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The FM30C256 is a 256-kilobit data collecTIonsubsystem including nonvolaTIle RAM, TImekeeping,CPU supervisor, and system tamper detecTIon. NonvolatileRAM is provided by FRAM technology,which is ideal for collection data and requires nobattery backup for nonvolatile storage. In otherrespects, it provides the same features as SRAM.FRAM performs write operations at bus speed withno write delays. Write cycles can be continuouswithout block limitations. In addition, it offers muchhigher write endurance than other nonvolatilememories. The FM30C256 supports up to 1010read/write cycles.The FM30C256 also includes timekeeping withexternal battery backup. The timekeeper consists ofregisters that represent time and date information inBCD format. The clock includes a calibration modethat allows a software adjustment for timekeepingaccuracy.To maintain system data integrity, the FM30C256provides a reset signal asserted when VDD is out oftolerance. /RST remains active for 100 ms after VDDreturns to proper levels. The FM30C256 alsoprovides a battery-backed tamper detect circuit thatrecords a rising edge on the TIN input. A batterybackedflag is set when the event occurs, but can onlybe cleared by software.The FM30C256 is provided in a 20-pin SOICpackage and is guaranteed over an industrialtemperature range of –40°C to +85°C.
