M41T0

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 ■ Operating temperature of –40 to 85 °C M41T0 Serial real-time clock 8 1 SO8 June 2011 Doc ID 9105 Rev 7 1/23 www.st.com 1 Contents Contents M41T0 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 2-wire bus characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.1 Bus not busy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.2 Start data transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.3 Stop data transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.4 Data valid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.1.5 Acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...