SH7763 Datasheet, PDF (846/2026 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC Engine Family SH-4A Series

Section 22 Realtime Clock (RTC)
22.5.3 Alarm Function
The use of the alarm function is illustrated in figure 22.4.
Clock running
Disable alarm interrupts
Clear RCR1.AIE to prevent erroneous interrupts.
Set alarm time
Clear alarm flag
Enable alarm interrupts
Be sure to reset the flag as it may have been
set during alarm time setting.
Set RCR1.AIE to 1.
Monitor alarm time
(Wait for interrupt or check alarm flag)
Figure 22.4 Example of Use of Alarm Function
An alarm can be generated by the second, minute, hour, day-of-week, day, month, or year value,
or a combination of these. Write 1 to the ENB bit in the alarm registers involved in the alarm
setting, and set the alarm time in the lower bits. Write 0 to the ENB bit in registers not involved in
the alarm setting.
When the counter and the alarm time match, RCR1.AF is set to 1. Alarm detection can be
confirmed by reading this bit, but normally an interrupt is used. If 1 has been written to
RCR1.AIE, an alarm interrupt is generated in the event of alarm, enabling the alarm to be
detected.
Rev. 1.00 Oct. 01, 2007 Page 780 of 1956
REJ09B0256-0100