FM31256/FM3164

Integrated Processor Companion with Memory

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

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

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.