DIRECT BUS CONNECTED CMOS REAL TIME CLOCK/CALENDAR

The MSM6242B is a silicon Gate CMOS Real-Time Clock Calendar for use in direct bus-connection Microprocessor Microcomputer applications. An on-chip 32.768 KHz crystal Oscillator time base is divided to provide addressable 4-bit I/O data for SECONDS, MINUTES, HOURS, DAY OF WEEK, DATE, MONTH and YEAR. Data access is controlled by 4-bit address, chip selects (*CSO, CS1), *WRITE, *READ, and ALE. Control Registers D, E and F provide for 30 SECOND error adjustment, INTERRUPT REQUEST (IRQ FLAG) and BUSY status bits, Clock STOP, HOLD, and RESET FLAG bits, 4 selectable INTERRUPTS rates are available at the STD.P (STANDARD PULSE) output utilizing Control Register inputs T0, T1 and the ITRPT/STND (INTERRUPT/STANDARD). Masking of the interrupt output (STD.P) CAN be accomplished via the MASK bit. The MSM6242B CAN operate in a 12/24 hour format and Leap Year Timing is Automatic The MSM6242B normally operates from a 5V 10% supply at -40 to 85C. Battery backup operation down to 2.0V allows continuation of time keeping when main power is off. The MSM6242B is offered in a 18-pin plastic DIP and a 24-pin plastic Small Outline package.
By Oki Semiconductor