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Cypress Semiconductor |
CY14C256I
CY14B256I, CY14E256I
256-Kbit (32 K × 8) Serial (I2C) nvSRAM
with Real Time Clock
256-Kbit (32 K × 8) Serial (I2C) nvSRAM with Real Time Clock
Features
■ 256-Kbit nonvolatile static random access memory (nvSRAM)
❐ Internally organized as 32 K × 8
❐ STORE to QuantumTrap nonvolatile elements initiated
automatically on power-down (AutoStore) or by using I2C
command (Software STORE) or HSB pin (Hardware STORE)
❐
RECALL
RECALL)
to
or
SRAM initiated on power-up (Power-Up
by I2C command (Software RECALL)
❐ Automatic STORE on power-down with a small capacitor
■ High reliability
❐ Infinite read, write, and RECALL cycles
❐ 1 million STORE cycles to QuantumTrap
❐ Data retention: 20 years at 85 °C
■ Real Time Clock (RTC)
❐ Full-featured RTC
❐ Watchdog timer
❐ Clock alarm with programmable interrupts
❐ Backup power fail indication
❐ Square wave output with programmable frequency (1 Hz,
512 Hz, 4096 Hz, 32.768 kHz)
❐ Capacitor or battery backup for RTC
❐ Backup current of 0.45 µA (typical)
■ High-speed I2C interface
❐ Industry standard 100 kHz and 400 kHz speed
❐ Fast mode Plus 1 MHz speed
❐ High speed: 3.4 MHz
❐ Zero cycle delay reads and writes
■ Write protection
❐ Hardware protection using Write Protect (WP) pin
❐ Software block protection for one-quarter, one-half, or entire
array
■ I2C access to special functions
❐ Nonvolatile STORE/RECALL
❐ 8-byte serial number
❐ Manufacturer ID and Product ID
❐ Sleep mode
■ Low power consumption
❐ Average active current of 1 mA at 3.4 MHz operation
❐ Average standby mode current of 250 µA
❐ Sleep mode current of 8 µA
■ Industry standard configurations
❐ Operating voltages:
• CY14C256I : VCC = 2.4 V to 2.6 V
• CY14B256I : VCC = 2.7 V to 3.6 V
• CY14E256I : VCC = 4.5 V to 5.5 V
❐ Industrial temperature
❐ 16-pin small outline integrated circuit (SOIC) package
❐ Restriction of hazardous substances (RoHS) compliant
Overview
The Cypress CY14C256I/CY14B256I/CY14E256I combines a
256-Kbit nvSRAM[1] with a full-featured RTC in a monolithic
integrated circuit with serial I2C interface. The memory is
organized as 64 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 I2C
commands.
Logic Block Diagram
VCC VCAP VRTCcap VRTCbat
Power Control
Block
Sleep
Serial Number
8x8
Manufacture ID/
Product ID
Memory Control Register
Command Register
SDA
SCL
A2, A1, A0
WP
2
I C Control Logic
Slave Address
Decoder
Control Registers Slave
Memory Slave
RTC Slave
Memory
Address and Data
Control
QuantrumTrap
32 K x 8
SRAM
32 K x 8
STORE
RECALL
X in RTC Control Logic
INT/SQW
Registers
Xout Counters
Note
1. Serial (I2C) nvSRAM will be referred to as nvSRAM throughout the datasheet.
Cypress Semiconductor Corporation • 198 Champion Court
wwwD.DocautamSheenett4#U: .0n0et1-65230 Rev. *B
• San Jose, CA 95134-1709 • 408-943-2600
Revised May 5, 2011
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CY14C256I
CY14B256I, CY14E256I
Contents
Pinouts .............................................................................. 3
Pin Definitions .................................................................. 3
I2C Interface ...................................................................... 4
Protocol Overview ............................................................ 4
I2C Protocol – Data Transfer ....................................... 4
Data Validity ...................................................................... 5
START Condition (S) ........................................................ 5
STOP Condition (P) .......................................................... 5
Repeated START (Sr) ....................................................... 5
Byte Format ....................................................................... 5
Acknowledge / No-acknowledge ..................................... 5
High-Speed Mode (Hs-mode) .......................................... 6
Serial Data Format in Hs-mode ................................... 6
Slave Device Address ...................................................... 7
Memory Slave Device ................................................. 7
RTC Registers Slave Device ....................................... 7
Control Registers Slave Device ................................... 7
Memory Control Register ............................................ 8
Command Register ..................................................... 8
Write Protection (WP) ....................................................... 9
AutoStore Operation ........................................................ 9
Hardware STORE and HSB pin Operation ..................... 9
Hardware RECALL (Power Up) ................................... 9
Write Operation ............................................................... 10
Read Operation ............................................................... 10
Memory Slave Access .................................................... 10
Write nvSRAM ........................................................... 10
Current nvSRAM Read .............................................. 12
Random Address Read ............................................. 13
RTC Registers Slave Access ......................................... 14
Write RTC Registers ................................................. 14
Current Address RTC Registers Read ...................... 15
Random Address RTC Registers Read .................... 15
Control Registers Slave ................................................. 16
Write Control Registers ............................................. 16
Current Control Registers Read ................................ 17
Random Control Registers Read .............................. 17
Serial Number ................................................................. 18
Serial Number Write .................................................. 18
Serial Number Lock ................................................... 18
Serial Number Read .................................................. 18
Device ID Read ......................................................... 19
Executing Commands Using Command Register ..... 19
Real Time Clock Operation ............................................ 20
nvTIME Operation ..................................................... 20
Clock Operations ....................................................... 20
Reading the Clock ..................................................... 20
Setting the Clock ....................................................... 20
Backup Power ........................................................... 20
Stopping and Starting the Oscillator .......................... 20
Calibrating the Clock ................................................. 21
Alarm ......................................................................... 21
Watchdog Timer ........................................................ 21
Programmable Square Wave Generator ................... 22
Power Monitor ........................................................... 22
Backup Power Monitor .............................................. 22
Interrupts ................................................................... 22
Interrupt Register ....................................................... 22
Flags Register ........................................................... 23
Best Practices ................................................................. 29
Maximum Ratings ........................................................... 30
Operating Range ............................................................. 30
DC Electrical Characteristics ........................................ 30
Data Retention and Endurance ..................................... 31
Thermal Resistance ........................................................ 31
AC Test Conditions ........................................................ 32
RTC Characteristics ....................................................... 32
AC Switching Characteristics ....................................... 33
nvSRAM Specifications ................................................. 34
Software Controlled STORE/RECALL Cycles .............. 35
Hardware STORE Cycle ................................................. 36
Ordering Information ...................................................... 37
Ordering Code Definitions ......................................... 37
Package Diagram ............................................................ 38
Acronyms ........................................................................ 39
Document Conventions ................................................. 39
Units of Measure ....................................................... 39
Document History Page ................................................. 40
Sales, Solutions, and Legal Information ...................... 41
Worldwide Sales and Design Support ....................... 41
Products .................................................................... 41
PSoC Solutions ......................................................... 41
Document #: 001-65230 Rev. *B
Page 2 of 41
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