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Freescale Semiconductor Technical Data
An Energy Efficient Solution by Freescale
MMA8450Q Rev 2, 03/2010
3-Axis, 8-bit/12-bit
Digital Accelerometer
The MMA8450Q is a smart low-power, three-axis, capacitive micromachined accelerometer featuring 12 bits of resolution. This accelerometer is packed with embedded functions with flexible user programmable options, configurable to two interrupt pins. Embedded interrupt functions allow for overall power savings relieving the host processor from continuously polling data. The MMA8450Q's Embedded FIFO buffer can be configured to log up to 32 samples of X,Y and Z-axis 12-bit (or 8-bit for faster download) data. The FIFO enables a more efficient analysis of gestures and user programmable algorithms, ensuring no loss of data on a shared I2C bus, and enables system level power saving (up to 96% of the total power consumption savings) by allowing the applications processor to sleep while data is logged. There is access to both low pass filtered data as well as high pass filtered data, which minimizes the data analysis required for jolt detection and faster transitions. The MMA8450Q has user selectable full scales of 2g/4g/8g. The device can be configured to generate inertial wake-up interrupt signals from any combination of the configurable embedded functions allowing the MMA8450Q to monitor events and remain in a low power mode during periods of inactivity. The MMA8450Q is available in a 3 x 3 x 1 mm QFN package. Features * 1.71 V to 1.89 V supply voltage * 2g/4g/8g dynamically selectable full-scale * Output Data Rate (ODR) from 400 Hz to 1.563 Hz * 375 g/Hz noise at normal mode ODR = 400 Hz * 12-bit digital output * I2C digital output interface (operates up to 400 kHz Fast Mode) * Programmable 2 interrupt pins for 8 interrupt sources * Embedded 4 channels of motion detection - Freefall or motion detection: 2 channels - Pulse Detection: 1 channel - Transient (Jolt) Detection: 1 channel * Orientation (Portrait/Landscape) detection with hysteresis compensation * Automatic ODR change for auto-wake and return-to-sleep * 32 sample FIFO * Self-Test * 10,000g high shock survivability * RoHS compliant
MMA8450Q
MMA8450Q: XYZ-AXIS ACCELEROMETER 2g/4g/8g
Top and Bottom View
16 PIN QFN CASE 2077-01
Top View
VDD NC NC
16
VDD NC NC SCL GND
15
14 13
GND GND INT1
1 2 3 4 5 6
SDA
MMA8450Q
16 Pin QFN 3mm x 3 mm x 1mm
12 11
10 GND 9 7
SA0
INT2
8
EN
Typical Applications Pin Connections * Static orientation detection (portrait/landscape, up/down, left/right, back/ front position identification) * Real-time orientation detection (virtual reality and gaming 3D user position feedback) * Real-time activity analysis (pedometer step counting, freefall drop detection for HDD, dead-reckoning GPS backup) * Motion detection for portable product power saving (auto-sleep and auto-wake for cell phone, PDA, GPS, gaming) * Shock and vibration monitoring (mechatronic compensation, shipping and warranty usage logging) * User interface (menu scrolling by orientation change, tap detection for button replacement ORDERING INFORMATION
Part Number MMA8450QT MMA8450QR1 Temperature Range -40C - +85C -40C - +85C Package Drawing QFN-16 QFN-16 Package Tray Tape and Reel
This document contains certain information on a new product. Specifications and information herein are subject to change without notice.
(c) Freescale Semiconductor, Inc., 2010. All rights reserved.
Contents
Application Notes for Reference ...............................................................................................................................................6 1 Block Diagram and Pin Description ..................................................................................................................................6 1.1 Block Diagram .............................................................................................................................................................6 Figure 1. Block Diagram ..............................................................................................................................................6 1.2 Pin Description ............................................................................................................................................................6 Figure 2. Direction of the Detectable Accelerations ....................................................................................................6 Figure 3. Application Diagram .....................................................................................................................................7 Table 1. Pin Description ..............................................................................................................................................7 1.3 Soldering Information ..................................................................................................................................................7 2 Mechanical and Electrical Specifications .........................................................................................................................8 2.1 Mechanical Characteristics .........................................................................................................................................8 Table 2. Mechanical Characteristics ...........................................................................................................................8 2.2 Electrical Characteristics .............................................................................................................................................9 Table 3. Electrical Characteristics @ VDD = 1.8 V, T = 25C unless otherwise noted. .............................................9 2.3 I2C Interface Characteristic .......................................................................................................................................10 Table 4. I2C Slave Timing Values .............................................................................................................................10 Figure 4. I2C Slave Timing Diagram ..........................................................................................................................11 2.4 Absolute Maximum Ratings .......................................................................................................................................11 Table 5. Maximum Ratings ........................................................................................................................................11 Table 6. ESD and Latch-Up Protection Characteristics ............................................................................................11 3 Terminology .......................................................................................................................................................................12 3.1 Sensitivity ..................................................................................................................................................................12 3.2 Zero-g Offset .............................................................................................................................................................12 3.3 Self-Test ....................................................................................................................................................................12 4 Modes of Operation ...........................................................................................................................................................12 Figure 5. MMA8450Q Mode Transition Diagram .......................................................................................................12 Table 7. Mode of Operation Description ....................................................................................................................12 5 Functionality ......................................................................................................................................................................13 5.1 Device Calibration .....................................................................................................................................................13 5.2 8-bit or 12-bit Data .....................................................................................................................................................13 5.3 Internal FIFO Data Buffer ..........................................................................................................................................13 5.4 Low Power Mode .......................................................................................................................................................13 5.5 Auto-Wake/Sleep Mode ............................................................................................................................................14 5.6 Freefall and Motion Detection ...................................................................................................................................14 5.6.1 Freefall Detection ...........................................................................................................................................14 5.6.2 Motion Detection ............................................................................................................................................14 5.7 Transient Detection ...................................................................................................................................................14 5.8 Orientation Detection .................................................................................................................................................15 Figure 6. Illustration of Landscape-to-Portrait Transition .........................................................................................15 Figure 7. Illustration of Portrait-to-Landscape Transition ..........................................................................................15 Figure 8. Illustration of Z-Tilt Angle Lockout Transition .............................................................................................15 Figure 9. Landscape/Portrait Orientation ..................................................................................................................16 5.9 Interrupt Register Configurations ..............................................................................................................................16 Figure 10. System Interrupt Generation Block Diagram ............................................................................................16 5.10 Serial I2C Interface ....................................................................................................................................................17 Table 8. Serial Interface Pin Description ...................................................................................................................17 5.10.1 I2C Operation .................................................................................................................................................17 Table 9. I2C Address Selection Table .......................................................................................................................17 Single Byte Read .........................................................................................................................................................17 Multiple Byte Read .......................................................................................................................................................18 Single Byte Write ..........................................................................................................................................................18 Multiple Byte Write .......................................................................................................................................................18 Table 10. I2C device Address Sequence ..................................................................................................................18 Figure 11. I2C Timing Diagram ..................................................................................................................................18 MMA8450Q Sensors Freescale Semiconductor 2
6
Register Descriptions .......................................................................................................................................................19 Table 11. Register Address Map ...............................................................................................................................19 6.1 Data Registers ...........................................................................................................................................................21 0x00, 0x04, 0x0B: STATUS Registers .........................................................................................................................21 Alias for DR_Status (0x0B) or F_Status (0x10) ...................................................................................................21 0X00, 0X04, 0X0B STATUS: Data Status Registers (Read Only) ......................................................................21 Table 12. STATUS Description .................................................................................................................................21 0x01, 0x02, 0x03: OUT_MSB 8-Bit XYZ Data Registers .............................................................................................22 0x01 OUT_X_MSB: X_MSB Register (Read Only) .............................................................................................22 0x02 OUT_Y_MSB: Y_MSB Register (Read Only) .............................................................................................22 0x03 OUT_Z_MSB: Z_MSB Register (Read Only) .............................................................................................22 0x05 - 0x0A: OUT_MSB and OUT_LSB 12-Bit XYZ Data Registers ...........................................................................22 0x05 OUT_X_LSB: X_LSB Register (Read Only) ...............................................................................................22 0x06 OUT_X_MSB: X_MSB Register (Read Only) .............................................................................................22 0x07 OUT_Y_LSB: Y_LSB Register (Read Only) ...............................................................................................22 0x08 OUT_Y_MSB: Y_MSB Register (Read Only) .............................................................................................22 0x09 OUT_Z_LSB: Z_LSB Register (Read Only) ...............................................................................................22 0x0A OUT_Z_MSB: Z_MSB Register (Read Only) .............................................................................................22 0x0C - 0x0E: OUT_X_DELTA, OUT_Y_DELTA, OUT_Z_DELTA AC Data Registers ................................................23 0x0C OUT_X_DELTA: AC X 8-Bit Data Register (Read Only) ...........................................................................23 0x0D OUT_Y_DELTA: AC Y 8-Bit Data Register (Read Only) ...........................................................................23 0x0E OUT_Z_DELTA: AC Z 8-Bit Data Register (Read Only) ............................................................................23 0x0F: WHO_AM_I Device ID Register .........................................................................................................................23 0x0F WHO_AM_I: Device ID Register (Read Only) ............................................................................................23 6.2 32 Sample FIFO ........................................................................................................................................................23 0x10: F_STATUS FIFO Status Register ......................................................................................................................23 0x10 F_STATUS: FIFO STATUS Register (Read Only) .....................................................................................23 Table 13. FIFO Flag Event Description .....................................................................................................................23 Table 14. FIFO Sample Count Description ...............................................................................................................24 0x11: F_8DATA 8-Bit FIFO Data .................................................................................................................................24 0x11 F_8DATA: 8-Bit FIFO Data Register Points to Register 0x01 (Read Only) ................................................24 0x12: F_12DATA 12-Bit FIFO Data .............................................................................................................................24 0x12 F_12DATA: 12-Bit FIFO Data Register Points to Register 0x05 (Read Only) ............................................24 0x13: F_SETUP FIFO Setup Register .........................................................................................................................24 0x13 F_SETUP: FIFO Setup Register (Read/Write) ...........................................................................................24 0x14: SYSMOD System Mode Register ......................................................................................................................25 0x14 SYSMOD: System Mode Register (Read Only) .........................................................................................25 Table 15. SYSMOD Description ................................................................................................................................25 Table 16. F_SETUP Description ...............................................................................................................................25 0x15: INT_SOURCE System Interrupt Status Register ...............................................................................................26 0x15 INT_SOURCE: System Interrupt Status Register (Read Only) ..................................................................26 Table 17. INT_SOURCE Description ........................................................................................................................26 0x16: XYZ_DATA_CFG Sensor Data Configuration Register .....................................................................................27 0x16 XYZ_DATA_CFG: Sensor Data Configuration Register (Read/Write) .......................................................27 Table 18. XYZ_DATA_CFG Description ................................................................................................................... 27 0x17: HP_FILTER_CUTOFF High Pass Filter Register ...............................................................................................27 0x17 HP_FILTER_CUTOFF: High Pass Filter Register (Read/Write) .................................................................27 Table 19. HP_FILTER_CUTOFF Setting Options .....................................................................................................27 6.3 Portrait/ Landscape Embedded Function Registers ..................................................................................................27 0x18: PL_STATUS Portrait/Landscape Status Register ..............................................................................................27 0x18 PL_STATUS Register (Read Only) ............................................................................................................27 0x19: PL_PRE_STATUS Portrait/Landscape Previous Data Status Register .............................................................28 0x19 PL_PRE_STATUS Register (Read Only) ...................................................................................................28 0x1A: PL_CFG Portrait/Landscape Configuration Register .........................................................................................28 0x1A PL_CFG Register (Read/Write) ..................................................................................................................28 Table 20. PL_CFG Register Description ...................................................................................................................28 0x1B: PL_COUNT Portrait Landscape Debounce Register .........................................................................................28 0x1B PL_COUNT Register (Read/Write) ............................................................................................................28 Table 21. PL_STATUS Register Description ............................................................................................................28 Table 22. PL_COUNT Relationship with the ODR ....................................................................................................29
MMA8450Q Sensors Freescale Semiconductor 3
0x1C: PL_BF_ZCOMP Back/Front and Z Compensation Register ..............................................................................29 0x1C: PL_BF_ZCOMP Register (Read/Write) ....................................................................................................29 Table 23. PL_BF_ZCOMP Description .....................................................................................................................29 Table 24. Back/Front Orientation Definitions .............................................................................................................29 0x1D - 0x1F: PL_P_L_THS_REG1, 2, 3 Portrait-to-Landscape Threshold Registers .................................................29 0x1D PL_P_L_THS_REG1 Register (Read/Write) ..............................................................................................29 Table 25. PL_P_L_THS_REG1 Description ..............................................................................................................29 0x1E PL_P_L_THS_REG2 Register (Read/Write) ..............................................................................................29 Table 26. PL_P_L_THS_REG2 Description ..............................................................................................................29 0x1F PL_P_L_THS_REG3 Register (Read/Write) ..............................................................................................29 0x20 - 0x22 PL_L_P_THS_REG1, 2, 3 Landscape-to-Portrait Threshold Registers ...................................................30 0x20 PL_L_P_THS_REG1 Register (Read/Write) ..............................................................................................30 Table 27. PL_L_P_THS_REG1 Description ..............................................................................................................30 0x21 PL_L_P_THS_REG2 Register (Read/Write) ..............................................................................................30 Table 28. PL_L_P_THS_REG2 Description ..............................................................................................................30 0x22 PL_L_P_THS_REG3 Register (Read/Write) ..............................................................................................30 Table 29. PL_L_P_THS_REG3 Description ..............................................................................................................30 Table 30. Landscape-to-Portrait Trip Angle Thresholds Look-up Table ....................................................................30 Table 31. PL_P_L_THS_REG3 Description ..............................................................................................................30 Table 32. Portrait-to-Landscape Trip Angle Thresholds Look-up Table ....................................................................30 6.4 Freefall & Motion Detection Registers .......................................................................................................................31 0x23: FF_MT_CFG_1 Freefall and Motion Configuration Register 1 ...........................................................................31 0x23 FF_MT_CFG_1 Register (Read/Write) .......................................................................................................31 Table 33. FF_MT_CFG_1 Description ......................................................................................................................31 0x24 FF_MT_SRC_1 Register (Read Only) ................................................................................................................32 0x24: FF_MT_SRC_ Freefall and Motion Source Register (0x24) ......................................................................32 Table 34. FF_MT_SRC_1 Description ......................................................................................................................32 0x25: FF_MT_THS_1 Freefall and Motion Threshold 1 Register ................................................................................32 0x25 FF_MT_THS_1 Register (Read/Write) .......................................................................................................32 Table 35. FF_MT_THS_1 Description .......................................................................................................................32 Figure 12. DBCNTM Bit Function ..............................................................................................................................33 0x26: FF_MT_COUNT_1 Freefall Motion Count 1 Register ........................................................................................33 0x26 FF_MT_COUNT_1 Register (Read/Write) ..................................................................................................33 Table 36. FF_MT_COUNT_1 Description .................................................................................................................33 Table 37. FF_MT_COUNT_1 and FF_MT_COUNT_2 Relationship with the ODR ..................................................33 0x27: FF_MT_CFG_2 Freefall and Motion Configuration 2 Register ...........................................................................34 0x27 FF_MT_CFG_2 Register (Read/Write) .......................................................................................................34 0x28: FF_MT_SRC_2 Freefall and Motion Source 2 Register .....................................................................................34 0x28 FF_MT_SRC_2 Register (Read Only) ........................................................................................................34 0x29: FF_MT_THS_2 Freefall and Motion Threshold 2 Register ................................................................................34 0x29 FF_MT_THS_2 Register (Read/Write) .......................................................................................................34 0x2A: FF_MT_COUNT_2 Freefall and Motion Debounce 2 Register ..........................................................................34 0x2A FF_MT_COUNT_2 Register (Read/Write) .................................................................................................34 6.5 Transient Detection Registers ...................................................................................................................................34 0x2B: TRANSIENT_CFG Transient Configuration Register ........................................................................................34 0x2B TRANSIENT_ CFG Register (Read/Write) .................................................................................................34 Table 38. TRANSIENT_ CFG Description ................................................................................................................34 0x2C: TRANSIENT_SRC Transient Source Register ..................................................................................................34 0x2C TRANSIENT_SRC Register (Read Only) ..................................................................................................34 0x2D: TRANSIENT_THS Transient Threshold Register ..............................................................................................35 0x2D TRANSIENT_THS Register (Read/Write) ..................................................................................................35 Table 39. TRANSIENT_THS Description ..................................................................................................................35 0x2E: TRANSIENT_COUNT Transient Debounce Register ........................................................................................35 0x2E TRANSIENT_COUNT Register (Read/Write) ............................................................................................35 Table 40. TRANSIENT_COUNT Description ............................................................................................................35 Table 41. TRANSIENT_COUNT relationship with the ODR .....................................................................................35 Table 42. TRANSIENT_SRC Description .................................................................................................................35 6.6 Tap Detection Registers ...........................................................................................................................................36 0x2F: PULSE_CFG Pulse Configuration Register .......................................................................................................36 0x2F PULSE_CFG Register (Read/Write) ..........................................................................................................36 Table 43. PULSE_CFG Description ..........................................................................................................................36
