Features: • Real time clock providing seconds, minutes, hours, days, months, years, and days of the week.
• Multiple alarm ranges covering seconds, minutes, hours, days, months, and days of the week. A desired alarm range can be selected.
• A periodic interrupt output interval can be selected over a wide range from 1/1024 seconds up to 10 minutes.
• Interface flexibility allows for connection to many types of microprocessors.
• Single read-out procedure (Read flag).
• Single power sense circuitry. (Data protect function).
• Unused registers can be used as RAM.
• 30-second adjustment by software or hardware (software only for the MSM6542- 1/-2).
• Stop and restart of clock by software or hardware (software only for the MSM6542- 1/-2).
• 1 Hz output for adjustment and check of oscillation frequency (MSM6542-3 only).
• User selection of 12 or 24 hour clock mode.
• Address latch enable (ALE) input pin.
• Advanced CMOS circuitry allows low stand-by voltage and current.
• User standard 32.768 kHz oscillator crystal
• Available in multiple packages 18-pin plastic DIP (for the MSM6542- 1RS/2RS) (DIP18-P-300). 20-pin plastic SOP (for the MSM6542- 1MS-K/2MS-K) (SSOP20-P-250-K). 24-pin plastic DIP (for the MSM6542- 3RS) (DIP24-P-600). 24-pin plastic SOP (for the MSM6542- 3GS-VK) (SOP24-P-430-VK).
• Pin assignment compatibility with the MSM6242BRS (The MSM6542-3MSK provides near compatibility.).
Pinout
Specifications
|
Rating |
Symbol |
Condition |
Value |
Unit |
|
Power supply voltage |
VDD |
Ta = 25°C |
0.3 to 7 |
V |
|
Input voltage |
VI |
Ta = 25°C |
0.3 to VDD+0.3 |
V |
|
Output voltage |
VO |
Ta = 25°C |
0.3 to VDD+0.3 |
V |
|
Storage temperature range |
TSTG |
|
55 to +150 |
°C |
DescriptionThe MSM6542-02 is a perpetual-calendar-based real time clock with an alarm function which can read and write data in units of seconds. It can be connected to various buses and can function as a peripheral IC of a microcomputer.
The clock ranges of MSM6542-02 are seconds, minutes, hours, days, months, years, and days of the week. The alarm ranges are seconds, minutes, hours, days, months, and days of the week.
An event trigger of MSM6542-02 is generated when the time matches the specified time and an alarm occurs or when the clock counter generates a carry. The interrupt and pulse outputs are provided for each of an alarm and a carry.
An interface of MSM6542-02 with a microcomputer is implemented by four data bus pins, four address busbus pins, three control bus pins, and two chip select pins. These pins are used to write or read data from the clock, alarm, and control registers, or to modify the data.
The MSM6542-02 has an address latch enable (ALE) input pin, allowing the data bus and address bus to be shared. When the ALE input pin is kept high, the data bus and address bus can be exclusively used.
Other functions of the MSM6542-02 are: a 30- second adjustment, stop and restart of clock, data registers as RAM, and data register (RAM) protection.
The CMOS circuitry used in the MSM6542-02 affords low power dissipation. The crystal oscillator operates at 32.768 kHz. Provisions for backup time keeping are included.
MSM6542-02 Data Sheet
