The DS12R885 is a functional drop-in replacement for
the DS12885 real-time clock (RTC). The device provides
an RTC/calendar, one time-of-day alarm, three
maskable interrupts with a common interrupt output, a
programmable square wave, and 114 bytes of batterybacked
static RAM. The date at the end of the month is
automatically adjusted for months with fewer than 31
days, including correction for leap years. It also operates
in either 24-hour or 12-hour format with an AM/PM
indicator. A precision temperature-compensated circuit
monitors the status of VCC. If a primary power failure is
detected, the device automatically switches to a backup
supply. The VBACKUP pin supports a rechargeable
battery or a super cap and includes an integrated,
always enabled trickle charger. The DS12R885 is
accessed through a multiplexed byte-wide interface,
which supports both Intel and Motorola modes. The
DS12CR887 and DS12R887 integrate the DS12R885
die with a crystal and battery.