH then DBGFL periodically, external host software can develop a profile of program execution. After eight reads from the FIFO, the ninth read will return the information that was stored as a result of the first read. To use the profiling feature, read the FIFO eight times without using the data to prime the sequence and then begin using the data to get a delayed picture of what addresses were being executed. The information stored into the FIFO on reads of DBGFL (while the FIFO is not armed) is the address of the most-recently fetched opcode.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 289
Development Support
15.4.3.7
Debug Control Register (DBGC)
This register can be read or written at any time.
7 6 5 4 3 2 1 0
R DBGEN W Reset 0 0 0 0 0 0 0 0 ARM TAG BRKEN RWA RWAEN RWB RWBEN
Figure 15-7. Debug Control Register (DBGC) Table 15-4. DBGC Register Field Descriptions
Field 7 DBGEN 6 ARM Description Debug Module Enable -- Used to enable the debug module. DBGEN cannot be set to 1 if the MCU is secure. 0 DBG disabled 1 DBG enabled Arm Control -- Controls whether the debugger is comparing and storing information in the FIFO. A write is used to set this bit (and ARMF) and completion of a debug run automatically clears it. Any debug run can be manually stopped by writing 0 to ARM or to DBGEN. 0 Debugger not armed 1 Debugger armed Tag/Force Select -- Controls whether break requests to the CPU will be tag or force type requests. If BRKEN = 0, this bit has no meaning or effect. 0 CPU breaks requested as force type requests 1 CPU breaks requested as tag type requests Break Enable -- Controls whether a trigger event will generate a break request to the CPU. Trigger events can cause information to be stored in the FIFO without generating a break request to the CPU. For an end trace, CPU break requests are issued to the CPU when the comparator(s) and R/W meet the trigger requirements. For a begin trace, CPU break requests are issued when the FIFO becomes full. TRGSEL does not affect the timing of CPU break requests. 0 CPU break requests not enabled 1 Triggers cause a break request to the CPU R/W Comparison Value for Comparator A -- When RWAEN = 1, this bit determines whether a read or a write access qualifies comparator A. When RWAEN = 0, RWA and the R/W signal do not affect comparator A. 0 Comparator A can only match on a write cycle 1 Comparator A can only match on a read cycle Enable R/W for Comparator A -- Controls whether the level of R/W is considered for a comparator A match. 0 R/W is not used in comparison A 1 R/W is used in comparison A R/W Comparison Value for Comparator B -- When RWBEN = 1, this bit determines whether a read or a write access qualifies comparator B. When RWBEN = 0, RWB and the R/W signal do not affect comparator B. 0 Comparator B can match only on a write cycle 1 Comparator B can match only on a read cycle Enable R/W for Comparator B -- Controls whether the level of R/W is considered for a comparator B match. 0 R/W is not used in comparison B 1 R/W is used in comparison B
5 TAG
4 BRKEN
3 RWA
2 RWAEN 1 RWB
0 RWBEN
MC9S08AC16 Series Data Sheet, Rev. 8 290 Freescale Semiconductor
Development Support
15.4.3.8
Debug Trigger Register (DBGT)
This register can be read any time, but may be written only if ARM = 0, except bits 4 and 5 are hard-wired to 0s.
7 6 5 4 3 2 1 0
R TRGSEL W Reset 0 0 BEGIN
0
0 TRG3 TRG2 0 TRG1 0 TRG0 0
0
0
0
= Unimplemented or Reserved
Figure 15-8. Debug Trigger Register (DBGT) Table 15-5. DBGT Register Field Descriptions
Field 7 TRGSEL Description Trigger Type -- Controls whether the match outputs from comparators A and B are qualified with the opcode tracking logic in the debug module. If TRGSEL is set, a match signal from comparator A or B must propagate through the opcode tracking logic and a trigger event is only signalled to the FIFO logic if the opcode at the match address is actually executed. 0 Trigger on access to compare address (force) 1 Trigger if opcode at compare address is executed (tag) Begin/End Trigger Select -- Controls whether the FIFO starts filling at a trigger or fills in a circular manner until a trigger ends the capture of information. In event-only trigger modes, this bit is ignored and all debug runs are assumed to be begin traces. 0 Data stored in FIFO until trigger (end trace) 1 Trigger initiates data storage (begin trace) Select Trigger Mode -- Selects one of nine triggering modes, as described below. 0000 A-only 0001 A OR B 0010 A Then B 0011 Event-only B (store data) 0100 A then event-only B (store data) 0101 A AND B data (full mode) 0110 A AND NOT B data (full mode) 0111 Inside range: A address B 1000 Outside range: address < A or address > B 1001 - 1111 (No trigger)
6 BEGIN
3:0 TRG[3:0]
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 291
Development Support
15.4.3.9
Debug Status Register (DBGS)
This is a read-only status register.
7 6 5 4 3 2 1 0
R W Reset
AF
BF
ARMF
0
CNT3
CNT2
CNT1
CNT0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 15-9. Debug Status Register (DBGS)
Table 15-6. DBGS Register Field Descriptions
Field 7 AF Description Trigger Match A Flag -- AF is cleared at the start of a debug run and indicates whether a trigger match A condition was met since arming. 0 Comparator A has not matched 1 Comparator A match Trigger Match B Flag -- BF is cleared at the start of a debug run and indicates whether a trigger match B condition was met since arming. 0 Comparator B has not matched 1 Comparator B match Arm Flag -- While DBGEN = 1, this status bit is a read-only image of ARM in DBGC. This bit is set by writing 1 to the ARM control bit in DBGC (while DBGEN = 1) and is automatically cleared at the end of a debug run. A debug run is completed when the FIFO is full (begin trace) or when a trigger event is detected (end trace). A debug run can also be ended manually by writing 0 to ARM or DBGEN in DBGC. 0 Debugger not armed 1 Debugger armed FIFO Valid Count -- These bits are cleared at the start of a debug run and indicate the number of words of valid data in the FIFO at the end of a debug run. The value in CNT does not decrement as data is read out of the FIFO. The external debug host is responsible for keeping track of the count as information is read out of the FIFO. 0000 Number of valid words in FIFO = No valid data 0001 Number of valid words in FIFO = 1 0010 Number of valid words in FIFO = 2 0011 Number of valid words in FIFO = 3 0100 Number of valid words in FIFO = 4 0101 Number of valid words in FIFO = 5 0110 Number of valid words in FIFO = 6 0111 Number of valid words in FIFO = 7 1000 Number of valid words in FIFO = 8
6 BF
5 ARMF
3:0 CNT[3:0]
MC9S08AC16 Series Data Sheet, Rev. 8 292 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications
Appendix A Electrical Characteristics and Timing Specifications
A.1 Introduction
This section contains electrical and timing specifications.
