BM-23MK2 - Sony Audio Service Manual (repair manual). Page 21

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21
BM-23MK2
• IC Pin Function Description
LCD BOARD  IC701  SYSTEM CONTROLLER (BU2456-24)
Pin No.
Pin Name
I/O
Description
1
INT
I
Reset terminal
2
GND
GND terminal
3
POWER
I
1. When POWER IN becomes level “L”, UP counter, BATT, or LTR is displayed
according to PHOTO IN change.
2. When POWER IN becomes level “H”, the HALT state is set, displaying is stopped,
and the detection of all inputs are also stopped.
4
IN CTL
O
Rc/Rd input control terminal
5
COM1
O
COM 1 First digit (first digit from the right)
6
COM2
O
COM 2 Second digit (second digit from the right)
7
BATT1 (RESET)
I
BATT IN
1. When BATT1=H, and BATT2=L, “u” is displayed.
2. When BATT1=H, and BATT2=L, “y” is displayed.
3. When BATT1=H, and BATT2=L, “t” is displayed.
4. When BATT1=H, and BATT2=L, “e” is displayed.
5. BATT IN will not be accepted during HALT.
RESET IN
8
BATT2 (LTR)
I
1. Forces the counter to display “
888” while it is displaying.
2. Set the RAM of the counter to display “
888” while the LTR is displayed.
3. RESET IN will not be accepted during HALT.
LTR IN
1. The counter is stopped if it is displaying and “L” is displayed.
2. Even if “L” is displayed, the counter will operate.
3. LTR IN will not be accepted during HALT.
9
PHOTO
I
1. When the tape is rotated while the tape recorder is operating, photo detection is input.
2. PHOTO IN will not be accepted during HALT.
10
BS
I
1. The DOWN counter is set when L and the UP counter is set when H.
2. BS IN will not be accepted during HALT.
11
SEG8
O
Segment output terminal
12
NC
13
NC
14
SEG1
O
Segment output terminal
15
SEG2
O
Segment output terminal
16
SEG3
O
Segment output terminal
17
SEG4
O
Segment output terminal
18
SEG5
O
Segment output terminal
19
SEG6
O
Segment output terminal
20
SEG7
O
Segment output terminal
21
COM3
O
COM 3 Third digit (third digit from the right)
22
OSC
O
X’tal oscillation terminal (1MHz)
23
OSC
I
X’tal oscillation terminal (1MHz)
24
VCC
Power supply terminal
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