DS12C887+

Real Time Clock Overview

The DS12C887+ is a Real-Time Clock (RTC) and calendar integrated into a 24-pin EDIP module. It provides timekeeping for seconds, minutes, hours, day of the week, date, month, and year with leap-year compensation through 2099. The device features a multiplexed parallel interface supporting Intel and Motorola bus protocols. It includes 113 bytes of battery-backed static RAM and an integrated lithium battery for data retention during power loss. Operating at 4.5V to 5.5V, it supports 12/24-hour formats, alarms, programmable square wave outputs, and three interrupt sources.

Real Time Clock Feature Summary

• Integrated RTC with Calendar: Counts seconds, minutes, hours, days, months, and years with automatic leap-year adjustment.
• Multiplexed Parallel Interface: Supports both Intel and Motorola bus timing modes via a single-byte wide interface.
• Battery-Backed Memory: Includes 113 bytes of general-purpose SRAM protected by an internal lithium battery.
• Interrupt and Output Control: Features three individually maskable interrupts and a programmable square wave output.

Real Time Clock Applications

• Embedded systems requiring precise timestamping
• Utility meters and smart grid devices
• Network hubs, bridges, and routers

Real Time Clock Procurement Notes

Verify the specific package variant, as the DS12C887 family includes surface-mount options like PLCC and TQFP alongside the EDIP module. Confirm that the application circuit supports the required multiplexed parallel bus signals, including address strobe and data strobe lines, for proper communication with the host microcontroller.

Real Time Clock Selection Notes

Select this component when a robust, all-in-one RTC solution with significant non-volatile memory is required. It is suitable for designs needing direct replacement for legacy IBM AT clock/calendar chips or those utilizing standard parallel bus architectures rather than serial interfaces like I2C or SPI.

Real Time Clock Part Context

The DS12C887+ belongs to the DS12887/DS12C887 series, which are designed to directly replace older DS1285 and DS1287 components. Unlike the DS12885, which requires external crystals and batteries, the DS12C887 integrates these elements within the DIP module package, simplifying board layout and assembly.

Real Time Clock Replacement Considerations

This part is a direct pin-compatible replacement for the DS1285 and DS1287. For modern designs, consider serial RTCs such as the DS1307 or DS3231 if space constraints or simplified software drivers are priorities over parallel bus performance.