MMA8450Q Sensors Freescale Semiconductor 4
0x30: PULSE_SRC Pulse Source Register .................................................................................................................36 0x30 PULSE_SRC Register (Read Only) ............................................................................................................36 Table 44. TPULSE_SRC Description ........................................................................................................................36 0x31 - 0x33: PULSE_THSX, Y, Z Pulse Threshold for X, Y & Z Registers ..................................................................37 0x31 PULSE_THSX Register (Read/Write) .........................................................................................................37 Table 45. PULSE_THSX Description ........................................................................................................................37 0x32 PULSE_THSY Register (Read/Write) .........................................................................................................37 Table 46. PULSE_THSY Description ........................................................................................................................37 0x33 PULSE_THSZ Register (Read/Write) .........................................................................................................37 Table 47. PULSE_THSZ Description ........................................................................................................................37 0x34: PULSE_TMLT Pulse Time Window 1 Register ..................................................................................................37 0x34 PULSE_TMLT Register (Read/Write) .........................................................................................................37 Table 48. Time Step for PULSE Time Limit at ODR and Power Mode .....................................................................37 0x35: PULSE_LTCY Pulse Latency Timer Register ....................................................................................................38 0x35 PULSE_LTCY Register (Read/Write) .........................................................................................................38 Table 49. Time Step for PULSE Latency at ODR and Power Mode .........................................................................38 0x36: PULSE_WIND Second Pulse Time Window Register ........................................................................................38 0x36 PULSE_WIND Register (Read/Write) .........................................................................................................38 Table 50. Time Step for PULSE Detection Window at ODR and Power Mode .........................................................38 6.7 Auto-Sleep Registers ................................................................................................................................................38 0x37: ASLP_COUNT Auto-Sleep Inactivity Timer Register .........................................................................................38 0x37 ASLP_COUNT Register (Read/Write) ........................................................................................................38 Table 51. ASLP_COUNT Description .......................................................................................................................38 Table 52. ASLP_COUNT Relationship with ODR .....................................................................................................39 0x38: CTRL_REG1 System Control 1 Register ...........................................................................................................39 0x38 CTRL_REG1 Register (Read/Write) ...........................................................................................................39 Table 53. CTRL_REG1 Description ..........................................................................................................................39 Table 54. Sleep Mode Poll Rate Description .............................................................................................................39 Table 55. System Output Data Rate Selection ..........................................................................................................39 Table 56. Full Scale Selection ...................................................................................................................................40 0x39: CTRL_REG2 System Control 2 Register ...........................................................................................................40 0x39 CTRL_REG2 Register (Read/Write) ...........................................................................................................40 Table 57. CTRL_REG2 Description ..........................................................................................................................40 0x3A: CTRL_REG3 Interrupt Control Register ............................................................................................................40 0x3A CTRL_REG3 Register (Read/Write) ..........................................................................................................40 Table 58. CTRL_REG3 Description ..........................................................................................................................41 0x3C: CTRL_REG5 Register (Read/Write) ..................................................................................................................41 0x3C CTRL_REG5 Register (Read/Write) ..........................................................................................................41 Table 59. interrupt Enable Register Description ........................................................................................................41 0x3C: CTRL_REG5 Interrupt Configuration Register ..................................................................................................42 0x3C CTRL_REG5 Register (Read/Write) ..........................................................................................................42 Table 60. Interrupt Configuration Register Description .............................................................................................42 6.8 User Offset Correction Registers ..............................................................................................................................42 0x3D: OFF_X Offset Correction X Register .................................................................................................................42 0x3D OFF_X Register (Read/Write) ....................................................................................................................42 Table 61. OFF_X Description ....................................................................................................................................42 0x3E: OFF_Y Offset Correction Y Register .................................................................................................................42 0x3E OFF_Y Register (Read/Write) ....................................................................................................................42 Table 62. OFF_Y Description ....................................................................................................................................42 0x3F: OFF_Z Offset Correction Z Register ..................................................................................................................42 0x3F OFF_Z Register (Read/Write) ....................................................................................................................42 Table 63. OFF_Z Description ....................................................................................................................................42 Appendix A ................................................................................................................................................................................43 Table 64. MMA8450Q Register Map .........................................................................................................................43 Table 65. Accelerometer Output Data .......................................................................................................................45 Appendix B ................................................................................................................................................................................46 Figure 13. Distribution of Pre Board Mounted Devices Tested in Sockets (1 count = 3.9 mg) .................................46 Figure 14. Distribution of Post Board Mounted Devices (1 count = 3.9 mg) .............................................................47 Figure 15. 8g Z-axis TCS ..........................................................................................................................................50 Figure 16. 8g X-axis TCO (mg/C) ............................................................................................................................51 Figure 17. 8g Y-axis TCO (mg/C) ............................................................................................................................52 Figure 18. 8g Z-axis TCO (mg/C) ............................................................................................................................53 Package Dimensions ............................................................................................................................................................... 54 MMA8450Q Sensors Freescale Semiconductor 5
Application Notes for Reference
The following is a list of Freescale Application Notes written for the MMA8450Q: * AN3915, Embedded Orientation Detection Using the MMA8450Q * AN3916, Offset Calibration of the MMA8450Q * AN3917, Motion and Freefall Detection Using the MMA8450Q * AN3918, High Pass Filtered Data and Transient Detection Using the MMA8450Q * AN3919, MMA8450Q Single/Double and Directional Tap Detection * AN3920, Using the 32 Sample First In First Out (FIFO) in the MMA8450Q * AN3921, Low Power Modes and Auto-Wake/Sleep Using the MMA8450Q * AN3922, Data Manipulation and Basic Settings of the MMA8450Q * AN3923, MMA8450Q Design Checklist and Board Mounting Guidelines
1
1.1
Block Diagram and Pin Description
Block Diagram
Internal OSC Clock GEN Embedded DSP Functions SDA SCL
VDD VSS
X-axis Transducer Y-axis Transducer Z-axis Transducer
C to V Converter
12-bit ADC
I2 C
32 Data Point Configurable FIFO Buffer with Watermark
Freefall and Motion Detection (2 channels)
Transient Detection (i.e., fast motion, jolt)
Enhanced Orientation with Hysteresis and Z-lockout
Shake Detection through Motion Threshold
Tap and Double Tap Detection
Auto-Wake/Auto-Sleep Configurable with debounce counter and multiple motion interrupts for control Normal Mode Low Power Mode
Active Mode
Auto-Wake Auto-Sleep
SLEEP Mode
(Reduced Sampling Rate)
Figure 1. Block Diagram
1.2
Pin Description
Z
X
1
13
1
Y
9
5
(TOP VIEW) DIRECTION OF THE DETECTABLE ACCLERATIONS
(BOTTOM VIEW)
Figure 2. Direction of the Detectable Accelerations MMA8450Q Sensors Freescale Semiconductor 6
1.8V
4.7F
16 1 2
NC
15
NC
14
VDD
VDD NC NC SCL
GND 13 GND
12 11 10 9
SDA
1.8V
SCL
1.8V
0.1F
3 4 5
MMA8450Q
INT1 GND
SDA
SA0
4.7k
4.7k
GND
EN
INT2
6
7
8
INT1 INT2 EN SA0
Figure 3. Application Diagram Table 1. Pin Description
Pin # Pin Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 VDD NC/GND NC/GND SCL GND SDA SA0 EN INT2 GND INT1 GND GND VDD NC NC Description Power Supply (1.8V only) Connect to Ground or Non Connection Connect to Ground or Non Connection I
2C
Pin Status Input Input Input Open Drain Input Open Drain Input Input Output Input Output Input Input Input Input Input
Serial Clock
Connect to Ground I2C Serial Data I2C Least Significant Bit of the Device Address (0: $1C 0: $1D) Device Enable (1: I2C Bus Enabled; 0: Shutdown Mode) Inertial Interrupt 2 Connect to Ground Inertial Interrupt 1 Connect to Ground Connect to Ground Power Supply (1.8V only) Internally not connected Internally not connected
When using MMA8450Q in applications, it is recommended that pin 1 and pin 14 (the VDD pins) be tied together. Power supply decoupling capacitors (100 nF ceramic plus 4.7 F bulk, or a single 4.7 F ceramic) should be placed as near as possible to the pins 1 and 5 of the device. The SDA and SCL I2C connections are open drain and therefore require a pull-up resistor as shown in Figure 3 Note: The above application diagram presents the recommended configuration for the MMA8450Q. For information on future products of this product family please review Freescale application note, AN3923, Design Checklist and Board Mounting Guidelines of the MMA8450Q.This application note details the small modifications between the MMA8450Q and the next generation products.
1.3
Soldering Information
The QFN package is compliant with the RoHS standard. Please refer to AN3923. MMA8450Q 7 Sensors Freescale Semiconductor
2
2.1
Mechanical and Electrical Specifications
Mechanical Characteristics
Parameter Test Conditions FS[1:0] set to 01 FS[1:0] set to 10 FS[1:0] set to 11 FS Symbol Min 1.8 3.6 7.2 0.878 So 1.758 3.515 TCSo Typ 2 4 8 0.976 1.953 3.906 0.05 Max 2.2 4.4 8.8 1.074 2.148 4.296 %/C mg/digit g Unit
Table 2. Mechanical Characteristics @ VDD = 1.8 V, T = 25C unless otherwise noted.
Full Scale Measurement Range
Sensitivity
FS[1:0] set to 01 FS[1:0] set to 10 FS[1:0] set to 11
Sensitivity Change vs. Temperature(1) Typical Zero-g Level Offset (2)
FS[1:0] set to 01 FS[1:0] set to 01 FS[1:0] set to 10 FS[1:0] set to 11
0g-Off
40
mg
Typical Zero-g Offset Post Board Mount (2), (3)
FS[1:0] set to 01 FS[1:0] set to 10 FS[1:0] set to 11 0g-OffBM 50 mg
Typical Zero-g Offset Change vs. Temperature Non Linearity Best Fit Straight Line
(2)
TCOff FS[1:0] set to 01 FS[1:0] set to 10 FS[1:0] set to 11 NL
0.5 0.25 0.5 1 -195
mg/C
% FS
Self-test Output
Change(4)
FS[1:0] set to 01, X-axis FS[1:0] set to 01, Y-axis FS[1:0] set to 01, Z-axis Vst
-195 +945
LSB
Output Noise Operating Temperature Range 1. 2. 3. 4.
Normal Mode ODR = 400 Hz
Noise Top -40
375 +85
g/Hz C
Before board mount. See appendix for distribution graphs. Post board mount offset specification are based on an 8 layer PCB. Self-test in one direction only. These are approximate values and can change by 100 counts.
MMA8450Q Sensors Freescale Semiconductor 8
Table 3. Electrical Characteristics @ VDD = 1.8 V, T = 25C unless otherwise noted.(1)
Parameter Supply Voltage Low Power Mode $39 CTRL_REG2: MOD[0]=1 EN = 1, ODR = 1.563 Hz EN = 1, ODR = 12.5 Hz EN = 1, ODR = 50 Hz EN = 1, ODR = 100 Hz EN = 1, ODR = 200 Hz EN = 1, ODR = 400 Hz Normal Mode $39 CTRL_REG2: MOD[0]=0 EN = 1, ODR = 1.563 Hz EN = 1, ODR = 12.5 Hz EN = 1, ODR = 50 Hz EN = 1, ODR = 100 Hz EN = 1, ODR = 200 Hz EN = 1, ODR = 400 Hz Current Consumption in Shutdown Mode Supply Current Drain in Standby Mode Digital High Level Input Voltage SCL, SDA, SA0, EN Digital Low Level Input Voltage SCL, SDA, SA0, EN High Level Output Voltage INT1, INT2 Low Level Output Voltage INT1, INT2 Low Level Output Voltage SDA Output Data Rate Signal Bandwidth Boot Time from EN = 1 to Boot Complete Turn-on time(1) IO = 500 A IO = 500 A IO = 500 A EN = 0 EN = 1 and FS[1:0] = 00 IddSdn IddStby VIH VIL VOH VOL VOLS ODR BW BT Ton 0.9*ODR ODR ODR/2 1.55 3/ODR 0.9*VDD 0.1*VDD 0.1*VDD 1.1*ODR 0.75*VDD 0.3*VDD Idd IddLP Test Conditions Symbol VDD Min 1.71 Typ 1.8 27 27 27 42 72 120 42 42 42 72 132 225 <1 3 A A V V V V V Hz Hz ms s A A Max 1.89 Unit V
2.2
Electrical Characteristics
1. Time to obtain valid data from Standby mode to Active mode.
MMA8450Q 9 Sensors Freescale Semiconductor
2.3
I2C Interface Characteristic
Parameter Symbol fSCL tBUF tHD;STA tSU;STA tSU;STO tHD;DAT tVD;DAT
(6)
Table 4. I2C Slave Timing Values(1)
I2C Standard Mode Min 0 4.7 4 4.7 4 0
(3) (4)
I2C Fast Mode Min 0 1.3 0.6 0.6 0.6 0
(3) (4)
Max 100
Max 400
Unit kHz s s s s s s s Ns s s
SCL Clock Frequency Bus Free Time between STOP and START Condition Repeated START Hold Time Repeated START Setup Time STOP Condition Setup Time SDA Data Hold Time SDA Valid Time
(5) (2)
3.45(4) 3.45(4) 250 4.7 4 1000 300 50 100
(7)
0.9(4) 0.9(4)
SDA Valid Acknowledge Time SDA Setup Time SCL Clock Low Time SCL Clock High Time SDA and SCL Rise Time SDA and SCL Fall Time
tVD;ACK tSU;DAT tLOW tHIGH tr tf tSP
1.3 0.6 20 + 0.1Cb 20 + 0.1Cb
(8) (8)
300 300 50
Ns Ns Ns
(3)(5)(8)(9)
Pulse width of spikes on SDA and SCL that must be suppressed by input filter
1. All values referred to VIH (min) and VIL (max) levels. 2. tHD;DAT is the data hold time that is measured from the falling edge of SCL, applies to data in transmission and the acknowledge. 3. A device must internally provide a hold time of at least 300 ns for the SDA signal (with respect to the VIH (min) of the SCL signal) to bridge the undefined region of the falling edge of SCL. 4. The maximum tHD;DAT could be 3.45 s and 0.9 s for Standard-mode and Fast-mode, but must be less than the maximum of tVD;DAT or tVD;ACK by a transition time. This maximum must only be met if the device does not stretch the LOW period (tLOW) of the SCL signal. If the clock stretches the SCL, the data must be valid by the set-up time before it releases the clock. 5. tVD;DAT = time for data signal from SCL LOW to SDA output (HIGH or LOW, depending on which one is worse). 6. tVD;ACK = time for Acknowledgement signal from SCL LOW to SDA output (HIGH or LOW, depending on which one is worse). 7. A Fast-mode I2C device can be used in a Standard-mode I2C system, but the requirement tSU;DAT 250 ns must then be met. This will automatically be the case if the device does not stretch the LOW period of the SCL signal. If such a device does stretch the LOW period of the SCL signal, it must output the next data bit to the SDA line tr(max) + tSU;DAT = 1000 + 250 = 1250 ns (according to the Standard-mode I2C specification) before the SCL line is released. Also the acknowledge timing must meet this set-up time. 8. Cb = total capacitance of one bus line in pF. 9. The maximum tf for the SDA and SCL bus lines is specified at 300 ns. The maximum fall time for the SDA output stage tf is specified at 250 ns. This allows series protection resistors to be connected in between the SDA and the SCL pins and the SDA/SCL bus lines without exceeding the maximum specified tf.
MMA8450Q Sensors Freescale Semiconductor 10
Figure 4. I2C Slave Timing Diagram
2.4
Absolute Maximum Ratings
Stresses above those listed as "absolute maximum ratings" may cause permanent damage to the device. Exposure to maximum rating conditions for extended periods may affect device reliability. Table 5. Maximum Ratings
Rating Maximum Acceleration (all axes, 100 s) Supply Voltage Input voltage on any control pin (SA0, EN, SCL, SDA) Drop Test Operating Temperature Range Storage Temperature Range Symbol gmax VDD Vin Ddrop TOP TSTG Value 10,000 -0.3 to +2 -0.3 to VDD + 0.3 1.8 -40 to +85 -40 to +125 Unit g V V M C C
Table 6. ESD and Latch-Up Protection Characteristics
Rating Human Body Model Machine Model Charge Device Model Latch-up Current at T = 85C Symbol HBM MM CDM -- Value 2000 200 500 100 Unit V V V mA
This device is sensitive to mechanical shock. Improper handling can cause permanent damage of the part or cause the part to otherwise fail. This is an ESD sensitive, improper handling can cause permanent damage to the part.
MMA8450Q 11 Sensors Freescale Semiconductor
3
3.1
Terminology
Sensitivity
Sensitivity describes the gain of the sensor and can be determined by applying a g acceleration to it, such as the earth's gravitational field. The sensitivity of the sensor can be determined by subtracting the -1g acceleration value from the +1g acceleration value and dividing by two.
3.2
Zero-g Offset
Zero-g Offset (TyOff) describes the deviation of an actual output signal from the ideal output signal if no acceleration is present. A sensor in a steady state on a horizontal surface will measure 0g in X-axis and 0g in Y-axis whereas the Z-axis will measure 1g. The output is ideally in the middle of the dynamic range of the sensor (content of OUT registers 0x00, data expressed as 2's complement number). A deviation from ideal value in this case is called Zero-g offset. Offset is to some extent a result of stress on the MEMS sensor and therefore the offset can slightly change after mounting the sensor onto a printed circuit board or exposing it to extensive mechanical stress.
3.3
Self-Test
Self-Test checks the transducer functionality without external mechanical stimulus. When Self-Test is activated, an electrostatic actuation force is applied to the sensor, simulating a small acceleration. In this case the sensor outputs will exhibit a change in their DC levels which are related to the selected full scale through the device sensitivity. When Self-Test is activated, the device output level is given by the algebraic sum of the signals produced by the acceleration acting on the sensor and by the electrostatic test-force.
4
Modes of Operation
VDD = OFF EN = VDD & VDD = ON
= EN GN D
OFF Mode
STANDBY Mode (00)
VDD = OFF
EN = GND VDD = ON
= EN
VD
D=
OF
F
FS = 0
D VD
SHUTDOWN Mode
EN = GND
WAKE Mode (01)
SLEEP Mode (10)
Figure 5. MMA8450Q Mode Transition Diagram Table 7. Mode of Operation Description
Mode OFF SHUTDOWN I2C Bus State Powered Down I2C communication ignored I2C communication possible STANDBY ON VDD <1.5 V ON EN ACTIVE
I2C communication possible
ON
EN = VDD Standby register reset
All register contents are preserved when transitioning from Active to Standby mode. Some registers are reset when transitioning from Standby to Active. These are all noted in the device memory map register table. For more detail on how to use the Sleep and Wake modes and how to transition between these modes, please refer to the functionality section of this document.
MMA8450Q Sensors Freescale Semiconductor 12
5
Functionality
The MMA8450Q is a low-power, digital output 3-axis linear accelerometer packaged in a QFN package. The complete device includes a sensing element and an IC interface able to take the information from the sensing element and to provide a signal to the external world through an I2C serial interface. There are many embedded features in this accelerometer with a very flexible interrupt routing scheme to 2 interrupt pins including: * 8-bit or 12-bit data, high pass filtered data, 8-bit or 12-bit configurable 32 sample FIFO * Low power and Auto-Wake/ Sleep for conservation of current consumption * Single and double pulse detection 1 channel * Motion detection and Freefall 2 channels * Transient detection based on a high pass filter and settable threshold for detecting the change in acceleration above a threshold * Flexible user configurable portrait landscape detection algorithm addressing many use cases for screen orientation All functionality is available in 2g, 4g or 8g dynamic ranges. There are many configuration settings for enabling all the different functions. Separate application notes have been provided to help configure the device for each embedded functionality.
5.1
Device Calibration
The IC interface is factory calibrated for sensitivity and zero-g offset for each axis. The trim values are stored in Non Volatile Memory (NVM). On power-up, the trim parameters are read from NVM and applied to the circuitry. In normal use, further calibration in the end application is not necessary. However, the MMA8450Q allows the user to adjust the zero-g offset for each axis after power-up, changing the default offset values. The user offset adjustments are stored in 6 volatile registers. For more information on device calibration, refer to Freescale application note, AN3916.
