Icom IC-A200 Service Manual - page 10
3-4
VOLTAGE LINES
3-5 CPU PORT ALLOCATIONS
LINE
DESCRIPTION
Vcc
A voltage line from the external DC power
connector.
T8V
Used for the transmitter circuit.
Produced by the T8V regulator (Q34, Q35, D32)
and controlled by the T/R switching circuit
(IC10a–IC10c).
R8V
Used for the receiver circuit.
Produced by the R8V regulator (Q32, Q33, D30).
8V
A common 8 V line from the 8V regulator (IC11).
5V
A common 5 V line from the 5V regulator (IC12).
–4.5V
Used for the AGC circuit.
Produced at D20, D21 by detecting the reference
oscillation signal.
Pin No. Port No.
Description
1
P72
Input port for the frequency exchange
switch.
2
P71
Input port for the channel switch.
3
P70
Input port for tuning step selection
LOW: 25 kHz
HIGH: 50 kHz
4, 5
P63, P62
Input ports for the large tuning control.
P63: MHz down P62: MHz up
6, 7
P61, P60
Input ports for the small tuning control.
P61: kHz down P60: kHz up
15
P41
Outputs the protect register enable
signal.
16
P40
Outputs the program enable signal.
20
RESET
When receiving the reset signal "HIGH"
to "LOW", the CPU starts its operation.
21
X1
Oscillator input port for the CPU clock
frequency.
22
X2
Oscillator output port connected in
parallel with the X1 port.
23
P33
Outputs the chip select signal to IC8.
24
P32
Outputs the serial clock to IC8.
25
P31
Serial data output to IC8.
26
P30
Serial data input from IC8.
27
P81
Input port for a remote exchange switch.
28
P80
Input port for a remote channel switch.
30
SO
Outputs PLL serial data.
31
SCK
Outputs serial clock to the PLL.
40
P23
Outputs beep tones.
41
P22
Outputs a PLL strobe signal.
42
P21
Outputs the chip enable signal to an
LCD driver.
43
P20
Outputs an inhibit signal to an LCD
driver.
44
P73
Input port for PTT control.
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