Port Allocations - Icom IC-M302 Service Manual

4-7 PORT ALLOCATIONS

4-7-1 CPU (LOGIC BOARD; IC1)
Pin Port
number name
Input port for the HM-141 key signals.
Pushed key
2 KEYM
Input port for the transmit detecting
3 TXDET signal.
High: While transmitting.
Input port for the squelch volume sig-
4 SQLV
nal.
Outputs the clock signal to the PLL IC
6 PCK
(MAIN unit; IC8, pin 4).
Outputs data signals to the PLL IC
7 PDATA
(MAIN unit; IC8, pin 5).
Input port for the WX alert decode sig-
8 WXDEC
nal.
9 DSCENC Outputs the DSC encode signal.
Outputs beep audio signals.
12 BEEP
High: While sounds beep audio.
Outputs strobe signals.for the PLL IC
13 PSTB
(MAIN unit; IC8, pin 3).
Outputs the clock signal to the EEP-
18 ECK
ROM (IC4, pin 6).
22 DSCDEC Input port for the DSC decode signal.
Input port for the PLL unlock signal.
23 UNLK
Low: While the PLL is unlocked.
24 EDATA I/O port for the EEPROM data signal.
30 SQL Input port for the squelch level signal.
Input port for the HM-141 PTT switch.
31 PTT Low: While
Input port for the SCAN switch.
40 SCAN Low: While the [SCAN] switch is
Input port for the [CH/WX] switch.
41 CH/WX Low: While the [CH/WX] switch is
Input port for the [CH16] switch.
42 CH16 Low: While the [CH16] switch is
Input port for the [√] switch.
43 DN
Low: While the [√] switch is pushed.
Input port for the [∫] switch.
UP
44
Low: While the [∫] switch is pushed.
Input port for the [DSC] switch.
45 DSC Low: While the [DSC] switch is
Description
Input voltage
[∫] 2.02 V ±0.12 V
[√] 3.00 V ±0.13 V
[Hi/Lo] 3.84 V ±0.10 V
the PTT switch
pushed.
pushed.
pushed.
pushed.
pushed.
Pin Port
number name
46 DTRS
47 PTTC
49 H/L
50 RMUTE
51 TMUTE
52 SEND
53 RCV
54 BPLVL
SEG1–
62–88
SEG27
COM3–
92–95
COM0
is
4 - 5
Description
Input port for the [Distress] switch.
Low: While the [Distress] switch is
pushed.
Outputs the microphone muting circuit
(IC7) control signal.
Low: While transmitting the DSC sig-
nal.
• Outputs the transmit power control
signal.
• Outputs the receiver RF attenuator
control signal.
Low: While the attenuator is ON.
Outputs the receiver mute control sig-
nal.
Low: While muting.
Outputs the transmitter mute control
signal.
High: While muting.
Outputs the T5 regulator (MAIN unit;
Q31, Q32) control signal.
High: While transmitting
Outputs the R5 regulator (MAIN unit;
Q33, Q34) control signal.
High: While receiving.
Outputs special alarm audio signals
(ex. when receiving distress signal).
Low: While sounds special alarm.
Output LCD segment signals.
Output LCD common signals.