The M41T80 is a serial access RTC chip with alarms. It operates at a voltage of 2.0-5.5V and has counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century. It supports the I2C bus (400KHz) and has programmable alarm and interrupt functions. It has a working current of 200µA and a working temperature of -40 to 85°C.