CDX-727 - Sony Car Audio Service Manual (repair manual). Page 37

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Pin No.

Pin Name

I/O

Function

1, 2

NC

O

Not used (open)

3

NC

I

Not used (fixed at “L”)

4

REQ

O

Request signal output to the system controller (IC201)    “L” active

5

CCLK

I

Serial data transfer clock signal input from the system controller (IC201)

6

CSI

I

Serial data input from the system controller (IC201)

7

CSO

O

Serial data output to the system controller (IC201)

8

SCLK

O

Clock signal output for subcode data reading to the CXD2530Q (IC101)

9

SSI

I

Subcode data input from the CXD2530Q (IC101)

10

NC

O

Not used (open)

11 to 18

ADD0 to ADD7

O

Address signal output to the S-RAM (IC502)

19

NC

I

Not used (fixed at “L”)

20 to 27

DATA0 to DATA7

I/O

Two-way data bus with the S-RAM (IC502)

28

RST

I

System reset signal input from the system controller (IC201), SONY bus interface (IC302) and 
reset signal generator (IC304)    “L”: reset
For several hundreds msec. after the power supply rises, “L” is input, then it changes to “H”

29

EXTAL

I

System clock input terminal (10 MHz)

30

XTAL

O

System clock output terminal (10 MHz)

31

VSS

—

Ground terminal

32 to 55

NC

O

Not used (open)

56

BUSY

O

Busy signal output to the system controller (IC201)    “L”: busy status

57 to 61

NC

O

Not used (open)

62

CE

O

Chip enable signal output to the S-RAM (IC502)    “L” active

63

WE

O

Data write enable signal output to the S-RAM (IC502)    “L” active

64 to 69

ADD8 to ADD13

O

Address signal output to the S-RAM (IC502)

70

VDD

—

Power supply terminal (+5V)

71

NC

O

Not used (open)

72

NC

I

Not used (fixed at “L”)

73

NC

I

Not used (fixed at “H”)

74

ADD14

O

Address signal output to the S-RAM (IC502)

75

NC

O

Not used (open)

76

SCOR

I

Subcode sync (S0+S1) detection signal input from the CXD2530Q (IC101)

77

WFCK

I

Write frame clock (7.35 kHz) signal input from the CXD2530Q (IC101)

78

BUCK

I

Backup power supply detection signal input terminal (used also to reset standby)

79, 80

NC

I

Not used (fixed at “L”)