Read Sony XR-4950X / XR-4954X Service Manual online
27
Pin No.
Pin Name
I/O
Function
Reference voltage (– side) of AD conversion Connect to power ground if no problems
such as noise
FM/AM common signal meter A/D conversion input terminal
AM (MW:SW:LW), FM S meter voltage detection terminal
FM AGC A/D conversion input terminal
FM AGC voltage detection terminal
4
KEYIN1
I
KEY input
5
KEYIN0
I
Use the AD conversion input
6
DSTSEL
I
Terminal for selecting and setting destination value Reads during reset
Rotary commander input
Use the AD conversion input
8, 9
QUALITY
O
Not used
Reference voltage (+ side) of AD conversion As current is always flowing, make sure that current
is supplied only when the power of the system is turned ON by the master microprocessor
11
VDD
—
Power supply terminal
12
OSCOUT
O
Terminal connected to the oscillator
13
OSCIN
I
Connected to the 18.432 MHz oscillator
14
VSS
—
Ground terminal
15
XIN
I
Terminal connected to the sub-clock (for clock) oscillator
16
XOUT
O
Connected to the 32.768 kHz oscillator
17
MMOD
—
Ground terminal
Front panel disconnection/attachment detection input terminal
A panel is present when “L”
BUS ON control output
Outputs “L” when UNI-LINK communication is activated
SYSTEM RESET control output
Outputs “L” when the UNI-LINK slave microprocessor is reset
LCD serial data output
Serial interface with LCD driver IC
Outputs “L” when OFF to prevent misoperations of the C-MOS port
LCD chip enable output terminal
Serial interface with LCD driver IC Outputs
“L” when OFF to prevent misoperations of the C-MOS port
LCD serial clock output
Serial interface with LCD driver IC
Outputs “L” when OFF to prevent misoperations of the C-MOS port
Rotary Commander Shift input terminal
Rotary Commander Shift input
RAM reset detection input
After clearing input reset to check if the RAM data has been damaged by decreasing
voltage, checks the RAM data within 50 ms Results
L= Clears the RAM as the power supply voltage of the microprocessor dropped
belowthe minimum data maintenance voltage
H= Checks the RAM damage check area as the power supply voltage of the
microproces sor has not dropped below the minimum data maintenance voltage
Clears the RAM if the RAM damage check area is damaged
7-8. IC PIN FUNCTION
• IC501 MASTER MICRO COMPUTER (MN101C49KTA) (MAIN Board)
1
VREF
—
2
VSM
I
3
FMAGC
I
7
RCIN0
I
10
VREF
—
18
NOSESW
I
19
BUSON
O
20
SYSRST
O
21
LCDSO
O
22
LCDCE
O
23
LCDCKO
O
24
RCIN1
I
25
RAMBU
I
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