HD6417705F133V Datasheet, PDF (419/741 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7700 Series

15.4.4 Alarm Function
Figure 15.4 shows how to use the alarm function.
Alarms can be generated using seconds, minutes, hours, day of the week, date, month, year, or any
combination of these. Set the ENB or YAEN bit for the register on which the alarm is placed to 1,
and then set the alarm time in the lower bits. Clear the ENB or YAEN bit for the register on which
the alarm is not placed to 0.
When the clock and alarm times match, 1 is set in the AF bit in RCR1. Alarm detection can be
checked by reading this bit, but normally it is done by interrupt. If 1 is placed in the AIE bit in
RCR1, an interrupt is generated when an alarm occurs.
Clock running
Disable interrupt to prevent erroneous
Cancel alarm interrupt interruption.(AIE bit in RCR1 is cleared)
Then write 1.
Set alarm time
Clear alarm flag
Always clear, since the flag may have been
set while the alarm time was being set.
(Write 0 to AF of RCR1 to clear it. )
Monitor alarm time
(wait for interrupt or
check alarm flag)
Figure 15.4 Using the Alarm Function
Rev. 2.00, 09/03, page 371 of 690