The FM30C256 is a 256-kilobit data collection subsystem including nonvolatile RAM, timekeeping, CPU supervisor, and system tamper detection. Nonvolatile RAM is provided by FRAM technology, which is ideal for collection data and requires no battery backup for nonvolatile storage. In other respects, it provides the same features as SRAM. FRAM performs write operations at bus speed with no write delays. Write cycles can be continuous without block limitations. In addition, it offers much higher write endurance than other nonvolatile memories. The FM30C256 supports up to 1010 read/write cycles. The FM30C256 also includes timekeeping with external battery backup. The timekeeper consists of registers that represent time and date information in BCD format. The clock includes a calibration mode that allows a software adjustment for timekeeping accuracy. To maintain system data integrity, the FM30C256 provides a reset signal asserted when VDD is out of tolerance. /RST remains active for 100 ms after VDD returns to proper levels. The FM30C256 also provides a battery-backed tamper detect circuit that records a rising edge on the TIN input. A batterybacked flag is set when the event occurs, but can only be cleared by software. The FM30C256 is provided in a 20-pin SOIC package and is guaranteed over an industrial temperature range of –40°C to +85°C.