A.2
Parameter Classification
The electrical parameters shown in this supplement are guaranteed by various methods. To give the customer a better understanding, the following classification is used and the parameters are tagged accordingly in the tables where appropriate:
Table A-1. Parameter Classifications P C
Those parameters are guaranteed during production testing on each individual device. Those parameters are achieved by the design characterization by measuring a statistically relevant sample size across process variations. Those parameters are achieved by design characterization on a small sample size from typical devices under typical conditions unless otherwise noted. All values shown in the typical column are within this category. Those parameters are derived mainly from simulations. NOTE The classification is shown in the column labeled "C" in the parameter tables where appropriate.
T
D
A.3
Absolute Maximum Ratings
Absolute maximum ratings are stress ratings only, and functional operation at the maxima is not guaranteed. Stress beyond the limits specified in Table A-2 may affect device reliability or cause permanent damage to the device. For functional operating conditions, refer to the remaining tables in this section. This device contains circuitry protecting against damage due to high static voltage or electrical fields; however, it is advised that normal precautions be taken to avoid application of any voltages higher than maximum-rated voltages to this high-impedance circuit. Reliability of operation is enhanced if unused inputs are tied to an appropriate logic voltage level (for instance, either VSS or VDD).
Table A-2. Absolute Maximum Ratings
Rating Supply voltage Input voltage Symbol VDD VIn Value -0.3 to + 5.8 - 0.3 to VDD + 0.3 Unit V V
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 293
Appendix A Electrical Characteristics and Timing Specifications
Table A-2. Absolute Maximum Ratings (continued)
Rating Instantaneous maximum current Single pin limit (applies to all port pins)1, 2, 3 Maximum current into VDD Storage temperature Maximum junction temperature
1
Symbol ID IDD Tstg TJ
Value 25 120 -55 to +150 150
Unit mA mA C C
Input must be current limited to the value specified. To determine the value of the required current-limiting resistor, calculate resistance values for positive (VDD) and negative (VSS) clamp voltages, then use the larger of the two resistance values. 2 All functional non-supply pins are internally clamped to VSS and VDD. 3 Power supply must maintain regulation within operating VDD range during instantaneous and operating maximum current conditions. If positive injection current (VIn > VDD) is greater than IDD, the injection current may flow out of VDD and could result in external power supply going out of regulation. Ensure external VDD load will shunt current greater than maximum injection current. This will be the greatest risk when the MCU is not consuming power. Examples are: if no system clock is present, or if the clock rate is very low which would reduce overall power consumption.
A.4
Thermal Characteristics
This section provides information about operating temperature range, power dissipation, and package thermal resistance. Power dissipation on I/O pins is usually small compared to the power dissipation in on-chip logic and it is user-determined rather than being controlled by the MCU design. In order to take PI/O into account in power calculations, determine the difference between actual pin voltage and VSS or VDD and multiply by the pin current for each I/O pin. Except in cases of unusually high pin current (heavy loads), the difference between pin voltage and VSS or VDD will be very small.
Table A-3. Thermal Characteristics Rating
Operating temperature range (packaged) Thermal resistance 1,2,3,4 48-pin QFN 44-pin LQFP 32-pin LQFP 42-pin SDIP
1
Symbol
TA
Value
TL to TH -40 to 125
Unit
C
1s 2s2p 1s 2s2p 1s 2s2p 1s 2s2p JA
84 27 73 56 85 56 58 47 C/W
Junction temperature is a function of die size, on-chip power dissipation, package thermal resistance, mounting site (board) temperature, ambient temperature, air flow, power dissipation of other components on the board, and board thermal resistance.
MC9S08AC16 Series Data Sheet, Rev. 8 294 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications
2 3
Junction to Ambient Natural Convection 1s - Single Layer Board, one signal layer 4 2s2p - Four Layer Board, 2 signal and 2 power layers
The average chip-junction temperature (TJ) in C can be obtained from:
TJ = TA + (PD x JA) Eqn. A-1
where: TA = Ambient temperature, C JA = Package thermal resistance, junction-to-ambient, C/W PD = Pint + PI/O Pint = IDD x VDD, Watts -- chip internal power PI/O = Power dissipation on input and output pins -- user determined For most applications, PI/O << Pint and can be neglected. An approximate relationship between PD and TJ (if PI/O is neglected) is:
PD = K / (TJ + 273C) Eqn. A-2
Solving equations 1 and 2 for K gives:
K = PD x (TA + 273C) + JA x (PD)2 Eqn. A-3
where K is a constant pertaining to the particular part. K can be determined from equation 3 by measuring PD (at equilibrium) for a known TA. Using this value of K, the values of PD and TJ can be obtained by solving equations 1 and 2 iteratively for any value of TA.
A.5
ESD Protection and Latch-Up Immunity
Although damage from electrostatic discharge (ESD) is much less common on these devices than on early CMOS circuits, normal handling precautions should be used to avoid exposure to static discharge. Qualification tests are performed to ensure that these devices can withstand exposure to reasonable levels of static without suffering any permanent damage. All ESD testing is in conformity with AEC-Q100 Stress Test Qualification for Automotive Grade Integrated Circuits. During the device qualification ESD stresses were performed for the Human Body Model (HBM), the Machine Model (MM) and the Charge Device Model (CDM). A device is defined as a failure if after exposure to ESD pulses the device no longer meets the device specification. Complete DC parametric and functional testing is performed per the applicable device specification at room temperature followed by hot temperature, unless specified otherwise in the device specification.