5.2
8-bit or 12-bit Data
The measured acceleration data is stored in the OUTX_MSB, OUTX_LSB, OUTY_MSB, OUTY_LSB, OUTZ_MSB, and OUTZ_LSB registers as 2's complement 12-bit numbers. The most significant 8-bits of each axis are stored in OUT_X (Y, Z)_MSB, so applications needing only 8-bit results can use these 3 registers and ignore OUT_X(Y, Z)_LSB. When the full-scale is set to 2g, the measurement range is -2g to +1.999g, and each LSB corresponds to 1g/1024 (0.98 mg) at 12-bits resolution. When the full-scale is set to 8g, the measurement range is -8g to +7.996g, and each LSB corresponds to 1g/256 (3.9 mg) at 12-bits resolution. The resolution is reduced by a factor of 16 if only the 8-bit results are used. For more information on the data manipulation between data formats and modes, refer to Freescale application note, AN3922. There is a device driver available that can be used with the Sensor Toolbox demo board (LFSTBEB8450Q) with this application note.
5.3
Internal FIFO Data Buffer
MMA8450Q contains a 32 sample internal FIFO data buffer minimizing traffic across the I2C bus. The FIFO can also provide power savings of the system by allowing the host processor/MCU to go into a sleep mode while the accelerometer independently stores the data, up to 32 samples per axis. The FIFO can run at all output data rates. There is the option of accessing the full 12bit data for accessing only the 8-bit data. When access speed is more important than high resolution the 8-bit data flush is a better option. The FIFO contains three modes (Fill Buffer Mode, Circular Buffer Mode, and Disabled) described in the F_SETUP Register 0x13. Fill Buffer Mode collects the first 32 samples and asserts the overflow flag when the buffer is full. It does not collect anymore data until the buffer is read. This benefits data logging applications where all samples must be collected. The Circular Buffer Mode allows the buffer to be filled and then new data replaces the oldest sample in the buffer. The most recent 32 samples will be stored in the buffer. This benefits situations where the processor is waiting for an specific interrupt to signal that the data must be flushed to analyze the event. The MMA8450Q FIFO Buffer also has a configurable watermark, allowing the processor to be interrupted after a configurable number of samples has filled in the buffer (1 to 32). For details on the configurations for the FIFO Buffer as well as more specific examples and application benefits, refer to Freescale application note, AN3920.
5.4
Low Power Mode
The MMA8450Q can be set to a low power mode option to further reduce the current consumption of the device. When the Low Power Mode is enabled, the device has access to all the configurable sampling rates and features as is available in the Normal power mode. To set the device into Low Power Mode, bit 0 in the System Control Register 2 (0x39) should be set (1) (this bit is cleared (0) for Normal Power Mode). Low Power Mode reduces the current consumption by internally sleeping longer and averaging the data less. The Low Power Mode is an additional feature that is independent of the sleep feature.The sleep feature can also be used to reduce the current consumption by automatically changing to a lower sample rate when no activity is detected. For more information on how to configure the MMA8450Q in Low Power Mode and the power consumption benefits of Low Power Mode and Auto-Wake/Sleep with specific application examples, refer to Freescale application note, AN3921. MMA8450Q 13 Sensors Freescale Semiconductor
5.5
Auto-Wake/Sleep Mode
The MMA8450Q can be configured to transition between sample rates (with their respective current consumption) based on five of the interrupt functions of the device. The advantage of using the Auto-Wake/Sleep is that the system can automatically transition to a higher sample rate (higher current consumption) when needed but spends the majority of the time in the Sleep Mode (lower current) when the device does not require higher sampling rates. Auto-Wake refers to the device being triggered by one of the interrupt functions to transition to a higher sample rate. This may also interrupt the processor to transition from a sleep mode to a higher power mode. Sleep Mode occurs after the accelerometer has not detected an interrupt for longer than the user definable time-out period. The device will transition to the specified lower sample rate. It may also alert the processor to go into a lower power mode to save on current during this period of inactivity. The Interrupts that can wake the device from sleep are the following: Tap Detection, Orientation Detection, Motion/Freefall1, Motion/Freefall2, and Transient Detection. The FIFO can be configured to hold the data in the buffer until it is flushed if the FIFO Gate bit is set in Register 0x3A but the FIFO cannot wake the device from sleep. The interrupts that can keep the device from falling asleep are the same interrupts that can wake the device with the addition of the FIFO. If the FIFO interrupt is enabled and data is being accessed continually servicing the interrupt then the device will remain in the wake mode. Refer to AN3921, for more detailed information for configuring the Auto-Wake/Sleep and for application examples of the power consumption savings.
5.6
Freefall and Motion Detection
MMA8450Q has flexible interrupt architecture for detecting Freefall and Motion with the two Motion/Freefall interrupt functions available. With two configurable interrupts for Motion and Freefall, one interrupt can be configured to detect a linear freefall while the other can be configured to detect a spin motion. The combination of these two events can be routed to separate interrupts or to the same interrupt pin to detect tumble which is the combination of spin with freefall. For details on the advantages of having the two embedded functions of Freefall and Motion detection with specific application examples with recommended configuration settings, refer to Freescale application note AN3917.
5.6.1
Freefall Detection
The detection of "Freefall" involves the monitoring of the X, Y, and Z axes for the condition where the acceleration magnitude is below a user specified threshold for a user definable amount of time. Normally the usable threshold ranges are between 0 mg and 500 mg.
5.6.2
Motion Detection
There are two programmable functions for motion (MFF1 and MFF2). Motion is configured using the high-g mechanism. Motion is often used to simply alert the main processor that the device is currently in use. When the acceleration exceeds a set threshold the motion interrupt is asserted. A motion can be a fast moving shake or a slow moving tilt. This will depend on the threshold and timing values configured for the event. The motion detection function can analyze static acceleration changes or faster jolts. For example, to detect that an object is spinning, all three axes would be enabled with a threshold detection of > 2g. This condition would need to occur for a minimum of 100 ms to ensure that the event wasn't just noise. The timing value is set by a configurable debounce counter. The debounce counter acts like a filter to determine whether the condition exists for configurable set of time (i.e., 100 ms or longer).
5.7
Transient Detection
The MMA8450Q has a built in high pass filter. Acceleration data goes through the high pass filter, eliminating the offset (DC) and low frequencies. The high pass filter cut-off frequency can be set by the user to four different frequencies which are dependent on the Output Data Rate (ODR). A higher cut-off frequency ensures the DC data or slower moving data will be filtered out, allowing only the higher frequencies to pass. The embedded Transient Detection function uses the high pass filtered data allowing the user to set the threshold and debounce counter. Many applications use the accelerometer's static acceleration readings (i.e., tilt) which measure the change in acceleration due to gravity only. These functions benefit from acceleration data being filtered from a low pass filter where high frequency data is considered noise. However, there are many functions where the accelerometer must analyze dynamic acceleration. Functions such as tap, flick, shake and step counting are based on the analysis of the change in the acceleration. It is simpler to interpret these functions dependent on dynamic acceleration data when the static component has been removed. The Transient Detection function can be routed to either interrupt pin through bit 5 in CTRL_REG5 Register (0x3C). Registers 0x2B - 0x2E are the dedicated Transient Detection configuration registers. For details on the benefits of the embedded Transient Detection function along with specific application examples and recommended configuration settings, please refer to Freescale application note, AN3918.
MMA8450Q Sensors Freescale Semiconductor 14
5.8
Orientation Detection
The MMA8450Q incorporates an advanced algorithm for orientation detection (ability to detect all 6 orientations including portrait/landscape) with a large amount of configuration available to provide extreme flexibility to the system designer. The configurability also allows for the function to work differently for various modes of the end system. For example, the MMA8450Q Orientation Detection allows up to 10 selectable trip angles for Portrait-to-Landscape, up to10 selectable trip angles for the transition for Landscape-to-Portrait, and 4 selectable front/back trip angles. Typically the desired hysteresis angle is 15 from a 45 trip reference point, resulting in |30| and |60| trip points. The algorithm is robust enough to handle typical process variation and uncompensated board mount offset, however, it may result in slight angle variations. The MMA8450Q Orientation Detection algorithm confirms the reliability of the function with a configurable Z-lock out angle. Based on known functionality of linear accelerometers, it is not possible to rotate the device about the Z-axis to detect change in acceleration at slow angular speeds. The angle at which the image no longer detects the orientation change is referred to as the "Z-Lock- out angle". The MMA8450Q Orientation Detection function has eight selectable1g-lockout thresholds; and there are 8 different settings for the Z-Angle lockout. The Orientation Detection function also considers when a device is experiencing acceleration above a set threshold not typical of orientation changes (i.e., When a person is jogging or due to acceleration changes from being on a bus or in a car). The screen orientation should not interpret this as a change and the screen should lock in the last known valid position. This added feature, called the 1g Lockout Threshold, enhances the Orientation Detection function and confirms the reliability of the algorithm for the system. The MMA8450Q allows for configuring the 1g Lockout Threshold from 1g up to 1.35g (in increments of 0.05g). For further information on the highly configurable embedded Orientation Detection Function, including recommendations for configuring the device to support various application use cases, refer to Freescale application note, AN3915. Figure 6 and Figure 7 show the definitions of the trip angles going from Landscape-to-Portrait and then also from Portrait-toLandscape.
PORTRAIT 90
PORTRAIT 90
Landscape-to-Portrait Trip Angle = 60 Portrait-to-Landscape Trip Angle = 60
0 Landscape
0 Landscape
Figure 6. Illustration of Landscape-to-Portrait Transition
Figure 7. Illustration of Portrait-to-Landscape Transition
Figure 8 illustrates the Z-angle lockout region. When lifting the device up from the flat position it will be active for orientation detection as low as 25 from flat. This is user configurable. The default angle is 32 but it can be set as low as 25.
PORTRAIT 90
NORMAL DETECTION REGION
ZLOCK = 32.142
LOCKOUT REGION
0 Landscape
Figure 8. Illustration of Z-Tilt Angle Lockout Transition MMA8450Q 15 Sensors Freescale Semiconductor
Figure 9 shows the device configuration in the 6 different orientation modes. These orientations are defined as the following: PU = Portrait UP, LR = Landscape Right, PD = Portrait Down, LL = Landscape Left, Back and Front.
Top View
PU
Pin 1 Earth Gravity Side View
LL Xout @ 0g Yout @ -1g Zout @ 0g LR BACK
Xout @ 0g Yout @ 0g Zout @ -1g PD Xout @ -1g Yout @ 0g Zout @ 0g Xout @ 1g Yout @ 0g Zout @ 0g FRONT
Xout @ 0g Yout @ 0g Zout @ 1g Xout @ 0g Yout @ 1g Zout @ 0g
Figure 9. Landscape/Portrait Orientation There are several registers to configure the orientation detection and are described in detail in the register setting section.
5.9
Interrupt Register Configurations
There are eight configurable interrupts in the MMA8450Q. These are Auto-Sleep, Data Ready, Motion/Freefall 1, Motion/ Freefall 2, Transient, Orientation Detection, Tap Detection and the FIFO events. These eight interrupt sources can be routed to one of two interrupt pins. The interrupt source must be enabled and configured. If the event flag is asserted because the event condition is detected, the corresponding interrupt pin, INT1 or INT2, will assert.
Func_En Func_En Func_En Func_En Func_En Func_En Func_En Auto-Sleep FIFO Transient Detect Orientation Detect Pulse Detect Freefall/Motion Data Ready
Event Flag 0 Event Flag 1 Event Flag 2 Event Flag 3 Event Flag 4 Event Flag 5 Event Flag 6 Event Flag 7
INT1
INTERRUPT CONTROLLER INT2
8 INT_ENABLE
8 INT_CFG
Figure 10. System Interrupt Generation Block Diagram
MMA8450Q Sensors Freescale Semiconductor 16
5.10
Serial I2C Interface
Acceleration data may be accessed through an I2C interface thus making the device particularly suitable for direct interfacing with a microcontroller. The MMA8450Q features an interrupt signal which indicates when a new set of measured acceleration data is available thus simplifying data synchronization in the digital system that uses the device. The MMA8450Q may also be configured to generate other interrupt signals accordingly to the programmable embedded functions of the device for Motion, Freefall, Transient, Orientation, and Tap. The registers embedded inside MMA8450Q are accessed through an I2C serial interface. To enable the I2C interface, the EN pin (pin 8) must be tied high. When EN is tied low, MMA8450Q is put into low power shutdown mode and communications on the I2C interface are ignored. The MMA8450Q is always in slave mode. The I2C interface may be used for communications between other I2C devices when EN is tied low and the MMA8450Q does not clamp the I2C bus. Table 8. Serial Interface Pin Description
Pin Name EN SCL SDA SA0 Pin Description Device enable (1: I2C mode enabled; 0: Shutdown mode) I2C Serial Clock I2C Serial Data I2C least significant bit of the device address
There are two signals associated with the I2C bus; the Serial Clock Line (SCL) and the Serial Data line (SDA). The latter is a bidirectional line used for sending and receiving the data to/from the interface. External 4.7 k pull-up resistors connected to VDD are expected for SDA and SCL. When the bus is free both the lines are high. The I2C interface is compliant with fast mode (400 kHz), and normal mode (100 kHz) I2C standards (Table 4).
5.10.1
I2C Operation
The transaction on the bus is started through a start condition (START) signal. START condition is defined as a HIGH to LOW transition on the data line while the SCL line is held HIGH. After START has been transmitted by the Master, the bus is considered busy. The next byte of data transmitted after START contains the slave address in the first 7 bits, and the eighth bit tells whether the Master is receiving data from the slave or transmitting data to the slave. When an address is sent, each device in the system compares the first seven bits after a start condition with its address. If they match, the device considers itself addressed by the Master. The 9th clock pulse, following the slave address byte (and each subsequent byte) is the acknowledge (ACK). The transmitter must release the SDA line during the ACK period. The receiver must then pull the data line low so that it remains stable low during the high period of the acknowledge clock period. The number of bytes transferred per transfer is unlimited. If a receiver can't receive another complete byte of data until it has performed some other function, it can hold the clock line, SCL low to force the transmitter into a wait state. Data transfer only continues when the receiver is ready for another byte and releases the data line. This delay action is called clock stretching. A LOW to HIGH transition on the SDA line while the SCL line is high is defined as a stop condition (STOP). A data transfer is always terminated by a STOP. A Master may also issue a repeated START during a data transfer. The MMA8450Q expects repeated STARTs to be used to randomly read from specific registers. The MMA8450Q's standard slave address is a choice between the two sequential addresses 0011100 and 0011101. The selection is made by the high and low logic level of the SA0 (pin 7) input respectively. The slave addresses are factory programmed and alternate addresses are available at customer request. The format is shown in Table 9. Table 9. I2C Address Selection Table
Slave Address (SA0 = 0) 0011100 Slave Address (SA0 = 1) 0011101 Comment Factory Default
Single Byte Read
The MMA8450Q has an internal ADC that can sample, convert and return sensor data on request. The transmission of an 8bit command begins on the falling edge of SCL. After the eight clock cycles are used to send the command, note that the data returned is sent with the MSB first once the data is received. Figure 11 shows the timing diagram for the accelerometer 8-bit I2C read operation. The Master (or MCU) transmits a start condition (ST) to the MMA8450Q, slave address ($1D), with the R/W bit set to "0" for a write, and the MMA8450Q sends an acknowledgement. Then the Master (or MCU) transmits the address of the register to read and the MMA8450Q sends an acknowledgement. The Master (or MCU) transmits a repeated start condition (SR) and then addresses the MMA8450Q ($1D) with the R/W bit set to "1" for a read from the previously selected register. The Slave then acknowledges and transmits the data from the requested register. The Master does not acknowledge (NAK) it received the transmitted data, but transmits a stop condition to end the data transfer. MMA8450Q 17 Sensors Freescale Semiconductor
Multiple Byte Read
When performing a multi-byte read or "burst read", the MMA8450Q automatically increments the received register address commands after a read command is received. Therefore, after following the steps of a single byte read, multiple bytes of data can be read from sequential registers after each MMA8450Q acknowledgment (AK) is received until a NACK is received from the Master followed by a stop condition (SP) signaling an end of transmission.
Single Byte Write
To start a write command, the Master transmits a start condition (ST) to the MMA8450Q, slave address ($1D) with the R/W bit set to "0" for a write, the MMA8450Q sends an acknowledgement. Then the Master (MCU) transmits the address of the register to write to, and the MMA8450Q sends an acknowledgement. Then the Master (or MCU) transmits the 8-bit data to write to the designated register and the MMA8450Q sends an acknowledgement that it has received the data. Since this transmission is complete, the Master transmits a stop condition (SP) to the data transfer. The data sent to the MMA8450Q is now stored in the appropriate register.
Multiple Byte Write
The MMA8450Q automatically increments the received register address commands after a write command is received. Therefore, after following the steps of a single byte write, multiple bytes of data can be written to sequential registers after each MMA8450Q acknowledgment (ACK) is received. Table 10. I2C device Address Sequence
Command Read Write Read Write < Single Byte Read >
Master ST Device Address [6:0] W Register Address [7:0] SR Device Address [6:0] R NAK SP
[6:1] Device Address 001110 001110 001110 001110
[0] SA0 0 0 1 1
[6:0] Device Address 0x1C 0x1C 0x1D 0x1D
R/W 1 0 1 0
8-bit Final Value 0x39 0x38 0x3B 0x3A
Slave
AK
AK
AK
Data [7:0]
< Multiple Byte Read >
Master ST Device Address [6:0] W Register Address [7:0] SR Device Address [6:0] R AK
Slave
AK
AK
AK
Data [7:0]
Master
AK
AK
NAK
SP
Slave
Data [7:0]
Data [7:0]
Data [7:0]
< Single Byte Write >
Master ST Device Address [6:0] W Register Address [7:0] Data [7:0] SP
Slave
AK
AK
AK
< Multiple Byte Write >
Master ST Device Address [6:0] W Register Address [7:0] Data [7:0] Data [7:0]
Slave
Legend ST: Start Condition SR: Repeated Start Condition
AK
AK
AK
AK
SP: Stop Condition AK: Acknowledge
NAK: No Acknowledge R: Read = 1
W: Write = 0
Figure 11. I2C Timing Diagram MMA8450Q Sensors Freescale Semiconductor 18
6
Register Descriptions
Table 11 is the memory map of the MMA8450Q.The user has access to all addresses from 0x00 to 0x3F.
Table 11. Register Address Map
Name Type Register Address 0x00 Auto-Increment Address 0x01 Default Comment Addresses 0x00, 0x04, 0x0B are aliases to the same register. Data Ready status information or FIFO status information. [7:0] are 8 MSBs of 12-bit real-time sample. Root pointer to XYZ FIFO 8-bit data.
STATUS(1)(2)
R
00000000
OUT_X_MSB(1)(2) OUT_Y_MSB(1)(2) OUT_Z_MSB
(1)(2)
R R R R
0x01 0x02 0x03 0x04
0x02 0x03 0x00 0x05
0x01
output output output 00000000
[7:0] are 8 MSBs of 12-bit real-time sample [7:0] are 8 MSBs of 12-bit real-time sample Addresses 0x00, 0x04, 0x0B are aliases to the same register. Data Ready status information or FIFO status information. [3:0] are 4 LSBs of 12-bit sample. Root pointer to XYZ FIFO 12-bit data.
