DS1321 - Maxim Integrated

DS1321 Flexible Nonvolatile Controller

VCCI VCCO VBAT A, B - +5V Power Supply Input - SRAM Power Supply Output - Backup Battery Input - Address Inputs CEI1 - CEI4 - Chip Enable Inputs CEO1 - CEO4 - Chip Enable Outputs TOL - VCC Tolerance Select BW - Battery Warning Output (Open Drain) RST - Reset Output (Open Drain) MODE - Mode Input GND - Ground NC - No Connection VCCO VBAT TOL CE.

Features

 Converts CMOS SRAM into nonvolatile memory
 Unconditionally write-protects SRAM when VCC is out of tolerance
 Automatically switches to battery backup supply when VCC power failure occurs
 Flexible memory organization - Mode 0: 4 banks with 1 SRAM each - Mode 1: 2 banks with 2 SRAMs each - Mode 2: 1 bank with 4 SRAMs each
 Monitors voltage of a lithium cell and provides advanced warning of impending battery failure
 Signals low-battery condition on active low Battery Warning output signal
 Resets processor when power failure occurs and holds processor in reset during system power-up
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