Table A-4. ESD and Latch-up Test Conditions Model Description Symbol Value Unit
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 295
Appendix A Electrical Characteristics and Timing Specifications
Table A-4. ESD and Latch-up Test Conditions (continued)
Series Resistance Human Body Storage Capacitance Number of Pulse per pin Series Resistance Machine Storage Capacitance Number of Pulse per pin Minimum input voltage limit Latch-up Maximum input voltage limit 7.5 V R1 C - R1 C - 1500 100 3 0 200 3 - 2.5 V
pF
pF
Table A-5. ESD and Latch-Up Protection Characteristics Num C
1 2 3 4
Rating
Symbol
VHBM VMM VCDM ILAT
Min
2000 200 500 100
Max
- - - -
Unit
V V V mA
C Human Body Model (HBM) C Machine Model (MM) C Charge Device Model (CDM) C Latch-up Current at TA = 125C
A.6
DC Characteristics
This section includes information about power supply requirements, I/O pin characteristics, and power supply current in various operating modes.
Table A-6. DC Characteristics
Num C Parameter Output high voltage -- Low Drive (PTxDSn = 0) 5 V, ILoad = -2 mA 3 V, ILoad = -0.6 mA 5 V, ILoad = -0.4 mA 3 V, ILoad = -0.24 mA 1 P Output high voltage -- High Drive (PTxDSn = 1) 5 V, ILoad = -10 mA 3 V, ILoad = -3 mA 5 V, ILoad = -2 mA 3 V, ILoad = -0.4 mA VOH VDD - 1.5 VDD - 1.5 VDD - 0.8 VDD - 0.8 -- -- -- -- -- -- -- -- Symbol Min Typ1 Max Unit
VDD - 1.5 VDD - 1.5 VDD - 0.8 VDD - 0.8
-- -- -- --
-- -- -- -- V
MC9S08AC16 Series Data Sheet, Rev. 8 296 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications
Table A-6. DC Characteristics (continued)
Num C Parameter Output low voltage -- Low Drive (PTxDSn = 0) 5 V, ILoad = 2 mA 3 V, ILoad = 0.6 mA 5 V, ILoad = 0.4 mA 3 V, ILoad = 0.24 mA 2 P Output low voltage -- High Drive (PTxDSn = 1) 5 V, ILoad = 10 mA 3 V, ILoad = 3 mA 5 V, ILoad = 2 mA 3 V, ILoad = 0.4 mA 5V 3V 4 P Output low current -- Max total IOL for all ports 5V 3V Input high 5 P voltage; all digital inputs 2.7v VDD 4.5v 4.5v VDD 5.5v IOLT VIH VIH VIL Vhys pins2 |IIn| |IOZ| RPU RPD CIn VPOR tPOR VLVDH -- -- 0.70xVDD 0.65xVDD -- 0.06 x VDD -- -- 20 20 -- 0.9 10 4.2 4.3 2.48 2.54 4.2 4.3 2.48 2.54 0.1 0.1 45 45 -- 1.4 -- 4.3 4.4 2.56 2.62 4.3 4.4 2.56 2.62 1 1 65 65 8 2.0 -- 4.4 4.5 2.64 2.7 4.4 4.5 2.64 2.7 -- -- -- -- -- 100 60 -- -- 0.35 x VDD V A A k k pF V s V V mA VOL -- -- -- -- IOHT -- -- -- -- -- -- -- -- 1.5 1.5 0.8 0.8 100 60 mA Symbol Min Typ1 Max Unit
-- -- -- --
-- -- -- --
1.5 1.5 0.8 0.8 V
3
P Output high current -- Max total IOH for all ports
6 7 8 9 10 11 12 13 14 15
P Input low voltage; all digital inputs P Input hysteresis; all digital inputs P Input leakage current; input only
P High Impedance (off-state) leakage current2 P Internal pullup resistors3
P Internal pulldown resistors4 C Input Capacitance; all non-supply pins P POR rearm voltage D POR rearm time P Low-voltage detection threshold -- high range VDD falling VDD rising P Low-voltage detection threshold -- low range VDD falling VDD rising Low-voltage warning threshold -- high range VDD falling VDD rising Low-voltage warning threshold -- low range VDD falling VDD rising
16
VLVDL
V
17
P
VLVWH
V
18
P
VLVWL
V
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 297
Appendix A Electrical Characteristics and Timing Specifications
Table A-6. DC Characteristics (continued)
Num C Parameter Low-voltage inhibit reset/recover hysteresis 19 20 P 5V 3V Vhys -- -- 1.185 100 35 1.202 -- -- 1.215 mV Symbol Min Typ1 Max Unit
P Bandgap voltage reference Factory trimmed at VDD = 5.0 V Temp = 25 C DC injection current5, 6, 7, 8 Single pin limit VIN > VDD
VBG
V
0 |IIC| 0
-- --
2 -0.2
mA mA
21
D
VIN < VSS Total MCU limit, includes sum of all stressed pins VIN > VDD VIN < VSS
0 0
-- --
25 -5
mA mA
1 2 3 4 5
6 7 8
