Rtc Control Register (Rcr3) And Year-Alarm Register (Ryrar); (Sh7751R Only) - Hitachi SH7751 Hardware Manual

11.2.17 RTC Control Register (RCR3) and Year-Alarm Register (RYRAR)

(SH7751R Only)

RCR3 and RYRAR are readable/writable registers. RYRAR is the alarm register for the RTC's
BCD-coded year-value counter RYRCNT. When the YENB bit of RCR3 is set to 1, the RYRCNT
value is compared with the RYRAR value. Comparison between the counter and the alarm register
only takes place with the alarm registers in which the ENB and YENB bits are set to 1. The alarm
flag of RCR1 is only set to 1 when the respective values all match.
The setting range of RYRAR is decimal 0000 to 9999, and normal operation is not obtained if a
value beyond this range is set here.
RCR3 is initialized by a power-on reset, but RYRAR will not be initialized by a power-on or
manual reset, or by the device entering standby mode.
Bits 6 to 0 of RCR3 are always read as 0. A write to these bits is invalid. If a value is written to
these bits, it should always be 0.
RCR3
Bit:
Initial value:
R/W:
RYRAR
Bit:
Initial value:
Undefined Undefined Undefined Undefined Undefined Undefined Undefined Undefined
R/W:
Bit:
Initial value:
Undefined Undefined Undefined Undefined Undefined Undefined Undefined Undefined
R/W:
Rev. 3.0, 04/02, page 280 of 1064
7 6
YENB —
0 0
R/W R
15 14
1000 years
R/W R/W R/W
7 6
10 years
R/W R/W R/W
5 4 3
— — —
0 0 0
R R R
13 12 11
R/W R/W
5 4 3
R/W R/W
2 1
— — —
0 0
R R
10 9
100 years
R/W R/W R/W
2 1
1 year
R/W R/W R/W
0
0
R
8
0