DS12C887+

Product Summary

The DS12C887+ is a real-time clock.The DS12C887+ is designed to be direct replacements for the DS1285 and DS1287. The DS12C887+ provides 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 batterybacked static RAM . The DS12C887+ integrates a quartz crystal and lithium energy source into a 24-pin encapsulated DIP package. The DS12C887+ adds a century byte at address 32h. For all devices, the date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. The devices also operate 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. A lithium coin-cell battery can be connected to the VBAT input pin on the DS12C887+ to maintain time and date operation when primary power is absent. The device is accessed through a multiplexed byte-wide interface, which supports both Intel and Motorola modes.

Parametrics

DS12C887+ absolute maximum ratings: (1)Voltage Range on VCC Pin Relative to Ground: -0.3V to +6.0V; (2)Operating Temperature Range, Commercial (noncondensing): 0°C to +70°C; (3)Operating Temperature Range, Industrial (noncondensing): -40°C to +85°C; (4)Storage Temperature Range: -55°C to +125°C; (5)Soldering Temperature: See IPC/JEDEC J-STD-020 Specification (Note 1); (6)Soldering Temperature (leads, 10s): +260°C.

Features

DS12C887+ features: (1) Drop-In Replacement for IBM AT Computer Clock/Calendar; (2) RTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap Year Compensation Through 2099; (3) Binary or BCD Time Representation; (4) 12-Hour or 24-Hour Clock with AM and PM in 12-Hour Mode; (5) Daylight Saving Time Option; (6) Selectable Intel or Motorola Bus Timing; (7) Interfaced with Software as 128 RAM Locations; (8) 14 Bytes of Clock and Control Registers; (9) 114 Bytes of General-Purpose, Battery-Backed RAM (113 Bytes in the DS12C887 and DS12C887A); (10) RAM Clear Function (DS12885, DS12887A, and DS12C887A).

Diagrams