Typical values are based on characterization data at 25C unless otherwise stated. Measured with VIn = VDD or VSS. Measured with VIn = VSS. Measured with VIn = VDD. Power supply must maintain regulation within operating VDD range during instantaneous and operating maximum current conditions. If positive injection current (VIN > VDD) is greater than IDD, the injection current may flow out of VDD and could result in external power supply going out of regulation. Ensure external VDD load will shunt current greater than maximum injection current. This will be the greatest risk when the MCU is not consuming power. Examples are: if no system clock is present, or if clock rate is very low which (would reduce overall power consumption). All functional non-supply pins are internally clamped to VSS and VDD. Input must be current limited to the value specified. To determine the value of the required current-limiting resistor, calculate resistance values for positive and negative clamp voltages, then use the larger of the two values. IRQ does not have a clamp diode to VDD. Do not drive IRQ above VDD. VDD-VOH (V)
Average of IOH -6.0E-3 -5.0E-3 -4.0E-3 -3.0E-3 -2.0E-3 -1.0E-3 000E+0 0 0.3 0.5
-40C 25C 125C IOH (A) 0.8 VSupply-VOH 0.9 1.2 1.5
Figure A-1. Typical IOH (Low Drive) vs VDD-VOH at VDD = 3 V
MC9S08AC16 Series Data Sheet, Rev. 8 298 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications
-20.0E-3 -18.0E-3 -16.0E-3 -14.0E-3 -12.0E-3 -10.0E-3 -8.0E-3 -6.0E-3 -4.0E-3 -2.0E-3 000.0E-3
Average of IOH
VDD-VOH (V)
-40C 25C 125C IOH (A) 0 0.3 0.5 0.8 VSupply-VOH 0.9 1.2 1.5
Figure A-2. Typical IOH (High Drive) vs VDD-VOH at VDD = 3 V
Average of IOH -7.0E-3 -6.0E-3 -5.0E-3 IOH (A) -4.0E-3 -3.0E-3 -2.0E-3 -1.0E-3 000E+0 0.00 0.30 0.50 0.80 VDD-VOH (V) VSupply-VOH 1.00 1.30 2.00 -40C 25C 125C
Figure A-3. Typical IOH (Low Drive) vs VDD-VOH at VDD = 5 V
Average of IOH -30.0E-3 -25.0E-3 -20.0E-3 IOH (A) -15.0E-3 -10.0E-3 -5.0E-3 000.0E+3 0.00 0.30 0.50 0.80 VSupply-VOH 1.00 1.30 2.00 -40C 25C 125C VDD-VOH (V)
Figure A-4. Typical IOH (High Drive) vs VDD-VOH at VDD = 5 V
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 299
Appendix A Electrical Characteristics and Timing Specifications
A.7
Num
Supply Current Characteristics
Table A-7. Supply Current Characteristics
C Parameter Run supply current measured at (CPU clock = 2 MHz, fBus = 1 MHz) Run supply current measured at (CPU clock = 16 MHz, fBus = 8 MHz) Run supply current7 measured at (CPU clock = 40 MHz, fBus = 20 MHz)
5 3
Symbol
VDD (V) 5
Typ1 0.988 0.570 6.84 5.5 16.8 11.5 1.36
Max2 1.24 0.770 86 5.70 18.5 12.5 11 20 604 10.5 17 50 12 20 904 11 19 85 500 500 500 500 150 180 140 160 6 8
Unit
Temp (C) -40 to 125C
1
C
RIDD
3 5
mA
2
C
RIDD RIDD
3 5 3 5
mA mA mA A
-40 to 125C -40 to 125C -40 to 125C 0 to 70C -40 to 85C -40 to 125C 0 to 70C -40 to 85C -40 to 125C 0 to 70C -40 to 85C -40 to 125C 0 to 70C -40 to 85C -40 to 125C -40 to 85C -40 to 125C -40 to 85C -40 to 125C -40 to 85C -40 to 125C -40 to 85C -40 to 125C -40 to 85C -40 to 125C
3
P
Stop2 mode supply current 4 C S2IDD
3
1.05
A
5 5 C Stop3 mode supply current S3IDD 3
1.49
A
1.15
A
5 6 C RTI adder to stop2 or stop38 S23IDDRTI 3 5 7 C LVD adder to stop3 (LVDE = LVDSE = 1) S3IDDLVD 3 5,3
300 300 116 90 5
nA nA A A A A
8
1 2 3 4 5 6 7 8 9
C
Adder to stop3 for oscillator enabled9 (OSCSTEN =1)
S3IDDOSC
Typical values are based on characterization data at 25C unless otherwise stated. See Figure A-5 through Figure A-7 for typical curves across voltage/temperature. Values given here are preliminary estimates prior to completing characterization. All modules except ADC active, ICG configured for FBE, and does not include any dc loads on port pins Every unit tested to this parameter. All other values in the Max column are guaranteed by characterization. All modules except ADC active, ICG configured for FBE, and does not include any dc loads on port pins Every unit tested to this parameter. All other values in the Max column are guaranteed by characterization. All modules except ADC active, ICG configured for FBE and does not include any DC loads on port pins Most customers are expected to find that auto-wakeup from stop2 or stop3 can be used instead of the higher current wait mode. Wait mode typical is 560 A at 3 V with fBus = 1 MHz. Values given under the following conditions: low range operation (RANGE = 0) with a 32.768kHz crystal, low power mode (HGO = 0), clock monitor disabled (LOCD = 1).
