Datasheet

Section 10 Realtime Clock (RTC)
Rev.5.00 Nov. 02, 2005 Page 150 of 500
REJ09B0027-0500
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.
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.
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
Figure 10.3 Initial Setting Procedure