Epson RA8804 CE Applications Manual page 13

RA8804 CE
8.2.2. Calendar counter (WEEK - YEAR)
Address
03

"o" indicates write-protected bits. A zero is always read from these bits.
1) Day of the WEEK counter

The day (of the week) is indicated by 7 bits, bit 0 to bit 6.

The day data values are counted as follows: Day 01hDay 02hDay 04hDay 08hDay
10hDay 20hDay 40hDay 01hDay 02h, etc.

The correspondence between days and count values is shown below.
WEEK bit 7
Write/Read
 Do not set "1" to more than one day at the same time.
Write prohibit
Address Function
04 DAY
05 MONTH
06 YEAR

"o" indicates write-protected bits. A zero is always read from these bits.

The auto calendar function updates all dates, months, and years from January 1, 00 to December 31, 99.

The data format is BCD format. For example, a date register value of "0011 0001" indicates the 31st.

Note with caution that writing non-existent date data may interfere with normal operation of the calendar
counter.
2) Date counter
Address
04

The updating of dates by the date counter 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", "0"3, to "28", "29", "01", etc.
DAY
Write/Read
3) Month counter
Address
05

The month counter counts from 01 (January), 02 (February), and up to 12 (December), then starts again
at 01 (January).
4) Year counter
Address
06

The year counter counts from 00, 01, 02 and up to 99, then starts again at 00.

Any year that is a multiple of four (04, 08, 12, 88, 92, 96, etc.) is handled as a leap year.
Function bit 7

WEEK
bit 6 bit 5 bit 4
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 1
0 0 1 0
0 1 0 0
Also, note with caution that any setting other than the
seven shown above should not be made as it may
interfere with normal operation.
bit 7 bit 6
 
 
80 40
Function bit 7

DAY
Month
1, 3, 5, 7, 8, 10, or 12
4, 6, 9, or 11
February in normal year
February in leap year
Function bit 7

MONTH
Function bit 7
YEAR Y80
bit 6 bit 5 bit 4
6 5 4
bit 3 bit 2 bit 1 bit 0
0 0 0 1
0 0 1 0
0 1 0 0
1 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
bit 5 bit 4 bit 3
20 10

10
20 10
bit 6 bit 5 bit 4

20 10
Date update pattern
01, 02, 03  30, 31, 01 
01, 02, 03  30, 01, 02 
01, 02, 03  28, 01, 02 
01, 02, 03  28, 29, 01 
bit 6 bit 5 bit 4
 
10
bit 6 bit 5 bit 4
Y40 Y20 Y10
Page - 9
bit 3 bit 2 bit 1
3 2 1
Day Data [h]
Sunday 01 h
Monday 02 h
Tuesday 04 h
Wednesday 08 h
Thursday 10 h
Friday 20 h
Saturday 40 h
 
bit 2 bit 1
8 4 2
8 4 2
8 4 2
bit 3 bit 2 bit 1
8 4 2
bit 3 bit 2 bit 1
8 4 2
bit 3 bit 2 bit 1
Y8 Y4 Y2
ETM60E-02
bit 0
0
bit 0
1
1
1
bit 0
1
bit 0
1
bit 0
Y1