FM31256-GTR

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, realtime 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) interrupt or other purpose. The family operates from 2.7 to 5.5V Each FM31xx provides nonvolatile RAM available in sizes including 4Kb,16Kb,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. Processor Companion Active- low Reset Output for VDD and Watchdog Programmable VDD Reset Trip Point Manual Reset Filtered and Debalanced 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 100kHz & 400kHz 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℃ to +85℃ Operation 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.

Key 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
• 4Kb,16Kb,64Kb,and 256Kb versions Unlimited Read/Write Endurance 10 year Data Retention NoDelayTM Writes
• Real-time Clock/Calendar
• Backup Current under 1μA 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
• Fast Two-wire Serial Interface
• Up to 1 MHz Maximum Bus Frequency Supports Legacy Timing for 100kHz & 400kHz 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