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PRELIMINARY
CY14B101P
1-Mbit (128 K x 8) Automotive Serial (SPI) nvSRAM with Real Time Clock
1 Mbit (128K x 8) Serial SPI nvSRAM with Real Time Clock
Features
1 Mbit nonvolatile static random access memory (nvSRAM) Internally organized as 128 K x 8 STORE to QuantumTrap nonvolatile elements initiated automatically on power-down (AutoStore) or by the user using HSB pin (hardware STORE) or SPI instruction (Software STORE) RECALL to SRAM initiated on power-up (power-up RECALL) or by SPI instruction (software RECALL) Automatic STORE on power-down with a small capacitor High reliability

Write protection Hardware protection using Write Protect (WP) pin Software protection using the Write Disable Instruction Software block protection for one-quarter, one-half, or entire array Low power consumption Operating voltages: * Automotive-A: VCC = 2.7 V to 3.6 V * Automotive-E: VCC = 3.0 V to 3.6 V Average active current of 10 mA at 40 MHz operation Industry standard configurations Temperature ranges * Automotive-A: -40 C to +85 C * Automotive-E: -40 C to +125 C 16-pin small outline integrated circuit (SOIC) package RoHS compliant

Infinite read, write, and RECALL cycles STORE cycles to QuantumTrap * Automotive-A: 1,000 K STORE cycles * Automotive-E: 100 K STORE cycles Data retention * Automotive-A: 20 years * Automotive-E: 2 years
Overview
The Cypress CY14B101P combines a 1 Mbit nonvolatile static RAM with full-featured real time clock in a monolithic integrated circuit with serial SPI interface. The memory is organized as 128 K words of 8 bits each. The embedded nonvolatile elements incorporate the QuantumTrap technology, creating the world's most reliable nonvolatile memory. The SRAM provides infinite read and write cycles, while the QuantumTrap cells provide highly reliable nonvolatile storage of data. Data transfers from SRAM to the nonvolatile elements (STORE operation) takes place automatically at power-down. On power-up, data is restored to the SRAM from the nonvolatile memory (RECALL operation). The STORE and RECALL operations can also be initiated by the user through SPI instruction.
Real time clock Full-featured real time clock Watchdog timer Clock alarm with programmable interrupts Capacitor or battery backup for RTC Backup current of 0.35 uA (typ) High-speed serial peripheral interface (SPI) 40 MHz clock rate - SRAM memory access 25 MHz clock rate - RTC memory access Supports SPI mode 0 (0,0) and mode 3 (1,1)
Logic Block Diagram
QuantumTrap 128 K X 8
VCC
VCAP
CS WP SCK HOLD
Power Control
Instruction decode Write protect Control logic
SRAM Array
128 K X 8
STORE RECALL
STORE/RECALL Control
HSB
Instruction register A0-A16 Address Decoder
D0-D7
RTC
Xout X in INT
MUX
SI
Data I/O register
SO
Status Register
Cypress Semiconductor Corporation Document #: 001-61932 Rev. *A
*
198 Champion Court
*
San Jose, CA 95134-1709 * 408-943-2600 Revised February 4, 2011
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PRELIMINARY
CY14B101P
Contents
Pinouts .............................................................................. 3 Device Operation .............................................................. 4 SRAM Write................................................................. 4 SRAM Read ................................................................ 4 STORE Operation ....................................................... 4 AutoStore Operation.................................................... 4 Software STORE Operation ........................................ 5 Hardware STORE and HSB pin Operation ................. 5 RECALL Operation...................................................... 5 Hardware RECALL (Power-Up) .................................. 5 Software RECALL ....................................................... 5 Serial Peripheral Interface ............................................... 6 SPI Overview............................................................... 6 SPI Modes ......................................................................... 7 SPI Operating Features.................................................... 8 Power-Up .................................................................... 8 Power On Reset .......................................................... 8 Power-Down................................................................ 8 Active Power and Standby Power Modes ................... 8 SPI Functional Description.............................................. 8 Status Register ................................................................. 9 Read Status Register (RDSR) Instruction ................... 9 Write Status Register (WRSR) Instruction .................. 9 Write Protection and Block Protection......................... 10 Write Enable (WREN) Instruction.............................. 10 Write Disable (WRDI) Instruction .............................. 10 Block Protection ........................................................ 10 Hardware Write Protection (WP Pin)......................... 10 Memory Access .............................................................. 11 Read Sequence (READ) Instruction.......................... 11 Write Sequence (WRITE) Instruction ........................ 11 RTC Access..................................................................... 12 READ RTC (RDRTC) Instruction .............................. 13 WRITE RTC (WRTC) Instruction............................... 13 nvSRAM Special Instructions........................................ 14 Software STORE (STORE) Instruction ..................... 14 Software RECALL (RECALL) Instruction .................. 14 HOLD Pin Operation ................................................. 14 Real Time Clock Operation............................................ nvTIME Operation ..................................................... Clock Operations....................................................... Reading the Clock ..................................................... Setting the Clock ....................................................... Backup Power ........................................................... Stopping and Starting the Oscillator.......................... Calibrating the Clock ................................................. Alarm ......................................................................... Watchdog Timer ........................................................ Power Monitor ........................................................... Interrupts ................................................................... Flags Register ........................................................... Accessing the Real Time Clock through SPI............. Best Practices................................................................. Maximum Ratings........................................................... DC Electrical Characteristics ........................................ Data Retention and Endurance .................................... Capacitance .................................................................... Thermal Resistance........................................................ AC Test Conditions ........................................................ RTC Characteristics ....................................................... AC Switching Characteristics ....................................... AutoStore or Power-Up RECALL .................................. Software Controlled STORE/RECALL Cycles.............. Hardware STORE Cycle ................................................. Ordering Information...................................................... Ordering Code Definition........................................... Package Diagrams.......................................................... Acronyms ........................................................................ Document Conventions ................................................. Units of Measure ....................................................... Document History Page ................................................ Sales, Solutions, and Legal Information ...................... Worldwide Sales and Design Support....................... Products .................................................................... PSoC Solutions ......................................................... 15 15 15 15 15 15 15 16 16 16 17 17 17 18 23 24 24 25 25 25 25 26 26 28 29 30 31 31 32 33 33 33 34 34 34 34 34
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PRELIMINARY
CY14B101P
Pinouts
Figure 1. Pin Diagram - 16-Pin SOIC
NC VRTCbat Xout Xin WP HOLD VRTCcap VSS
1 2 3 4 5 6 7 8 Top View not to scale
16 15 14 13 12 11 10 9
VCC INT VCAP SO SI SCK CS HSB
Table 1. Pin Definitions Pin Name CS SCK SI SO WP HOLD HSB I/O Type Input Input Input Output Input Input Input/Output Description Chip Select. Activates the device when pulled LOW. Driving this pin HIGH puts the device in low power standby mode. Serial clock. Runs at speeds up to maximum of fSCK. Serial input is latched at the rising edge of this clock. Serial output is driven at the falling edge of the clock. Serial input. Pin for input of all SPI instructions and data. Serial output. Pin for output of data through SPI. Write Protect. Implements hardware write protection in SPI. HOLD Pin. Suspends serial operation. Hardware STORE Busy: Output: Indicates busy status of nvSRAM when LOW. After each Hardware and Software STORE operation, HSB is driven HIGH for a short time (tHHHD) with standard output high current and then a weak internal pull-up resistor keeps this pin HIGH (external pull-up resistor connection optional). Input: Hardware STORE implemented by pulling this pin LOW externally. AutoStore capacitor. Supplies power to the nvSRAM during power loss to STORE data from the SRAM to nonvolatile elements. Specified value of capacitor must be connected for proper device operation. An inadequate value of capacitor will corrupt the device. Capacitor backup for RTC. Left unconnected if VRTCbat is used. Battery backup for RTC. Left unconnected if VRTCcap is used. Crystal output connection. Drives crystal on startup. Crystal input connection. For 32.768 kHz crystal. Interrupt output. Programmable to respond to the clock alarm, the watchdog timer, and the power monitor. Also programmable to either active HIGH (push or pull) or LOW (open drain). No connect. This pin is not connected to the die. Ground Power supply
VCAP
Power supply
VRTCcap VRTCbat Xout Xin INT NC VSS VCC
Power supply Power supply Output Input Output No connect Power supply Power supply
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PRELIMINARY
CY14B101P
Device Operation
CY14B101P is a 1-Mbit nvSRAM memory with integrated RTC and SPI interface. All the reads and writes to nvSRAM happen to the SRAM which gives nvSRAM the unique capability to handle infinite writes to the memory. The data in SRAM is secured by a STORE sequence that transfers the data in parallel to the nonvolatile QuantumTrap cells. A small capacitor (VCAP) is used to AutoStore the SRAM data in nonvolatile cells when power goes down providing power-down data security. The QuantumTrap nonvolatile elements built in the reliable SONOS technology make nvSRAM the ideal choice for secure data storage. In CY14B101P, the 1-Mbit memory array is organized as 128 K words x 8 bits. The memory is accessed through a standard SPI interface that enables very high clock speeds up to 40 MHz with zero delay read and write cycles. CY14B101P supports SPI modes 0 and 3 (CPOL, CPHA = 0, 0 and 1, 1) and operates as SPI slave. The device is enabled using the Chip Select (CS) pin and accessed through serial input (SI), serial output (SO), and serial clock (SCK) pins. CY14B101P provides the feature for hardware and software write protection through WP pin and WRDI instruction. CY14B101P also provides mechanisms for block write protection (one quarter, one-half, or full array) using BP0 and BP1 pins in the Status Register. Further, the HOLD pin is used to suspend any serial communication without resetting the serial sequence. CY14B101P uses the standard SPI opcodes for memory access. In addition to the general SPI instructions for read and write, CY14B101P provides two special instructions that enable access to two nvSRAM specific functions: STORE and RECALL. The major benefit of serial (SPI) nvSRAM over serial EEPROMs is that all reads and writes to nvSRAM are performed at the speed of SPI bus with zero cycle delay. Therefore, no wait time is required after any of the memory accesses. The STORE and RECALL operations need finite time to complete and all memory accesses are inhibited during this time. While a STORE or RECALL operation is in progress, the busy status of the device is indicated by the Hardware STORE Busy (HSB) pin and also reflected on the RDY bit of the Status Register.
The SPI write cycle sequence is defined in the Memory Access section of SPI Protocol Description.
