RX8804CE
Page - 9
ETM59E-05
8.2. Details of Registers
8.2.1. Clock Counter (SEC - YEAR)
•
The data format is BCD format. For example, when the “seconds” register value is “0101 1001” it indicates 59 seconds.
24hours system is available.
Table 13 Clock, Calendar Register
Address
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
00
SEC
40
20
10
8
4
2
1
01
MIN
40
20
10
8
4
2
1
02
HOUR
20
10
8
4
2
1
03
WEEK
6
5
4
3
2
1
0
04
DAY
20
10
8
4
2
1
05
MONTH
10
8
4
2
1
06
YEAR
80
40
20
10
8
4
2
1
1) SEC register
This second register counts from
“00” to “01”, “02”, and up to 59 seconds, after 59 it starts again from 00 second.
When written any data to SEC register, less than a SEC counter (512 Hz from 2 Hz) is cleared to zero.
Thus, the time accuracy becomes 0 s to 30.5
s. * (refer to Figure 6)
If highly precise time synchronization is needed, RESET bit setting to 1 is most suitable operation.
When 60 seconds were written to SEC register, it returns to 00 second in next update. This special update is the
same as plus-adjustment of Leap second. This behavior is useful in the adjustments of Leap second.
*Note Several data writing into SEC register might cumulative time delay.
2) MIN register
This minute register counts from
“00” to “01”, “02”, and up to 59 minutes, after 59 it starts again from 00 minute.
3) HOUR register
This 24 hours register counts from
“00” hour to “01”, “02”, “23”, ”00”, ”01”. “o” indicates write-protected bits. Zero is
always read from these bits.
4) WEEK register
This WEEK register consists of 7bit shift registers.
The data values are counted as follows: Day 01h
→
Day 02h
→
Day 04h
→
Day 08h
→
Day 10h
→
Day
20h
→
Day 40h
→
Day 01h
→
Day 02h
The correspondence between days and count values is shown below.
Table 14 WEEK Register
WEEK
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Day of week
Data h
Write / Read
0
0
0
0
0
0
0
1
Sunday
01h
0
0
0
0
0
0
1
0
Monday
02h
0
0
0
0
0
1
0
0
Tuesday
04h
0
0
0
0
1
0
0
0
Wednesday
08h
0
0
0
1
0
0
0
0
Thursday
10h
0
0
1
0
0
0
0
0
Friday
20h
0
1
0
0
0
0
0
0
Saturday
40h
Write prohibit
Do NOT set “1” more than one day at the same time.
Also, note with caution that any setting other than the
seven shown above should not be made as it may
interfere with normal operation.
−
−
5) DAY Register
The updating of DAY register varies according to the month setting.
A leap year is set whenever the year value is a multiple of four (such as 04, 08, 12, 88, 92, or 96).
In February of a leap year, the counter counts dates from
“01”, “02”, “03”, to “28”, “29”, “01”.
Table 15 DAY Register
DAY
Month
Date update pattern
Write / Read
1, 3, 5, 7, 8, 10, or 12
01, 02, 03
30, 31, 01
4, 6, 9, or 11
01, 02, 03
30, 01, 02
February in common year
01, 02, 03
28, 01, 02
February in leap year
01, 02, 03
28, 29, 01
