DESCRIPTION

The MSM6542 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.

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.).