XR-1800RD - Sony Car Audio Service Manual (repair manual). Page 22

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Pin No.

Pin Name

I/O

Description

43

LCD CE

O

Chip enable output to the liquid crystal display driver (IC900)

44

LCD CLK

O

Serial data transfer clock signal output to the liquid crystal display driver (IC900)

45

NCO

O

Not used (open)

46

LCD SO

O

Serial data output to the liquid crystal display driver (IC900)

47

VDD2

—

Power supply terminal (+5V)

48

AVDD

—

Power supply terminal (+5V) (for A/D converter)

49

AVREF+

I

Reference voltage input terminal (+5V) (for A/D converter)

50

KEYIN1

I

Key input terminal (A/D input)    OFF, LOUD PTY, 6/5/3/2/4/1 ATA keys input (S950 to 957)

51

KEYIN0

I

Key input terminal (A/D input)    AF/TA, TUNER BTM, SEEK MANU +/–, DSPL, LEVEL +, 
SEL, LEVEL – keys input (S920 to 927)

52

KEYSEL1

I

Setting terminal for the key function (fixed at “L”)

53

KEYSEL0

I

Setting terminal for the key function (fixed at “L”)

54

DSTSEL1

I

Destination setting terminal (fixed at “L”)

55

DSTSEL0

I

Destination setting terminal (fixed at “L”)

56

NIL

I

Not used (fixed at “L”)

57

FM VSM

I

FM and AM signal meter voltage detection input from the FM/AM tuner unit (TU100)

58

AVREF–

I

Reference ground terminal

59

AVSS

—

Ground terminal (for A/D converter)

60

GND

—

Ground terminal

61, 62

NCO

O

Not used (open)

63

SEEK OUT

O

Seek control signal output to the FM/AM tuner unit (TU100)

64

TUN ON

O

Tuner system power supply on/off control signal output terminal    “H”: tuner on

65

FM ON

O

FM system power supply on/off control signal output terminal    “H”: FM on

66

MUTE

O

Line muting control signal output terminal    “H”: line muting on    Not used (open)

67

AF SEEK

O

PLL low-pass filter time constant selection signal output at AF seek
“H” is output when AF seek

68

NCO

O

Not used (open)

69

NOSESW

I

Detects the removal of the attaching and removing type front panel block    “L”: attaching

70

ST IN

I/O

71

SD IN

I

Station detector detect input from the FM/AM tuner unit (TU100)                                                     
Stop level for SEEK, BTM, etc. is determined    SD is present at input of “H”

72

NIL

I

Not used (fixed at “L”)

73

PW SEL

I

Power select switch input terminal
“L”: halt mode, “H”: operation mode    Not used (fixed at “L” in this set)

74 to 78

NIL

I

Not used (fixed at “L”)

79

TEST

I

Setting terminal for the test mode    “L”: test mode (normally fixed at “H”)

80

NIL

I

Not used (fixed at “L”)

Input of FM stereo detection signal from FM/AM tuner unit (TU100), and output of forced 
monaural control signal to FM/AM tuner unit (TU100)  (Commonly used for stereo display 
input and forced monaural output) 
FM stereo detection at input of “L”, forced monaural at output of “L”