X1242

The X1242 is a Real Time Clock with calendar/CPU supervisor circuits and two polled alarms. The dual port clock and alarm registers allow the clock to operate, without loss of accuracy, even during read and write operations.

The clock/calendar provides functionality that is controllable and readable through a set of registers. The clock, using a low cost 32.768kHz crystal input, accurately tracks the time in seconds, minutes, hours, date, day, month and years. The X1242 has leap year correction and automatic adjustment for months with less than 31 days.

The X1242 provides a watchdog timer with 3 selectable time out periods and off. The watchdog activates a RESET pin when it expires. The reset also goes active when V_CC drops below a fixed trip point. There are two alarms where a match is monitored by polling status bits.

The X1242 offers a backup power input pin. This V BACK pin allows the device to be backed up by a nonrechargeable battery. The RTC is fully operational from 1.8 to 5.5 volts.

The X1242 provides a 2Kbyte EEPROM array, giving a safe, secure memory for critical user and configuration data. This memory is unaffected by complete failure of the main and backup supplies.