Read Sony CDX-A251C Service Manual online
36
CDX-A251C
IC501 MB90487APF-G-171E1 (SYSTEM CONTROL) (MAIN BOARD (3/4))
Pin No.
Pin Name
I/O
Pin Description
1
AREASEL2
I
Destination setting pin (L: US, CND, E, MX model, H: AEP, UK model)
2
AREASEL1
I
Destination setting pin (L: AEP, UK, E, MX model, H: US, CND model)
3
AREASEL0
I
Destination setting pin (L: 9K, H: 10K)
4
COL_SW
I
Illumination color select signal input (Fixed at H in this set)
5
BEEP
O
Beep signal output to power amp IC.
6
CYRIL_SEL
I
Cyril select signal input (Fixed at L in this set)
7
NOSE_SW
I
Front panel detach detection signal input
8
DIAG
I
Status signal input from power amp IC.
9
VOLATT
O
Attenuator control signal output to electronic volume IC.
10
NCO
O
Not used. (Open)
11
VSS
—
Ground
12
TUATT
O
Tuner mute control signal output
13
NSMASK
O
Noise mask signal output (AEP, UK model)
14
ILLUMI_SEL1
I
Illumination voltage setting pin (Fixed at L in this set)
15
ILLUMI_SEL2
I
Illumination voltage setting pin (Fixed at H in this set)
16 to 22
NCO
O
Not used. (Open)
23
VCC5
—
Power supply pin (+3.3 V)
24
EEP_SIO
I/O
Serial data signal input/output for EEPROM communication.
25
EEP_CKO
O
Serial clock signal output for EEPROM communication.
26
AMPSTB
O
Standby signal output to power amp IC.
27
LCD_CE
O
Chip enable signal output to LCD drive IC.
28
LCD_SO
O
Serial data signal output to LCD drive IC.
29
LCD_CKO
O
Serial clock signal output to LCD drive IC.
30
RDS_ON
O
RDS ON signal output (AEP, UK model)
31
RE_IN0
I
Rotary encoder signal input 0
32
RE_IN1
I
Rotary encoder signal input 1
33
I2C_CKO
O
I2C bus serial clock signal output
34
I2C_SIO
I/O
I2C bus serial data signal input/output
35
DAVDD
—
Power supply pin for A/D converter. (+3.3 V)
36
AVRH
—
External reference power supply pin for A/D converter. (+3.3 V)
37
DAVSS
—
Ground for A/D converter.
38
QUALITY
I
Noise detection signal input (AEP, UK model)
39
VSM
I
S meter voltage detection signal input
40
KEYIN1
I
Key signal input 1
41
KEYIN0
I
Key signal input 0
42
VSS
—
Ground
43
RC_IN0
I
Rotary commander key signal input
44 to 48
NCO
O
Not used. (Open)
49, 50
MD0, MD1
I
Signal input for operation mode designation. (Fixed at H in this set)
51
MD2
I
Signal input for operation mode designation. (Fixed at L in this set)
52
KEYACK
I
Key acknowledge detection signal input
53
TU_ATTIN
I
Tuner mute zero cross detection signal input (AEP, UK model)
54
BUIN
I
Backup power supply detection signal input
55
NCO
O
Not used. (Open)
56
DAVN
I
RDS data block synchronized detection signal input from RDS demodulator IC.
(AEP, UK model)
57
NCO
O
Not used. (Open)
58
UNISI
I
SONY-BUS data signal input
59
UNISO
O
SONY-BUS data signal output
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