[STMicroelectronics]

Description
The M41T0 real-time clock is a low power serial real-time clock with a built-in 32.768 kHz oscillator (external crystal controlled). Eight registers 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.

FEATUREs
■ Counters for seconds, minutes, hours, day, date, month, years, and century
■ 32 KHz crystal oscillator integrating load capacitance (12.5 pF) providing exceptional oscillator stability and high crystal series resistance operation
■ Oscillator stop detection monitors clock operation
■ Serial interface supports I2C bus (400 kHz protocol)
■ Low standby current 0.9 µA (typ at 3 V)
■ 2.0 to 5.5 V clock operating voltage
■ Special software programmable output
■ Software clock calibration to compensate crystal deviation due to temperature
■ Operating temperature of –40 to 85°C