DS 12887+ – Echtzeituhr, Uhr/Kalender, EDIP-24

The DS12885, DS12887, and DS12C887 real-timeclocks (RTCs) are designed to be direct replacementsfor the DS1285 and DS1287. The devices provide areal-time clock/calendar, one time-of-day alarm, threemaskable interrupts with a common interrupt output, aprogrammable square wave, and 114 bytes of batterybackedstatic RAM (113 bytes in the DS12C887 andDS12C887A). The DS12887 integrates a quartz crystaland lithium energy source into a 24-pin encapsulatedDIP package. The DS12C887 adds a century byte ataddress 32h. For all devices, the date at the end of themonth is automatically adjusted for months with fewerthan 31 days, including correction for leap years. Thedevices also operate in either 24-hour or12-hour format with an AM/PM indicator. A precisiontemperature-compensated circuit monitors the status ofVCC. If a primary power failure is detected, the deviceautomatically switches to a backup supply. A lithiumcoin-cell battery can be connected to the VBAT inputpin on the DS12885 to maintain time and date operationwhen primary power is absent. The device is accessedthrough a multiplexed byte-wide interface, which supportsboth Intel and Motorola modes.Drop-In Replacement for IBM AT Computer Clock/CalendarRTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap Year Compensation Through 2099Binary or BCD Time Representation12-Hour or 24-Hour Clock with AM and PM in 12-Hour ModeDaylight Saving Time OptionSelectable Intel or Motorola Bus TimingInterfaced with Software as 128 RAM Locations14 Bytes of Clock and Control Registers