SRAM Read
A read cycle in CY14B101P is performed at the SPI bus speed and the data is read out with zero cycle delay after the READ instruction is executed. The READ instruction is issued through the SI pin of the nvSRAM and consists of the READ opcode and three bytes of address. The data is read out on the SO pin. CY14B101P enables burst mode reads to be performed through SPI. This enables reads on consecutive addresses without issuing a new READ instruction. When the last address in memory is reached in burst mode read, the address rolls over to 0x0000 and the device continues to read. The SPI read cycle sequence is defined in the Memory Access section of SPI Protocol Description
STORE Operation
STORE operation transfers the data from the SRAM to the nonvolatile QuantumTrap cells. The CY14B101P stores data to the nonvolatile cells using one of the three STORE operations: AutoStore, activated on device power-down; Software STORE, activated by a STORE instruction; and Hardware STORE, activated by the HSB. During the STORE cycle, an erase of the previous nonvolatile data is first performed, followed by a program of the nonvolatile elements. After a STORE cycle is initiated, read/write to CY14B101P is inhibited until the cycle is completed. The HSB signal or the RDY bit in the Status Register can be monitored by the system to detect if a STORE or Software RECALL cycle is in progress. The busy status of nvSRAM is indicated by HSB being pulled LOW or RDY bit being set to `1'. To avoid unnecessary nonvolatile STOREs, Hardware STORE operation is ignored unless at least one write operation has taken place since the most recent STORE or RECALL cycle. However, software initiated STORE cycles are performed regardless of whether a write operation has taken place.
AutoStore Operation
The AutoStore operation is a unique feature of nvSRAM which automatically stores the SRAM data to QuantumTrap during power-down. This STORE makes use of an external capacitor (VCAP) which enables the device to safely STORE the data in the nonvolatile memory when power goes down. During normal operation, the device draws current from VCC to charge the capacitor connected to the VCAP pin. When the voltage on the VCC pin drops below VSWITCH during power-down, the device inhibits all memory accesses to nvSRAM and automatically performs a STORE operation using the charge from the VCAP capacitor. Note The nvSRAM should not be powered down without the specified capacitor on VCAP pin. Without proper VCAP, the AutoStore operation will corrupt the nvSRAM and make the part nonfunctional.
SRAM Write
All writes to nvSRAM are carried out on the SRAM and do not use up any endurance cycles of the nonvolatile memory. This enables the user to perform infinite write operations. A write cycle is performed through the WRITE instruction. The WRITE instruction is issued through the SI pin of the nvSRAM and consists of the WRITE opcode, 3 bytes of address, and 1 byte of data. Write to nvSRAM is done at SPI bus speed with zero cycle delay. CY14B101P allows burst mode writes to be performed through SPI. This enables write operations on consecutive addresses without issuing a new WRITE instruction. When the last address in memory is reached in burst mode, the address rolls over to 0x0000 and the device continues to write.
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PRELIMINARY
CY14B101P
Figure 2 shows the proper connection of the storage capacitor (VCAP) for AutoStore operation. Refer to DC Electrical Characteristics on page 24 for the size of the VCAP. Figure 2. AutoStore Mode
VCC
RECALL Operation
A RECALL operation transfers the data stored in the nonvolatile QuantumTrap elements to the SRAM. In CY14B101P, a RECALL may be initiated in two ways: Hardware RECALL, initiated on power-up; and Software RECALL, initiated by a SPI RECALL instruction. Internally, RECALL is a two step procedure. First, the SRAM data is cleared. Next, the nonvolatile information is transferred into the SRAM cells. All memory accesses are inhibited while a RECALL cycle is in progress. The RECALL operation does not alter the data in the nonvolatile elements.
0.1 uF 10 kOhm VCC
Hardware RECALL (Power-Up)
CS VCAP VCAP
During power-up, when VCC crosses VSWITCH, an automatic RECALL sequence is initiated which transfers the content of nonvolatile memory on to the SRAM. A Power-Up RECALL cycle takes tFA time to complete and the memory access is disabled during this time. HSB pin is used to detect the Ready status of the device.
VSS
Software RECALL Software STORE Operation
Software STORE allows the user to trigger a STORE operation through a special SPI instruction. STORE operation is initiated by executing STORE instruction irrespective of whether a write has been performed since the last NV operation. A STORE cycle takes tSTORE time to complete, during which all the memory accesses to nvSRAM are inhibited. The RDY bit of the Status Register or the HSB pin may be polled to find the Ready/Busy status of the nvSRAM. After the tSTORE cycle time is completed, the SRAM is activated again for read and write operations. Software RECALL allows the user to initiate a RECALL operation to restore the content of nonvolatile memory on to the SRAM. In CY14B101P, this can be done by issuing a RECALL instruction in SPI. A Software RECALL takes tRECALL time to complete during which all memory accesses to nvSRAM are inhibited. The controller must provide sufficient delay for the RECALL operation to complete before issuing any memory access instructions.
Hardware STORE and HSB pin Operation
The HSB pin in CY14B101P is used to control and acknowledge STORE operations. If no STORE/RECALL is in progress, this pin can be used to request a Hardware STORE cycle. When the HSB pin is driven LOW, the CY14B101P conditionally initiates a STORE operation after tDELAY duration. An STORE cycle starts only if a write to the SRAM has been performed since the last STORE or RECALL cycle. Reads and Writes to the memory are inhibited for tSTORE duration or as long as HSB pin is LOW. The HSB pin also acts as an open drain driver (internal 100 k weak pull-up resistor) that is internally driven LOW to indicate a busy condition when the STORE (initiated by any means) is in progress. Note After each Hardware and Software STORE operation HSB is driven HIGH for a short time (tHHHD) with standard output high current and then remains HIGH by internal 100 k pull-up resistor. Note For successfull last data byte STORE, a hardware STORE should be initiated atleast one clock cycle after the last data bit D0 is recieved. Upon completion of the STORE operation, the nvSRAM memory access is inhibited for tLZHSB time after HSB pin returns HIGH. Leave the HSB unconnected if it is not used. Document #: 001-61932 Rev. *A Page 5 of 35
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PRELIMINARY
CY14B101P
Serial Peripheral Interface
SPI Overview
The SPI is a four-pin interface with Chip Select (CS), Serial Input (SI), Serial Output (SO), and Serial Clock (SCK) pins. CY14B101P provides serial access to nvSRAM through SPI interface. The SPI bus on CY14B101P can run at speeds up to 40 MHz for all instructions except RDRTC which runs at 25 MHz. The SPI is a synchronous serial interface which uses clock and data pins for memory access and supports multiple devices on the data bus. A device on SPI bus is activated using the CS pin. The relationship between chip select, clock, and data is dictated by the SPI mode. CY14B101P supports SPI modes 0 and 3. In both these modes, data is clocked into the nvSRAM on the rising edge of SCK starting from the first rising edge after CS goes active. The SPI protocol is controlled by opcodes. These opcodes specify the commands from the bus master to the slave device. After CS is activated the first byte transferred from the bus master is the opcode. Following the opcode, any addresses and data are then transferred. The CS must go inactive after an operation is complete and before a new opcode can be issued. The commonly used terms used in SPI protocol are as follows: SPI Master The SPI master device controls the operations on a SPI bus. A SPI bus may have only one master with one or more slave devices. All the slaves share the same SPI bus lines and master may select any of the slave devices using the CS pin. All the operations must be initiated by the master activating a slave device by pulling the CS pin of the slave LOW. The master also generates the SCK and all the data transmission on SI and SO lines are synchronized with this clock. SPI Slave SPI slave device is activated by the master through the chip select line. A slave device gets the SCK as an input from the SPI master and all the communication is synchronized with this clock. SPI slave never initiates a communication on the SPI bus and acts on the instruction from the master. CY14B101P operates as a slave device and may share the SPI bus with multiple CY14B101P devices or other SPI devices. Chip Select (CS) For selecting any slave device, the master needs to pull-down the corresponding CS pin. Any instruction can be issued to a slave device only when the CS pin is LOW. The CY14B101P is selected when the CS pin is LOW. When the device is not selected, data through the SI pin is ignored and the SO remains in a high impedance state. Note A new instruction must begin with the falling edge of CS. Therefore, only one opcode can be issued for each active Chip Select cycle.
Serial Clock (SCK) Serial clock is generated by the SPI master and the communication is synchronized with this clock after CS goes LOW. CY14B101P allows SPI modes 0 and 3 for data communication. In both these modes, the inputs are latched by the slave device on the rising edge of SCK and outputs are issued on the falling edge. Therefore, the first rising edge of SCK signifies the arrival of first bit (MSB) of SPI instruction on the SI pin. Further, all data inputs and outputs are synchronized with SCK. Data Transmission SI/SO SPI data bus consists of two lines, SI and SO, for serial data communication. The SI is also referred to as Master Out Slave In (MOSI) and SO is referred to as Master In Slave Out (MISO). The master issues instructions to the slave through the SI pin, while slave responds through the SO pin. Multiple slave devices may share the SI and SO lines as described earlier. CY14B101P has two separate pins for SI and SO which can be connected with the master as shown in Figure 3 on page 7. Most Significant Bit (MSB) The SPI protocol requires that the first bit to be transmitted is the most significant bit (MSB). This is valid for both address and data transmission. CY14B101P requires a 3-byte address for any read or write operation. However, since the actual address is only 17 bits, it implies that the first seven bits, which are fed in, are ignored by the device. Although these seven bits are `don't care', Cypress recommends that these bits are treated as 0s to enable seamless transition to higher memory densities. Serial Opcode After the slave device is selected with CS going LOW, the first byte received is treated as the opcode for the intended operation. CY14B101P uses the standard opcodes for memory accesses. In addition to the memory accesses, CY14B101P provides additional opcodes for the nvSRAM specific functions: STORE, and RECALL. Refer to Table 2 on page 8 for details on opcodes. Invalid Opcode If an invalid opcode is received, the opcode is ignored and the device ignores any additional serial data on the SI pin till the next falling edge of CS and the SO pin remains tristated. Status Register CY14B101P has an 8-bit Status Register. The bits in the Status Register are used to configure the SPI bus. These bits are described in the Table 4 on page 9.
