Description
The DS12R885 is a functional drop-in replacement for the DS12885 real-time clock (RTC). The device pro-vides an RTC/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 114 bytes of battery-backed 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 oper-ates 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 back-up supply. The VBACKUPpin 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.
Features
Trickle-Charge Capability for a Rechargeable Battery or Super Cap
Selectable Intel or Motorola Bus Timing
RTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap-Year Compensation to 2100
Interrupt Output with Three Independently Maskable Interrupt Flags
Time-of-Day Alarm is Once-per-Second to Once-per-Day
Periodic Rates from 122µs to 500ms
End-of-Clock Update Cycle Flag
14 Bytes of Clock and Control Registers
114 Bytes of General-Purpose Battery-Backed NV RAM with Clear Input
Programmable Square-Wave Output
Automatic Power-Fail Detect and Switch Circuitry
+5.0V or +3.3V Operation
Industrial Temperature Range
DS12CR887 Encapsulated DIP (EDIP) Module with Integrated Battery and Crystal
DS12R887 BGA Module Surface-Mountable Package with Integrated Crystal and Rechargeable Battery
