HD64F3687HV Datasheet, PDF (184/538 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Tiny Series

Section 10 Realtime Clock (RTC)
10.4 Operation
10.4.1 Initial Settings of Registers after Power-On
The RTC registers that store second, minute, hour, and day-of week data are not reset by a RES
input. Therefore, all registers must be set to their initial values after power-on. Once the register
setting are made, the RTC provides an accurate time as long as power is supplied regardless of a
RES input.
10.4.2 Initial Setting Procedure
Figure 10.3 shows the procedure for the initial setting of the RTC. To set the RTC again, also
follow this procedure.
RUN in RTCCR1 = 0
RST in RTCCR1 = 1
RST in RTCCR1 = 0
Set RTCCSR, RSECDR,
RMINDR, RHRDR,
RWKDR, 12/24 in
RTCCR1, and PM
RUN in RTCCR1 = 1
RTC operation is stopped.
RTC registers and clock count
controller are reset.
Clock output and clock source are
selected and second, minute, hour,
day-of-week, operating mode, and
a.m/p.m are set.
RTC operation is started.
Figure 10.3 Initial Setting Procedure
Rev.5.00 Nov. 02, 2005 Page 150 of 500
REJ09B0027-0500