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PRELIMINARY
CY14B101P
Figure 3. System Configuration Using SPI nvSRAM
SCK M OSI M IS O
SCK
SI
SO
SCK
SI
SO
u C o n tro lle r C Y14B 101P C Y14B 101P
CS
HO LD
CS
HO LD
CS1 HO LD 1 CS2 HO LD 2
SPI Modes
CY14B101P device may be driven by a microcontroller with its SPI peripheral running in either of the following two modes:

The two SPI modes are shown in Figure 4 and Figure 5. The status of clock when the bus master is in standby mode and not transferring data is:
SCK remains at 0 for Mode 0
SPI Mode 0 (CPOL=0, CPHA=0) SPI Mode 3 (CPOL=1, CPHA=1)
For both these modes, input data is latched in on the rising edge of SCK starting from the first rising edge after CS goes active. If the clock starts from a HIGH state (in mode 3), the first rising edge after the clock toggles is considered. The output data is available on the falling edge of SCK. Figure 4. SPI Mode 0
CS
SCK remains at 1 for Mode 3 CPOL and CPHA bits must be set in the SPI controller for the either Mode 0 or Mode 3. CY14B101P detects the SPI mode from the status of SCK pin when the device is selected by bringing the CS pin LOW. If SCK pin is LOW when the device is selected, SPI Mode 0 is assumed and if SCK pin is HIGH, CY14B101P works in SPI Mode 3.
Figure 5. SPI Mode 3
CS
0
SCK
1
2
3
4
5
6
7
SCK
0
1
2
3
4
5
6
7
SI
7 MSB
6
5
4
3
2
1
0 LSB
SI
7 MSB
6
5
4
3
2
1
0 LSB
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PRELIMINARY
CY14B101P
SPI Operating Features
Power-Up
Power-up is defined as the condition when the power supply is turned on and VCC crosses Vswitch voltage. During this time, the CS must be enabled to follow the VCC voltage. Therefore, CS must be connected to VCC through a suitable pull-up resistor. As a built in safety feature, CS is both edge sensitive and level sensitive. After power-up, the device is not selected until a falling edge is detected on CS. This ensures that CS must have been HIGH, before going Low to start the first operation. As described earlier, nvSRAM performs a Power-Up RECALL operation after power-up and therefore, all memory accesses are disabled for tFA duration after power-up. The HSB pin can be probed to check the ready/busy status of nvSRAM after power-up.
Active Power and Standby Power Modes
When CS is LOW, the device is selected, and is in the active power mode. The device consumes ICC current, as specified in DC Electrical Characteristics on page 24. When CS is HIGH, the device is deselected and the device goes into the standby power mode if a STORE or RECALL cycle is not in progress. If a STORE/RECALL cycle is in progress, the device goes into the standby power mode after the STORE/RECALL cycle is completed. In the standby power mode the current drawn by the device drops to ISB.
SPI Functional Description
The CY14B101P uses an 8-bit instruction register. Instructions and their operation codes are listed in Table 2. All instructions, addresses, and data are transferred with the MSB first and start with a HIGH to LOW CS transition. There are, in all, 10 SPI instructions which provide access to most of the functions in nvSRAM. Further, the WP, HOLD and HSB pins provide additional functionality driven through hardware. Table 2. Instruction Set Instruction Category Instruction Name WREN WRDI RDSR WRSR READ WRITE RDRTC WRTC STORE RECALL - Reserved Opcode 0000 0110 0000 0100 0000 0101 0000 0001 0000 0011 0000 0010 0001 0011 0001 0010 0011 1100 0110 0000 0001 1110 Operation Set write enable latch Reset write enable latch Read Status Register Write Status Register Read data from memory array Write data to memory array Read RTC registers Write RTC registers Software STORE Software RECALL
Power On Reset
A power on reset (POR) circuit is included to prevent inadvertent writes. At power-up, the device does not respond to any instruction until the VCC reaches the POR threshold voltage (VSWITCH). After VCC transitions the POR threshold, the device is internally reset and performs a power-up RECALL operation. During Power-Up RECALL all device accesses are inhibited. The device is in the following state after POR:

Deselected (after power-up, a falling edge is required on CS before any instructions are started). Standby power mode Not in the Hold condition
Status Register Instructions
Status Register state: Write Enable (WEN) bit is reset to 0. WPEN, BP1, BP0 unchanged from previous STORE operation Don't care bits 4-6 are reset to 0. The WPEN, BP1, and BP0 bits of the Status Register are nonvolatile bits and remain unchanged from the previous STORE operation. Before selecting and issuing instructions to the memory, a valid and stable VCC voltage must be applied. This voltage must remain valid until the end of the instruction transmission.
SRAM Read/Write Instructions RTC Read/Write Instructions Special NV Instructions Reserved
Power-Down
At power-down (continuous decay of VCC), when VCC drops from the normal operating voltage and below the VSWITCH threshold voltage, the device stops responding to any instruction sent to it. If a write cycle is in progress and the last data bit D0 has been received when the power goes down, it is allowed tDELAY time to complete the write. After this, all memory accesses are inhibited and a AutoStore operation is performed. However, to avoid the possibility of inadvertent writes during power-down, ensure that the device is deselected and is in standby power mode, and the CS follows the voltage applied on VCC.
The SPI instructions in CY14B101P are divided based on their functionality in following types:

Status Register access: RDSR and WRSR instructions Write protection functions: WREN and WRDI instructions along with WP pin and WEN, BP0 and BP1 bits SRAM memory access: READ and WRITE instructions RTC access: RDRTC and WRTC instructions nvSRAM special instructions: STORE and RECALL
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CY14B101P
Status Register
The Status Register bits are listed in Table 3. The Status Register consists of a Ready bit (RDY) and data protection bits WEN, BP1, BP0 and WPEN. The RDY bit can be polled to check the Ready/Busy status while a nvSRAM STORE or Software RECALL cycle is in progress. The Status Register can be modified by WRSR instruction and read by RDSR instruction. However, only WPEN, BP1 and BP0 bits of the Status Register can be modified by using the WRSR instruction. The WRSR instruction has no effect on WEN and RDY bits. The default value shipped from the factory for WEN, BP0, BP1, bits 4-6 and WPEN bits is `0'. Table 3. Status Register Format Bit 7 WPEN (0) Bit 6 X (0) Bit 5 X (0) Bit 4 X (0) Bit 3 BP1 (0) Bit 2 BP0 (0) Bit 1 WEN (0) Bit 0 RDY
Table 4. Status Register Bit Definition Bit Bit 0 (RDY) Bit 1 (WEN) Ready Write enable Definition Description Read only bit indicates the ready status of device to perform a memory access. This bit is set to `1' by the device while a STORE or Software RECALL cycle is in progress. WEN indicates if the device is write enabled. This bit defaults to 0 (disabled) on power-up. WEN = '1' --> Write enabled WEN = '0' --> Write disabled Used for block protection. For details see Table 5 on page 10. Used for block protection. For details see Table 5 on page 10. Bits are writable and volatile. On power-up, bits are written with `0'. Used for enabling the function of Write Protect (WP) Pin. For details see Table 6 on page 11. 0 and bit 1 (RDY and WEN). The BP0 and BP1 bits can be used to select one of four levels of block protection. Further, WPEN bit must be set to `1' to enable the use of Write Protect (WP) pin. WRSR instruction is a write instruction and needs writes to be enabled (WEN bit set to `1') using the WREN instruction before it is issued. The instruction is issued after the falling edge of CS using the opcode for WRSR followed by eight bits of data to be stored in the Status Register. Since, only bits 2, 3, and 7 can be modified by WRSR instruction, it is recommended to leave the other bits as `0' while writing to the Status Register. Note In CY14B101P, the values written to Status Register are saved to nonvolatile memory only after a STORE operation.
Bit 2 (BP0) Bit 3 (BP1) Bits 4-6
Block protect bit `0' Block protect bit `1' Don't care
Bit 7(WPEN) Write protect enable bit
Read Status Register (RDSR) Instruction
The Read Status Register instruction provides access to the Status Register. This instruction is used to probe the Write Enable Status of the device or the Ready status of the device. RDY bit is set by the device to 1 whenever a STORE or Software RECALL cycle is in progress. The block protection and WPEN bits indicate the extent of protection employed. This instruction is issued after the falling edge of CS using the opcode for RDSR.
Write Status Register (WRSR) Instruction
The WRSR instruction enables the user to write to the Status Register. However, this instruction cannot be used to modify bit
Figure 6. Read Status Register (RDSR) Instruction Timing
CS
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
SCK
SI
0
0
0
0
HI-Z
0
1
0
1
0 MSB
LSB
SO
D7 D6 D5 D4 D3 D2 D1 D0
MSB
Data
LSB
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PRELIMINARY
CY14B101P
Figure 7. Write Status Register (WRSR) Instruction Timing
CS
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
SCK
Opcode Data in
SI
0
0
0
0
HI-Z
0
0
0
1 D7 X MSB
X
X D3 D2 X
X
LSB
SO
Write Protection and Block Protection
CY14B101P provides features for both software and hardware write protection using WRDI instruction and WP. Additionally, this device also provides block protection mechanism through BP0 and BP1 pins of the Status Register. The write enable and disable status of the device is indicated by WEN bit of the Status Register. The write instructions (WRSR, WRITE, and WRTC) and nvSRAM special instruction (STORE, and RECALL) need the write to be enabled (WEN bit = 1) before they can be issued.
Write Disable (WRDI) Instruction
Write Disable instruction disables the write by clearing the WEN bit to `0' to protect the device against inadvertent writes. This instruction is issued following the falling edge of CS followed by opcode for WRDI instruction. The WEN bit is cleared on the rising edge of CS following a WRDI instruction. Figure 9. WRDI Instruction
CS 0 SCK SI SO 0 0 0 0 0 1 0 0 1 2 3 4 5 6 7
Write Enable (WREN) Instruction
On power-up, the device is always in the write disable state. The following WRITE, WRSR, WRTC, or nvSRAM special instruction must therefore be preceded by a Write Enable instruction. If the device is not write enabled (WEN = `0'), it ignores the write instructions and returns to the standby state when CS is brought HIGH. A new CS falling edge is required to re-initiate serial communication. The instruction is issued following the falling edge of CS. When this instruction is used, the WEN bit of Status Register is set to `1'. Note After completion of a write instruction (WRSR, WRITE, or WRTC) or nvSRAM special instruction (STORE or RECALL) instruction, WEN bit is cleared to `0'. This is done to provide protection from any inadvertent writes. Therefore, WREN instruction must be used before a new write instruction can be issued. Figure 8. WREN Instruction
CS 0 SCK SI SO 0 0 0 0 0 1 1 0 1 2 3 4 5 6 7
HI-Z
Block Protection
Block protection is provided using the BP0 and BP1 pins of the Status Register. These bits can be set using WRSR instruction and probed using the RDSR instruction. The nvSRAM is divided into four array segments. One-quarter, one-half, or all of the memory segments can be protected. Any data within the protected segment is read only. Table 5 shows the function of block protect bits. Table 5. Block Write Protect Bits Status Register Bits Array Addresses Protected BP1 BP0 0 0 0 None 1 (1/4) 0 1 0x18000-0x1FFFF 2 (1/2) 1 0 0x10000-0x1FFFF 3 (All) 1 1 0x00000-0x1FFFF Level
HI-Z
Hardware Write Protection (WP Pin)
The write protect pin (WP) is used to provide hardware write protection. WP pin allows all normal read and write operations when held HIGH. When the WP pin is brought LOW and WPEN bit is `1', all write operations to the Status Register are inhibited. The hardware write protection function is blocked when the WPEN bit is `0'. This allows the user to install the CY14B101P in a system with the WP pin tied to ground, and still write to the Status Register. Page 10 of 35
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CY14B101P
WP pin can be used along with WPEN and block protect bits (BP1 and BP0) of the Status Register to inhibit writes to memory. When WP pin is LOW and WPEN is set to `1', any modifications to Status Register are disabled. Therefore, the memory is protected by setting the BP0 and BP1 bits and the WP pin inhibits any modification of the Status Register bits, providing hardware write protection. Note WP going LOW when CS is still LOW has no effect on any of the ongoing write operations to the Status Register. Table 6 summarizes all the protection features provided in the CY14B101P. Table 6. Write Protection Operation WPEN X 0 1 1 WP X X LOW HIGH Status WEN Protected Unprotected Register Blocks Blocks 0 1 1 1 Protected Protected Protected Protected Protected Writable Writable Writable Protected Writable Protected Writable
CY14B101P allows reads to be performed in bursts through SPI which can be used to read consecutive addresses without issuing a new READ instruction. If only one byte is to be read, the CS line must be driven HIGH after one byte of data comes out. However, the read sequence may be continued by holding the CS line LOW and the address is automatically incremented and data continues to shift out on SO pin. When the last data memory address (0x1FFFF) is reached, the address rolls over to 0x0000 and the device continues to read.
