DS12C887

• Product introduction

DS12C887 overview

The DS12C887 real-time clock (RTC) can be used as a drop-in replacement for the DS1287. The DS12C887 provides a real-time clock/calendar, timed alarm, three maskable interrupts sharing an interrupt output, a programmable square-wave output, and 113 bytes of RAM. The DS12887 integrates a crystal and a lithium battery in a 24-pin module DIP package. The DS12C887 adds the century byte to address 32h. For months with fewer than 31 days, the date for all devices can be automatically adjusted at the end of the month with leap year compensation. The DS12C887 can be configured in 24-hour or 12-hour format with AM/PM indication. Accurate temperature compensation circuitry is used to monitor VCCState. Once a failure of the main power supply is detected, the device automatically switches to the standby supply. The DS12C887 is accessed through a multiplexed, byte-width interface that supports Intel and Motorola modes.

DS12C887 features

• A direct replacement for IBM AT computer clocks/calendars
• RTC calculates second, minute, hour, day, day, month, and year information, with annual compensation, valid until 2099
• Time is expressed in binary or BCD
• 12-hour mode or 24-hour mode with AM and PM labels
• Daylight saving time selection
• Choose from Intel or Motorola bus timing
• The interface works with software to address 128 RAM
• 14-byte clock with control registers
• 113 bytes of general-purpose, battery-backed RAM3
• Three interrupts can be shielded and detected by software separately
• Alarms can be set from once per second to once a week
• The period can be set from 122μs to 500ms
• The clock terminates the refresh cycle flag
• Programmable square wave output signal
• Automatic power fail detection and switching circuitry
• A DIP module (EDIP) package with integrated crystal and battery is optional
• Optional industrial temperature range
• Certified by the Underwriters Laboratories Association (UL).

DS12C887 applications

• Embedded systems
• Network hubs, bridges, and routers
• Security systems
• ammeter