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.
RTC operation is stopped.
RUN in RTCCR1=0
RST in RTCCR1=1
RST in RTCCR1=0
RTC registers and clock count
controller are reset.
Set RTCCSR, RSECDR,
RMINDR,RHRDR,
RWKDR,12/24 in
Clock output and clock source are
selected and second, minute, hour,
day-of-week,operating mode, and
a.m/p.m are set.
RTCCR1, and PM
RTC operation is started.
RUN in RTCCR1=1
Figure 10.3 Initial Setting Procedure
Rev. 3.00 Sep. 10, 2007 Page 176 of 528
REJ09B0216-0300
RENESAS [ RENESAS TECHNOLOGY CORP ]