Write Sequence (WRITE) Instruction
The write operations on CY14B101P are performed through the SI pin. To perform a write operation, if the device is write disabled, then the device must first be write enabled through the WREN instruction. When the writes are enabled (WEN = `1'), WRITE instruction is issued after the falling edge of CS. A WRITE instruction constitutes transmitting the WRITE opcode on SI line followed by 3-bytes of address and the data (D7-D0) which is to be written. The Most Significant address byte contains A16 in bit 0 with other bits being don't cares. Address bits A15 to A0 are sent in the following two address bytes. CY14B101P allows writes to be performed in bursts through SPI which can be used to write consecutive addresses without issuing a new WRITE instruction. If only one byte is to be written, the CS line must be driven HIGH after the D0 (LSB of data) is transmitted. However, if more bytes are to be written, CS line must be held LOW and address incremented automatically. The following bytes on the SI line are treated as data bytes and written in the successive addresses. When the last data memory address (0x1FFFF) is reached, the address rolls over to 0x0000 and the device continues to write. The WEN bit is reset to `0' on completion of a WRITE sequence. Note When a burst write reaches a protected block address, it continues the address increment into the protected space but does not write any data to the protected memory. If the address roll over takes the burst write to unprotected space, it resumes writes. The same operation is true if a burst write is initiated within a write protected block.
Memory Access
All memory accesses are done using the READ and WRITE instructions. These instructions cannot be used while a STORE or RECALL cycle is in progress. A STORE cycle in progress is indicated by the RDY bit of the Status Register and the HSB pin.
Read Sequence (READ) Instruction
The read operations on CY14B101P are performed by giving the instruction on SI pin and reading the output on SO pin. The following sequence needs to be followed for a read operation: After the CS line is pulled LOW to select a device, the read opcode is transmitted through the SI line followed by three bytes of address. The most significant address byte contains A16 in bit 0 and other bits as don't cares. Address bits A15 to A0 are sent in the following two address bytes. After the last address bit is transmitted on the SI pin, the data (D7-D0) at the specific address is shifted out on the SO line on the falling edge of SCK starting with D7. Any other data on SI line after the last address bit is ignored.
Figure 10. Read Instruction Timing
CS
SCK
Op-Code
17-bit Address
SI
0
0
0
0
0
0
1
1
00 MSB
0
0
0
0
0 A16
~~ ~~
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
20 21 22 23 0
1
2
3
4
5
6
7
A3 A2 A1 A0 LSB
D7 D6 D5 D4 D3 D2 D1 D0 MSB LSB Data
SO
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CY14B101P
Figure 11. Burst Mode Read Instruction Timing
CS
SCK
Op-Code
SI
0
0
0
0
0
0
1
1
0
0
0
0
0
0
0
A16
~ ~
17-bit Address
A3 A2 A1 A0
MSB
~ ~
LSB Data Byte 1 Data Byte N
SO
D7 D6 D5 D4 D3 D2 D1 D0 D7 D0 D7 D6 D5 D4 D3 D2 D1 D0
~ ~
~ ~
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
20 21 22 23 0
1
2
3
4
5
6
7
0
7
0
1
2
3
4
5
6
7
MSB
LSB
MSB
LSB
Figure 12. Write Instruction Timing
CS
SCK
Op-Code
17-bit Address
1 0 0
MSB
SI
0
0
0
0
0
0
0
0
0
0
0
0
A16
~~ ~~
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
20 21
22 23
0
1
2
3
4
5
6
7
A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0
LSB MSB Data LSB
SO
HI-Z
Figure 13. Burst Mode Write Instruction Timing
CS
SCK
~ ~
~ ~
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
20 21 22 23 0
1
2
3
4
5
6
7
0
7
0
1
2
3
4
5
6
7
Data Byte 1
Data Byte N
SI
0
0
0
0
0
0
1
0
0 MSB
0
0
0
0
0
0
A16
~ ~
A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D0 D7 D6 D5 D4 D3 D2 D1 D0 LSB MSB LSB
SO
HI-Z
RTC Access
CY14B101P uses 16 registers for RTC. These registers can be read out or written to by accessing all 16 registers in burst mode or accessing each register, one at a time. The RDRTC and WRTC instructions are used to access the RTC. All the RTC registers can be read in burst mode by issuing the RDRTC instruction and reading all 16 bytes without bringing the CS pin HIGH. The `R' bit must be set while reading the RTC
timekeeping registers to ensure that transitional values of time are not read. Writes to the RTC register are performed using the WRTC instruction. Writing RTC timekeeping registers and control registers, except for the flags register needs the `W' bit of the flags register to be set to `1'. The internal counters are updated with the new date and time setting when the `W' bit is cleared to `0'. All the RTC registers can also be written in burst mode using the WRTC instruction.
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~ ~
Op-Code
17-bit Address
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CY14B101P
The `R' bit in RTC flags register must be set to '1' before reading RTC time keeping registers to avoid reading transitional data. Read RTC (RDRTC) instruction allows the user to read the Modifying the RTC Flag registers requires a Write RTC cycle. contents of RTC registers. Reading the RTC registers through The R bit must be cleared to '0' after completion of the read the SO pin requires the following sequence: After the CS line is operation. pulled LOW to select a device, the RDRTC opcode is transmitted The easiest way to read RTC registers is to perform RDRTC in through the SI line followed by eight address bits for selecting the burst mode. The read may start from the first RTC register (0x00) register. Any data on the SI line after the address bits is ignored. and the CS must be held LOW to allow the data from all 16 RTC The data (D7-D0) at the specified address is then shifted out onto registers to be transmitted through the SO pin. the SO line. RDRTC also allows burst mode read operation. Note Read RTC (RDRTC) instruction operates at a maximum When reading multiple bytes from RTC registers, the address clock frequency of 25 MHz. The opcode cycles, address cycles rolls over to 0x00 after the last RTC register address (0x0F) is and dataout cycles need to run at 25 MHz for the instruction to work properly. reached. Figure 14. Read RTC (RDRTC) Instruction Timing
CS
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
READ RTC (RDRTC) Instruction
SCK
Op-Code
SI
0
0
0
1
0
0
1
1
00 MSB
0
0 A3 A2 A1 A0 LSB
D7 D6 D5 D4 D3 D2 D1 D0 MSB Data LSB
SO
WRITE RTC (WRTC) Instruction
WRITE RTC (WRTC) instruction allows the user to modify the contents of RTC registers. The WRTC instruction requires the WEN bit to be set to '1' before it can be issued. If WEN bit is '0', a WREN instruction needs to be issued before using WRTC. Writing RTC registers requires the following sequence: After the CS line is pulled LOW to select a device, WRTC opcode is transmitted through the SI line followed by eight address bits identifying the register which is to be written to and one or more bytes
of data. WRTC allows burst mode write operation. When writing more than one registers in burst mode, the address rolls over to 0x00 after the last RTC address (0x0F) is reached. Note that writing to RTC timekeeping and control registers require the `W' bit to be set to '1'. The values in these RTC registers take effect only after the `W' bit is cleared to '0'. Write Enable bit (WEN) is automatically cleared to `0' after completion of the WRTC instruction.
Figure 15. Write RTC (WRTC) Instruction Timing
CS
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
SCK
Op-Code
4-bit Address
1 0 0 0 0 0
SI
0
0
0
1
0
0
A3 A2 A1 A0
D7 D6 D5 D4 D3 D2 D1 D0
MSB
LSB MSB HI-Z
Data
LSB
SO
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CY14B101P
nvSRAM Special Instructions
CY14B101P provides two special instructions that allow access to the nvSRAM specific functions: STORE and RECALL. Table 7 lists these instructions. Table 7. nvSRAM Special Instructions Function Name STORE RECALL Opcode 0011 1100 0110 0000 Operation Software STORE Software RECALL
Figure 17. Software RECALL Operation
CS 0 SCK SI SO 0 1 1 0 0
HI-Z
1
2
3
4
5
6
7
0
0
0
Software STORE (STORE) Instruction
When a STORE instruction is executed, CY14B101P performs a Software STORE operation. The STORE operation is performed irrespective of whether a write has taken place since the last STORE or RECALL operation. Figure 16. Software STORE Operation
CS 0 SCK SI SO 0 0 1 1 1 1 0 0 1 2 3 4 5 6 7
HOLD Pin Operation
The HOLD pin is used to pause the serial communication. When the device is selected and a serial sequence is underway, HOLD is used to pause the serial communication with the master device without resetting the ongoing serial sequence. To pause, the HOLD pin must be brought LOW when the SCK pin is LOW. CS pin must remain LOW along with HOLD pin to pause serial communication. While the device serial communication is paused, inputs to the SI pin are ignored and the SO pin is in the high impedance state. To resume serial communication, the HOLD pin must be brought HIGH when the SCK pin is LOW (SCK may toggle during HOLD). Figure 18. HOLD Operation
CS SCK HOLD SO
~ ~
HI-Z
To issue this instruction, the device must be write enabled (WEN bit = `1').The instruction is performed by transmitting the STORE opcode on the SI pin following the falling edge of CS. The WEN bit is cleared on the positive edge of CS following the STORE instruction.
