FM3104

The FM31xxx is a family of integrated devices that includes the most commonly needed functions for processor-based systems. Major features of FM31xxx 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 FM31xxx 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. FM31xxx 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.