资 源 简 介
The FM31xxx is a family of integrated devices thatincludes the most commonly needed funcTIons forprocessor-based systems. Major features includenonvolaTIle memory available in various sizes, realTImeclock, low-VDD reset, watchdog TImer,nonvolatile event counter, lockable 64-bit serialnumber area, and general purpose comparator thatcan be used for an early power-fail (NMI) interrupt orother purpose. The family operates from 2.7 to 5.5V.Each FM31xxx provides nonvolatile RAM availablein sizes including 4Kb, 16Kb, 64Kb, and 256Kbversions. Fast write speed and unlimited enduranceallow the memory to serve as extra RAM orconventional nonvolatile storage. This memory istruly nonvolatile rather than battery backed.The real-time clock (RTC) provides time and dateinformation in BCD format. It can be permanentlypowered from external backup voltage source, eithera battery or a capacitor. The timekeeper uses acommon external 32.768 kHz crystal and provides acalibration mode that allows software adjustment oftimekeeping accuracy.
