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)