STATUS(1)(2)
OUT_X_LSB(1)(2) OUT_X_MSB(1)(2) OUT_Y_LSB
(1)(2) (1)(2)
R R R R R R R R R R R R R R R/W R R R/W R/W R R
0x05 0x06 0x07 0x08 0x09 0x0A 0x0B 0x0C 0x0D 0x0E 0x0F 0x10 0x11 0x12 0x13 0x14 0x15 0x16 0x17 0x18 0x19
0x06 0x07 0x08 0x09 0x0A 0x04 0x0C 0x0D 0x0E 0x0B 0xC6 0x11 0x11 0x12 0x14 0x15 0x16 0x17 0x18 0x19 0x1A
0x05
output output output output output output 00000000 output output output 11000110 00000000 Output Output 00000000 Output Output 00000000 00000000 00000000 00000000
[7:0] are 8 MSBs of 12-bit real-time sample [3:0] are 4 LSBs of 12-bit real-time sample [7:0] are 8 MSBs of 12-bit real-time sample [3:0] are 4 LSBs of 12-bit real-time sample [7:0] are 8 MSBs of 12-bit real-time sample Addresses 0x00, 0x04, 0x0B are aliases to the same register. Data Ready status information or FIFO status information. 8-bit AC X-axis data 8-bit AC Y-axis data 8-bit AC Z-axis data NWM Programmable Fixed Device ID No. FIFO Status: No FIFO event Detected FIFO status and 8-bit samples FIFO status and 12-bit samples FIFO setup Current System Mode Interrupt status Acceleration data event flag configuration Cutoff frequency is set to 4Hz @ 400Hz Landscape/Portrait orientation status Landscape/Portrait previous orientation Landscape/Portrait configuration. 1g Lockout offset is set to default value of 1.15g. Debounce counters are clear during invalid sequence condition. Landscape/Portrait debounce counter Back-Front Trip threshold is 75. Z-Lockout angle is 32.14 Portrait-to-Landscape Trip Angle is 30
OUT_Y_MSB OUT_Z_LSB
(1)(2) (1)(2)
OUT_Z_MSB
STATUS(1)(2) OUT_X_DELTA(1)(2) OUT_Y_DELTA(1)(2) OUT_Z_DELTA(1)(2) WHO_AM_I(1) F_STATUS(1)(2) F_8DATA(1)(2) F_12DATA(1)(2) F_SETUP(1)(3) SYSMOD(1)(2) INT_SOURCE(1)(2) XYZ_DATA_CFG(1)(4) HP_FILTER_CUTOFF1,3 PL_STATUS(1)(2) PL_PRE_STATUS(1)(2)
PL_CFG(1)(4)
R/W
0x1A
0x1B
10000011
PL_COUNT(1)(3) PL_BF_ZCOMP(1)(4) PL_P_L_THS_REG1(1)(4)
R/W R/W R/W
0x1B 0x1C 0x1D
0x1C 0x1D 0x1E
00000000 00000010 00011010
MMA8450Q 19 Sensors Freescale Semiconductor
Table 11. Register Address Map
PL_P_L_THS_REG2(1)(4) PL_P_L_THS_REG3 PL_L_P_THS_REG1 PL_L_P_THS_REG2 PL_L_P_THS_REG3 FF_MT_CFG_1 FF_MT_SRC_1 FF_MT_THS_1
(1)(4) (1)(4) (1)(4) (1)(4)
R/W R/W R/W R/W R/W R/W R R/W R/W R/W R R/W R/W R/W R R/W R/W R/W R R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W
0x1E 0x1F 0x20 0x21 0x22 0x23 0x24 0x25 0x26 0x27 0x28 0x29 0x2A 0x2B 0x2C 0x2D 0x2E 0x2F 0x30 0x31 0x32 0x33 0x34 0x35 0x36 0x37 0x38 0x39 0x3A 0x3B 0x3C 0x3D 0x3E 0x3F
0x1F 0x20 0x21 0x22 0x23 0x24 0x25 0x26 0x27 0x28 0x29 0x2A 0x2B 0x2C 0x2D 0x2E 0x2F 0x30 0x31 0x32 0x33 0x34 0x35 0x36 0x37 0x38 0x39 0x3A 0x3B 0x3C 0x3D 0x3E 0x3F 0x0F
00100010 11010100 00101101 01000001 10100010 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
Portrait-to-Landscape Trip Angle is 30 Portrait-to-Landscape Trip Angle is 30 Landscape-to-Portrait Trip Angle is 60 Landscape-to-Portrait Trip Angle is 60 Landscape-to-Portrait Trip Angle is 60 Freefall/Motion1 configuration Freefall/Motion1 event source register Freefall/Motion1 threshold register Freefall/Motion1 debounce counter Freefall/Motion2 configuration Freefall/Motion2 event source register Freefall/Motion2 threshold register Freefall/Motion2 debounce counter Transient configuration Transient event status register Transient event threshold Transient debounce counter ELE, Double_XYZ or Single_XYZ EA, Double_XYZ or Single_XYZ X and Y pulse threshold Z pulse threshold Z pulse threshold Time limit for pulse Latency time for 2nd pulse Window time for 2nd pulse Counter setting for auto-sleep ODR = 400Hz, Standby Mode. ST = Disabled, SLPE = Disabled, MODS = normal mode. IPOL, PP_OD Interrupt enable register Interrupt pin (INT1/INT2) map configuration X-axis offset adjust Y-axis offset adjust Z-axis offset adjust
(1)(4) (1)(2)
(1)(3) (1)(3)
FF_MT_COUNT_1 FF_MT_CFG_2 FF_MT_SRC_2 FF_MT_THS_2
(1)(4) (1)(2)
(1)(3) (1)(3)
FF_MT_COUNT_2 TRANSIENT_CFG TRANSIENT_SRC TRANSIENT_THS
(1)(4) (1)(2)
(1)(3) (1)(3)
TRANSIENT_COUNT PULSE_CFG PULSE_SRC
(1)(4) (1)(2) (1)(3) (1)(3)
PULSE_THSX PULSE_THSY PULSE_THSZ PULSE_TMLT PULSE_LTCY
(1)(3) (1)(4)
(1)(4) (1)(4) (1)(4)
PULSE_WIND
ASLP_COUNT CTRL_REG1
(1)(4)
CTRL_REG2(1)(4) CTRL_REG3(1)(4) CTRL_REG4(1)(4) CTRL_REG5(1)(4) OFF_X(1)(4) OFF_Y(1)(4) OFF_Z(1)(4) 1. 2. 3. 4.
Register contents are preserved when transition from "ACTIVE" to "STANDBY" mode occurs. Register contents are reset when transition from "STANDBY" to "ACTIVE" mode occurs. Modification of this register's contents can only occur when device is "STANDBY" mode Register contents can be modified anytime in "STANDBY" or "ACTIVE" mode. A write to this register will cause a reset of the corresponding internal system debounce counter.
Note: Auto-increment addresses which are not a simple increment are highlighted in bold. The auto-increment addressing is only enabled when device registers are read using I2C burst read mode. Therefore the internal storage of the auto-increment address is clear whenever a stop-bit is detected.
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6.1
Data Registers
The following are the data registers for the MMA8450Q. For more information on data manipulation of the MMA8450Q, refer to application note, AN3922. 0x00, 0x04, 0x0B: STATUS Registers
.
Alias for DR_Status (0x0B) or F_Status (0x10) (Read Only) FDE (FIFO Data Enable Bit 7, Reg 0x16) Setting FDE = 0 FDE = 1 Alias Status 0x00 = 0x04 = DR_STATUS (0x0B) 0x00 = 0x04 = F_STATUS (0x10)
When FDE bit found in register 0x16 (XYZ_DATA_CFG), bit 7 is cleared (the FIFO is not on) register 0x00, 0x04 and 0x0B should all be the same value and reflect the real-time status information of the X, Y and Z sample data. When FDE is set (the FIFO is on) Register 0x00, 0x04 and 0x10 will have the same value and 0x0B will reflect the status of the transient data. The aliases allow the STATUS register to be read easily before reading the current 8-bit, 12-bit, or FIFO sample data using the register address auto-incrementing mechanism.
0X00, 0X04, 0X0B STATUS: Data Status Registers (Read Only) Bit 7 ZYXOW Bit 6 ZOW Bit 5 YOW Bit 4 XOW Bit 3 ZYXDR Bit 2 ZDR Bit 1 YDR Bit 0 XDR
Table 12. STATUS Description
ZYXOW X, Y, Z-axis Data Overwrite. Default value: 0 0: No data overwrite has occurred 1: Previous X, Y, or Z data was overwritten by new X, Y, or Z data before it was read Z-axis Data Overwrite. Default value: 0 0: No data overwrite has occurred 1: Previous Z-axis data was overwritten by new Z-axis data before it was read Y-axis Data Overwrite. Default value: 0 0: No data overwrite has occurred 1: Previous Y-axis data was overwritten by new Y-axis data before it was read X-axis Data Overwrite. Default value: 0 0: No data overwrite has occurred 1: Previous X-axis data was overwritten by new X-axis data before it was read X, Y, Z-axis new Data Ready. Default value: 0 0: No new set of data ready 1: A new set of data is ready Z-axis new Data Available. Default value: 0 0: No new Z-axis data is ready 1: A new Z-axis data is ready Z-axis new Data Available. Default value: 0 0: No new Y-axis data ready 1: A new Y-axis data is ready Z-axis new Data Available. Default value: 0 0: No new X-axis data ready 1: A new X-axis data is ready
ZOW
YOW
XOW
ZYXDR
ZDR
YDR
XDR
ZYXOW is set whenever a new acceleration data is produced before completing the retrieval of the previous set. This event occurs when the content of at least one acceleration data register (i.e., OUTX, OUTY, OUTZ) has been overwritten. ZYXOW is cleared when the high-bytes of the acceleration data (OUTX_MSB, OUTY_MSB, OUTZ_MSB) of all the active channels are read. ZOW is set whenever a new acceleration sample related to the Z-axis is generated before the retrieval of the previous sample. When this occurs the previous sample is overwritten. ZOW is cleared anytime OUTZ_MSB register is read. YOW is set whenever a new acceleration sample related to the Y-axis is generated before the retrieval of the previous sample. When this occurs the previous sample is overwritten. YOW is cleared anytime OUTY_MSB register is read. XOW is set whenever a new acceleration sample related to the X-axis is generated before the retrieval of the previous sample. When this occurs the previous sample is overwritten. XOW is cleared anytime OUTX_MSB register is read. ZYXDR signals that a new sample for any of the enabled channels is available. ZYXDR is cleared when the high-bytes of the acceleration data (OUTX_MSB, OUTY_MSB, OUTZ_MSB) of all the enabled channels are read. ZDR is set whenever a new acceleration sample related to the Z-axis is generated. ZDR is cleared anytime OUTZ_MSB register is read. In order to enable the monitoring and assertion of this bit, the ZDR bit requires the Z-axis event detection flag to be enabled (bit ZDEFE = 1 inside XYZ_DATA_CFG register).
MMA8450Q 21 Sensors Freescale Semiconductor
YDR is set whenever a new acceleration sample related to the Y-axis is available. YDR is cleared anytime OUTY_MSB register is read. In order to enable the monitoring and assertion of this bit, the YDR bit requires the Y-axis event detection flag to be enabled (bit YDEFE = 1 inside XYZ_DATA_CFG register). XDR is set to 1 whenever a new acceleration sample related to the X-axis is available. XDR is cleared anytime OUTX_MSB register is read. In order to enable the monitoring and assertion of this bit, the XDR bit requires the X-axis to event detection flag to be enabled (bit XDEFE = 1 inside XYZ_DATA_CFG register). The ZDR and ZOW flag generation requires the Z-axis event flag generator to be enabled (ZDEFE = 1) in the XYZ_DATA_CFG register. The YDR and YOW flag generation requires the Y-axis event flag generator to be enabled (YDEFE = 1) in the XYZ_DATA_CFG register. The XDR and XOW flag generation requires the X-axis event flag generator to be enabled (XDEFE = 1) in the XYZ_DATA_CFG register. The ZYXDR and ZYXOW flag generation is requires the Z-axis, Y-axis, X-axis event flag generator to be enabled (ZDEFE = 1, YDEFE = 1, XDEFE = 1) in the XYZ_DATA_CFG register. 0x01, 0x02, 0x03: OUT_MSB 8-Bit XYZ Data Registers X, Y and Z-axis data is expressed as 2's complement numbers. The most significant 8-bits are stored together in OUT_X_MSB, OUT_Y_MSB, OUT_Z_MSB so applications needing only 8-bit results can use these registers and can ignore the OUT_X_LSB, OUT_Y_LSB, OUT_Z_LSB. The status Register 0x00, OUT_X_MSB, OUT_Y_MSB, OUT_Z_MSB are duplicated in the auto-incrementing address range of 0x00 to 0x03 to reduce reading the status followed by 8-bit axis data to a 4 byte sequence.
0x01 OUT_X_MSB: X_MSB Register (Read Only) Bit 7 XD11 Bit 6 XD10 Bit 5 XD9 Bit 4 XD8 Bit 3 XD7 Bit 2 XD6 Bit 1 XD5 Bit 0 XD4
0x02 OUT_Y_MSB: Y_MSB Register (Read Only) Bit 7 YD11 Bit 6 YD10 Bit 5 YD9 Bit 4 YD8 Bit 3 YD7 Bit 2 YD6 Bit 1 YD5 Bit 0 YD4
0x03 OUT_Z_MSB: Z_MSB Register (Read Only) Bit 7 ZD11 Bit 6 ZD10 Bit 5 ZD9 Bit 4 ZD8 Bit 3 ZD7 Bit 2 ZD6 Bit 1 ZD5 Bit 0 ZD4
0x05 - 0x0A: OUT_MSB and OUT_LSB 12-Bit XYZ Data Registers X, Y and Z-axis data is expressed as 2's complement numbers. The STATUS (0x04), OUT_X_LSB (0x05), OUT_X_MSB (0x06), OUT_Y_LSB (0x07), OUT_Y_MSB (0x08), OUT_Z_LSB(0x09), OUT_Z_MSB (0x0A) are stored in auto-incrementing address range of 0x04 to 0x0A to reduce reading the status followed by 12-bit axis data to 7 bytes.
0x05 OUT_X_LSB: X_LSB Register (Read Only) Bit 7 0 Bit 6 0 Bit 5 0 Bit 4 0 Bit 3 XD3 Bit 2 XD2 Bit 1 XD1 Bit 0 XD0
0x06 OUT_X_MSB: X_MSB Register (Read Only) Bit 7 XD11 Bit 6 XD10 Bit 5 XD9 Bit 4 XD8 Bit 3 XD7 Bit 2 XD6 Bit 1 XD5 Bit 0 XD4
0x07 OUT_Y_LSB: Y_LSB Register (Read Only) Bit 7 0 Bit 6 0 Bit 5 0 Bit 4 0 Bit 3 YD3 Bit 2 YD2 Bit 1 YD1 Bit 0 YD0
0x08 OUT_Y_MSB: Y_MSB Register (Read Only) Bit 7 YD11 Bit 6 YD10 Bit 5 YD9 Bit 4 YD8 Bit 3 YD7 Bit 2 YD6 Bit 1 YD5 Bit 0 YD4
0x09 OUT_Z_LSB: Z_LSB Register (Read Only) Bit 7 0 Bit 6 0 Bit 5 0 Bit 4 0 Bit 3 ZD3 Bit 2 ZD2 Bit 1 ZD1 Bit 0 ZD0
0x0A OUT_Z_MSB: Z_MSB Register (Read Only) Bit 7 ZD11 Bit 6 ZD10 Bit 5 ZD9 Bit 4 ZD8 Bit 3 ZD7 Bit 2 ZD6 Bit 1 ZD5 Bit 0 ZD4
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The sample data output registers store the current sample data if the FIFO data output register driver is disabled, but if the FIFO data output register driver is enabled,12 the sample data output registers point to the head of the FIFO buffer which contains the previous 32 X, Y, and Z data samples. This applies for the 8-bit data and the 12-bit data. When the FDE bit is set to logic 1, the F_8DATA (0x11) FIFO root data pointer shares the same address location as the OUT_X_MSB register (0x01); therefore all 8-bit accesses of the FIFO buffer data must use the I2C address 0x01. The F_12DATA (0x12) FIFO root data pointer shares the same address location as the OUT_X_LSB register (0x05); therefore all 12-bit accesses of the FIFO buffer data must use the I2C address 0x05. All reads to register addresses 0x02, 0x03, 0x06, 0x07, 0x08, 0x09, and 0x0A returns a value of 0x00. 0x0C - 0x0E: OUT_X_DELTA, OUT_Y_DELTA, OUT_Z_DELTA AC Data Registers X, Y, and Z-axis 8-bit high pass filtered output data is expressed as 2's complement numbers. The data is obtained from the output of the user definable high pass filter. The data cuts out the low frequency data, which is useful in that the offset data is removed. The value of the high pass filter cut off frequency is set in Register 0x17.
Note: The OUT_X_DELTA, OUT_Y_DELTA, OUT_Z_DELTA registers store the high pass filtered "delta data" information regardless of the state of the FIFO data output register driver bit. Register 0x0B always reflects the status of the delta data. 0x0C OUT_X_DELTA: AC X 8-Bit Data Register (Read Only) Bit 7 XD7 Bit 6 XD6 Bit 5 XD5 Bit 4 XD4 Bit 3 XD3 Bit 2 XD2 Bit 1 XD1 Bit 0 XD0
0x0D OUT_Y_DELTA: AC Y 8-Bit Data Register (Read Only) Bit 7 YD7 Bit 6 YD6 Bit 5 YD5 Bit 4 YD4 Bit 3 YD3 Bit 2 YD2 Bit 1 YD1 Bit 0 YD0
0x0E OUT_Z_DELTA: AC Z 8-Bit Data Register (Read Only) Bit 7 ZD7 Bit 6 ZD6 Bit 5 ZD5 Bit 4 ZD4 Bit 3 ZD3 Bit 2 ZD2 Bit 1 ZD1 Bit 0 ZD0
0x0F: WHO_AM_I Device ID Register This register contains the device identifier which for MMA8450Q is set to 0xC6 by default. The value is factory programmed by a byte of NVM. A custom alternate value can be set by customer request.
0x0F WHO_AM_I: Device ID Register (Read Only) Bit 7 1 Bit 6 1 Bit 5 0 Bit 4 0 Bit 3 0 Bit 2 1 Bit 1 1 Bit 0 0
6.2
32 Sample FIFO
The following registers are used to configure the FIFO. The following are the FIFO registers for the MMA8450Q. For more information on the FIFO please refer to AN3920. 0x10: F_STATUS FIFO Status Register The FIFO Status Register is used to retrieve information about the FIFO. This register has a flag for the overflow and watermark. It also has a counter that can be read to obtain the number of samples stored in the buffer.
