RTC , DIRECT BUS CONNECTED CMOS REAL TIME CLOCK/CALENDAR
The MSM6242B is a silicon gate CMOS Real Time Clock/Calendar for use in direct busconnection 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 – 40C to 85 C. 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. |
