STMICROELECTRONICS M41T56M6F

M41T56M6F is a low-power, serial real-time clock (RTC) with 56 bytes of NVRAM. A built-in 32,768Hz oscillator (external crystal controlled) and the first 8 bytes of the RAM are used for the clock/calendar function and are configured in binary-coded decimal (BCD) format. Addresses and data are transferred serially via a two-line, bidirectional bus. The built-in address register is incremented automatically after each WRITE or READ data byte. The M41T56 clock has a built-in power sense circuit that detects power failures and automatically switches to the battery supply during power failures. The energy needed to sustain the RAM and clock operations can be supplied from a small lithium coin cell.