0x10 F_STATUS: FIFO STATUS Register (Read Only) Bit 7 F_OVF Bit 6 F_WMRK_FLAG Bit 5 F_CNT5 Bit 4 F_CNT4 Bit 3 F_CNT3 Bit 2 F_CNT2 Bit 1 F_CNT1 Bit 0 F_CNT0
Table 13. FIFO Flag Event Description
F_OVF 0 1 -- -- F_WMRK_FLAG -- -- 0 1 No FIFO overflow events detected. FIFO event detected; FIFO has overflowed. No FIFO watermark events detected. FIFO event detected; FIFO sample count is greater than watermark value. Event Description
The F_OVF and F_WMRK_FLAG flags remain asserted while the event source is still active, but the user can clear the FIFO interrupt bit flag in the interrupt source register (INT_SOURCE) by reading the F_STATUS register. Therefore the F_OVF bit flag will remain asserted while the FIFO has overflowed and the F_WMRK_FLAG bit flag will remain asserted while the F_CNT value is greater than the F_WMRK value. MMA8450Q 23 Sensors Freescale Semiconductor
Table 14. FIFO Sample Count Description
F_CNT[5:0] FIFO sample counter. Default value 00_0000. (00_0001 to 10_0000 indicates 1 to 32 samples stored in FIFO
F_CNT[5:0] bits indicate the number of acceleration samples currently stored in the FIFO buffer. Count 000000 indicates that the FIFO is empty. 0x11: F_8DATA 8-Bit FIFO Data F_8DATA provides access to the previous (up to) 32 samples of X, Y, and Z-axis acceleration data at 8-bit resolution. Use F_12DATA to access the same FIFO data at 12-bit resolution. The advantage of F_8DATA access is much faster download of the sample data, since it is represented by only 3 bytes per sample (OUT_X_MSB, OUT_Y_MSB, and OUT_Z_MSB). All reads to address 0x01 returns the sensor sampled data in the FIFO buffer, 3 bytes per sample (one byte per axis), with the oldest samples first, in order OUT_X_MSB, OUT_Y_MSB, and OUT_Z_MSB. When all samples indicated by the FIFO_Status register have been read from the FIFO, subsequent reads will return 0x00. Since the FIFO holds a maximum of 32 samples, a maximum of 3 x 32 = 96 data bytes of samples can be read. The FIFO will not accumulate more sample data during an access to F_8DATA until a STOP or repeated START occurs.
0x11 F_8DATA: 8-Bit FIFO Data Register Points to Register 0x01 (Read Only) Bit 7 XD11 Bit 6 XD10 Bit 5 XD9 Bit 4 XD8 Bit 3 XD7 Bit 2 XD6 Bit 1 XD5 Bit 0 XD4
The host application should initially perform a single byte read of the FIFO status byte (address 0x10) to determine the status of the FIFO and if it is determined that the FIFO contains data sample(s), the FIFO contents can also be read from register address location 0x01 or 0x05. 0x12: F_12DATA 12-Bit FIFO Data F_12DATA provides access to the previous (up to) 32 samples of X, Y, and Z-axis acceleration data, at 12-bit resolution. Use F_8DATA to access the same FIFO data at 8-bit resolution. The advantage of F_8DATA access is much faster download of the sample data, since it is represented by only 3 bytes per sample (OUT_X_MSB, OUT_Y_MSB, and OUT_Z_MSB). When the FDE bit is set to logic 1, the F_12DATA FIFO root data pointer shares the same address location as the OUT_X_MSB register (0x05); therefore all 12-bit accesses of the FIFO buffer data must use the I2C register address 0x05. All reads to the register address 0x02, 0x03, 0x06, 0x07, 0x08, 0x09, and 0x0A return a value of 0x00. All reads from address (0x05) return the sample data, oldest samples first, in order OUT_X_LSB OUT_X_MSB, OUT_Y_LSB, OUT_Y_MSB, OUT_Z_LSB, and OUT_Z_MSB. When all samples indicated by the F_Status byte have been read from the FIFO, subsequent reads will return 0x00. Since the FIFO holds a maximum of 32 samples, a maximum of 6 x 32 = 192 data bytes can be read. The FIFO will not accumulate more sample data during an access to F_12DATA until a STOP or repeated START occurs.
0x12 F_12DATA: 12-Bit FIFO Data Register Points to Register 0x05 (Read Only) Bit 7 0 Bit 6 0 Bit 5 0 Bit 4 0 Bit 3 XD3 Bit 2 XD2 Bit 1 XD1 Bit 0 XD0
0x13: F_SETUP FIFO Setup Register This setup register is used to configure the options for the FIFO. The FIFO can operate in 3 states which are defined in the Mode Bits. The watermark bits are configurable to set the number of samples of data to trigger the watermark event flag. The maximum number of samples is 32. For more information on the FIFO configuration refer to AN3920.
0x13 F_SETUP: FIFO Setup Register (Read/Write) Bit 7 F_MODE1 Bit 6 F_MODE0 Bit 5 F_WMRK5 Bit 4 F_WMRK4 Bit 3 F_WMRK3 Bit 2 F_WMRK2 Bit 1 F_WMRK1 Bit 0 F_WMRK0
MMA8450Q Sensors Freescale Semiconductor 24
Table 15. F_SETUP Description
BITS Description FIFO buffer overflow mode. Default value 0. 00: FIFO is disabled. 01: FIFO contains the most recent samples when overflowed (circular buffer). Oldest sample is discarded to be replaced by new sample. 10: FIFO stops accepting new samples when overflowed. 11: Not Used. The FIFO is flushed whenever the FIFO is disabled, during an automatic ODR change (Auto-Wake/Sleep), or transitioning from "STANDBY" mode to "ACTIVE" mode. Disabling the FIFO (F_MODE = 00) resets the F_OVF, F_WMRK_FLAG, F_CNT to zero. A FIFO overflow event (i.e., F_CNT = 32) will assert the F_OVF flag and a FIFO sample count equal to the sample count watermark (i.e., F_WMRK) asserts the F_WMRK_FLAG event flag. FIFO Event Sample Count Watermark. Default value 00_0000. These bits set the number of FIFO samples required to trigger a watermark interrupt. A FIFO watermark event flag (F_WMK_FLAG) is raised when FIFO sample count F_CNT[5:0] value is equal to the F_ WMRK[5:0] watermark. Setting the F_WMRK[5:0] to 00_0000 will disable the FIFO watermark event flag generation.
F_MODE[1:0](1)(2)(3)
F_WMRK[5:0](2)
1. Bit field can be written in ACTIVE mode. 2. Bit field can be written in STANDBY mode. 3. The FIFO mode (F_MODE) cannot be switched between the two operational modes (01and 10) in Active Mode.
A FIFO sample count exceeding the watermark event does not stop the FIFO from accepting new data. The FIFO update rate is dictated by the selected system ODR. In active mode the ODR is set by the DR register in the CTRL_REG1 register and when Auto-Sleep is active the ODR is set by the ASLP_RATE field in the CTRL_REG1 register. When a byte is read from the FIFO buffer the oldest sample data in the FIFO buffer is returned and also deleted from the front of the FIFO buffer, while the FIFO sample count is decremented by one. It is assumed that the host application shall use the I2C multi-read transaction to empty the FIFO. The FIFO mode can be changed while in the active state. The mode must first be disabled F_MODE = 00 then the Mode can be changed. 0x14: SYSMOD System Mode Register The system mode register indicates the current device operating mode. Applications using the Auto-Sleep/Auto-Wake mechanism should use this register to synchronize the application with the device operating mode transitions. The system mode register also indicates the status of the NVM parity error and FIFO gate error flags.
0x14 SYSMOD: System Mode Register (Read Only) Bit 7 PERR Bit 6 FGERR Bit 5 0 Bit 4 0 Bit 3 0 Bit 2 0 Bit 1 SYSMOD1 Bit 0 SYSMOD0
Table 16. SYSMOD Description
PERR NVM Parity Error Flag Bit. Default Value: 0. 0: No NVM parity error was detected. 1: NVM parity error detected. FIFO Gate Error. Default value: 0. 0: No FIFO Gate Error detected. 1: FIFO Gate Error was detected. System Mode. Default value: 00. 00: Standby mode 01: Wake mode 10: Sleep mode
FGERR
SYSMOD
The FIFO Gate is set in Register 0x3A for the device configured for Auto-Wake/Sleep mode to allow the buffer to preserve the data without automatically flushing. If the FIFO buffer is not emptied before the arrival of the next sample, then the FGERR bit in register 0x14 is asserted. The FGERR remains asserted as long as the FIFO buffer remains un-emptied. Emptying the FIFO buffer clears the FGERR bit.
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0x15: INT_SOURCE System Interrupt Status Register In the interrupt source register the status of the various embedded features can be determined.The bits that are set (logic `1') indicate which function has asserted an interrupt and conversely the bits that are cleared (logic `0') indicate which function has not asserted or has de-asserted an interrupt. The interrupts are rising edge sensitive. The bits are set by a low to high transition and are cleared by reading the appropriate interrupt source register.
0x15 INT_SOURCE: System Interrupt Status Register (Read Only) Bit 7 SRC_ASLP Bit 6 SRC_FIFO Bit 5 SRC_TRANS Bit 4 SRC_LNDPRT Bit 3 SRC_PULSE Bit 2 Bit 1 Bit 0 SRC_DRDY SRC_FF_MT_1 SRC_FF_MT_2
Table 17. INT_SOURCE Description
INT_SOURCE Auto-Sleep/Wake interrupt status bit Logic `1' indicates that an interrupt event that can cause a "Wake-to-Sleep" or "Sleep-to-Wake" system mode transition has occurred. Logic `0' indicates that no "Wake-to-Sleep" or "Sleep-to-Wake" system mode transition interrupt event has occurred. SRC_ASLP "Wake-to-Sleep" transition occurs when no interrupt occurs for a time period that exceeds the user specified limit (ASLP_COUNT). This causes the system to transition to a user specified low ODR setting. "Sleep-to-Wake" transition occurs when the user specified interrupt event has woken the system; thus causing the system to transition to a user specified high ODR setting. Reading the SYSMOD register clears the SRC_ASLP bit. FIFO interrupt status bit Logic `1' indicates that a FIFO interrupt event such as an overflow event or watermark has occurred. Logic `0' indicates that no FIFO interrupt event has occurred. FIFO interrupt event generators: FIFO Overflow, or (Watermark: F_CNT = F_WMRK) and the interrupt has been enabled. This bit is cleared by reading the F_STATUS register. Transient interrupt status bit SRC_TRANS Logic `1' indicates that an acceleration transient value greater than user specified threshold has occurred. Logic `0' indicates that no transient event has occurred. This bit is asserted whenever "EA" bit in the TRANS_SRC is asserted and the interrupt has been enabled. This bit is cleared by reading the TRANS_SRC register. Landscape/Portrait Orientation interrupt status bit SRC_LNDPRT Logic `1' indicates that an interrupt was generated due to a change in the device orientation status. Logic `0' indicates that no change in orientation status was detected. This bit is asserted whenever "NEWLP" bit in the PL_STATUS is asserted and the interrupt has been enabled. This bit is cleared by reading the PL_STATUS register. Pulse interrupt status bit SRC_PULSE Logic `1' indicates that an interrupt was generated due to single and/or double pulse event. Logic `0' indicates that no pulse event was detected. This bit is asserted whenever "EA" bit in the PULSE_SRC is asserted and the interrupt has been enabled. This bit is cleared by reading the PULSE_SRC register. Freefall/Motion1 interrupt status bit Logic `1' indicates that the Freefall/Motion1 function interrupt is active. SRC_FF_MT_1 Logic `0' indicates that no Freefall or Motion event was detected. This bit is asserted whenever "EA" bit in the FF_MT_SRC_1 register is asserted and the FF_MT interrupt has been enabled. This bit is cleared by reading the FF_MT_SRC_1 register. Freefall/Motion2 interrupt status bit Logic `1' indicates that the Freefall/Motion2 function interrupt is active. SRC_FF_MT_2 Logic `0' indicates that no Freefall or Motion event was detected. This bit is asserted whenever "EA" bit in the FF_MT_SRC_2 register is asserted and the FF_MT interrupt has been enabled. This bit is cleared by reading the FF_MT_SRC_2 register. Description
SRC_FIFO
MMA8450Q Sensors Freescale Semiconductor 26
Table 17. INT_SOURCE Description
Data Ready interrupt bit status SRC_DRDY Logic `1' indicates that the X,Y,Z data ready interrupt is active indicating the presence of new data and/or data overrun. Otherwise if it is a logic `0' the X,Y,Z interrupt is not active. This bit is asserted when the ZYXOW and/or ZYXDR is set and the interrupt has been enabled. This bit is cleared by reading the STATUS and X, Y, or Z register.
0x16: XYZ_DATA_CFG Sensor Data Configuration Register The XYZ_DATA_CFG register configures the 3-axis acceleration data and event flag generator based on the ODR.
0x16 XYZ_DATA_CFG: Sensor Data Configuration Register (Read/Write) Bit 7 FDE Bit 6 0 Bit 5 0 Bit 4 0 Bit 3 0 Bit 2 ZDEFE Bit 1 YDEFE Bit 0 XDEFE
Table 18. XYZ_DATA_CFG Description
FDE FIFO Data Output Register Driver Enable. Default value: 0. 0: The sample data output registers store the current X, Y, & Z sample data; 1: The sample data output registers point to the previously stored X, Y, & Z samples data in the FIFO buffer. Data Event Flag Enable on new Z-axis data. Default value: 0 0: Event detection disabled; 1: Raise event flag on new Z-axis data Data Event Flag Enable on new Y-axis data. Default value: 0 0: Event detection disabled; 1: Raise event flag on new Y-axis data Data Event Flag Enable on new X-axis data. Default value: 0 0: Event detection disabled; 1: Raise event flag on new X-axis data
ZDEFE YDEFE XDEFE
0x17: HP_FILTER_CUTOFF High Pass Filter Register This register sets the high-pass filter cut-off frequency for the detection of instantaneous acceleration. The output of this filter is indicated by the OUT_X_DELTA, OUT_Y_DELTA, and OUT_Z_DELTA registers. The filter cut-off options change based on the data rate selected as shown in Table 19. For details of implementation on the high pass filter, refer to Freescale application note AN3918.
0x17 HP_FILTER_CUTOFF: High Pass Filter Register (Read/Write) Bit 7 0 Bit 6 0 Bit 5 0 Bit 4 0 Bit 3 0 Bit 2 0 Bit 1 SEL1 Bit 0 SEL0
Table 19. HP_FILTER_CUTOFF Setting Options
SEL1 0 0 1 1 SEL0 0 1 0 1 Fc (Hz) @ ODR = 400 Hz 4 2 1 0.5 Fc (Hz) @ ODR = 200 Hz 2 1 0.5 0.25 Fc (Hz) @ ODR = 100 Hz 1 0.5 0.25 0.125 Fc (Hz) @ ODR = 50 Hz 0.5 0.25 0.125 0.062 Fc (Hz) @ ODR = 12.5 Hz 0.125 0.063 0.031 0.016 Fc (Hz) @ ODR = 1.563 Hz 0.01 0.007 0.004 0.002
6.3
Portrait/ Landscape Embedded Function Registers
For more details on the meaning of the different user configurable settings and for example code refer to Freescale application note AN3915. 0x18: PL_STATUS Portrait/Landscape Status Register This status register can be read to get updated information on any change in orientation by reading Bit 7, or on the specifics of the orientation by reading Bit0 to Bit 4. For further understanding of Portrait Up, Portrait Down, Landscape Left, Landscape Right, Back and Front please refer to Figure 9
0x18 PL_STATUS Register (Read Only) Bit 7 NEWLP Bit 6 LO Bit 5 -- Bit 4 LAPO[2] Bit 3 LAPO[1] Bit 2 LAPO[0] Bit 1 BAFRO[1] Bit 0 BAFRO[0]
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Table 20. PL_STATUS Register Description
NEWLP Landscape-Portrait status change flag. Default value: 0. 0: No change, 1: BAFRO and/or LAPO and/or Z-tilt lockout value has changed Z-Tilt Angle Lockout. Default value: 0. 0: Lockout condition has not been detected. 1: Z-Tilt lockout trip angle has been exceeded. Lockout has been detected. Back or Front orientation. Default value: 00 00: Undefined. This is the default power up state. 01: Front: Device is in the front facing orientation. 10: Back: Device is in the back facing orientation. Landscape/Portrait orientation. Default value: 000 000: Undefined. This is the default power up state. 001: Portrait Up 010: Portrait Down 011: Landscape Right 100: Landscape Left
LO
BAFRO[1:0]
LAPO[2:0](1)
1. The default power up state is BAFRO (Undefined), LAPO (Undefined), and no Lockout for orientation function.
NEWLP is set to 1 whenever a change in LO, BAFRO, or LAPO occurs. NEWLP bit is cleared anytime PL_STATUS register is read. 0x19: PL_PRE_STATUS Portrait/Landscape Previous Data Status Register This register provides the previous orientation data from the previous reading. These register definitions are the same as what has been described in Register 0x18.
0x19 PL_PRE_STATUS Register (Read Only) Bit 7 -- Bit 6 LO Bit 5 --- Bit 4 LAPO[2] Bit 3 LAPO[1] Bit 2 LAPO[0] Bit 1 BAFRO[1] Bit 0 BAFRO[0]
0x1A: PL_CFG Portrait/Landscape Configuration Register This register configures the behavior of the debounce counters and also sets the Landscape/Portrait 1g lockout mechanism threshold offset.
0x1A PL_CFG Register (Read/Write) Bit 7 DBCNTM Bit 6 PL_EN Bit 5 -- Bit 4 -- Bit 3 -- Bit 2 GOFF[2] Bit 1 GOFF[1] Bit 0 GOFF[0]
Table 21. PL_CFG Register Description
DBCNTM Debounce counter mode selection. Default value: 1 0: Decrements debounce whenever condition of interest is no longer valid. 1: Clears counter whenever condition of interest is no longer valid. Portrait-Landscape Detection Enable. Default value: 0 0: Portrait-Landscape Detection is Disabled. 1: Portrait-Landscape Detection is Enabled. 1g lockout threshold offset expressed in steps of 50mg. Default value: 011 = 1.15g. The offset specified by the GOFF is added or subtracted from 1g to achieve the optimal 1g lockout threshold. If GOFF = 011, then the resulting 1g lockout threshold is (1g + 150mg). 000: No offset.
