9 REAL-TIME CLOCK (RTCA)
9-12
Seiko Epson Corporation
S1C17M20/M21/M22/M23/M24/M25
TECHNICAL MANUAL (Rev. 1.0)
Table 9.6.2 Correspondence between the count value and day of the week
RTCYAR.RTCWK[2:0] bits
Day of the week
0x6
Saturday
0x5
Friday
0x4
Thursday
0x3
Wednesday
0x2
Tuesday
0x1
Monday
0x0
Sunday
Note
: Be sure to avoid writing to the RTCYAR.RTCWK[2:0] bits while the RTCCTL.RTCBSY bit = 1.
Bits 7–4
RTCYH[3:0]
Bits 3–0
RTCYL[3:0]
The RTCYAR.RTCYH[3:0] bits and the RTCYAR.RTCYL[3:0] bits are used to set and read the 10-
year digit and the 1-year digit of the year counter, respectively. The setting/read values are a BCD
code within the range from 0 to 99.
Note
: Be sure to avoid writing to the RTCYAR.RTCYH[3:0]/RTCYL[3:0] bits while the RTCCTL.RT-
CBSY bit = 1.
RTC Interrupt Flag Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
RTCINTF
15 RTCTRMIF
0
H0
R/W Cleared by writing 1.
14 SW1IF
0
H0
R/W
13 SW10IF
0
H0
R/W
12 SW100IF
0
H0
R/W
11–9 –
0x0
–
R
–
8
ALARMIF
0
H0
R/W Cleared by writing 1.
7
1DAYIF
0
H0
R/W
6
1HURIF
0
H0
R/W
5
1MINIF
0
H0
R/W
4
1SECIF
0
H0
R/W
3
1_2SECIF
0
H0
R/W
2
1_4SECIF
0
H0
R/W
1
1_8SECIF
0
H0
R/W
0
1_32SECIF
0
H0
R/W
Bit 15
RTCTRMIF
Bit 14
SW1IF
Bit 13
SW10IF
Bit 12
SW100IF
These bits indicate the real-time clock interrupt cause occurrence status.
1 (R):
Cause of interrupt occurred
0 (R):
No cause of interrupt occurred
1 (W):
Clear flag
0 (W):
Ineffective
The following shows the correspondence between the bit and interrupt:
RTCINTF.RTCTRMIF bit: Theoretical regulation completion interrupt
RTCINTF.SW1IF bit:
Stopwatch 1 Hz interrupt
RTCINTF.SW10IF bit:
Stopwatch 10 Hz interrupt
RTCINTF.SW100IF bit: Stopwatch 100 Hz interrupt
Bits 11–9 Reserved