![background image](http://html.mh-extra.com/html/icom/ic-m45/ic-m45_service-manual_612807010.webp)
3 - 4
Description
Outputs the R5 regulator (Q19, Q20)
control signal.
Low : While receiving
Outputs the T5 regulator (Q17, Q18)
control signal.
Low : While transmitting
Output port fo RF output power (High
or Low) select signal.
Low : While low power is selected
Outputs the reset signal for optional
unit via J5 (MAIN unit).
Outputs the analog switch (IC5) con-
trol signal.
Low : While squelched
Outputs transmit mute signal.
Low : While transmitting
Port
name
RCV
SEND
HI/LO
OP.RST
RMUT
TMUT
Pin
number
4
5
11
12
13
14
3-5 PORT ALLOCATIONS
3-5-1 CPU (LOGIC unit; IC1)
Pin
number
3
5
6
7
8
10
13
14
15
16
17
22
23
24
26, 27
31
33
34
35
36
37
38
Port
name
LBATT
PTT.M
TXDET
SQLV
KEY.M
BEEP
OEX.STB
P.STB
DATA
CK
ESI
SQL
UNLK
TONE
LAMP2,
LAMP1
HANG
DOWN
UP
H/L
SCAN
CH/WX
CH16/9
Description
Input port for the connected power
supply voltage detection (low voltage
indicator).
Input port for the PTT switch.
Input port for the “TX” indicator from
the power detector circuit (Main unit;
D11, D12).
Input port for the squelch volume level.
Input port for the smart mic functions.
2.02 V: [UP] is pushed
3.00 V: [DN] is pushed
3.84 V: [HI/LO] is pushed
Outputs beep audio signals.
Outputs strobe signals for the output
expander (MAIN unit; IC7).
Outputs strobe signals for the PLL cir-
cuit.
Outputs data signals to the EEPROM
(IC4), PLL IC (MAIN unit; IC3) and
expander ICs (MAIN unit; IC7), etc.
Outputs clock signal to the EEPROM
(IC4), PLL IC (MAIN unit; IC3) and
expander ICs (MAIN unit; IC7), etc.
Input port for the data signals from the
EEPROM (IC4).
Input port from the FM IF IC (MAIN
unit; IC1) for the squelch operation.
Input port for the PLL unlock signal.
Low : While PLL is locked.
Input port for the weather alert tone
decode signal.
Low : Weather alert tone (1050 Hz)
is detected.
Outputs LCD backlight control signal.
High : While LCD backlight is ON.
Input port for the microphone hanger
detection signal.
Low : Microphone on hook
Input port for the [DOWN] switch.
Input port for the [UP] switch.
Input port for the [H/L] switch.
Input port for the [SCAN] switch.
Input port for the [CH/WX] switch.
Input port for the [16/9] switch.
3-5-2 OUTPUT EXPANDER (MAIN unit; IC7)