General Description
The DS12885, DS12887, and DS12C887 real-time clocks (RTCs) are
designed to be direct replacements for the DS1285 and DS1287. The
devices provide a real-time clock/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 (113 bytes in the DS12C887 and DS12C887A). The DS12887
integrates a quartz crystal and lithium energy source into a 24-pin
encapsulated DIP package.
Features
♦ Drop-In Replacement for IBM AT Computer Clock/Calendar
♦ RTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year
with Leap Year Compensation Through 2099
♦ Binary or BCD Time Representation
♦ 12-Hour or 24-Hour Clock with AM and PM in 12-Hour Mode
♦ Daylight Saving Time Option
♦ Selectable Intel or Motorola Bus Timing
♦ Interfaced with Software as 128 RAM Locations
♦ 14 Bytes of Clock and Control Registers
♦ 114 Bytes of General-Purpose, Battery-Backed RAM (113 Bytes in
the DS12C887 and DS12C887A)
♦ RAM Clear Function (DS12885, DS12887A, and DS12C887A)
♦ Interrupt Output with Three Independently Maskable Interrupt
Flags
♦ Time-of-Day Alarm Once Per Second to Once Per Day
♦ Periodic Rates from 122μs to 500ms
♦ End-of-Clock Update Cycle Flag
♦ Programmable Square-Wave Output
♦ Automatic Power-Fail Detect and Switch Circuitry
♦ Optional 28-Pin PLCC Surface Mount Package or 32-Pin TQFP
(DS12885)
♦ Optional Encapsulated DIP (EDIP) Package with Integrated Crystal
and Battery (DS12887, DS12887A, DS12C887, DS12C887A)
♦ Optional Industrial Temperature Range Available
♦ Underwriters Laboratory (UL) Recognized