PL_EN
GOFF
0x1B: PL_COUNT Portrait Landscape Debounce Register This register sets the debounce counter for the orientation state transition. The minimum debounce latency is determined by the data rate set by the selected system ODR and PL_COUNT registers. Any change to the ODR or device mode transitioning from ACTIVE to STANDBY or vice versa resets the internal landscape/portrait internal debounce counters.
0x1B PL_COUNT Register (Read/Write) Bit 7 DBNCE[7] Bit 6 DBNCE[6] Bit 5 DBNCE[5] Bit 4 DBNCE[4] Bit 3 DBNCE[3] Bit 2 DBNCE [2] Bit 1 DBNCE [1] Bit 0 DBNCE [0]
The debounce counter scales with the ODR, like many of the debounce counters in the other functional blocks. Table 22 shows the relationship between the ODR, the step per count and the duration.
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Table 22. PL_COUNT Relationship with the ODR
Output Data Rate (Hz) 400 200 100 50 12.5 1.56 Step 2.5 ms 5 ms 10 ms 20 ms 80 ms 640 ms Duration Range 2.5 ms - 0.637s 5 ms - 1.275s 10 ms - 2.55s 20 ms - 5.1s 80 ms - 20.4s 640 ms - 163s
0x1C: PL_BF_ZCOMP Back/Front and Z Compensation Register The Z-Tilt angle compensation bits allow the user to adjust the Z-lockout region from 25 up to 50. The default Z-lockout angle is set to the default value of 32 upon power up. The Back to Front trip angle is set by default to 75 but this angle also can be adjusted from a range of 65 to 80 with 5 step increments.
0x1C: PL_BF_ZCOMP Register (Read/Write) Bit 7 BKFR[1] Bit 6 BKFR[0] Bit 5 -- Bit 4 -- Bit 3 -- Bit 2 ZLOCK[2] Bit 1 ZLOCK[1] Bit 0 ZLOCK[0]
Table 23. PL_BF_ZCOMP Description
ZLOCK BKFR Z-Lock Angle Threshold. Range is from 25 to 50. Step size is 3.6. Default value: 010 32.1. Maximum value: 111 50. Back Front Trip Angle Threshold. Default: 10 75. Step size is 5. Range: (65 to 80).
Table 24. Back/Front Orientation Definitions
BKFR 00 01 10 11 Back Front Transition Z < 80 or Z > 280 Z < 75 or Z > 285 Z < 70 or Z > 290 Z < 65 or Z > 295 Front Back Transition Z > 100 and Z < 260 Z > 105 and Z < 255 Z > 110 and Z < 250 Z > 115 and Z < 245
0x1D - 0x1F: PL_P_L_THS_REG1, 2, 3 Portrait-to-Landscape Threshold Registers The following registers represent the Portrait-to-Landscape trip threshold registers. These registers are used to set the trip angle for the image transition from the Portrait orientation to the Landscape orientation. The angle can be selected from Table 28 and the corresponding values for that angle should be written into the three PL_P_L_THS Registers.
0x1D PL_P_L_THS_REG1 Register (Read/Write) Bit 7 P_L_THS[7] Bit 6 P_L_THS[6] Bit 5 P_L_THS[5] Bit 4 P_L_THS[4] Bit 3 P_L_THS[3] Bit 2 P_L_THS[2] Bit 1 P_L_THS[1] Bit 0 P_L_THS[0]
Table 25. PL_P_L_THS_REG1 Description
P_L_THS Portrait-to-Landscape Threshold Register 1. Default value: 30 0001_1010.
0x1E PL_P_L_THS_REG2 Register (Read/Write) Bit 7 P_L_THS[7] Bit 6 P_L_THS[6] Bit 5 P_L_THS[5] Bit 4 P_L_THS[4] Bit 3 P_L_THS[3] Bit 2 P_L_THS[2] Bit 1 P_L_THS[1] Bit 0 P_L_THS[0]
Table 26. PL_P_L_THS_REG2 Description
P_L_THS Portrait-to-Landscape Threshold Register 2. Default value: 30 0010_0010.
0x1F PL_P_L_THS_REG3 Register (Read/Write) Bit 7 P_L_THS[7] Bit 6 P_L_THS[6] Bit 5 P_L_THS[5] Bit 4 P_L_THS[4] Bit 3 P_L_THS[3] Bit 2 P_L_THS[2] Bit 1 P_L_THS[1] Bit 0 P_L_THS[0]
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Table 27. PL_P_L_THS_REG3 Description
P_L_THS Portrait-to-Landscape Threshold Register 3. Default value: 30 1101_0100.
Table 28. Portrait-to-Landscape Trip Angle Thresholds Look-up Table
Portrait-to-Landscape Trip Angle 15 20 25 30 35 40 45 50 55 60 PL_P_L_THS_REG1 0x17 0x18 0x18 0x1A 0x1B 0x1D 0x20 0x23 0x27 0x2D PL_P_L_THS_REG2 0x75 0x14 0xF3 0xA2 0x1A 0x92 0x00 0x31 0x71 0x41 PL_P_L_THS_REG3 0x77 0x23 0x59 0x77 0x1A 0x33 0x00 0xD9 0xBA 0xA2
0x20 - 0x22 PL_L_P_THS_REG1, 2, 3 Landscape-to-Portrait Threshold Registers The following registers represent the Landscape-to-Portrait trip threshold registers. These registers are used to set the trip angle for the image transition from the Landscape orientation to the Portrait orientation. The angle can be selected from Table 32 and the corresponding values for that angle should be written into the three PL_L_P_THS Registers.
0x20 PL_L_P_THS_REG1 Register (Read/Write) Bit 7 L_P_THS[7] Bit 6 L_P_THS[6] Bit 5 L_P_THS[5] Bit 4 L_P_THS[4] Bit 3 L_P_THS[3] Bit 2 L_P_THS[2] Bit 1 L_P_THS[1] Bit 0 L_P_THS[0]
Table 29. PL_L_P_THS_REG1 Description
L_P_THS Landscape-to-Portrait Threshold Register 1. Default value: 60 0010_1101.
0x21 PL_L_P_THS_REG2 Register (Read/Write) Bit 7 L_P_THS[7] Bit 6 L_P_THS[6] Bit 5 L_P_THS[5] Bit 4 L_P_THS[4] Bit 3 L_P_THS[3] Bit 2 L_P_THS[2] Bit 1 L_P_THS[1] Bit 0 L_P_THS[0]
Table 30. PL_L_P_THS_REG2 Description
L_P_THS Landscape-to-Portrait Threshold Register 2. Default value: 60 0100_0001.
0x22 PL_L_P_THS_REG3 Register (Read/Write) Bit 7 L_P_THS[7] Bit 6 L_P_THS[6] Bit 5 L_P_THS[5] Bit 4 L_P_THS[4] Bit 3 L_P_THS[3] Bit 2 L_P_THS[2] Bit 1 L_P_THS[1] Bit 0 L_P_THS[0]
Table 31. PL_L_P_THS_REG3 Description
L_P_THS Landscape-to-Portrait Threshold Register 3. Default value: 60 1010_0010.
Table 32. Landscape-to-Portrait Trip Angle Thresholds Look-up Table
Landscape-to-Portrait Trip Angle 30 35 40 45 50 PL_L_P_THS_REG1 0x1A 0x1B 0x1D 0x20 0x23 PL_L_P_THS_REG2 0x22 0xA2 0x92 0x00 0x31 PL_L_P_THS_REG3 0xD4 0x77 0x33 0x00 0xD9
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Table 32. Landscape-to-Portrait Trip Angle Thresholds Look-up Table
55 60 65 70 75 0x27 0x2D 0x35 0x42 0x57 0x71 0x41 0x91 0x31 0x71 0xBA 0xA2 0x8F 0x81 0x77
6.4
Freefall & Motion Detection Registers
For details on how to configure the device for Freefall and/or Motion detection and for sample code, refer to application note AN3917. Note: There are two Freefall and Motion Detection Functions. The registers from 0x27 - 0x2A have the same descriptions as registers 0x23 - 0x26. 0x23: FF_MT_CFG_1 Freefall and Motion Configuration Register 1
0x23 FF_MT_CFG_1 Register (Read/Write) Bit 7 ELE Bit 6 OAE Bit 5 ZHEFE Bit 4 ZLEFE Bit 3 YHEFE Bit 2 YLEFE Bit 1 XHEFE Bit 0 XLEFE
Table 33. FF_MT_CFG_1 Description
ELE Event Latch Enable: Event flag is latched into FF_MT_SRC_1 register. Reading of the FF_MT_SRC_1 register clears the EA event flag. Default value: 0 0: Event flag latch disabled; 1: Event flag latch enabled Logical Or/And combination of events flags. Default value: 0 0: Logical AND combination of events flags; 1: Logical OR combination of events flags Event flag enable on Z High event. Default value: 0 0: Event detection disabled; 1: Event detection enabled Event flag enable on Z Low event. Default value: 0 0: Event detection disabled; 1: Event detection enabled Event flag enable on Y High event. Default value: 0 0: Event detection disabled; 1: Event detection enabled Event flag enable on Y Low event. Default value: 0 0: Event detection disabled; 1: Event detection enabled Event flag enable on X High event. Default value: 0 0: Event detection disabled; 1: Event detection enabled Event flag enable on X Low event. Default value: 0 0: Event detection disabled; 1: Event detection enabled
OAE ZHEFE ZLEFE YHEFE YLEFE XHEFE XLEFE
OAE bit allows the selection between Motion (logical OR combination of X, Y, Z-axis event flags) and Freefall (logical AND combination of X, Y, Z-axis event flags) detection. ELE denotes whether the enabled event flag will be latched in the FF_MT_SRC_1 register or the event flag status in the FF_MT_SRC_1 will indicate the real-time status of the event. If ELE bit is set to a logic 1, then the event active "EA" flag is cleared by reading the FF_MT_SRC_1 source register. ZHEFE, YHEFE, XHEFE enables the detection of a high g event when the measured acceleration data on X, Y, or Z-axis is higher than the threshold set in FF_MT_THS_1 register. ZLEFE, YLEFE, XLEFE enables the detection of a low g event when the measured acceleration data on X, Y, or Z-axis is lower than the threshold set in FF_MT_THS_1 register. FF_MT_THS_1 is the threshold register used by the Freefall/Motion function to detect Freefall or Motion events. The unsigned 7-bit FF_MT_THS_1 threshold register holds the threshold for the low g event detection where the magnitude of the X and Y and Z acceleration values are lower than the threshold value. Conversely the FF_MT_THS_1 also holds the threshold for the high g event detection where the magnitude of the X, or Y, or Z-axis acceleration values is higher than the threshold value.
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0x24 FF_MT_SRC_1 Register
0x24: FF_MT_SRC_ Freefall and Motion Source Register (0x24) (Read Only) Bit 7 -- Bit 6 EA Bit 5 ZHE Bit 4 ZLE Bit 3 YHE Bit 2 YLE Bit 1 XHE Bit 0 XLE
Table 34. FF_MT_SRC_1 Description
EA ZHE ZLE YHE YLE XHE XLE Event Active Flag. Default value: 0 0: No event flag has been asserted; 1: one or more event flags have been asserted. Z High Event Flag. Default value: 0 0: No Z High event detected, 1: Z High event has been detected Z Low Event Flag. Default value: 0 0: No Z Low event detected, 1: Z Low event has been detected Y High Event Flag. Default value: 0 0: No Y High event detected, 1: Y High event has been detected Y Low Event Flag. Default value: 0 0: No Y Low event detected, 1: Y Low event has been detected X High Event Flag. Default value: 0 0: No X High event detected, 1: X High event has been detected X Low Event Flag. Default value: 0 0: No X Low event detected, 1: X Low event has been detected
This register keeps track of the acceleration event which is triggering (or has triggered, in case of ELE bit in FF_MT_CFG_1 register being set to 1) the event flag. In particular EA is set to a logic 1 when the logical combination of acceleration events flags specified in FF_MT_CFG_1 register is true. This bit is used in combination with the values in INT_EN_FF_MT_1 and INT_CFG_FF_MT_1 register to generate the Freefall/Motion interrupts. An X,Y, or Z high or an X,Y, and Z high event is true when the acceleration value of the X or Y or Z axes is higher than the preset threshold value defined in the FF_MT_THS_1 register. Conversely X,Y, or Z high or an X,Y, and Z low event is true when the acceleration value of the X and Y and Z axes are lower than the preset threshold value defined in the FF_MT_THS_1 register. When the ELE bit is set, only the EA bit is latched. The other bits are not latched. To see the events that have been detected, the register must be read immediately. The EA bit will remain high until the source register is read. 0x25: FF_MT_THS_1 Freefall and Motion Threshold 1 Register
0x25 FF_MT_THS_1 Register (Read/Write) Bit 7 DBCNTM Bit 6 THS6 Bit 5 THS5 Bit 4 THS4 Bit 3 THS3 Bit 2 THS2 Bit 1 THS1 Bit 0 THS0
Table 35. FF_MT_THS_1 Description
DBCNTM THS[6:0] Debounce counter mode selection. Default value: 0. 0: increments or decrements debounce, 1: increments or clears counter. Freefall /Motion Threshold: default value: 000 0000
The minimum threshold resolution is dependent on the selected acceleration g range and the threshold register has a range of 0 to 127. Therefore: * If the selected acceleration g range is 8g mode (FS = 11), the minimum threshold resolution is 0.063g/LSB. The maximum value is 8g. * If the selected acceleration g range is 4g mode (FS = 10), the minimum threshold resolution is 0.0315g/LSB. The maximum value is 4g. * If the selected acceleration g range is 2g mode (FS = 01), the minimum threshold resolution is 0.01575g/LSB. The maximum value is 2g. When DBCNTM bit is a logic `1', the debounce counter is cleared to 0 whenever the event of interest is no longer true (Figure 12 part b) while if the DBCNTM bit is set a logic `0' the debounce counter is decremented by 1 whenever the event of interest is no longer true (Figure 12 part c) until the debounce counter reaches 0 or the event of interest becomes active. Decrementing of the debounce counter acts as a median filter enabling the system to filter out irregular spurious events which might impede the detection of the event.
MMA8450Q Sensors Freescale Semiconductor 32
Low g Event on all 3-axis (Freefall) Count Threshold FF_MT Counter Value (a)
EA FF
Low g Event on all 3-axis (Freefall) DBCNTM = 1 Count Threshold FF_MT Counter Value EA FF (b)
Low g Event on all 3-axis (Freefall) Count Threshold FF_MT Counter Value DBCNTM = 0
(c)
EA FF
Figure 12. DBCNTM Bit Function 0x26: FF_MT_COUNT_1 Freefall Motion Count 1 Register This register sets the number of debounce sample counts for the event trigger.
0x26 FF_MT_COUNT_1 Register (Read/Write) Bit 7 D7 Bit 6 D6 Bit 5 D5 Bit 4 D4 Bit 3 D3 Bit 2 D2 Bit 1 D1 Bit 0 D0
Table 36. FF_MT_COUNT_1 Description
D[7-0] Count value. Default value: 0000_0000
D7 - D0 define the number of debounce sample counts for the event trigger. When the debounce counter exceeds the FF_MT_COUNT_1 value, a Freefall/Motion event flag is set. The time step used for the debounce sample count depends on the ODR chosen (Table 37). Table 37. FF_MT_COUNT_1 and FF_MT_COUNT_2 Relationship with the ODR
Output Data Rate (Hz) 400 200 100 50 12.5 1.56 Step 2.5 ms 5 ms 10 ms 20 ms 80 ms 640 ms Duration Range 2.5 ms - 0.63s 5 ms - 1.275s 10 ms - 2.55s 20 ms - 5.1s 80 ms - 20.4s 640 ms - 163s
An ODR of 100 Hz and a FF_MT_COUNT_1 value of 15 would result in a debounce response time of 150 ms. MMA8450Q 33 Sensors Freescale Semiconductor
0x27: FF_MT_CFG_2 Freefall and Motion Configuration 2 Register These registers all have the same descriptions as above for Registers 0x23 - 0x26.
0x27 FF_MT_CFG_2 Register (Read/Write) Bit 7 ELE Bit 6 OAE Bit 5 ZHEFE Bit 4 ZLEFE Bit 3 YHEFE Bit 2 YLEFE Bit 1 XHEFE Bit 0 XLEFE
0x28: FF_MT_SRC_2 Freefall and Motion Source 2 Register
0x28 FF_MT_SRC_2 Register (Read Only) Bit 7 -- Bit 6 EA Bit 5 ZHE Bit 4 ZLE Bit 3 YHE Bit 2 YLE Bit 1 XHE Bit 0 XLE
0x29: FF_MT_THS_2 Freefall and Motion Threshold 2 Register
0x29 FF_MT_THS_2 Register (Read/Write) Bit 7 DBCNTM Bit 6 THS6 Bit 5 THS5 Bit 4 THS4 Bit 3 THS3 Bit 2 THS2 Bit 1 THS1 Bit 0 THS0
0x2A: FF_MT_COUNT_2 Freefall and Motion Debounce 2 Register
0x2A FF_MT_COUNT_2 Register (Read/Write) Bit 7 D7 Bit 6 D6 Bit 5 D5 Bit 4 D4 Bit 3 D3 Bit 2 D2 Bit 1 D1 Bit 0 D0
6.5
Transient Detection Registers
For more information on the uses of the transient function and sample code, refer to application note AN3918. 0x2B: TRANSIENT_CFG Transient Configuration Register The transient detection mechanism can be configured to raise an interrupt when the magnitude of the high pass filtered data is greater than a user definable threshold. The TRANSIENT_CFG register is used to enable the transient interrupt generation mechanism for each of the 3 axes (X, Y, Z) of acceleration.
0x2B TRANSIENT_ CFG Register (Read/Write) Bit 7 -- Bit 6 -- Bit 5 -- Bit 4 -- Bit 3 ELE Bit 2 ZTEFE Bit 1 YTEFE Bit 0 XTEFE
Table 38. TRANSIENT_ CFG Description
ELE Transient event flag is latched into the TRANSIENT_SRC register. Reading of the TRANSIENT_SRC register clears the event flag. Default value: 0 0: event flag latch disabled; 1: Event flag latch enabled Event flag enable on Z-axis. Default value: 0 0: Event detection disabled; 1: Event detection Enabled Event flag enable on Y-axis. Default value: 0 0: Event detection disabled; 1: Event detection Enabled Event flag enable on X-axis. Default value: 0 0: Event detection disabled; 1: Event detection Enabled
ZTEFE YTEFE XTEFE
0x2C: TRANSIENT_SRC Transient Source Register The transient source register is read to determine the source of an interrupt. When the ELE bit is set in Register0x2B the "EA" event Active bit in the source register is latched. The other bits in the source register are not latched. The source register must be read immediately following the interrupt to determine the axes the event occurred on.
