Serial Access Real-Time Clock With Alarms

The M41T81S is a low power Serial RTC with a built-in 32.768kHz Oscillator (external crystal controlled). Eight bytes of the SRAM (see Table 2: Clock Register map on page 15) are used for the Clock calendar function and are configured in binary coded decimal (BCD) format. An additional 12 bytes of SRAM provide status/control of Alarm, Watchdog and Square Wave 2 functions. Addresses and data are transferred serially via a two line, bi-directional I C Interface The built-in address Register is incremented automatically after each WRITE or READ data byte. By STMicroelectronics