Software RECALL (RECALL) Instruction
When a RECALL instruction is executed, CY14B101P performs a Software RECALL operation. To issue this instruction, the device must be write enabled (WEN = `1'). The instruction is performed by transmitting the RECALL opcode on the SI pin following the falling edge of CS. The WEN bit is cleared on the positive edge of CS following the RECALL instruction.
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CY14B101P
Real Time Clock Operation
nvTIME Operation
The CY14B101P offers internal registers that contain clock, alarm, watchdog, interrupt, and control functions. The RTC registers occupy a separate address space from nvSRAM and are accessible through Read RTC (RDRTC) and Write RTC (WRTC) instructions on register addresses 0x00 to 0x0F. Internal double buffering of the clock and the timer information registers prevents accessing transitional internal clock data during a read or write operation. Double buffering also circumvents disrupting normal timing counts or the clock accuracy of the internal clock when accessing clock data. Clock and alarm registers store data in BCD format.
Backup Power
The RTC in the CY14B101P is intended for permanently powered operation. The VRTCcap or VRTCbat pin is connected depending on whether a capacitor or battery is chosen for the application. When the primary power, VCC, fails and drops below the VSWITCH, the device switches to the backup power supply. The clock oscillator uses very little current, which maximizes the backup time available from the backup source. Regardless of the clock operation with the primary source removed, the data stored in the nvSRAM is secure, having been stored in the nonvolatile elements when power was lost. During backup operation, the CY14B101P consumes a 0.35 A (typ) at room temperature. The user must choose capacitor or battery values according to the application. Backup time values based on maximum current specifications are shown in the following table. Nominal backup times are approximately two times longer. Table 8. RTC Backup Time Capacitor Value Automotive-A Automotive-E 0.1 F 0.15 F 0.47 F 0.68 F 1.0 F 1.5 F Backup Time 72 hours 14 days 30 days
Clock Operations
The clock registers maintain time up to 9,999 years in one-second increments. The time can be set to any calendar time and the clock automatically keeps track of days of the week and month, leap years, and century transitions. There are eight registers dedicated to the clock functions, which are used to set time with a write cycle and to read time during a read cycle. These registers contain the time of day in BCD format. Bits defined as `0' are currently not used and are reserved for future use by Cypress.
Reading the Clock
The double buffered RTC register structure reduces the chance of reading incorrect data from the clock. The user must stop internal updates to the CY14B101P time keeping registers before reading clock data, to prevent reading of data in transition. Stopping the register updates does not affect clock accuracy. The updating process is stopped by writing a `1' to the read bit `R' (in the flags register at 0x00), and does not restart until a `0' is written to the read bit. The RTC registers are read while the internal clock continues to run. After a `0' is written to the read bit (`R'), all RTC registers are simultaneously updated within 20 ms.
Using a capacitor has the obvious advantage of recharging the backup source each time the system is powered up. If a battery is used, a 3 V lithium is recommended and the CY14B101P sources current only from the battery when the primary power is removed. However, the battery is not recharged at any time by the CY14B101P. The battery capacity must be chosen for total anticipated cumulative down time required over the life of the system.
Stopping and Starting the Oscillator
The OSCEN bit in the calibration register at 0x08 controls the enable and disable of the oscillator. This bit is nonvolatile and is shipped to customers in the enabled (set to 0) state. To preserve the battery life when the system is in storage, OSCEN must be set to `1'. This turns off the oscillator circuit, extending the battery life. If the OSCEN bit goes from disabled to enabled, it takes approximately one second (two seconds maximum) for the oscillator to start. While system power is off, if the voltage on the backup supply (VRTCcap or VRTCbat) falls below their respective minimum level, the oscillator may fail.The CY14B101P has the ability to detect oscillator failure when system power is restored. This is recorded in the oscillator fail flag (OSCF) of the flags register at the address 0x00. When the device is powered on (VCC rises higher than VSWITCH) the OSCEN bit is checked for enabled status. If the OSCEN bit is enabled and the oscillator is not active within the first 5 ms, the OSCF bit is set to `1'. The system must check for this condition and then write `0' to clear the flag. Note that in addition to setting the OSCF flag bit, the time registers are reset to the "Base Time" (see Setting the Clock on page 15), which is the value last written to the timekeeping registers. The control or calibration registers and the OSCEN bit are not affected by the `oscillator failed' condition.
Setting the Clock
Setting the write bit `W' (in the flags register at 0x00) to a `1' stops updates to the time keeping registers and enables the time to be set. The correct day, date, and time is then written into the registers and must be in 24-hour BCD format. The time written is referred to as the "Base Time". This value is stored in nonvolatile registers and used in the calculation of the current time. Resetting the write bit to `0' transfers the values of timekeeping registers to the actual clock counters, after which the clock resumes normal operation. If the time written to the timekeeping registers is not in the correct BCD format, each invalid nibble of the RTC registers continue counting to 0xF before rolling over to 0x0 after which RTC resumes normal operation. Note After `W' bit is set to `0', values written into the timekeeping, alarm, calibration, and interrupt registers are transfered to the RTC time keeping counters in tRTCp time. These counter values must be saved to nonvolatile memory either by initiating a Software/Hardware STORE or AutoStore operation.
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CY14B101P
The value of OSCF must be reset to `0' when the time registers are written for the first time. This initializes the state of this bit that may have become set when the system was first powered on. To reset OSCF, set the write bit `W' (in the flags register at 0x00) to a `1' to enable writes to the Flag register. Write a `0' to the OSCF bit and then reset the write bit to `0' to disable writes.
Calibrating the Clock
The RTC is driven by a quartz controlled crystal with a nominal frequency of 32.768 kHz. Clock accuracy depends on the quality of the crystal and calibration. The crystals available in market typically have an error of +20 ppm to +35 ppm. However, CY14B101P employs a calibration circuit that improves the accuracy to +1/-2 ppm at 25 C. This implies an error of +2.5 seconds to -5 seconds per month. The calibration circuit adds or subtracts counts from the oscillator divider circuit to achieve this accuracy. The number of pulses that are suppressed (subtracted, negative calibration) or split (added, positive calibration) depends upon the value loaded into the five calibration bits found in calibration register at 0x08. The calibration bits occupy the five lower order bits in the calibration register. These bits are set to represent any value between `0' and 31 in binary form. Bit D5 is a sign bit, where a `1' indicates positive calibration and a `0' indicates negative calibration. Adding counts speeds the clock up and subtracting counts slows the clock down. If a binary `1' is loaded into the register, it corresponds to an adjustment of 4.068 or -2.034 ppm offset in oscillator error, depending on the sign. Calibration occurs within a 64-minute cycle. The first 62 minutes in the cycle may, once per minute, have one second shortened by 128 or lengthened by 256 oscillator cycles. If a binary `1' is loaded into the register, only the first two minutes of the 64 minute cycle are modified. If a binary 6 is loaded, the first 12 are affected, and so on. Therefore, each calibration step has the effect of adding 512 or subtracting 256 oscillator cycles for every 125,829,120 actual oscillator cycles, that is, 4.068 or -2.034 ppm of adjustment per calibration step in the Calibration register. To determine the required calibration, the CAL bit in the flags register (0x00) must be set to `1'. This causes the INT pin to toggle at a nominal frequency of 512 Hz. Any deviation measured from the 512 Hz indicates the degree and direction of the required correction. For example, a reading of 512.01024 Hz indicates a +20 ppm error. Hence, a decimal value of -10 (001010b) must be loaded into the Calibration register to offset this error. Note Setting or changing the calibration register does not affect the test output frequency. To set or clear CAL, set the write bit `W' (in the flags register at 0x00) to `1' to enable writes to the flags register. Write a value to CAL, and then reset the write bit to `0' to disable writes.
There are four alarm match fields - date, hours, minutes, and seconds. Each of these fields has a match bit that is used to determine if the field is used in the alarm match logic. Setting the match bit to `0' indicates that the corresponding field is used in the match process. Depending on the match bits, the alarm occurs as specifically as once a month or as frequently as once every minute. Selecting none of the match bits (all 1s) indicates that no match is required and therefore, alarm is disabled. Selecting all match bits (all 0s) causes an exact time and date match. There are two ways to detect an alarm event: by reading the AF flag or monitoring the INT pin. The AF flag in the flags register at 0x00 indicates that a date or time match has occurred. The AF bit is set to "1" when a match occurs. Reading the flags register clears the alarm flag bit (and all others). A hardware interrupt pin may also be used to detect an alarm event. To set, clear or enable an alarm, set the `W' bit (in flags register - 0x00) to `1' to enable writes to alarm registers. After writing the alarm value, clear the `W' bit back to `0' for the changes to take effect. Note CY14B101P requires the alarm match bit for seconds (0x02 - D7) to be set to `0' for proper operation of alarm flag and interrupt.
Watchdog Timer
The watchdog timer is a free running down counter that uses the 32 Hz clock (31.25 ms) derived from the crystal oscillator. The oscillator must be running for the watchdog to function. It begins counting down from the value loaded in the Watchdog Timer register. The timer consists of a loadable register and a free running counter. On power-up, the watchdog time out value in register 0x07 is loaded into the counter load register. Counting begins on power-up and restarts from the loadable value any time the watchdog strobe (WDS) bit is set to `1'. The counter is compared to the terminal value of `0'. If the counter reaches this value, it causes an internal flag and an optional interrupt output. You can prevent the time out interrupt by setting WDS bit to `1' prior to the counter reaching `0'. This causes the counter to reload with the watchdog time out value and to be restarted. As long as the user sets the WDS bit prior to the counter reaching the terminal value, the interrupt and WDT flag never occur. New time out values are written by setting the watchdog write bit to `0'. When the WDW is `0', new writes to the watchdog time out value bits D5-D0 are enabled to modify the time out value. When WDW is `1', writes to bits D5-D0 are ignored. The WDW function enables a user to set the WDS bit without concern that the watchdog timer value is modified. A logical diagram of the watchdog timer is shown in Figure 19 on page 17. Note that setting the watchdog time out value to `0' disables the watchdog function. The output of the watchdog timer is the flag bit WDF that is set if the watchdog is allowed to time out. If the watchdog interrupt enable (WIE) bit in the interrupt register is set, a hardware interrupt on INT pin is also generated on watchdog timeout. The flag and the hardware interrupt are both cleared when user reads the flags registers.
