Section 11 Realtime Clock (Rtc); Overview; Features - Hitachi SH7751 Hardware Manual

11.1

Overview

The SH7751 Series includes an on-chip realtime clock (RTC) and a 32.768 kHz crystal oscillator
for use by the RTC.
11.1.1

Features

The RTC has the following features.


Clock and calendar functions (BCD display)
Counts seconds, minutes, hours, day-of-week, days, months, and years.


1 to 64 Hz timer (binary display)
The 64 Hz counter register indicates a state of 64 Hz to 1 Hz within the RTC frequency divider


Start/stop function


30-second adjustment function


Alarm interrupts
Comparison with second, minute, hour, day-of-week, day, month, or year (SH7751R only) can
be selected as the alarm interrupt condition


Periodic interrupts
An interrupt period of 1/256 second, 1/64 second, 1/16 second, 1/4 second, 1/2 second, 1
second, or 2 seconds can be selected


Carry interrupt
Carry interrupt function indicating a second counter carry, or a 64 Hz counter carry when the
64 Hz counter is read


Automatic leap year adjustment

Section 11 Realtime Clock (RTC)

Rev. 3.0, 04/02, page 263 of 1064