Overview
The RTC-58321/58323 is a CMOS real time clock modules with perpetual calendar function developed for microcomputer applications. It has a built-in 32.768 kHz quartz resonator, and provides clock and calendar registers for year, month, day, day-of-week, hours, minutes and seconds, with 12-hour/24-hour selection, plus automatic leap-year correction with software selection for local calendars, and an additional periodic reference signal output. Being a CMOS device, it has a very low power consumption for battery back-up purposes.

Features
● Adjustment-free built-in quartz resonator keeps component count low.
● Built-in clock and calendar registers for year, month, day, day-of-week, hours, minutes and seconds.
● 12-hour/24-hour selection.
● Automatic leap-year correction, with software selection for local calendars.
● Counter start, stop and reset functions.
● Periodic reference signal output selectable: 1024 Hz, or 1 second, 1 minute or 1 hour intervals.
● Data bus is 4-bit bidirectional, with memory-type reads and writes.
● CMOS device, for very low power consumption, and long battery back-up period.
● Compatible at pin and function levels with the MSM58321 RS.