Alarm
The alarm function compares user programmed values of alarm time and date (stored in the registers 0x01-5) with the corresponding time of day and date values. When a match occurs, the alarm internal flag (AF) is set and an interrupt is generated on INT pin if alarm interrupt enable (AIE) bit is set.
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CY14B101P
.
Figure 19. Watchdog Timer Block Diagram
Clock Divider
32 Hz
Oscillator
32,768 KHz
1 Hz
Counter
Zero Compare
interrupt register and can be used to drive level or pulse mode output from the INT pin. In pulse mode, the pulse width is internally fixed at approximately 200 ms. This mode is intended to reset a host microcontroller. In the level mode, the pin goes to its active polarity until the flags register is read by the user. This mode is used as an interrupt to a host microcontroller. The control bits are summarized in the following section.
WDF
Interrupts are only generated while working on normal power and are not triggered when system is running in backup power mode. Note CY14B101P generates valid interrupts only after the Powerup RECALL sequence is completed. All events on INT pin must be ignored for tFA duration after powerup.
WDS
Load Register
D
Q
WDW
Q
Interrupt Register
Watchdog Register
write to Watchdog Register
Watchdog Interrupt Enable (WIE). When set to `1', the watchdog timer drives the INT pin and an internal flag when a watchdog time out occurs. When WIE is set to `0', the watchdog timer only affects the WDF flag in flags register. Alarm Interrupt Enable (AIE). When set to `1', the alarm match drives the INT pin and an internal flag. When AIE is set to `0', the alarm match only affects the AF flag in flags register. Power Fail Interrupt Enable (PFE). When set to `1', the power fail monitor drives the pin and an internal flag. When PFE is set to `0', the power fail monitor only affects the PF flag in flags register. High/Low (H/L). When set to a `1', the INT pin is active HIGH and the driver mode is push pull. The INT pin drives HIGH only when VCC is greater than VSWITCH. When set to a `0', the INT pin is active LOW and the drive mode is open drain. The INT pin must be pulled up to Vcc by a 10 k resistor while using the interrupt in active LOW mode. Pulse/Level (P/L). When set to a `1' and an interrupt occurs, the INT pin is driven for approximately 200 ms. When P/L is set to a `0', the INT pin is driven HIGH or LOW (determined by H/L) until the flags register is read. When an enabled interrupt source activates the INT pin, an external host reads the flags registers to determine the cause. Remember that all flags are cleared when the register is read. If the INT pin is programmed for Level mode, then the condition clears and the INT pin returns to its inactive state. If the pin is programmed for pulse mode, then reading the flag also clears the flag and the pin. The pulse does not complete its specified duration if the flags register is read. If the INT pin is used as a host reset, the flags register is not read during a reset.
Power Monitor
The CY14B101P provides a power management scheme with power fail interrupt capability. It also controls the internal switch to backup power for the clock and protects the memory from low VCC access. The power monitor is based on an internal band gap reference circuit that compares the VCC voltage to VSWITCH threshold. As described in the section "AutoStore Operation" on page 4, when VSWITCH is reached as VCC decays from power loss, a data STORE operation is initiated from SRAM to the nonvolatile elements, securing the last SRAM data state. Power is also switched from VCC to the backup supply (battery or capacitor) to operate the RTC oscillator. When operating from the backup source, read and write operations to nvSRAM are inhibited and the clock functions are not available to the user. The RTC clock continues to operate in the background. The updated RTC time keeping registers data are available to the user after VCC is restored to the device (see "AutoStore or Power-Up RECALL" on page 28).
Interrupts
The CY14B101P has a flags register, interrupt register, and interrupt logic that can signal interrupt to the microcontroller. There are three potential sources for interrupt: watchdog timer, power monitor, and alarm timer. Each of these can be individually enabled to drive the INT pin by appropriate setting in the interrupt register (0x06). In addition, each has an associated flag bit in the flags register (0x00) that the host processor uses to determine the cause of the interrupt. The INT pin driver has two bits that specify its behavior when an interrupt occurs. An interrupt is raised only if both a flag is raised by one of the three sources and the respective interrupt enable bit in interrupts register is enabled (set to `1'). After an interrupt source is active, two programmable bits, H/L and P/L, determine the behavior of the output pin driver on INT pin. These two bits are located in the
Flags Register
The flags register has three flag bits: WDF, AF, and PF, which can be used to generate an interrupt. These flags are set by the watchdog timeout, alarm match, or power fail monitor respectively. The processor can either poll this register or enable interrupts to be informed when a flag is set. These flags are automatically reset when the register is read. The flags register is automatically loaded with the value 0x00 on power-up (except for the OSCF bit. See "Stopping and Starting the Oscillator" on page 15.)
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Accessing the Real Time Clock through SPI
CY14B101P uses 16 registers for RTC. These registers can be read out or written to by accessing all 16 registers in burst mode or accessing each register, one at a time. The RDRTC and WRTC instructions are used to access the RTC. All the RTC registers can be read in burst mode by issuing the RDRTC instruction and reading all 16 bytes without bringing the CS pin HIGH. The `R' bit must be set while reading the RTC timekeeping registers to ensure that transitional values of time are not read.
Writes to the RTC register are performed using the WRTC instruction. Writing RTC timekeeping registers and control registers, except for the flag register needs the `W' bit of the flag register to be set to `1'. The internal counters are updated with the new date and time setting when the `W' bit is cleared to `0'. All the RTC registers can also be written in burst mode using the WRTC instruction.
Figure 20. RTC Recommended Component Configuration
Recommended Values Y1 = 32.768 KHz (12.5 pF) C1 = 10 pF C2 = 67 pF
C1 Y1 C2
Xout Xin
Note: The recommended values for C1 and C2 include board trace capacitance.
Figure 21. Interrupt Block Diagram
WDF Watchdog Timer WIE P/L PF Power Monitor VINT H/L AF Clock Alarm AIE PFE Pin Driver INT
VCC
VSS
WDF - Watchdog Timer Flag WIE - Watchdog Interrupt Enable PF - Power Fail Flag PFE - Power Fail Enable AF - Alarm Flag AIE - Alarm Interrupt Enable P/L - Pulse/Level H/L - High/Low
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Table 9. RTC Register Map[1, 2] Register 0x0F 0x0E 0x0D 0x0C 0x0B 0x0A 0x09 0x08 0x07 0x06 0x05 0x04 0x03 0x02 0x01 0x00 WDF 0 0 0 0 0 0 OSCEN (0) WIE (0) M (1) M (1) M (1) M (1) AF 0 BCD Format Data D7 D6 0 0 0 0 D5 0 D4 10s months 0 0 D3 D2 Years Months Day of month Day of week Hours Minutes Seconds Calibration (00000) WDT (000000) PFE (0) 0 H/L (1) P/L (0) 0 0 10s alarm date 10s alarm hours 10 alarm minutes 10 alarm seconds 10s centuries PF OSCF[4] 0 Alarm day Alarm hours Alarm minutes Alarm seconds Centuries CAL (0) W (0) R (0) D1 D0 10s years Function/Range Years: 00-99 Months: 01-12 Day of month: 01-31 Day of week: 01-07 Hours: 00-23 Minutes: 00-59 Seconds: 00-59 Calibration values [3] Watchdog [3] Interrupts [3] Alarm, Day of month: 01-31 Alarm, hours: 00-23 Alarm, minutes: 00-59 Alarm, seconds: 00-59 Centuries: 00-99 Flags [3]
10s day of month 0 10s minutes 10s seconds Cal sign (0) 10s hours
WDS (0) WDW (0) AIE (0) 0 0
Notes 1. () designates values shipped from the factory. 2. The unused bits of RTC registers are reserved for future use and should be set to `0' 3. This is a binary value, not a BCD value. 4. When user resets OSCF flag bit, the flags register will be updated after tRTCp time.
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Table 10. Register Map Detail Register D7 0x0F D6 10s years D5 Description Time Keeping - Years D4 D3 D2 Years D1 D0
Contains the lower two BCD digits of the year. Lower nibble (four bits) contains the value for years; upper nibble (four bits) contains the value for 10s of years. Each nibble operates from 0 to 9. The range for the register is 0-99. Time Keeping - Months D7 0x0E 0 D6 0 D5 0 D4 10s month D3 D2 Months D1 D0
Contains the BCD digits of the month. Lower nibble (four bits) contains the lower digit and operates from 0 to 9; upper nibble (one bit) contains the upper digit and operates from 0 to 1. The range for the register is 1-12. Time Keeping - Date D7 0x0D 0 D6 0 D5 D4 D3 D2 D1 D0 10s day of month Day of month
Contains the BCD digits for the date of the month. Lower nibble (four bits) contains the lower digit and operates from 0 to 9; upper nibble (two bits) contains the 10s digit and operates from 0 to 3. The range for the register is 1-31. Leap years are automatically adjusted for. Time Keeping - Day D7 0x0C 0 D6 0 D5 0 D4 0 D3 0 D2 D1 Day of week D0
Lower nibble (three bits) contains a value that correlates to day of the week. Day of the week is a ring counter that counts from 1 to 7 then returns to 1. The user must assign meaning to the day value, because the day is not integrated with the date. Time Keeping - Hours D7 0x0B 0 D6 0 D5 10s hours D4 D3 D2 Hours D1 D0
Contains the BCD value of hours in 24 hour format. Lower nibble (four bits) contains the lower digit and operates from 0 to 9; upper nibble (two bits) contains the upper digit and operates from 0 to 2. The range for the register is 0-23. Time Keeping - Minutes D7 0x0A 0 D6 D5 10s minutes D4 D3 D2 Minutes D1 D0
Contains the BCD value of minutes. Lower nibble (four bits) contains the lower digit and operates from 0 to 9; upper nibble (three bits) contains the upper minutes digit and operates from 0 to 5. The range for the register is 0-59. Time Keeping - Seconds D7 0x09 0 D6 D5 10s seconds D4 D3 D2 Seconds D1 D0
Contains the BCD value of seconds. Lower nibble (four bits) contains the lower digit and operates from 0 to 9; upper nibble (three bits) contains the upper digit and operates from 0 to 5. The range for the register is 0-59. Calibration/Control 0X08 D7 OSCEN OSCEN D6 0 D5 Calibration sign D4 D3 D2 Calibration D1 D0
Oscillator Enable. When set to `1', the oscillator is stopped. When set to `0', the oscillator runs. Disabling the oscillator saves battery or capacitor power during storage.
Calibration Determines if the calibration adjustment is applied as an addition (1) to or as a subtraction (0) from the time-base. sign Calibration These five bits control the calibration of the clock.
