XR-C6120 - Sony Car Audio Service Manual (repair manual). Page 24

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Pin No.

Pin Name

I/O

Function

1

AVREF–

I

Reference voltage (0V) input terminal (for A/D converter)

2

VSM

I

FM and AM signal meter voltage detection input from the FM/AM tuner unit (TU1)
(A/D input)

3

KEYIN1

I

Key input terminal (A/D input)
(LSW921 to LSW923, LSW925, LSW926, LSW928 to LSW933)
6, PRESET DISC –/+, DSPL, LIST, 6, 5 ENTER, 4 n, 3 PLAY MODE, 2 SET UP, 1 N 
keys input

4

KEYIN0

I

Key input terminal (A/D input) (LSW901 to LSW903, S901, LSW905, LSW906)
OFF, SOURCE, MODE  

*, SEEK/AMS = 0 –  + ) +, SOUND, SHIFT keys

input

5

D-BASS IN

I

D-BASS switch (S981) input terminal (A/D input)

6

DSTSEL

I

Destination setting terminal (fixed at center voltage in this set)

7

FUNC-SEL

I

Setting terminal for the function select (fixed at “L” in this set)

8

NCO

O

Not used (open)

9

RC-IN0

I

Rotary remote commander key input terminal (A/D input)

10

AVREF+

I

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

11

VDD

—

Power supply terminal (+5V)

12

OSC OUT

O

Main system clock output terminal (18.432 MHz)

13

OSC IN

I

Main system clock input terminal (18.432 MHz)

14

GND

—

Ground terminal

15

XT IN

I

Sub system clock input terminal (32.768 kHz)

16

XT OUT

O

Sub system clock output terminal (32.768 kHz)

17

GND

—

Ground terminal

18

RC-IN1

I

Rotary remote commander shift key input terminal    “L”: shift

19

SYSRST

O

Reset signal output to the SONY bus interface (IC581)    “L”: reset

20

BUS-ON

O

Bus on/off control signal output to the SONY bus interface (IC581)    “L”: bus on

21

UNISO

O

Serial data output to the SONY bus interface (IC581)

22

UNISI

I

Serial data input from the SONY bus interface (IC581)

23

UNICKO

O

Serial data transfer clock signal output to the SONY bus interface (IC581)

24

UNICKI

I

Serial data reading clock signal input for the SONY bus interface    Not used (open)

25

NCO

O

Not used (open)

26

KEYACK

I

Input of acknowledge signal for the key entry    Acknowledge signal is input to accept function 
and eject keys in the power off status    On at input of “H”

27

NOSESW

I

Front panel block remove/attach detection signal input terminal
“L”: front panel is attached

28

BU-IN

I

Battery detect signal input from the SONY bus interface (IC581) and battery detect circuit
“L” is input at low voltage

29

SIRCS

I

Sircs remote control signal input from the remote control receiver (IC951)

30

TEL-ATT

I

Telephone muting signal input terminal    At input of “H”, the signal is attenuated by –20 dB
Not used (fixed at “L”)

31

TEST-IN

I

Setting terminal for the test mode    “L”: test mode, Normally: fixed at “H”

32

RAMBU

I

Internal RAM reset detection signal input from the XC61BN3312MR (IC552)
Input terminal to check that RAM data are not destroyed due to low voltage
This checking is made within 100 msec after reset

33

RESET

I

System reset signal input from the reset signal generator (IC551) and reset switch (S551)
“L”: reset    “L” is input for several 100 msec after power on, then it changes to “H”

34

VOL-MUT

O

Muting control signal output to the electrical volume (IC331)
Volume minimum: “

∞

” output (“H” active)