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Page - 12 MQ372-02
8.2.8. Calendar counter (Reg 4 to 6)
Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
4 DAY
!
!
20 10 8 4 2 1
5 MONTH
!
!
!
10 8 4 2 1
6 YEAR 80 40 20 10 8 4 2 1
∗)
"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, 2001 to December 31, 2099.
• 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.
1) Date counter
Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
4 DAY
!
!
20 10 8 4 2 1
• 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," "03," to "28," "29," "01," etc.
DAY Month Date update pattern
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 normal year
01, 02, 03 ∼ 28, 01, 02 ∼
Write/Read
February in leap year
01, 02, 03 ∼ 28, 29, 01 ∼
2) Month counter
Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
5 MONTH
!
!
!
10 8 4 2 1
• The month counter counts from 01 (January), 02 (February), and up to 12 (December), then starts again
at 01 (January).
3) Year counter
Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
6 Years Y80 Y40 Y20 Y10 Y8 Y4 Y2 Y1
• 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.
8.2.9. Alarm registers (Reg - 8 ∼ A)
Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
8 MIN Alarm AE 40 20 10 8 4 2 1
9 HOUR Alarm AE
•
20 10 8 4 2 1
WEEK Alarm 6 5 4 3 2 1 0
A
DAY Alarm
AE
•
20 10 8 4 2 1
• The alarm interrupt function is used, along with the AEI, AF, and WADA bits, to set alarms for specified date, day,
hour, and minute values.
• When the settings in the above alarm registers and the WADA bit match the current time, the /INT pin goes to low
level and "1" is set to the AF bit to report that and alarm interrupt event has occurred.
∗
For details, see "8.5. Alarm Interrupt Function".
8.2.10. Fixed-cycle timer control registers (Reg - B ∼ C)
Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
B Timer Counter 0 128 64 32 16 8 4 2 1
C Timer Counter 1
• • • •
2048 1024 512 256
• These registers are used to set the preset countdown value for the fixed-cycle timer interrupt function.
The TE, TF, TIE, and TSEL0/1 bits are also used to set the fixed-cycle timer interrupt function.
• When the value in the above fixed-cycle timer control register changes from 001h to 000h, the /INT pin goes to
low level and "1" is set to the TF bit to report that a fixed-cycle timer interrupt event has occurred.
∗
For details, see "8.3. Fixed-cycle Timer Interrupt Function".