Datasheet

Section 11 Realtime Clock (RTC)
Rev.7.00 Dec. 24, 2008 Page 354 of 698
REJ09B0074-0700
11.3.5 RTC Control Register 1 (RTCCR1)
RTCCR1 controls start/stop and reset of the clock timer. Bits 7 to 5 of this register are initialized
to H'00 by a STBY input or the RST bit in RTCCR1, but not initialized by a RES input. For the
definition of time expression, see figure 11.2.
Bit Bit Name Initial Value* R/W Description
7 RUN — R/W RTC Operation Start
0: Stops RTC and free running counter operation
1: Starts RTC and free running counter operation
6 12/24 — R/W Operating Mode
0: RTC operates in 12-hour mode. RHRDR counts on 0
to 11.
1: RTC operates in 24-hour mode. RHRDR counts on 0
to 23.
5 PM — R/W A.M./P.M.
0: Indicates a.m. when RTC is in the 12-hour mode.
1: Indicates p.m. when RTC is in the 12-hour mode.
4 RST 0 R/W Reset
0: Normal operation
1: Resets registers and control circuits except RTCCSR
and this bit. Clear this bit to 0 after having been set to 1.
3 to
0
— All 0 — Reserved
These bits are always read as 0.
Note: * Initial value after RES.
24-hour count 01234567891011121314151617
12-hour count 0
PM
24-hour count
12-hour count
PM
0 (Morning) 1 (Afternoon)
Noon
1234567891011012345
18 19 20 21 22 23 0
6
1 (Afternoon) 0
78910110
Figure 11.2 Definition of Time Expression