¡ Semiconductor
MSM6242B
¡ Semiconductor
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 ad-
dressable 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
MSM6242B
DIRECT BUS CONNECTED CMOS REAL TIME CLOCK/CALENDAR
(STANDARD PULSE) output utilizing Con-
trol 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.
The MSM6242B normally operates from a 5V
±10%
supply at –40 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.
FEATURES
DIRECT MICROPROCESSOR/MICROCONTROLLER BUS CONNECTION
TIME
23:59:59
MONTH
12
DATE
31
YEAR
80
•
•
•
•
•
•
DAY OF WEEK
7
• 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 V
DD
= 2.0V
Low power dissipation:
20µW max at V
DD
= 2V
150µW max at V
DD
= 5V
• 18 pin Plastic DIP (DIP18-P-300)
• 24 Pin-V Plastic SOP (SOP24-P-430-VK)
23
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