DESCRIPTION

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 (IRQFLAG) 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). Mask

ing of the interrupt output (STD.P) can be accomplished via the MASK bit. The MSM6242B can operate in a 12/24 hour for mat and Leap Year timing is automatic.

FEATURES

? 4-bit data bus

? 4-bit address bus

? READ, WRITE, ALE and CHIP SELECT INPUTS

? Status registers – IRQ and BUSY

? Selectable interrupt outputs – 1/64 second, 1 second, 1 minute, 1 hour

? Interrupt masking

? 32.768 KHz crystal controlled operation

? 12/24 hour format

? Auto leap year

? ±30 second error correction

? Single 5V supply

? Battery backup down to VDD = 2.0V

? Low power dissipation: 20μW max at VDD = 2V, 150μW max at VDD = 5V

? 18 pin Plastic DIP (DIP18-P-300)

? 24 Pin-V Plastic SOP (SOP24-P-430-VK)