3-WIRE REAL-TIME CLOCK
S-35190A
Rev.2.4_00
4. INT register 1 and INT register 2
The INT register 1 is to set up the output of user-set frequency, or to set up alarm 1 interrupt. The INT register 2 is for
setting alarm 2 interrupt. Users are able to switch the output mode by using the status register 2. If selecting to use the
output mode for alarm interrupt by status register 2; this register works as the alarm-time data register. In the INT register
1, if selecting the output of user-set frequency by status register 2; this register works as the data register to set the
frequency for clock output. From the INT pin, a clock pulse and alarm interrupt are output, according to the or-condition
that these two registers have.
(1) Alarm interrupt
Users can set the alarm time (the data of day of the week, hour, minute) by using the INT register 1 and 2 which are
3-byte data registers. The configuration of register is as well as the data register of day of the week, hour, minute, in
the real-time data register; is expressed by the BCD code. Do not set a nonexistent day. Users are necessary to set
up the alarm-time data according to the 12/24 hour expression that they set by using the status register 1.
INT register 1
W1 W2
B7
INT register 2
W1
W4
W2
W4
0
0
0
A2WE
0
0
0
0
0
A1WE
B7
B0
B0
AM/
PM
AM/
PM
H10
H2 H4 H8
A1HE
H2
A2HE
H1
B7
H20
H20
H10
m10
H1
B7
H4 H8
B0
B0
m10
A2mE
m40 A1mE
B0
m2
m20
m1
B7
m40
m1
B7
m4
m8
m2
m8
m4
m20
B0
Figure 17 INT Register 1 and INT Register 2 (Alarm-Time Data)
The INT register 1 has A1WE, A1HE, A1mE at B0 in each byte. It is possible to make data valid; the data of day of the
week, hour, minute which are in the corresponded byte; by setting these bits to “1”. This is as well in A2WE, A2HE,
A2mE in the INT register 2.
Setting example: alarm time “7:00 pm” in the INT register 1
(a) 12-hour expression (status register 1 B6 = 0)
set up 7:00 PM
Data written to INT register 1
*1
*1
*1
*1
*1
*1
*1
Day of the week
Hour
−
−
−
−
−
−
−
0
1
1
1
1
0
0
0
1
Minute
0
B7
0
0
0
0
0
0
1
B0
*1. Don’t care (Both of 0 and 1 are acceptable).
(b) 24-hour expression (status register 1 B6 = 1)
set up 19:00 PM
Data written to INT register 1
*1
*1
*1
*1
*1
*1
*1
Day of the week
Hour
−
1
−
0
−
−
−
−
−
0
1
1
0
0
1
0
1
0
0
0
1*2
0
Minute
0
0
B7
B0
*1. Don’t care (Both of 0 and 1 are acceptable).
*2. Set up AM / PM flag along with the time setting.
Seiko Instruments Inc.
15
SII [ SEIKO INSTRUMENTS INC ]
