Voltage Lines; Cpu Port Allocations - Icom IC-A200 Service Manual

3-4 VOLTAGE LINES

LINE DESCRIPTION
A voltage line from the external DC power
Vcc
connector.
Used for the transmitter circuit.
Produced by the T8V regulator (Q34, Q35, D32)
T8V
and controlled by the T/R switching circuit
(IC10a–IC10c).
Used for the receiver circuit.
R8V
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).
Used for the AGC circuit.
–4.5V Produced at D20, D21 by detecting the reference
oscillation signal.

3-5 CPU PORT ALLOCATIONS

Pin No. Port No.
Input port for the frequency exchange
1 P72
switch.
2 P71 Input port for the channel switch.
Input port for tuning step selection
3 P70
LOW: 25 kHz HIGH: 50 kHz
Input ports for the large tuning control.
4, 5 P63, P62
P63: MHz down P62: MHz up
Input ports for the small tuning control.
6, 7 P61, P60
P61: kHz down P60: kHz up
Outputs the protect register enable
15 P41
signal.
16 P40 Outputs the program enable signal.
When receiving the reset signal "HIGH"
20 RESET
to "LOW", the CPU starts its operation.
Oscillator input port for the CPU clock
21 X1
frequency.
Oscillator output port connected in
22 X2
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.
Outputs the chip enable signal to an
42 P21
LCD driver.
Outputs an inhibit signal to an LCD
43 P20
driver.
44 P73 Input port for PTT control.
3 - 5
Description