MC9S08AC16 Series Data Sheet, Rev. 8 300 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications 18
16
20 MHz, ADC off, FEE, 25C 20 MHz, ADC off, FBE, 25C
14
12
10
IDD
8
8 MHz, ADC off, FEE, 25C 8 MHz, ADC off, FBE, 25C
6
4
1 MHz, ADC off, FEE, 25C 1 MHz, ADC off, FBE, 25C
2
0 2.2 2.6 3.0 3.4 3.8 4.2 4.6 5.0 5.4
VDD Note: External clock is square wave supplied by function generator. For FEE mode, external reference frequency is 4
Figure A-5. Typical Run IDD for FBE and FEE Modes, IDD vs. VDD
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 301
Appendix A Electrical Characteristics and Timing Specifications
Stop2 IDD (A) -8.0E-3 -7.0E-3 -6.0E-3 -5.0E-3 IDD (A) -4.0E-3 -3.0E-3 -2.0E-3 -1.0E-3 000E+0 1.8 2 2.5 3 VDD (V) 3.5 4 4.5 Average of Measurement IDD
-40C 25C 55C 85C
5
Figure A-6. Typical Stop2 IDD
-40C 25C 55C 85C
Stop3 IDD (A) -8.0E-3 -7.0E-3 -6.0E-3 -5.0E-3 IDD (A) -4.0E-3 -3.0E-3 -2.0E-3 -1.0E-3 000E+0 1.8 2 2.5 3 VDD (V) 3.5 4 4.5 Average of Measurement IDD
5
Figure A-7. Typical Stop3 IDD
MC9S08AC16 Series Data Sheet, Rev. 8 302 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications
A.8
ADC Characteristics
Table A-8. 5 Volt 10-bit ADC Operating Conditions
Characteristic Conditions Absolute Delta to VDD (VDD-VDDAD)2 Symb VDDAD VDDAD VSSAD VREFH VREFL Stop, reset, module off IDDAD VADIN CADIN RADIN 10-bit mode fADCK > 4MHz fADCK < 4MHz 8-bit mode (all valid fADCK) RAS -- -- -- fADCK 0.4 0.4 -- -- -- -- -- 5 10 10 8.0 4.0 MHz Min 2.7 -100 -100 2.7 VSSAD -- VREFL -- -- Typ1 -- 0 0 VDDAD VSSAD 0.011 -- 4.5 3 Max 5.5 +100 +100 VDDAD VSSAD 1 VREFH 5.5 5 Unit V mV mV V V A V pF k k
Supply voltage
Ground voltage Ref voltage high Ref voltage low Supply current Input Voltage Input capacitance Input resistance Analog source resistance External to MCU
Delta to VSS (VSS-VSSAD)2
ADC conversion clock frequency
High speed (ADLPC = 0) Low power (ADLPC = 1)
Typical values assume VDDAD = 5.0 V, Temp = 25C, fADCK = 1.0MHz unless otherwise stated. Typical values are for reference only and are not tested in production. 2 dc potential difference.
1
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 303
Appendix A Electrical Characteristics and Timing Specifications SIMPLIFIED INPUT PIN EQUIVALENT CIRCUIT ZAS RAS VADIN VAS Pad leakage due to input protection
ZADIN SIMPLIFIED CHANNEL SELECT CIRCUIT RADIN
ADC SAR ENGINE
+ -
+ -
CAS
RADIN INPUT PIN
RADIN
INPUT PIN
RADIN CADIN
INPUT PIN
Figure A-8. ADC Input Impedance Equivalency Diagram Table A-9. 5 Volt 10-bit ADC Characteristics (VREFH = VDDAD, VREFL = VSSAD)
Characteristic Supply current ADLPC = 1 ADLSMP = 1 ADCO = 1 Supply current ADLPC = 1 ADLSMP = 0 ADCO = 1 Supply current ADLPC = 0 ADLSMP = 1 ADCO = 1 Supply current ADLPC = 0 ADLSMP = 0 ADCO = 1 ADC asynchronous clock source tADACK = 1/fADACK Conversion time (Including sample time) Conditions C T Symb IDDAD Min -- Typ1 133 Max -- Unit A
T
IDDAD
--
218
--
A
T
IDDAD
--
327
--
A
T VDDAD < 5.5 V P
IDDAD
-- --
582 --
-- 1
A mA
High speed (ADLPC = 0) Low power (ADLPC = 1) Short sample (ADLSMP = 0) Long sample (ADLSMP = 1)
P
fADACK
2 1.25
3.3 2 20 40
5 3.3 -- --
MHz
P
tADC
-- --
ADCK cycles
MC9S08AC16 Series Data Sheet, Rev. 8 304 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications
Table A-9. 5 Volt 10-bit ADC Characteristics (VREFH = VDDAD, VREFL = VSSAD) (continued)
Characteristic Sample time Conditions Short sample (ADLSMP = 0) Long sample (ADLSMP = 1) Total unadjusted error Includes quantization Differential non-linearity 10-bit mode 8-bit mode 10-bit mode 8-bit mode P DNL P ETUE C P Symb tADS Min -- -- -- -- -- -- Typ1 3.5 23.5 1 0.5 0.5 0.3 Max -- -- 2.5 1.0 1.0 0.5 LSB2 Unit ADCK cycles LSB2
Monotonicity and no-missing-codes guaranteed Integral non-linearity 10-bit mode 8-bit mode Zero-scale error VADIN = VSSA Full-scale error VADIN = VDDA Quantization error 10-bit mode 8-bit mode 10-bit mode 8-bit mode 10-bit mode 8-bit mode Input leakage error Pad leakage3 * RAS Temp Sensor Slope Temp Sensor Voltage
1 P P
C
INL
-- --
0.5 0.3 0.5 0.5 0.5 0.5 -- -- 0.2 0.1 3.266 3.636 1.396
1.0 0.5 1.5 0.5 1.5 0.5 0.5 0.5 2.5 1 -- -- --
LSB2
EZS
-- --
LSB2
EFS
-- --
LSB2
D
EQ
-- --
LSB2
10-bit mode 8-bit mode -40C- 25C 25C- 125C 25C
D
EIL
-- --
LSB2
D
m
-- --
mV/C
D
VTEMP25
--
mV
Typical values assume VDDAD = 5.0V, Temp = 25C, fADCK=1.0 MHz unless otherwise stated. Typical values are for reference only and are not tested in production. 2 1 LSB = (V N REFH - VREFL)/2 3 Based on input pad leakage current. Refer to pad electricals.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 305
Appendix A Electrical Characteristics and Timing Specifications
A.9
Internal Clock Generation Module Characteristics
ICG EXTAL XTAL RS
RF
C1
Crystal or Resonator C2
Table A-10. ICG DC Electrical Specifications (Temperature Range = -40 to 125C Ambient)
Characteristic Load capacitors Feedback resistor Low range (32k to 100 kHz) High range (1M - 16 MHz) Series resistor Low range Low Gain (HGO = 0) High Gain (HGO = 1) High range Low Gain (HGO = 0) High Gain (HGO = 1) 8 MHz 4 MHz 1 MHz
1 2
Symbol C1 C2 RF
Min
Typ1 See Note 2
Max
Unit
10 1
M M
-- -- RS -- -- -- --
0 100 0 0 10 20
-- -- -- -- -- -- k
Typical values are based on characterization data at VDD = 5.0V, 25C or is typical recommended value. See crystal or resonator manufacturer's recommendation.
