DETAILED DESCRIPTION

The DS1384 watchdog timekeeping controller is a self-contained real-time clock, alarm, watchdog timer, and interval timer that provides control of up to 128k x 8 of external low-power CMOS static RAM in a 44-pin quad flat-pack package. An external crystal and battery are the only components required to maintain time of day and RAM memory contents in the absence of power. Access to all RTC functions and the external RAM is the same as conventional bytewide SRAM.

FEATURES

■ Keeps Track of Hundredths of Seconds, Seconds, Minutes, Hours, Days, Date of the Month, Months, and Years with Leap Year Compensation Valid Up to 2100

■ Watchdog Timer Restarts an Out-ofControl Processor

■ Alarm Function Schedules Real-Time Related Activities

■ Programmable Interrupts and SquareWave Outputs

■ Bytewide RAM-Like Access

■ 50 Bytes of On-Board User RAM

■ Greater Than 10 Years Timekeeping and Data Retention in the Absence of Power with Small Lithium Coin Cells

■ Supports Up to 128k x 8 of External Static RAM

■ All Timekeeping Registers and On-Board RAM are Individually Addressable via the Address and Data Bus