Sony BM-21 Service Manual page 45

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