14. Functions
RX8130CE
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ETM50E-07
Seiko Epson Corporation
25
14.1.2. Week counter
The day (of the week) is indicated by 7 bits, bit 0 to bit 6.
The day data values are counted as: Day 01h
Day 02h
Day 04h
Day 08h
Day 10h
Day 20h
Day
40h
Day 01h
Day 02h, etc.
It is incremented when carry is generated from the HOUR register. This register does not generate carry to
a higher register. Since this register is not connected with the YEAR, MONTH and DAY registers, it needs to be
set again with the matching day of the week if any of the YEAR, MONTH or DAY registers have been changed.
Table 15 Setting example of the week register value.
Day
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Data h
Sunday
0
0
0
0
0
0
0
1
01 h
Monday
0
0
0
0
0
0
1
0
02 h
Tuesday
0
0
0
0
0
1
0
0
04 h
Wednesday
0
0
0
0
1
0
0
0
08 h
Thursday
0
0
0
1
0
0
0
0
10 h
Friday
0
0
1
0
0
0
0
0
20 h
Saturday
0
1
0
0
0
0
0
0
40 h
Do not set "1" to more than one day at the same time.
14.1.3. Calendar counter
1) [
DAY
],
[
MONTH
]
register
The DAY register is a variable (between 28-base and 31-base) BCD counter that is influenced by the month and
the leap year. The MONTH register is a 12-base BCD counter triggered by carryover of the day register.
[
2)
YEAR
]
register
This register is a BCD counter for years 00 to 99.
The leap year is automatically determined and influences the DAY register.
This RTC processes following years as leap years: 00,04,08,12,,, 96.
User software correction is needed in the years 2100,2200,2300 as they are common years.
< Definition of leap years>
Leap year : year divisible by 4 , year divisible by 400
Ex. 2000,2004,2008,2012,,, 2096,2400,2800,,,
Common year: year indivisible by 4, year divisible by 100
Ex. 2001,2002,2003,2005,,, 2099,2100,2200,2300,2500,,
Jan.
Feb.
Mar
Apr.
May
Jun
e
July
Aug.
Sep.
Oct.
Nov.
Dec.
Days
Common
year
31
28
31
30
31
30
31
31
30
31
30
31
Leap year
29