MC9S08AC16 Series Data Sheet, Rev. 8 306 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications
A.9.1
ICG Frequency Specifications
Table A-11. ICG Frequency Specifications (VDDA = VDDA (min) to VDDA (max), Temperature Range = -40 to 125C Ambient)
Num
C
Characteristic Oscillator crystal or resonator (REFS = 1) (Fundamental mode crystal or ceramic resonator) Low range High range High Gain, FBE (HGO = 1,CLKS = 10) High Gain, FEE (HGO = 1,CLKS = 11) Low Power, FBE (HGO = 0, CLKS = 10) Low Power, FEE (HGO = 0, CLKS = 11) Input clock frequency (CLKS = 11, REFS = 0) Low range High range Input clock frequency (CLKS = 10, REFS = 0) Internal reference frequency (untrimmed) Duty cycle of input clock (REFS = 0) Output clock ICGOUT frequency CLKS = 10, REFS = 0 All other cases Minimum DCO clock (ICGDCLK) frequency Maximum DCO clock (ICGDCLK) frequency Self-clock mode (ICGOUT) frequency
3 2
Symbol
Min
Typ1
Max
Unit
flo fhi_byp fhi_eng flp_byp flp_eng flo fhi_eng fExtal fICGIRCLK tdc
32 1 2 1 2 32 2 0 182.25 40
-- -- --
100 16 10 8 8 100 10 40 303.75 60 fExtal (max) fICGDCLKmax( max) 40 fICGDCLKmax
kHz MHz MHz MHz MHz kHz MHz MHz kHz %
1
2 3 4 5
-- -- -- 243 --
6
fICGOUT
fExtal (min) flo (min) 8 fICGDCLKmin 5.5 5 50 0.5 -- -- -- -- -4*N -2*N --
-- -- -- --
MHz MHz MHz MHz MHz
7 8 9 10 11 12 13
fICGDCLKmin fICGDCLKmax fSelf fSelf_reset fLOR fLOD
t t CSTL
Self-clock mode reset (ICGOUT) frequency Loss of reference frequency Low range High range Loss of DCO frequency 4 Crystal start-up time Low range High range FLL lock time , 7 Low range High range FLL frequency unlock range FLL frequency lock range ICGOUT period jitter, , 8 measured at fICGOUT Max Long term jitter (averaged over 2 ms interval)
5, 6
8
10.5 25 500 1.5
kHz MHz
CSTH
430 4
-- -- 2 2 4*N 2*N 0.2
ms ms counts counts % fICG
14 15 16 17
tLockl tLockh nUnlock nLock CJitter
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 307
Appendix A Electrical Characteristics and Timing Specifications
Table A-11. ICG Frequency Specifications (continued) (VDDA = VDDA (min) to VDDA (max), Temperature Range = -40 to 125C Ambient)
Num C Characteristic MC9S08ACxx: Internal oscillator deviation from trimmed frequency9 VDD = 2.7 - 5.5 V, (constant temperature) VDD = 5.0 V 10%, -40 C to 125C 18 S9S08AWxxA: Internal oscillator deviation from trimmed frequency10 VDD = 2.7 - 5.5 V, (constant temperature) C P P
1 2
Symbol
Min
Typ1 0.5 0.5
Max 2 2
Unit
ACCint
-- --
%
VDD = 5.0 V 10%, -40 C to 85C VDD = 5.0 V 10%, -40 C to 125C
ACCint
-- -- --
0.5 0.5 0.5
1.5 1.5 2.0 %
Typical values are based on characterization data at VDD = 5.0V, 25C unless otherwise stated. Self-clocked mode frequency is the frequency that the DCO generates when the FLL is open-loop. 3 Loss of reference frequency is the reference frequency detected internally, which transitions the ICG into self-clocked mode if it is not in the desired range. 4 Loss of DCO frequency is the DCO frequency detected internally, which transitions the ICG into FLL bypassed external mode (if an external reference exists) if it is not in the desired range. 5 This parameter is characterized before qualification rather than 100% tested. 6 Proper PC board layout procedures must be followed to achieve specifications. 7 This specification applies to the period of time required for the FLL to lock after entering FLL engaged internal or external modes. If a crystal/resonator is being used as the reference, this specification assumes it is already running. 8 Jitter is the average deviation from the programmed frequency measured over the specified interval at maximum f ICGOUT. Measurements are made with the device powered by filtered supplies and clocked by a stable external clock signal. Noise injected into the FLL circuitry via VDDA and VSSA and variation in crystal oscillator frequency increase the CJitter percentage for a given interval. 9 See Figure A-9. 10 See Figure A-9.
MC9S08AC16 Series Data Sheet, Rev. 8 308 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications
Internal Oscillator Deviation from Trimmed Frequency Variable 5V 3V
0.0
-0.5 Percent (%)
-1.0
-1.5
-2.0 -50 -25 0 25 50 Temp 75 100 125
Device trimmed at 25C at 3.0 V. Figure A-9. Typical Internal Oscillator Deviation from Trimmed Frequency
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 309
Appendix A Electrical Characteristics and Timing Specifications
A.10
AC Characteristics
This section describes ac timing characteristics for each peripheral system. For detailed information about how clocks for the bus are generated, see Chapter 8, "Internal Clock Generator (S08ICGV4)."