0x2C TRANSIENT_SRC Register (Read Only) Bit 7 -- Bit 6 -- Bit 5 -- Bit 4 -- Bit 3 EA Bit 2 ZTRANSE Bit 1 YTRANSE Bit 0 XTRANSE
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Table 39. TRANSIENT_SRC Description
EA ZTRANSE YTRANSE XTRANSE Event Active Flag. Default value: 0 0: No event flag asserted; 1: one or more event flag has been asserted. Z transient event. Default value: 0 0: No Z event detected, 1: Z event detected Y transient event. Default value: 0 0: No Y event detected, 1: Y event detected X transient event. Default value: 0 0: No X event detected, 1: X event detected
0x2D: TRANSIENT_THS Transient Threshold Register The TRANSIENT_THS register sets the threshold limit for the high pass filtered acceleration. The value in the TRANSIENT_THS register corresponds to a g value which is compared against the values of OUT_X_DELTA, OUT_Y_DELTA, and OUT_Z_DELTA. If the acceleration exceeds the threshold limit an event flag is raised and an interrupt is generated if interrupts are enabled.
0x2D TRANSIENT_THS Register (Read/Write) Bit 7 DBCNTM Bit 6 THS6 Bit 5 THS5 Bit 4 THS4 Bit 3 THS3 Bit 2 THS2 Bit 1 THS1 Bit 0 THS0
Table 40. TRANSIENT_THS Description
DBCNTM THS[6:0] Debounce counter mode selection. Default value: 0 0: increments or decrements debounce; 1: increments or clears counter Transient Threshold: default value: 000_0000
The minimum threshold resolution is dependent on the selected acceleration g range and the threshold register has a range of 0 to 127. Therefore: * If the selected acceleration g range is 8g mode (FS = 11), the minimum threshold resolution is 0.063g/LSB. The maximum is 8g. * If the selected acceleration g range is 4g mode (FS = 10), the minimum threshold resolution is 0.0315g/LSB. The maximum is 4g. * If the selected acceleration g range is 2g mode (FS = 01), the minimum threshold resolution is 0.01575g/LSB. The maximum is 2g. * The DBCNTM bit behaves in the same manner described previously for the Motion/Freefall 1. 0x2E: TRANSIENT_COUNT Transient Debounce Register The TRANSIENT_COUNT sets the minimum number of debounce counts continuously matching the condition where the unsigned value of OUT_X_DELTA or OUT_Y_DELTA or OUT_Z_DELTA register is greater than the user specified value of TRANSIENT_THS.
0x2E TRANSIENT_COUNT Register (Read/Write) Bit 7 D7 Bit 6 D6 Bit 5 D5 Bit 4 D4 Bit 3 D3 Bit 2 D2 Bit 1 D1 Bit 0 D0
Table 41. TRANSIENT_COUNT Description
D[7-0] Count value. Default value: 0000_0000
The time step for the Transient detection debounce counter is set by the value of the system ODR. Table 42. TRANSIENT_COUNT relationship with the ODR
Output Data Rate (Hz) 400 200 100 50 12.5 1.56 Step 2.5 ms 5 ms 10 ms 20 ms 80 ms 640 ms Duration Range 2.5 ms - 0.637s 5 ms - 1.275s 10 ms - 2.55s 20 ms - 5.1s 80 ms - 20.4s 640 ms - 163s
An ODR of 100 Hz and a TRANSIENT_COUNT value of 15 would result in a debounce response time of 150 ms.
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6.6
Tap Detection Registers
For more details of how to configure the tap detection and sample code please refer to Freescale application note, AN3919. The tap detection registers are referred to as "Pulse". 0x2F: PULSE_CFG Pulse Configuration Register This register configures the event flag for the tap detection for enabling/disabling the detection of a single and double pulse on each of the axes.
0x2F PULSE_CFG Register (Read/Write) Bit 7 DPA Bit 6 ELE Bit 5 ZDPEFE Bit 4 ZSPEFE Bit 3 YDPEFE Bit 2 YSPEFE Bit 1 XDPEFE Bit 0 XSPEFE
Table 43. PULSE_CFG Description
Double Pulse Abort. 0: Double Pulse detection is not aborted if the start of a pulse is detected during the time period specified by the PULSE_LTCY register. 1: Setting the DPA bit momentarily suspends the double tap detection if the start of a pulse is detected during the time period specified by the PULSE_LTCY register and the pulse ends before the end of the time period specified by the PULSE_LTCY register. Pulse event flags are latched into the PULSE_SRC register. Reading of the PULSE_SRC register clears the event flag. Default value: 0 0: Event flag latch disabled; 1: Event flag latch enabled Event flag enable on double pulse event on Z-axis. Default value: 0 0: Event detection disabled; 1: Event detection enabled Event flag enable on single pulse event on Z-axis. Default value: 0 0: Event detection disabled; 1: Event detection enabled Event flag enable on double pulse event on Y-axis. Default value: 0 0: Event detection disabled; 1: Event detection enabled Event flag enable on single pulse event on Y-axis. Default value: 0 0: Event detection disabled; 1: Event detection enabled Event flag enable on double pulse event on X-axis. Default value: 0 0: Event detection disabled; 1: Event detection enabled Event flag enable on single pulse event on X-axis. Default value: 0 0: Event detection disabled; 1: Event detection enabled
DPA
ELE
ZDPEFE ZSPEFE YDPEFE YSPEFE XDPEFE XSPEFE
0x30: PULSE_SRC Pulse Source Register This register indicates a double or single pulse event has occurred. The corresponding axis and event must be enabled in Register 0x2F for the event to be seen in the source register.
0x30 PULSE_SRC Register (Read Only) Bit 7 -- Bit 6 EA Bit 5 ZDPE Bit 4 ZSPE Bit 3 YDPE Bit 2 YSPE Bit 1 XDPE Bit 0 XSPE
Table 44. TPULSE_SRC Description
EA ZDPE ZSPE YDPE YSPE XDPE XSPE Event Active Flag. Default value: 0 0: no event flag has been asserted; 1: one or more events have been asserted Double pulse on Z-axis event. Default value: 0 0: no event detected; 1: Double Z event detected Single pulse on Z-axis event. Default value: 0 0: no event detected; 1: Single Z event detected Double pulse on Y-axis event. Default value: 0 0: no event detected; 1: Double Y event detected Single pulse on Y-axis event. Default value: 0 0: no event detected; 1: Single Y event detected Double pulse on X-axis event. Default value: 0 0: no event detected; 1: Double X event detected Single pulse on X-axis event. Default value: 0 0: no event detected; 1: Single X event detected
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0x31 - 0x33: PULSE_THSX, Y, Z Pulse Threshold for X, Y & Z Registers The pulse threshold can be set separately for the X, Y and Z axes. The threshold values range from 0 to 31 counts with steps of 0.258g/LSB at a fixed 8g acceleration range, thus the minimum resolution is always fixed at 0.258g/LSB irrespective of the selected g range. The PULSE_THSX, PULSE_THSY and PULSE_THSZ registers define the threshold which is used by the system to start the pulse detection procedure. The threshold value is expressed over 5-bits as an unsigned number.
0x31 PULSE_THSX Register (Read/Write) Bit 7 0 Bit 6 0 Bit 5 0 Bit 4 THSX4 Bit 3 THSX3 Bit 2 THSX2 Bit 1 THSX1 Bit 0 THSX0
Table 45. PULSE_THSX Description
THSX4, THSX0 Pulse Threshold on X-axis. Default value: 0_0000
0x32 PULSE_THSY Register (Read/Write) Bit 7 0 Bit 6 0 Bit 5 0 Bit 4 THSY4 Bit 3 THSY3 Bit 2 THSY2 Bit 1 THSY1 Bit 0 THSY0
Table 46. PULSE_THSY Description
THSY4, THSY0 Pulse Threshold on Y-axis. Default value: 0_0000
0x33 PULSE_THSZ Register (Read/Write) Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0
0
0
THSZ4
THSZ3
THSZ2
THSZ1
THSZ0
Table 47. PULSE_THSZ Description
THSZ4, THSZ0 Pulse Threshold on Z-axis. Default value: 0_0000
0x34: PULSE_TMLT Pulse Time Window 1 Register
0x34 PULSE_TMLT Register (Read/Write) Bit 7 Tmlt7 Bit 6 Tmlt6 Bit 5 Tmlt5 Bit 4 Tmlt4 Bit 3 Tmlt3 Bit 2 Tmlt2 Bit 1 Tmlt1 Bit 0 Tmlt0
The bits Tmlt7 through Tmlt0 define the maximum time interval that can elapse between the start of the acceleration on the selected axis exceeding the specified threshold and the end when the acceleration on the selected axis must go below the specified threshold to be considered a valid pulse. The minimum time step for the pulse time limit is defined in Table 48. Maximum time for a given ODR is the minimum time step at the given power mode multiplied by 255. The time steps available are dependent on whether the device is in Normal Power mode or in Low Power mode. Notice in the table below that the time step is twice as long in Low Power mode. Table 48. Time Step for PULSE Time Limit at ODR and Power Mode
Output Data Rate (Hz) 400 200 100 50 12.5 1.56 Step at Normal Mode 0.625 ms 1.25 ms 2.5 ms 5 ms 5 ms 5 ms Step at Low Power Mode 1.25 ms 2.5 ms 5.0 ms 10 ms 10 ms 10 ms
Therefore an ODR setting of 400 Hz with normal power mode would result in a maximum pulse time limit of (0.625 ms * 255) 159 ms.
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0x35: PULSE_LTCY Pulse Latency Timer Register
0x35 PULSE_LTCY Register (Read/Write) Bit 7 Ltcy7 Bit 6 Ltcy6 Bit 5 Ltcy5 Bit 4 Ltcy4 Bit 3 Ltcy3 Bit 2 Ltcy2 Bit 1 Ltcy1 Bit 0 Ltcy0
The bits Ltcy7 through Ltcy0 define the time interval that starts after the first pulse detection. During this time interval, all pulses are ignored. Note: This timer must be set for single pulse and for double pulse. The minimum time step for the pulse latency is defined in Table 49. The maximum time is the time step at the ODR and Power Mode multiplied by 255. Notice that the time step is twice the duration if the device is operating in Low Power mode, as shown below. Table 49. Time Step for PULSE Latency at ODR and Power Mode
Output Data Rate (Hz) 400 200 100 50 12.5 1.56 Step at Normal Mode 1.25 ms 2.5 ms 5.0 ms 10 ms 10 ms 10 ms Step at Low Power Mode 2.5 ms 5.0 ms 20 ms 20 ms 20 ms 20 ms
0x36: PULSE_WIND Second Pulse Time Window Register
0x36 PULSE_WIND Register (Read/Write) Bit 7 Wind7 Bit 6 Wind6 Bit 5 Wind5 Bit 4 Wind4 Bit 3 Wind3 Bit 2 Wind2 Bit 1 Wind1 Bit 0 Wind0
The bits Wind7 through Wind0 define the maximum interval of time that can elapse after the end of the latency interval in which the start of the second pulse event must be detected provided the device has been configured for double pulse detection. The detected second pulse width must be shorter than the time limit constraints specified by the PULSE_TMLT register, but the end of the double pulse need not finish within the time specified by the PULSE_WIND register. The minimum time step for the pulse window is defined in Table 50. The maximum time is the time step at the ODR and Power Mode multiplied by 255. Table 50. Time Step for PULSE Detection Window at ODR and Power Mode
Output Data Rate (Hz) 400 200 100 50 12.5 1.56 Step at Normal Mode 1.25 ms 2.5 ms 5.0 ms 10 ms 10 ms 10 ms Step at Low Power Mode 2.5 ms 5.0 ms 20 ms 20 ms 20 ms 20 ms
6.7
Auto-Sleep Registers
For additional information on how to configure the device for the Auto-Sleep/Wake feature, refer to AN3921. 0x37: ASLP_COUNT Auto-Sleep Inactivity Timer Register The ASLP_COUNT register sets the minimum time period of inactivity required to change current ODR value from the value specified in the DR[2:0] to ASLP_RATE (Reg 0x38) value provided the SLPE bit is set to a logic `1' in the CTRL_REG2 register.
0x37 ASLP_COUNT Register (Read/Write) Bit 7 D7 Bit 6 D6 Bit 5 D5 Bit 4 D4 Bit 3 D3 Bit 2 D2 Bit 1 D1 Bit 0 D0
Table 51. ASLP_COUNT Description
D[7-0] Duration value. Default value: 0000 0000
MMA8450Q Sensors Freescale Semiconductor 38
D7-D0 defines the minimum duration time to change current ODR value from DR to ASLP_RATE. Time step and maximum value depend on the ODR chosen (see Table 52). Table 52. ASLP_COUNT Relationship with ODR
Output Data Rate (ODR) 400 200 100 50 12.5 1.56 Duration 0 to 81s 0 to 81s 0 to 81s 0 to 81s 0 to 81s 0 to 325.125s Step 320 ms 320 ms 320 ms 320 ms 320 ms 640 ms
In order to wake the device, the desired function or functions must be enabled and set to "Wake From Sleep". All enabled functions will still function in sleep mode at the sleep ODR. Only the functions that have been selected for "Wake From Sleep" will wake the device. MMA8450Q has 6 functions that can be used to keep the sensor from falling asleep namely, Transient, Orientation, Tap, Motion/FF1 and Motion/FF2 and the FIFO. One or more of these functions can be enabled. In order to wake the device, functions are provided namely, Transient, Orientation, Tap, and the two Motion/Freefall. Note that the FIFO does not wake the device. The Auto-Wake/Sleep interrupt does not affect the wake/sleep, nor does the data ready interrupt. The FIFO gate (bit 7) in Register 0x3A, when set, will hold the last data in the FIFO before transitioning to a different ODR. After the buffer is flushed, it will accept new sample data at the current ODR. See Register 0x3A for the wake from sleep bits. If the Auto-Sleep bit is disabled, then the device can only toggle between Standby and Wake Mode by writing to the FS0 and FS1 bits in Register 0x38 Ctrl Reg1. If Auto-Sleep interrupt is enabled, transitioning from Active mode to Auto-Sleep mode and vice versa generates an interrupt. 0x38: CTRL_REG1 System Control 1 Register
0x38 CTRL_REG1 Register (Read/Write) Bit 7 ASLP_RATE1 Bit 6 ASLP_RATE0 Bit 5 0 Bit 4 DR2 Bit 3 DR1 Bit 2 DR0 Bit 1 FS1 Bit 0 FS0
Table 53. CTRL_REG1 Description
ASLP_RATE [1:0] DR[2:0] FS[1:0] This register configures the Auto-Wake sample frequency when the device is in Sleep Mode. See Table 54 for more information. Data rate selection. Default value: 000 Full Scale selection. Default value: 00 (00: Standby mode; 01: active mode 2g; 10: active mode 4g; 11: active mode 8g)
Table 54. Sleep Mode Poll Rate Description
ASLP_RATE1 0 0 1 1 ASLP_RATE0 0 1 0 1 Frequency (Hz) 50 25 12.5 1.56
It is important to note that when the device is in Auto-Sleep mode, the system ODR and the data rate for all the system functional blocks are overwritten by the data rate set by the ASLP_RATE field in Register 0x38. DR[2:0] bits select the output data rate (ODR) for acceleration samples. The default value is 000 for a data rate of 400 Hz. Table 55. System Output Data Rate Selection
DR2 0 0 DR1 0 0 DR0 0 1 Output Data Rate (ODR) 400 Hz 200 Hz Time Between Data Samples 2.5 ms 5 ms
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Table 55. System Output Data Rate Selection
0 0 1 1 1 1 0 0 0 1 0 1 100 Hz 50 Hz 12.5 Hz 1.563 Hz 10 ms 20 ms 80 ms 640 ms
FS[1:0] bits select between standby mode and active mode. The default value is 00 for standby mode. Table 56. Full Scale Selection
FS1 0 0 1 1 FS0 0 1 0 1 Mode Standby Active Active Active g Range -- 2g 4g 8g
0x39: CTRL_REG2 System Control 2 Register
0x39 CTRL_REG2 Register (Read/Write) Bit 7 ST Bit 6 BOOT Bit 5 0 Bit 4 0 Bit 3 0 Bit 2 0 Bit 1 SLPE Bit 0 MODS
Table 57. CTRL_REG2 Description
ST BOOT SLPE(1) Self-Test Enable. Default value: 0 0: Self-Test disabled; 1: Self-Test enabled Reboot device content (Software Reset). Default value: 0 0: device reboot disabled; 1: device reboot enabled. Auto-Sleep enable. Default value: 0 0: Auto-Sleep is not enabled; 1: Auto-Sleep is enabled. Low power mode / Normal mode selection. Default value: 0 0: normal mode; 1: low power mode.
MODS
1. When SLPE = 1, the transitioning between sleep mode and wake mode results in a FIFO flush and a reset of internal functional block counters. All functional block
status information are preserve except otherwise stated. See Table 58 for more information about the FIFO_GATE bit in CTRL_REG3 register.
