Port Allocations - Icom IC-M402 Service Manual

4-7 PORT ALLOCATIONS

4-7-1 CPU (LOGIC BOARD; IC1)
Pin Port
number name
Outputs control signal for the LCD
contrast.
1 CONT1
CONT1
2 CONT2
3 BEEP Outputs beep audio signal.
Input port for the CH16 switch.
5 CH16
Low: While CH16 switch is pushed.
Input port for the CHWX switch.
6 CHWX
Low: While CHWX switch is pushed.
Input port for the H/L switch.
7 H/L
Low: While H/L switch is pushed.
Input port for ATIS/DSC decode sig-
8 DSDEC
nal.
Outputs clock signal to the PLL IC
16 PCK
(MAIN unit; IC2, pin 4).
Outputs strobe signals to the PLL IC
17 PSTB
(MAIN unit; IC2, pin 3).
Outputs data signals to the PLL IC
18 PDATA
(MAIN unit; IC2, pin 5).
Outputs control signal to swtich NMEA
20 ICFC
or ICF3 (Optional unit; HM-127).
Outputs beep volume control signal.
21 BPLVL
Low: Beep audio is maximum.
Outputs clock signal for the EEPROM
22 ECK
(IC2, pin 6).
23 EDA I/O port for the EEPROM data signals.
Output port for RF output power (High
27 HI/LO
or Low) select signal.
Input port for the communication data
28 RRXD
from HM-127.
Outputs communication data to HM-
29 RRXD
127.
Outputs bandpass filter select signals.
31 BPFV Low: Receiving more than 160 MHz.
High: Receiving less than 160 MHz.
Outputs transmit mute signal.
83 TMUT
High: While transmitting.
84 NMEAI Input port for GGA and NMEA data.
88 WXDEC Input port for WX alert signal.
Input port for the squelch volume
89 SQLV
level.
Input port from the FM IF IC (MAIN
90 SQL
unit; IC1) for the squelch operation.
Input port for the connected power
91 LBAT supply voltage detection (low battery
indicator).
Description
CONT2
CONTRAST
0
LIGHT
0
1 DEEP
1
Pin Port
number name
92 TXDET
93 KEYM
94 PTT
95 DTRS
96 DSC
97 UP
98 DOWN
99 UNLK
4-7-2 I/O EXPANDER IC (LOGIC BOARD; IC3)
Pin Port
number name
4 RMUTM
5 RMUTS
6 PTTM
7 PTTS
11 MMUTE
12 SMUTE
13 SEND
14 RCV
4 - 5
Description
Input port for TX LED control signal.
Input port for the smart mic functions.
2.02 V: [UP] is pushed.
3.00 V: [DN]] is pushed.
3.84 V: [16/9] is pushed.
Input port for the PTT switch from HM-
129.
Low: While PTT is pushed.
Input port for the DTRS switch.
Low: While DISTRESS switch is
pushed.
Input port for the DSC switch.
Low: While DSC switch is pushed.
Input port for the UP switch.
Low: While UP switch is pushed.
Input port for the DOWN switch.
Low: While DOWN switch is pushed.
Input port for the PLL unlock signal.
Low: While PLL is locked.
Description
Outputs the AF mute swtich (MAIN
unit; IC5) control signal for main body.
Low: While squelched
Outputs the AF mute swtich (MAIN
unit; IC5) control signal for the option-
al remote microphone (HM-127).
Low: While squelched
Outputs main microphone (HM-129)
select signal to the analog swtich
(IC4) while intercom operation.
Outputs optional microphone (HM-
127) select signal to the analog swtich
(IC4) while intercom operation.
Outputs select signal for the speaker
of the main microphone (HM-129) to
the analog swtich (IC5) while intercom
operation.
Outputs select signal for the speaker
of the optional microphone (HM-127)
to the analog swtich (IC5) while inter-
com operation.
Outputs the T5 regulator (MAIN unit;
Q24, Q25) control signal.
High: While transmitting
Outputs the R5 regulator (MAIN unit;
Q22, Q23) control signal.
High: While receiving.