A.10.1
Num 1 2 3 C
Control Timing
Table A-12. Control Timing
Parameter Bus frequency (tcyc = 1/fBus) Real-time interrupt internal oscillator period External reset pulse width2 (tcyc = 1/fSelf_reset) Reset low drive3 Active background debug mode latch setup time Active background debug mode latch hold time IRQ pulse width Asynchronous path2 Synchronous path4 KBIPx pulse width Asynchronous path2 Synchronous path3 Port rise and fall time (load = 50 pF)5 Slew rate control disabled (PTxSE = 0) Slew rate control enabled (PTxSE = 1) Symbol fBus tRTI textrst trstdrv tMSSU tMSH tILIH, tIHIL Min dc 700 1.5 x tSelf_reset 34 x tcyc 25 25 100 1.5 x tcyc 100 1.5 x tcyc -- -- -- Typ1 -- Max 20 1300 -- -- -- -- -- Unit MHz s ns ns ns ns ns
4
5
6
7
8
tILIH, tIHIL
--
--
ns
9
1 2
tRise, tFall
3 30
ns
Typical values are based on characterization data at VDD = 5.0V, 25C unless otherwise stated. This is the shortest pulse that is guaranteed to be recognized as a reset pin request. Shorter pulses are not guaranteed to override reset requests from internal sources. 3 When any reset is initiated, internal circuitry drives the reset pin low for about 34 bus cycles and then samples the level on the reset pin about 38 bus cycles later to distinguish external reset requests from internal requests. 4 This is the minimum pulse width that is guaranteed to pass through the pin synchronization circuitry. Shorter pulses may or may not be recognized. In stop mode, the synchronizer is bypassed so shorter pulses can be recognized in that case. 5 Timing is shown with respect to 20% V DD and 80% VDD levels. Temperature range -40C to 125C.
textrst RESET PIN
Figure A-10. Reset Timing
MC9S08AC16 Series Data Sheet, Rev. 8 310 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications
BKGD/MS
RESET tMSH tMSSU
Figure A-11. Active Background Debug Mode Latch Timing
tIHIL IRQ/KBIP6-KBIP4
IRQ/KBIPx tILIH
Figure A-12. IRQ/KBIPx Timing
A.10.2
Timer/PWM (TPM) Module Timing
Synchronizer circuits determine the shortest input pulses that can be recognized or the fastest clock that can be used as the optional external source to the timer counter. These synchronizers operate from the current bus rate clock.
Table A-13. TPM Input Timing
Function External clock frequency External clock period External clock high time External clock low time Input capture pulse width Symbol fTPMext tTPMext tclkh tclkl tICPW Min dc 4 1.5 1.5 1.5 Max fBus/4 -- -- -- -- Unit MHz tcyc tcyc tcyc tcyc
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 311
Appendix A Electrical Characteristics and Timing Specifications
tTPMext tclkh
TPMxCLK tclkl
Figure A-13. Timer External Clock
tICPW TPMxCHn
TPMxCHn tICPW
Figure A-14. Timer Input Capture Pulse
MC9S08AC16 Series Data Sheet, Rev. 8 312 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications
A.11
SPI Characteristics
Table A-14. SPI Electrical Characteristic
Num C Characteristic1 Operating frequency Master Slave 1 Cycle time Master Slave 2 Enable lead time Master Slave 3 Enable lag time Master Slave 4 5 6 Clock (SPSCK) high time Master and Slave Clock (SPSCK) low time Master and Slave Data setup time (inputs) Master Slave 7 Data hold time (inputs) Master Slave 8 9 10 Access time, slave2 Disable time, slave3 tSCK tSCK 2 4 -- 1/2 2048 Symbol Min Max Unit Hz
Table A-14 and Figure A-15 through Figure A-18 describe the timing requirements for the SPI system.
fop fop
fBus/2048 dc
fBus/2 fBus/4
-- 1/2 -- 1/2 --
-- -- -- --
tcyc tcyc
tLead tLead tLag tLag tSCKH tSCKL tSI(M) tSI(S) tHI(M) tHI(S) tA tdis tSO tSO tHO tHO
tSCK tSCK tSCK tSCK
ns ns ns ns
-- 1/2
1/2 tSCK - 25 1/2 tSCK - 25 30 30
30 30 0 -- 25 25
-- -- 40 40 -- --
ns ns ns ns ns ns
Data setup time (outputs) Master Slave Data hold time (outputs) Master Slave
11
-10 -10
-- --
ns ns
1
All timing is shown with respect to 20% VDD and 70% VDD, unless noted; 100 pF load on all SPI pins. All timing assumes slew rate control disabled and high drive strength enabled for SPI output pins. 2 Time to data active from high-impedance state. 3 Hold time to high-impedance state.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 313
Appendix A Electrical Characteristics and Timing Specifications
SS1 (OUTPUT) 2 SCK (CPOL = 0) (OUTPUT) SCK (CPOL = 1) (OUTPUT) 6 MISO (INPUT) MSB IN2 10 MOSI (OUTPUT) MSB OUT2 7 BIT 6 . . . 1 10 BIT 6 . . . 1 LSB OUT LSB IN 11 1 5 4 3
5 4
NOTES: 1. SS output mode (MODFEN = 1, SSOE = 1). 2. LSBF = 0. For LSBF = 1, bit order is LSB, bit 1, ..., bit 6, MSB.
Figure A-15. SPI Master Timing (CPHA = 0)
SS(1) (OUTPUT) 1 2 SCK (CPOL = 0) (OUTPUT) SCK (CPOL = 1) (OUTPUT) MISO (INPUT) 10 MOSI (OUTPUT) MSB OUT(2) 5 4 5 4 6 7 MSB IN(2) BIT 6 . . . 1 11 BIT 6 . . . 1 LSB OUT LSB IN 3
NOTES: 1. SS output mode (MODFEN = 1, SSOE = 1). 2. LSBF = 0. For LSBF = 1, bit order is LSB, bit 1, ..., bit 6, MSB.