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Table 10. Register Map Detail (continued) Register 0x07 WDS WDW D7 WDS D6 WDW D5 Description Watchdog Timer D4 D3 WDT D2 D1 D0
Watchdog strobe. Setting this bit to `1' reloads and restarts the watchdog timer. Setting the bit to `0' has no effect. The bit is cleared automatically after the watchdog timer is reset. The WDS bit is write only. Reading it always returns a 0. Watchdog write enable. Setting this bit to `1' disables any WRITE to the watchdog timeout value (D5-D0). This enables the user to set the watchdog strobe bit without disturbing the timeout value. Setting this bit to `0' allows bits D5-D0 to be written to the watchdog register when the next write cycle is complete. This function is explained in more detail in Watchdog Timer on page 16. Watchdog timeout selection. The watchdog timer interval is selected by the 6-bit value in this register. It represents a multiplier of the 32 Hz count (31.25 ms). The range of timeout value is 31.25 ms (a setting of 1) to 2 seconds (setting of 3 Fh). Setting the watchdog timer register to 0 disables the timer. These bits can be written only if the WDW bit was set to 0 on a previous cycle. Interrupt Status/Control D7 WIE D6 AIE D5 PFE D4 0 D3 H/L D2 P/L D1 0 D0 0
WDT
0x06 WIE AIE PFE 0 H/L P/L
Watchdog interrupt enable. When set to `1' and a watchdog timeout occurs, the watchdog timer drives the INT pin and the WDF flag. When set to `0', the watchdog timeout affects only the WDF flag. Alarm interrupt enable. When set to `1', the alarm match drives the INT pin and the AF flag. When set to `0', the alarm match only affects the AF flag. Power fail enable. When set to `1', the alarm match drives the INT pin and the PF flag. When set to `0', the power fail monitor affects only the PF flag. Reserved for future use HIGH/LOW. When set to `1', the INT pin is driven active HIGH. When set to `0', the INT pin is open drain, active LOW. Pulse/Level. When set to `1', the INT pin is driven active (determined by H/L) by an interrupt source for approximately 200 ms. When set to 0, the INT pin is driven to an active level (as set by H/L) until the flags register is read. Alarm - Day D7 M D6 0 D5 D4 D3 D2 D1 Alarm date D0
0x05
10s alarm date
Contains the alarm value for the date of the month and the mask bit to select or deselect the date value. M Match. When this bit is set to `0', the date value is used in the alarm match. Setting this bit to `1' causes the match circuit to ignore the date value. Alarm - Hours D7 0x04 M D6 0 D5 D4 D3 D2 D1 Alarm hours D0 10s alarm hours
Contains the alarm value for the hours and the mask bit to select or deselect the hours value. M Match. When this bit is set to `0', the hours value is used in the alarm match. Setting this bit to `1' causes the match circuit to ignore the hours value. Alarm - Minutes 0x03 D7 M D6 D5 10s alarm minutes D4 D3 D2 D1 D0 Alarm minutes
Contains the alarm value for the minutes and the mask bit to select or deselect the minutes value. M Match. When this bit is set to `0', the minutes value is used in the alarm match. Setting this bit to `1' causes the match circuit to ignore the minutes value.
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Table 10. Register Map Detail (continued) Register D7 M D6 D5 10s alarm seconds Description Alarm - Seconds 0x02 D4 D3 D2 D1 D0 Alarm seconds
Contains the alarm value for the seconds and the mask bit to select or deselect the seconds' value. M Match. When this bit is set to `0', the seconds value is used in the alarm match. Setting this bit to `1' causes the match circuit to ignore the seconds value. Time Keeping - Centuries 0x01 D7 D6 D5 10s centuries D4 D3 D2 D1 Centuries D0
Contains the BCD value of centuries. Lower nibble contains the lower digit and operates from 0 to 9; upper nibble contains the upper digit and operates from 0 to 9. The range for the register is 0-99 centuries. Flags 0x00 WDF AF PF OSCF D7 WDF D6 AF D5 PF D4 OSCF D3 0 D2 CAL D1 W D0 R
Watchdog timer flag. This read only bit is set to `1' when the watchdog timer is allowed to reach 0 without being reset by the user. It is cleared to `0' when the flags register is read or on power-up. Alarm flag. This read only bit is set to `1' when the time and date match the values stored in the alarm registers with the match bits = 0. It is cleared when the flags register is read or on power-up. Power fail flag. This read only bit is set to `1' when power falls below the power fail threshold VSWITCH. It is cleared to `0' when the flags register is read or on power-up. Oscillator fail flag. Set to `1' on power-up if the oscillator is enabled and not running in the first 5 ms of operation. This indicates that RTC backup power failed and clock value is no longer valid. This bit survives the power cycle and is never cleared internally by the chip. The user must check for this condition and write '0' to clear this flag.When user resets OSCF flag bit, the bit will be updated after tRTCp time. Calibration mode. When set to `1', a 512 Hz square wave is output on the INT pin. When set to `0', the INT pin resumes normal operation. This bit defaults to 0 (disabled) on power-up. Write enable: Setting the `W' bit to `1' freezes updates of the RTC registers. The user can then write to RTC registers, alarm registers, calibration register, interrupt register and flags register. Setting the `W' bit to `0' causes the contents of the RTC registers to be transferred to the time keeping counters if the time has changed . This transfer process takes tRTCp time to complete. This bit defaults to 0 on power-up. Read enable: Setting `R' bit to `1', stops clock updates to user RTC registers so that clock updates are not seen during the reading process. Set `R' bit to `0' to resume clock updates to the holding register. Setting this bit does not require W bit to be set to `1'. This bit defaults to 0 on power-up.
CAL W
R
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Best Practices
nvSRAM products have been used effectively for over 27 years. While ease-of-use is one of the product's main system values, experience gained working with hundreds of applications has resulted in the following suggestions as best practices:

The nonvolatile cells in this nvSRAM product are delivered from Cypress with 0x00 written in all cells. Incoming inspection routines at customer or contract manufacturer's sites sometimes reprogram these values. Final NV patterns are typically repeating patterns of AA, 55, 00, FF, A5, or 5A. End product's firmware should not assume an NV array is in a set programmed state. Routines that check memory content values to determine first time system configuration, cold or warm boot status, and so on should always program a unique NV pattern (that is, complex 4-byte pattern of 46 E6 49 53 hex or more random bytes) as part of the final system manufacturing test to ensure these system routines work consistently.
Power-up boot firmware routines should rewrite the nvSRAM into the desired state. While the nvSRAM is shipped in a preset state, best practice is to again rewrite the nvSRAM into the desired state as a safeguard against events that might flip the bit inadvertently such as program bugs and incoming inspection routines. The VCAP value specified in this datasheet includes a minimum and a maximum value size. Best practice is to meet this requirement and not exceed the maximum VCAP value because the nvSRAM internal algorithm calculates VCAP charge and discharge time based on this max VCAP value. Customers that want to use a larger VCAP value to make sure there is extra store charge and store time should discuss their VCAP size selection with Cypress to understand any impact on the VCAP voltage level at the end of a tRECALL period. When base time is updated, these updates are transferred to the time keeping registers when `W' bit is set to `0'. This transfer takes tRTCp time to complete. It is recommended to initiate software STORE or Hardware STORE after tRTCp time to save the base time into nonvolatile memory.
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Maximum Ratings
Exceeding maximum ratings may shorten the useful life of the device. These user guidelines are not tested. Storage temperature ................................ -65 C to +150 C Maximum storage time At 150 C ambient temperature........ ............... 1000 h At 125 C ambient temperature........ .............. 2 Years At 85 C ambient temperature..................... 20 Years Note Maximum storage time is the data retention time calculated from the last power-down. Ambient temperature with power applied ........................................... -55 C to +150 C Supply voltage on VCC relative to VSS ..........-0.5 V to +4.1 V DC voltage applied to outputs in High-Z state ..................................... -0.5 V to VCC + 0.5 V Input voltage ........................................ -0.5 V to VCC + 0.5 V Transient voltage (<20 ns) on any pin to ground potential .................. -2.0 V to VCC + 2.0 V Package power dissipation capability (TA = 25 C) .................................................. 1.0 W Surface mount lead soldering temperature (3 Seconds).......................................... +260 C DC output current (1 output at a time, 1s duration). .... 15 mA Static discharge voltage.......................................... > 2001 V (per MIL-STD-883, Method 3015) Latch up current..................................................... > 140 mA Table 11. Operating Range Range Automotive-A Automotive-E Ambient Temperature -40 C to +85 C -40 C to +125 C VCC 2.7 V to 3.6 V 3.0 V to 3.6 V
DC Electrical Characteristics
Over the Operating Range Parameter Description VCC Power supply voltage ICC1 ICC2 ICC4 ISB Test Conditions Automotive-A Automotive-E Automotive-A Average Vcc current At fSCK = 40 MHz. Values obtained without output loads (IOUT Automotive-E = 0 mA) Average VCC current All inputs don't care, VCC = Max. Automotive-A - during STORE Average current for duration tSTORE Automotive-E - Average VCAP current All inputs don't care. Average current for Automotive-A - during AutoStore duration tSTORE Automotive-E - cycle VCC standby current CS > (VCC - 0.2 V). VIN < 0.2 V or > (VCC Automotive-A - - 0.2 V). W bit set to `0'. Standby current Automotive-E - level after nonvolatile cycle is complete. Inputs are static. f = 0 MHz. Input leakage current VCC = Max, VSS < VIN < VCC Automotive-A -1 (except HSB) Automotive-E -5 Input leakage current VCC = Max, VSS < VIN < VCC Automotive-A -100 (for HSB) Automotive-E -100 Off state output VCC = Max, VSS < VOUT < VCC Automotive-A -1 leakage current Automotive-E -5 Input HIGH voltage Automotive-A 2.0 Automotive-E 2.2 Input LOW voltage VSS - 0.5 Output HIGH voltage IOUT = -2 mA 2.4 Output LOW voltage IOUT = 4 mA - Storage capacitor Between VCAP pin and VSS, 5 V Rated 61 Min 2.7 3.0 - - Typ[5] 3.0 3.3 - - - - - - - - - - - - - - - - - - - 68 Max 3.6 3.6 10 15 10 15 5 8 5 10 +1 +5 +1 +5 +1 +5 VCC + 0.5 VCC + 0.5 0.8 - 0.4 180 Unit V V mA mA mA mA mA mA mA mA A A A A A A V V V V V F
IIX[6]
IOZ VIH VIL VOH VOL VCAP
Notes 5. Typical values are at 25 C, VCC = VCC (Typ). Not 100% tested. 6. The HSB pin has IOUT = -2 uA for VOH of 2.4 V when both active HIGH and LOW drivers are disabled. When they are enabled standard VOH and VOL are valid. This parameter is characterized but not tested.
