FM31256-G Datasheet, PDF (1/27 Pages) Cypress Semiconductor – Integrated Processor Companion with Memory

FM31256/FM3164
Integrated Processor Companion with Memory
Features
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 Counters
Serial Number with Write-lock for Security
Ferroelectric Nonvolatile RAM
64Kb, and 256Kb versions
Virtually Unlimited Read/Write Endurance
38 year Data Retention (+75 C)
NoDelay™ Writes
Real-time Clock/Calendar
Backup Current at 2V, 1.15 A (max.) at +25°C
Seconds through Centuries in BCD format
Tracks Leap Years through 2099
Uses Standard 32.768 kHz Crystal (6pF)
Software Calibration
Supports Battery or Capacitor Backup
Processor Companion
Active-low Reset Output for V_DD and Watchdog
Programmable V_DD Reset Trip Point
Manual Reset Filtered and Debounced
Programmable Watchdog Timer
Dual Battery-backed Event Counter Tracks
System Intrusions or other Events
Comparator for Early Power-Fail Interrupt
64-bit Programmable Serial Number with Lock
Fast Two-wire Serial Interface
Up to 1 MHz Maximum Bus Frequency
Supports Legacy Timing for 100 kHz & 400 kHz
Device Select Pins for up to 4 Memory Devices
RTC, Supervisor Controlled via 2-wire Interface
Easy to Use Configurations
Operates from 2.7 to 5.5V
Small Footprint 14-pin “Green” SOIC (-G)
Low Operating Current
-40 C to +85 C Operation
Description
The FM31xx is a family of integrated devices that
includes the most commonly needed functions for
processor-based systems. Major features include
nonvolatile memory available in various sizes, 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 an early power-fail (NMI) interruptor
other purpose. The family operates from 2.7 to 5.5V.
Each FM31xx provides nonvolatile RAM available
in sizes including 64Kb and 256Kb versions. Fast
write speed and unlimited endurance allow the
memory to serve as extra RAM or conventional
nonvolatile storage. This memory is truly nonvolatile
rather than battery backed.
The real-time clock (RTC) provides time and date
information in BCD format. It can be permanently
powered from 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.
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.
A general-purpose comparator compares an external
input pin to the onboard 1.2V 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
dedicated input pins.
This product conforms to specifications per the terms of the Ramtron standard warranty. The product has completed Ramtron’s
internal qualification testing and has reached production status.
Cypress Semiconductor Corporation • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600
Document Number: 001-86391 Rev. *B
Revised May 02, 2013