The PCF2129AT/2,518 is an accurate Real Time Clock with an integrated temperature compensated crystal (Xtal) oscillator (TCXO) and a 32.768kHz quartz crystal optimized for very high accuracy and very low power consumption. This has a selectable I2C-bus or SPI-bus, a backup battery switch-over circuit, a programmable watchdog function and a timestamp function.
Timestamp function with interrupt capability
3 Line SPI-bus with separate data input and output
Battery backup input pin and switch-over circuitry