ST bit activates the Self-Test function. When ST is set to one, an output change will occur to the device outputs (refer to Table 2 and Table 3) thus allowing host application to check the functionality of the entire signal chain. BOOT bit is used to activate the software reset. The Boot mechanism can be enabled in STANDBY and ACTIVE mode. When the Boot bit is enabled the Boot mechanism resets all functional block registers and loads the respective internal registers with default NVM values. The system will automatically transition to standby mode if not already in standby mode before the software reset (re-BOOT process) can occur. Note: The I2C communication system is reset to avoid accidental corrupted data access. 0x3A: CTRL_REG3 Interrupt Control Register
0x3A CTRL_REG3 Register (Read/Write) Bit 7 FIFO_GATE Bit 6 WAKE_TRANS Bit 5 WAKE_LNDPRT Bit 4 Bit 3 Bit 2 Bit 1 IPOL Bit 0 PP_OD WAKE_PULSE WAKE_FF_MT_1 WAKE_FF_MT_2
MMA8450Q Sensors Freescale Semiconductor 40
Table 58. CTRL_REG3 Description
0: FIFO gate is bypassed. FIFO is flushed upon the system mode transitioning from wake-to-sleep mode or from sleep-towake mode. 1: The FIFO input buffer is blocked when transitioning from "wake-to-sleep" mode or from "sleep-to-wake" mode until the FIFO_GATE FIFO is flushed. Although the system transitions from "wake-to-sleep" or from "sleep-to-wake" the contents of the FIFO buffer are preserved, new data samples are ignored until the FIFO is emptied by the host application. If the FIFO_GATE bit is set to logic 1 and the FIFO buffer is not emptied before the arrival of the next sample, then the FGERR bit in the SYS_MOD register (0x14) will be asserted. The FGERR bit remains asserted as long as the FIFO buffer remains un-emptied. Emptying the FIFO buffer clears the FGERR bit in the SYS_MOD register. 0: Transient function is bypassed in sleep mode 1: Transient function interrupt can wake up system 0: Orientation function is bypassed in sleep mode 1: Orientation function interrupt can wake up system 0: Pulse function is bypassed in sleep mode 1: Pulse function interrupt can wake up system 0: Freefall/Motion1 function is bypassed in sleep mode 1: Freefall/Motion1 function interrupt can wake up 0: Freefall/Motion2 function is bypassed in sleep mode 1: Freefall/Motion2 function interrupt can wake up system Interrupt polarity active high, or active low. Default value 0. 0: active low; 1: active high Push-pull/Open Drain selection on interrupt pad. Default value 0. 0: push-pull; 1: open drain
WAKE_TRANS WAKE_LNDPRT WAKE_PULSE WAKE_FF_MT_1 WAKE_FF_MT_2 IPOL PP_OD
IPOL bit selects the polarity of the interrupt signal. When IPOL is `0' any interrupt event will signalled with a logical 0. PP_OD bit configures the interrupt pin to Push-Pull or in Open Drain mode. The open drain configuration can be used for connecting multiple interrupt signals on the same interrupt line. 0x3C: CTRL_REG5 Register (Read/Write)
0x3C CTRL_REG5 Register (Read/Write) Bit 7
INT_EN_ASLP
Bit 6
INT_EN_FIFO
Bit 5
INT_EN_TRANS
Bit 4
INT_EN_LNDPRT
Bit 3
INT_EN_PULSE
Bit 2
INT_EN_FF_MT_1
Bit 1
INT_EN_FF_MT_2
Bit 0
INT_EN_DRDY
Table 59. interrupt Enable Register Description
Interrupt Enable INT_EN_ASLP INT_EN_FIFO INT_EN_TRANS Description Interrupt Enable. Default value: 0 0: Auto-Sleep/Wake interrupt disabled; 1: Auto-Sleep/Wake interrupt enabled. Interrupt Enable. Default value: 0 0: FIFO interrupt disabled; 1: FIFO interrupt enabled. Interrupt Enable. Default value: 0 0: Transient interrupt disabled; 1: Transient interrupt enabled. Interrupt Enable. Default value: 0 0: Orientation (Landscape/Portrait) interrupt disabled. 1: Orientation (Landscape/Portrait) interrupt enabled. Interrupt Enable. Default value: 0 0: Pulse Detection interrupt disabled; 1: Pulse Detection interrupt enabled Interrupt Enable. Default value: 0 0: Freefall/Motion1 interrupt disabled; 1: Freefall/Motion1 interrupt enabled Interrupt Enable. Default value: 0 0: Freefall/Motion2 interrupt disabled; 1: Freefall/Motion2 interrupt enabled Interrupt Enable. Default value: 0 0: Data Ready interrupt disabled; 1: Data Ready interrupt enabled
INT_EN_LNDPRT
INT_EN_PULSE INT_EN_FF_MT_1 INT_EN_FF_MT_2 INT_EN_DRDY
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The corresponding functional block interrupt enable bit allows the functional block to route its event detection flags to the system's interrupt controller. The interrupt controller routes the enabled functional block interrupt to the INT1 or INT2 pin. 0x3C: CTRL_REG5 Interrupt Configuration Register
0x3C CTRL_REG5 Register (Read/Write) Bit 7
INT_CFG_ASLP
Bit 6
INT_CFG_FIFO
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INT_CFG_TRANS INT_CFG_LNDPRT INT_CFG_PULSE INT_CFG_FF_MT_1INT_CFG_FF_MT_2 INT_CFG_DRDY
Table 60. Interrupt Configuration Register Description
Interrupt Configuration INT_CFG_ASLP INT_CFG_FIFO INT_CFG_TRANS INT_CFG_LNDPRT INT_CFG_PULSE INT_CFG_FF_MT_1 INT_CFG_FF_MT_2 INT_CFG_DRDY Description INT1/INT2 Configuration. Default value: 0 0: Interrupt is routed to INT2 pin; 1: Interrupt is routed to INT1 pin INT1/INT2 Configuration. Default value: 0 0: Interrupt is routed to INT2 pin; 1: Interrupt is routed to INT1 pin INT1/INT2 Configuration. Default value: 0 0: Interrupt is routed to INT2 pin; 1: Interrupt is routed to INT1 pin INT1/INT2 Configuration. Default value: 0 0: Interrupt is routed to INT2 pin; 1: Interrupt is routed to INT1 pin INT1/INT2 Configuration. Default value: 0 0: Interrupt is routed to INT2 pin; 1: Interrupt is routed to INT1 pin INT1/INT2 Configuration. Default value: 0 0: Interrupt is routed to INT2 pin; 1: Interrupt is routed to INT1 pin INT1/INT2 Configuration. Default value: 0 0: Interrupt is routed to INT2 pin; 1: Interrupt is routed to INT1 pin INT1/INT2 Configuration. Default value: 0 0: Interrupt is routed to INT2 pin; 1: Interrupt is routed to INT1 pin
The system's interrupt controller shown in Figure 10 uses the corresponding bit field in the CTRL_REG5 register to determine the routing table for the INT1 and INT2 interrupt pins. If the bit value is logic `0' the functional block's interrupt is routed to INT2, and if the bit value is logic `1' then the interrupt is routed to INT1. One or more functions can assert an interrupt pin; therefore a host application responding to an interrupt should read the INT_SOURCE (0x15) register to determine the appropriate sources of the interrupt.
6.8
User Offset Correction Registers
For more information on how to calibrate the 0g Offset refer to AN3916 Offset Calibration Using the MMA8450Q. The 2's complement offset correction registers values are used to realign the zero g position of the X, Y, and Z-axis after device board mount. The resolution of the offset registers is 3.906 mg per LSB. The 2's complement 8-bit value would result in an offset compensation range 0.5g. 0x3D: OFF_X Offset Correction X Register
0x3D OFF_X Register (Read/Write) Bit 7 D7 Bit 6 D6 Bit 5 D5 Bit 4 D4 Bit 3 D3 Bit 2 D2 Bit 1 D1 Bit 0 D0
Table 61. OFF_X Description
D7-D0 X -axis offset trim LSB value. Default value: 0000_0000.
0x3E: OFF_Y Offset Correction Y Register
0x3E OFF_Y Register (Read/Write) Bit 7 D7 Bit 6 D6 Bit 5 D5 Bit 4 D4 Bit 3 D3 Bit 2 D2 Bit 1 D1 Bit 0 D0
Table 62. OFF_Y Description
D7-D0 Y-axis offset trim LSB value. Default value: 0000_0000.
0x3F: OFF_Z Offset Correction Z Register
0x3F OFF_Z Register (Read/Write) Bit 7 D7 Bit 6 D6 Bit 5 D5 Bit 4 D4 Bit 3 D3 Bit 2 D2 Bit 1 D1 Bit 0 D0
Table 63. OFF_Z Description
D7-D0 Z-axis offset trim LSB value. Default value: 0000_0000.
MMA8450Q Sensors Freescale Semiconductor 42
Appendix A
Table 64. MMA8450Q Register Map
Reg 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 20 21 22 23 24 25 26 27 28 Name STATUS OUT_X_MSB OUT_Y_MSB OUT_Z_MSB STATUS OUT_X_LSB OUT_X_MSB OUT_Y_LSB OUT_Y_MSB OUT_Z_LSB OUT_Z_MSB STATUS OUT_X_DELTA OUT_Y_DELTA OUT_Z_DELTA WHO_AM_I F_STATUS F_8DATA F_12DATA F_SETUP SYSMOD INT_SOURCE XYZ_DATA_CFG HP_FILTER_CUTOFF PL_STATUS PL_PRE_STATUS PL_CFG PL_COUNT PL_BF_ZCOMP PL_P_L_THS_REG1 PL_P_L_THS_REG2 PL_P_L_THS_REG3 PL_L_P_THS_REG1 PL_L_P_THS_REG2 PL_L_P_THS_REG3 FF_MT_CFG_1 FF_MT_SRC_1 FF_MT_THS_1 FF_MT_COUNT_1 FF_MT_CFG_2 FF_MT_SRC_2 Definition Data Status R 8-bit X Data R 8-bit Y Data R 8-bit Z Data R Data Status R 12-bit X Data R 12-bit X Data R 12-bit Y Data R 12-bit Y Data R 12-bit Z Data R 12-bit Z Data R Data Status R 8-bit Transient X Data R 8-bit Transient Y Data R 8-bit Transient Z Data R ID Register R FIFO Status R 8-bit FIFO Data R 12-bit FIFO Data R FIFO Setup R/W System Mode R Interrupt Status R Data Config. R/W HP Filter Setting R/W PL Status R Previous PL Status R PL Configuration R/W PL Debounce R/W PL Back/Front and Z Compensation R/W Portrait-to-Landscape Threshold Setting 1 R/W Portrait-to-Landscape Threshold Setting 2 R/W Portrait-to-Landscape Threshold Setting 3 R/W Landscape-to-Portrait Threshold Setting 1 R/W Landscape-to-Portrait Threshold Setting21 R/W Landscape-to-Portrait Threshold Setting 3 R/W FF/Motion Config. 1 R/W FF/Motion Source 1 R FF/Motion Threshold 1 R/W FF/Motion Debounce 1 R/W FF/Motion Config. 2 R/W FF/Motion Source 2 R Bit 7 ZYXOW XD11 YD11 ZD11 ZYXOW 0 XD11 0 YD11 0 ZD11 ZYXOW XD7 YD7 ZD7 -- F_OVF XD11 0 F_MODE1 PERR SRC_ASLP FDE 0 NEWLP DBCNTM DBNCE[7] BKFR[1] P_L_THS[7] P_L_THS[7] P_L_THS[7] L_P_THS[7] L_P_THS[7] L_P_THS[7] ELE -- DBCNTM D7 ELE -- Bit 6 ZOW XD10 YD10 ZD10 ZOW 0 XD10 0 YD10 0 ZD10 ZOW XD6 YD6 ZD6 -- F_WMRK_FLAG XD10 0 F_MODE0 FGERR SRC_FIFO 0 0 LO LO PL_EN DBNCE[6] BKFR[0] P_L_THS[6] P_L_THS[6] P_L_THS[6] L_P_THS[6] L_P_THS[6] L_P_THS[6] OAE EA THS6 D6 OAE EA Bit 5 YOW XD9 YD9 ZD9 YOW 0 XD9 0 YD9 0 ZD9 YOW XD5 YD5 ZD5 -- F_CNT5 XD9 0 F_WMRK5 0 SRC_TRANS 0 0 DBNCE[5] P_L_THS[5] P_L_THS[5] P_L_THS[5] L_P_THS[5] L_P_THS[5] L_P_THS[5] ZHEFE ZHE THS5 D5 ZHEFE ZHE Bit 4 XOW XD8 YD8 ZD8 XOW 0 XD8 0 YD8 0 ZD8 XOW XD4 YD4 ZD4 -- F_CNT4 XD8 0 F_WMRK4 0 SRC_LNDPRT 0 0 LAPO[2] LAPO[2] DBNCE[4] P_L_THS[4] P_L_THS[4] P_L_THS[4] L_P_THS[4] L_P_THS[4] L_P_THS[4] ZLEFE ZLE THS4 D4 ZLEFE ZLE Bit 3 ZYXDR XD7 YD7 ZD7 ZYXDR XD3 XD7 YD3 YD7 ZD3 ZD7 ZYXDR XD3 YD3 ZD3 -- F_CNT3 XD7 XD3 F_WMRK3 0 SRC_PULSE -- 0 LAPO[1] LAPO[1] DBNCE[3] P_L_THS[3] P_L_THS[3] P_L_THS[3] L_P_THS[3] L_P_THS[3] L_P_THS[3] YHEFE YHE THS3 D3 YHEFE YHE Bit 2 ZDR XD6 YD6 ZD6 ZDR XD2 XD6 YD2 YD6 ZD2 ZD6 ZDR XD2 YD2 ZD2 -- F_CNT2 XD6 XD2 F_WMRK2 0 SRC_FF_MT_1 ZDEFE 0 LAPO[0] LAPO[0] GOFF[2] DBNCE [2] ZLOCK[2] P_L_THS[2] P_L_THS[2] P_L_THS[2] L_P_THS[2] L_P_THS[2] L_P_THS[2] YLEFE YLE THS2 D2 YLEFE YLE Bit 1 YDR XD5 YD5 ZD5 YDR XD1 XD5 YD1 YD5 ZD1 ZD5 YDR XD1 YD1 ZD1 -- F_CNT1 XD5 XD1 F_WMRK1 SYSMOD1 SRC_FF_MT_2 YDEFE SEL1 BAFRO[1] BAFRO[1] GOFF[1] DBNCE [1] ZLOCK[1] P_L_THS[1] P_L_THS[1] P_L_THS[1] L_P_THS[1] L_P_THS[1] L_P_THS[1] XHEFE XHE THS1 D1 XHEFE XHE Bit 0 XDR XD4 YD4 ZD4 XDR XD0 XD4 YD0 YD4 ZD0 ZD4 XDR XD0 YD0 ZD0 -- F_CNT0 XD4 XD0 F_WMRK0 SYSMOD0 SRC_DRDY XDEFE SEL0 BAFRO[0] BAFRO[0] GOFF[0] DBNCE [0] ZLOCK[0] P_L_THS[0] P_L_THS[0] P_L_THS[0] L_P_THS[0] L_P_THS[0] L_P_THS[0] XLEFE XLE THS0 D0 XLEFE XLE
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Table 64. MMA8450Q Register Map
29 2A 2B 2C 2D 2E 2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F FF_MT_THS_2 FF_MT_COUNT_2 TRANSIENT_CFG TRANSIENT_SRC TRANSIENT_THS TRANSIENT_COUNT PULSE_CFG PULSE_SRC PULSE_THSX PULSE_THSY PULSE_THSZ PULSE_TMLT PULSE_LTCY PULSE_WIND ASLP_COUNT CTRL_REG1 CTRL_REG2 CTRL_REG3 CTRL_REG4 CTRL_REG5 OFF_X OFF_Y OFF_Z FF/Motion Threshold 2 R/W FF/Motion Debounce 2 R/W Transient Config. R/W Transient Source R Transient Threshold R/W Transient Debounce R/W Pulse Config. R/W Pulse Source R Pulse X Threshold R/W Pulse Y Threshold R/W Pulse Z Threshold R/W Pulse First Timer R/W Pulse Latency R/W Pulse 2nd Window R/W Auto-Sleep Counter R/W Control Reg 1 R/W Control Reg 2 R/W Control Reg3 R/W (Wake Interrupts from Sleep) Control Reg4 R/W (Interrupt Enable Map) Control reg5 R/W (Interrupt Configuration) X 8-bit offset Y 8-bit offset Z 8-bit offset DBCNTM D7 -- -- DBCNTM D7 DPA -- 0 0 0 Tmlt7 Ltcy7 Wind7 D7 ASLP_RATE1 ST FIFO_GATE INT_EN_ASLP THS6 D6 -- -- THS6 D6 ELE EA 0 0 0 Tmlt6 Ltcy6 Wind6 D6 ASLP_RATE0 RST WAKE_TRANS INT_EN_FIFO THS5 D5 -- -- THS5 D5 ZDPEFE ZDPE 0 0 0 Tmlt5 Ltcy5 Wind5 D5 0 0 WAKE_LNDPRT INT_EN_TRANS THS4 D4 -- -- THS4 D4 ZSPEFE ZSPE THSX4 THSY4 THSZ4 Tmlt4 Ltcy4 Wind4 D4 DR2 0 WAKE_PULSE INT_EN_LNDPRT THS3 D3 ELE EA THS3 D3 YDPEFE YDPE THSX3 THSY3 THSZ3 Tmlt3 Ltcy3 Wind3 D3 DR1 0 WAKE_FF_MT_1 INT_EN_PULSE INT_CFG_PULSE D3 D3 D3 THS2 D2 ZTEFE ZTRANSE THS2 D2 YSPEFE YSPE THSX2 THSY2 THSZ2 Tmlt2 Ltcy2 Wind2 D2 DR0 0 WAKE_FF_MT_2 INT_EN_FF_MT_1 THS1 D1 YTEFE YTRANSE THS1 D1 XDPEFE XDPE THSX1 THSY1 THSZ1 Tmlt1 Ltcy1 Wind1 D1 FS1 SLPE IPOL INT_EN_FF_MT_2 THS0 D0 XTEFE XTRANSE THS0 D0 XSPEFE XSPE THSX0 THSY0 THSZ0 Tmlt0 Ltcy0 Wind0 D0 FS0 MODS PP_OD INT_EN_DRDY
INT_CFG_ASLP INT_CFG_FIFO INT_CFG_TRANS INT_CFG_LNDPRT D7 D7 D7 D6 D6 D6 D5 D5 D5 D4 D4 D4
INT_CFG_FF_MT_1 INT_CFG_FF_MT_2 INT_CFG_DRDY D2 D2 D2 D1 D1 D1 D0 D0 D0
MMA8450Q Sensors Freescale Semiconductor 44
Table 65. Accelerometer Output Data
12-bit Data 0111 1111 1111 0111 1111 1110 -- 0000 0000 0001 0000 0000 0000 1111 1111 1111 -- 1000 0000 0001 1000 0000 0000 8- bit Data 0111 1111 0111 1110 -- 0000 0001 0000 0000 1111 1111 -- 1000 0001 1000 0000 Range 2g 1.999g 1.998g -- 0.001g 0.000g -0.001g -- -1.999g -2.000g Range 2g 1.984g 1.968g -- +0.016g 0.000g -0.016g -- -1.984g -2.000g Range 4g +3.998g +3.996g -- +0.002g 0.000g -0.002g -- -3.998g -4.000g Range 4g +3.968g +3.936g -- +0.032g 0.000g -0.032g -- -3.968g -4.000g Range 8g +7.996g +7.992g -- +0.004g 0.000g -0.004g -- -7.996g -8.000g Range 8g +7.936g +7.872g -- +0.064g 0.000g -0.064g -- -7.936g -8.000g
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Appendix B
Figure 13. Distribution of Pre Board Mounted Devices Tested in Sockets (1 count = 3.9 mg)
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Figure 14. Distribution of Post Board Mounted Devices (1 count = 3.9 mg)
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Figure 15. 8g X-axis TCS
MMA8450Q Sensors Freescale Semiconductor 48
Figure 16. 8g Y-axis TCS
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Figure 17. 8g Z-axis TCS
MMA8450Q Sensors Freescale Semiconductor 50
Figure 18. 8g X-axis TCO (mg/C)
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Figure 19. 8g Y-axis TCO (mg/C)
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Figure 20. 8g Z-axis TCO (mg/C)
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PACKAGE DIMENSIONS
CASE 2077-01 ISSUE O 16-LEAD QFN
MMA8450Q Sensors Freescale Semiconductor 54
PACKAGE DIMENSIONS
CASE 2077-01 ISSUE O 16-LEAD Q
MMA8450Q 55 Sensors Freescale Semiconductor
PACKAGE DIMENSIONS
CASE 2077-01 ISSUE O 16-LEAD Q
MMA8450Q Sensors Freescale Semiconductor 56
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