Datasheet

Table Of Contents
Section 10 Realtime Clock (RTC)
Rev. 2.00 Jul. 04, 2007 Page 224 of 692
REJ09B0309-0200
10.5 Interrupt Sources
There are eight kinds of RTC interrupts: a free-running counter overflow, week interrupt, day
interrupt, hour interrupt, minute interrupt, one-second interrupt, 0.5-second interrupt, and 0.25-
second interrupt.
When using an interrupt, set the IENRTC (RTC interrupt request enable) bit in IENR1 to 1 last
after other registers are set.
When an interrupt request of the RTC occurs, the corresponding flag in RTCFLG is set to 1. When
clearing the flag, write 0.
Table 10.2 shows a interrupt sources.
Table 10.2 Interrupt Sources
Interrupt Name Interrupt Source Interrupt Enable Bit
Overflow interrupt Occurs when the free running counter is
overflowed.
FOIE
Week periodic interrupt Occurs every week when the day-of-week date
register value becomes 0.
WKIE
Day periodic interrupt Occurs every day when the day-of-week date
register is counted.
DYIE
Hour periodic interrupt Occurs every hour when the hour date register
is counted.
HRIE
Minute periodic interrupt Occurs every minute when the minute date
register is counted.
MNIE
One-second periodic
interrupt
Occurs every second when the one-second
date register is counted.
1SEIE
0.5-second periodic
interrupt
Occurs every 0.5 seconds. 05SEIE
0.25-second periodic
interrupt
Occurs every 0.25 seconds. 025SEIE