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Data Retention and Endurance
Parameter DATAR NVC Data retention Nonvolatile STORE operations Description Description Automotive-A Automotive-E Automotive-A Automotive-E Min 20 2
CY14B101P
Unit Years Years K K
1,000 100
Capacitance
Parameter[7] CIN COUT Description Input capacitance Output pin capacitance Test Conditions TA = 25 C, f = 1 MHz, VCC = VCC (Typ) Max 6 8 Unit pF pF
Thermal Resistance
Parameter[7] Description Thermal resistance (Junction to ambient) Thermal resistance (Junction to case) Test Conditions Test conditions follow standard test methods and procedures for measuring thermal impedance, per EIA / JESD51. 16-SOIC 55.17 2.64 Unit C/W C/W
JA JC
Figure 22. AC Test Loads and Waveforms
577 3.0 V OUTPUT 30 pF R2 789 R1
for tri-state specs 577 3.0 V OUTPUT 5 pF R2 789 R1
AC Test Conditions
Input pulse levels.................................................... 0 V to 3 V Input rise and fall times (10% - 90%)............................ <3 ns Input and output timing reference levels........................ 1.5 V
Note 7. These parameters are guaranteed by design and are not tested.
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RTC Characteristics
Parameters VRTCbat IBAK[8] RTC battery pin voltage RTC backup current TA (Min) 25 C TA (Max) VRTCcap[9] RTC capacitor pin voltage TA (Min) 25 C TA (Max) tRTCp tOCS RBKCHG RTC processing time from end of `W' bit set to `0' RTC oscillator time to start RTC backup capacitor charge current-limiting resistor Automotive-A Automotive-E Description Min 1.8 - - - - 1.6 1.5 1.4 - - 350 Typ[5] 3.0 - 0.35 - - - 3.0 - - 1 - 0.5 0.75 3.6 3.6 3.6 350 2 850 Max 3.6 0.35 Units V A A A A V V V s sec
AC Switching Characteristics
Parameter fSCK tCL tCH tCS tCSS tCSH tSD tHD tHH tSH tCO tHHZ[11] tHLZ[11] tOH tHZCS Alt. Parameter fSCK tWL tWH tCE tCES tCEH tSU tH tHD tCD tV tHZ tLZ tHO tDIS Description Min Clock frequency, SCK Clock pulse width LOW Clock pulse width HIGH CS HIGH time CS setup time CS hold time Data in setup time Data in hold time HOLD hold time HOLD setup time Output valid HOLD to output HIGH-Z HOLD to output LOW-Z Output hold time Output disable time - 11 11 20 10 10 5 5 5 5 - - - 0 - 40 MHz Max 40 - - - - - - - - - 9 15 15 - 25 - - 0 - 25 MHz (RDRTC Instruction)[10] Min - 18 18 20 10 10 5 5 5 5 Max 25 - - - - - - - - - 15 15 15 - 25 MHz ns ns ns ns ns ns ns ns ns ns ns ns ns ns Unit
Notes 8. Current drawn from either VRTCcap or VRTCbat when VCC < VSWITCH. 9. If VRTCcap > 0.5 V or if no capacitor is connected to VRTCcap pin, the oscillator starts in tOCS time. If a backup capacitor is connected and VRTCcap < 0.5 V, the capacitor must be allowed to charge to 0.5 V for oscillator to start. 10. Applicable for RTC opcode cycles, address cycles and dataout cycles. 11. These parameters are guaranteed by design and are not tested.
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Figure 23. Synchronous Data Timing (Mode 0)
tCS
CS
tCSS tCH tCL tCSH
SCK
tSD tHD
SI
VALID IN
tCO tOH tHZCS
SO
HI-Z
~ ~
HI-Z
Figure 24. HOLD Timing
CS
SCK tHH tSH HOLD tHHZ SO
~ ~
tHH tSH
tHLZ
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AutoStore or Power-Up RECALL
Parameter tFA [12] tSTORE tDELAY VSWITCH
[13]
Description Power-Up RECALL duration STORE cycle duration Time allowed to complete SRAM write cycle Low voltage trigger level VCC rise time HSB output disable voltage HSB high to nvSRAM active time HSB high active time Automotive-A Automotive-E
CY14B101P Min - - - Max 20 8 25 2.65 2.95 - 1.9 5 500
Unit ms ms ns V V s V s ns
tVCCRISE[14] VHDIS[14] tLZHSB[14] tHHHD[14]
150 - - -
Switching Waveforms
Figure 25. AutoStore or Power-Up RECALL[15]
VCC VSWITCH VHDIS
t VCCRISE
16
tHHHD
tSTORE tHHHD
tSTORE
16
Note HSB OUT
Note tDELAY
AutoStore
tLZHSB tDELAY
tLZHSB
POWERUP RECALL Read & Write Inhibited (RWI) POWER-UP RECALL
tFA
tFA
Read & Write
BROWN OUT AutoStore
POWER-UP RECALL
Read & Write
POWER DOWN AutoStore
Notes 12. tFA starts from the time VCC rises above VSWITCH. 13. On a Hardware STORE and AutoStore initiation, SRAM write operation continues to be enabled for time tDELAY. 14. These parameters are guaranteed by design and are not tested. 15. Read and Write cycles are ignored during STORE, RECALL, and while VCC is below VSWITCH. 16. During power-up and power-down, HSB glitches when HSB pin is pulled up through an external resistor.
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Software Controlled STORE/RECALL Cycles
CY14B101P Parameter tRECALL tSS
[17, 18]
Description Min RECALL duration Soft sequence processing time - - Max 200 100
Unit s s
Figure 26. Software STORE Cycle[18]
Figure 27. Software RECALL Cycle[18]
CS 0 SCK SI 0 0 1 1 1 1 0 0
tSTORE
CS 1 2 3 4 5 6 7 SCK SI 0 1 1 0 0 0 0 0
tRECALL
0
1
2
3
4
5
6
7
RWI RDY
HI-Z
RWI RDY
HI-Z
Notes 17. This is the amount of time it takes to take action on a soft sequence command. Vcc power must remain HIGH to effectively register command. 18. Commands such as STORE and RECALL lock out IO until operation is complete which further increases this time. See the specific command.
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Hardware STORE Cycle
CY14B101P Parameter tPHSB Description Min Hardware STORE pulse width Figure 28. Hardware STORE Cycle[19] 15 Max - ns Unit
Write Latch set
HSB (IN) tDELAY HSB (OUT)
tSTORE
~ ~
tPHSB
tHHHD
~ ~
tLZHSB
RWI
Write Latch not set
HSB (IN)
~ ~
tPHSB
HSB pin is driven HIGH to VCC only by Internal 100 K resistor, HSB driver is disabled SRAM is disabled as long as HSB (IN) is driven LOW.
HSB (OUT)
tDELAY
RWI
Note 19. If an SRAM write has not taken place since the last nonvolatile cycle, no Hardware STORE takes place.
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Ordering Information
Ordering Code CY14B101P-SFXA CY14B101P-SFXE
These parts are Pb-free.
Package Diagram 51-85022
Package Type 16-pin SOIC
Operating Range Automotive-A Automotive-E
Ordering Code Definition
CY 14 B 101 P - SF X A T Option: T - Tape and Reel Blank - Std. Pb-Free Package: SF - 16 SOIC
Temperature: A - Automotive-A (-40 to 85 C) E - Automotive-E (-40 to 125 C)
P - Serial SPI nvSRAM with RTC Density: Voltage: B - 3.0 V 101 - 1 Mb
14 - nvSRAM
Cypress
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Package Diagrams
Figure 29. 16-Pin (300 mil) SOIC Package (51-85022)
51-85022 *C
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Acronyms
Acronym nvSRAM SPI RoHS I/O CMOS SOIC SONOS CPHA CPOL EEPROM JEDEC BCD CRC EIA RWI Description nonvolatile Static Random Access Memory Serial Peripheral Interface Restriction of Hazardous Substances Input/Output Complementary Metal Oxide Semiconductor Small Outline Integrated Circuit Silicon-Oxide-Nitride-Oxide-Silicon Clock Phase Clock Polarity Electrically Erasable Programmable Read-Only Memory Joint Electron Devices Engineering Council Binary Coded Decimal Cyclic Redundancy Check Electronic Industries Alliance Read and Write Inhibited
Document Conventions
Units of Measure
Symbol C Hz kbit kHz K A mA f MHz s ms ns pF ps V W Hertz 1024 bits kilohertz kilo ohms microamperes milliampere microfarads megahertz microseconds millisecond nanoseconds picofarads picoseconds volts ohms watts Unit of Measure degrees Celsius
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CY14B101P
Document History Page
Document Title: CY14B101P 1-Mbit (128 K x 8) Automotive Serial (SPI) nvSRAM with Real Time Clock Document Number: 001-61932 Orig. of Submission Rev. ECN No. Description of Change Change Date ** 2959612 GVCH 06/23/10 New Datasheet *A 3117045 GVCH 12/21/2010 Changed ground naming convention from GND to VSS Added Automotive-E related specs Removed AutoStore Disable feature Hardware STORE and HSB pin Operation: Added more clarity on HSB pin operation Updated Power-Down description Updated HOLD Pin Operation, Figure 18 and Figure 24 to indicate that CS pin must remain LOW along with HOLD pin to pause serial communication Updated Setting the Clock description Added footnote 4 Register Map Detail: Updated OSCF flag bit and `W' bit description Updated best practices Added tRTCp parameter to RTC Characteristics table Updated tLZHSB parameter description Figure 25: Typo error fixed Added Units of Measure
Document #: 001-61932 Rev. *A
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CY14B101P
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(c) Cypress Semiconductor Corporation, 2010-2011. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to be used for medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. Any Source Code (software and/or firmware) is owned by Cypress Semiconductor Corporation (Cypress) and is protected by and subject to worldwide patent protection (United States and foreign), United States copyright laws and international treaty provisions. Cypress hereby grants to licensee a personal, non-exclusive, non-transferable license to copy, use, modify, create derivative works of, and compile the Cypress Source Code and derivative works for the sole purpose of creating custom software and or firmware in support of licensee product to be used only in conjunction with a Cypress integrated circuit as specified in the applicable agreement. Any reproduction, modification, translation, compilation, or representation of this Source Code except as specified above is prohibited without the express written permission of Cypress. Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cypress reserves the right to make changes without further notice to the materials described herein. Cypress does not assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress' product in a life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. Use may be limited by and subject to the applicable Cypress software license agreement.
Document #: 001-61932 Rev. *A
Revised February 4, 2011
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