FM3164/FM31256
64-Kbit/256-Kbit Integrated Processor
Companion with F-RAM
256-Kbit (32 K × 8) Serial (SPI) F-RAM
Features
Functional Overview
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64-Kbit/256-Kbit ferroelectric random access memory (F-RAM)
❐ Logically organized as 8 K × 8 (FM3164) / 32 K × 8 (FM31256)
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❐ High-endurance 100 trillion (10 ) read/writes
❐ 151-year data retention (See the Data Retention and
Endurance table)
❐ NoDelay™ writes
❐ Advanced high-reliability ferroelectric process
The FM3164/FM31256 device integrates F-RAM memory with
the most commonly needed functions for processor-based
systems. Major features include nonvolatile memory, real time
clock, low-VDD reset, watchdog timer, nonvolatile event counter,
lockable 64-bit serial number area, and general purpose
comparator that can be used for a power-fail (NMI) interrupt or
any other purpose.
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High Integration Device Replaces Multiple Parts
❐ Serial nonvolatile memory
❐ Real time clock (RTC)
❐ Low voltage reset
❐ Watchdog timer
❐ Early power-fail warning/NMI
❐ Two 16-bit event counter
❐ Serial number with write-lock for security
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Real-time Clock/Calendar
❐ Backup current at 2 V: 1.15 A at +25 C
❐ Seconds through centuries in BCD format
❐ Tracks leap years through 2099
❐ Uses standard 32.768 kHz crystal (6 pF)
❐ Software calibration
❐ Supports battery or capacitor backup
The FM3164/FM31256 is a 64-Kbit/256-Kbit nonvolatile memory
employing an advanced ferroelectric process. A ferroelectric
random access memory or F-RAM is nonvolatile and performs
reads and writes similar to a RAM. This memory is truly
nonvolatile rather than battery backed. It provides reliable data
retention for 151 years while eliminating the complexities,
overhead, and system-level reliability problems caused by other
nonvolatile memories. The FM3164/FM31256 is capable of
supporting 1014 read/write cycles, or 100 million times more write
cycles than EEPROM.
The real time clock (RTC) provides time and date information in
BCD format. It can be permanently powered from an external
backup voltage source, either a battery or a capacitor. The
timekeeper uses a common external 32.768 kHz crystal and
provides a calibration mode that allows software adjustment of
timekeeping accuracy.
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Processor Companion
❐ Active-low reset output for VDD and watchdog
❐ Programmable low-VDD reset trip point
❐ Manual reset filtered and debounced
❐ Programmable watchdog timer
❐ Dual Battery-backed event counter tracks system intrusions
or other events
❐ Comparator for power-fail interrupt
❐ 64-bit programmable serial number with lock
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Fast 2-wire serial interface (I2C)
❐ Up to 1-MHz frequency
❐ Supports legacy timings for 100 kHz and 400 kHz
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❐ RTC, Supervisor controlled via I C interface
❐ Device select pins for up to 4 memory devices
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Low power consumption
❐ 1.5 mA active current at 1 MHz
❐ 150 A standby current
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Industrial temperature: –40 C to +85 C
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14-pin small outline integrated circuit (SOIC) package
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A comparator on PFI compares an external input pin to the
onboard 1.2 V reference. This is useful for generating a
power-fail interrupt (NMI) but can be used for any purpose. The
family also includes a programmable 64-bit serial number that
can be locked making it unalterable. Additionally it offers a dual
battery-backed event counter that tracks the number of rising or
falling edges detected on a dedicated input pin.
Operating voltage: VDD = 2.7 V to 5.5 V
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The processor companion includes commonly needed CPU
support functions. Supervisory functions include a reset output
signal controlled by either a low VDD condition or a watchdog
timeout. RST goes active when VDD drops below a
programmable threshold and remains active for 100 ms after
VDD rises above the trip point. A programmable watchdog timer
runs from 100 ms to 3 seconds. The watchdog timer is optional,
but if enabled it will assert the reset signal for 100 ms if not
restarted by the host before the timeout. A flag-bit indicates the
source of the reset.
Restriction of hazardous substances (RoHS) compliant
Cypress Semiconductor Corporation
Document Number: 001-86391 Rev. *D
For a complete list of related documentation, click here.
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198 Champion Court
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San Jose, CA 95134-1709
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408-943-2600
Revised November 5, 2014