Figure A-16. SPI Master Timing (CPHA = 1)
MC9S08AC16 Series Data Sheet, Rev. 8 314 Freescale Semiconductor
Appendix A Electrical Characteristics and Timing Specifications
SS (INPUT) 1 SCK (CPOL = 0) (INPUT) 2 SCK (CPOL = 1) (INPUT) 8 MISO (OUTPUT) SLAVE 6 MOSI (INPUT)
NOTE:
3 5
4
5 4 10 MSB OUT 7 MSB IN BIT 6 . . . 1 LSB IN BIT 6 . . . 1 11 SLAVE LSB OUT SEE NOTE 9
1. Not defined but normally MSB of character just received
Figure A-17. SPI Slave Timing (CPHA = 0)
SS (INPUT) 1 2 SCK (CPOL = 0) (INPUT) SCK (CPOL = 1) (INPUT) MISO (OUTPUT) SEE NOTE 8 MOSI (INPUT) 5 4 5 4 10 SLAVE 6 MSB IN MSB OUT 7 BIT 6 . . . 1 LSB IN 11 BIT 6 . . . 1 SLAVE LSB OUT 9 3
NOTE: 1. Not defined but normally LSB of character just received
Figure A-18. SPI Slave Timing (CPHA = 1)
A.12
FLASH Specifications
This section provides details about program/erase times and program-erase endurance for the FLASH memory.
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 315
Appendix A Electrical Characteristics and Timing Specifications
Program and erase operations do not require any special power sources other than the normal VDD supply. For more detailed information about program/erase operations, see Chapter 4, "Memory."
Table A-15. FLASH Characteristics
Num 1 2 3 4
5
C
Characteristic Supply voltage for program/erase Supply voltage for read operation Internal FCLK frequency2 Internal FCLK period (1/FCLK) Byte program time (random location)(2) Byte program time (burst mode)(2) Page erase time3 Mass erase time(2) Program/erase endurance4 TL to TH = -40C to + 125C T = 25C Data retention5
Symbol Vprog/erase VRead fFCLK tFcyc tprog tBurst tPage tMass
Min 2.7 2.7 150 5
Typ1
Max 5.5 5.5 200 6.67
Unit V V kHz s tFcyc tFcyc tFcyc tFcyc
9 4 4000 20,000
6
7
8
9
C
10,000 -- tD_ret 15
-- 100,000 100
-- -- --
cycles
10
1 2
years
Typical values are based on characterization data at VDD = 5.0 V, 25C unless otherwise stated. The frequency of this clock is controlled by a software setting. 3 These values are hardware state machine controlled. User code does not need to count cycles. This information supplied for calculating approximate time to program and erase. 4 Typical endurance for FLASH was evaluated for this product family on the 9S12Dx64. For additional information on how Freescale Semiconductor defines typical endurance, please refer to Engineering Bulletin EB619, Typical Endurance for Nonvolatile Memory. 5 Typical data retention values are based on intrinsic capability of the technology measured at high temperature and de-rated to 25C using the Arrhenius equation. For additional information on how Freescale Semiconductor defines typical data retention, please refer to Engineering Bulletin EB618, Typical Data Retention for Nonvolatile Memory.
A.13
EMC Performance
Electromagnetic compatibility (EMC) performance is highly dependant on the environment in which the MCU resides. Board design and layout, circuit topology choices, location and characteristics of external components as well as MCU software operation all play a significant role in EMC performance. The system designer should consult Freescale applications notes such as AN2321, AN1050, AN1263, AN2764, and AN1259 for advice and guidance specifically targeted at optimizing EMC performance.
MC9S08AC16 Series Data Sheet, Rev. 8 316 Freescale Semiconductor
Appendix B Ordering Information and Mechanical Drawings
Appendix B Ordering Information and Mechanical Drawings
B.1 Ordering Information
This section contains ordering information for the MC9S08AC16 Series devices. See below for an example of the device numbering system.
Table B-1. Device Comparison
1
Memory FLASH RAM 1024 768 1024 768
Device Number
Available Packages2 Type 48-pin QFN 44-pin LQFP 42-pin SDIP 32-pin LQFP 48-pin QFN 44-pin LQFP 32-pin LQFP
Qualification Type Consumer and Industrial
MC9S08AC16 MC9S08AC8 S9S08AW16A S9S08AW8A
1 2
16,384 8192 16,384 8192
Automotive
See Table 1-1 for a complete description of modules included on each device. See Table B-2 and Table B-3 for package information.
B.2
Orderable Part Numbering System
The orderable part numbers for the MC9S08AC16 Series devices varies according to the device family. Refer to Figure B-1 and Figure B-2 for examples.
MC
Status - MC = Consumer & Industrial Main Memory Type - 9 = Flash-based Core Family
- AC
9
S08
AC n
C
xx
E
Pb Free Indicator - E = Pb Free Package Designator Two letter descriptor (refer to Table B-2). Temperature Option - C = -40 to 85 C - V = -40 to 105 C - M = -40 to 125 C Memory Size (Approx) - 16 Kbytes - 8 Kbytes
Figure B-1. Consumer & Industrial Device Numbering System
MC9S08AC16 Series Data Sheet, Rev. 8 Freescale Semiconductor 317
Appendix B Ordering Information and Mechanical Drawings
S
Status - S = Auto Qualified
9
S08
AW n
A
E0
C
xx
Package Designator Two letter descriptor (refer to Table B-3). Temperature Range - C = -40 to 85 C - V = -40 to 105 C - M = -40 to 125 C
Mask Set Identifier - Alpha character references wafer fab. - E = Chandler - Numeric character identifies mask revision.
Main Memory Type - 9 = Flash-based Core Family
- AW
Memory Size (Approx) - 16 Kbytes - 8 Kbytes
Device Version
Figure B-2. Automotive Device Numbering System
B.3
Mechanical Drawings
This following pages contain mechanical specifications for MC9S08AC16 Series package options. See the following tables for the document numbers that correspond to each package type.
Table B-2. MC9S08AC16 and MC9S08AC8 Consumer & Industrial Package Information
Pin Count 48 44 42 32 Type QFN LQFP SDIP LQFP Designator FD FG B FJ Document No. 98ARH99048A 98ASS23225W 98ASB42767B 98ASH70029A
Table B-3. S9S08AW16A and S9S08AW8A Automotive Package Information
Pin Count 48 44 32 Type QFN LQFP LQFP Designator FT LD LC Document No. 98ARH99048A 98ASS23225W 98ASH70029A
MC9S08AC16 Series Data Sheet, Rev. 8 318 Freescale Semiconductor
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MC9S08AC16
Rev. 8, 9/2009

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