Icom IC-400PRO Service Manual page 11

CPU-Continued
Pin Port
number name
I/O ports for the optional board control
OPT3–
44–46
OPT1 signals.
Input port for the clock signal from the
48 SI
optional board via J1.
49 CLI Input port for the cloning signal.
50 CLO Output port for the cloning signal.
51 POSW Input port for the POWER switch.
• Input port for the remote power con-
trol signal from the external connector
52 DIM
(J6).
• Input port for the dimmer control.
Input port for the "NOIS" signal from
the FM IF IC (MAIN unit; IC1) for noise
53 NOIS
squelch operation.
Input port for interruption signal from
54 CIRQ
the optional board via J1.
Outputs chip select signal for the
55 CCS
optional board via J1.
Input port for the PTT switch from
56 PTT
microphone.
Input port for the PTT switch from the
57 EPTT external connector (J6).
Low : External PTT switch is ON.
Input port for the microphone hanger
58 HANG detection signal.
Low : Microphone on hook.
Input port for the AF volume control
signal (R14).
59 AFVI
High : [VOL] is maximum clockwise.
Input port for the CTCSS/DTCS decod-
60 CDEC
ing signals.
Input port for the single tone decoding
61 SDEC
signal.
Input port for the optional board detec-
62 OV12
tion signal.
Input port for receiving signal strength
63 RSSI
level detection.
64 LVIN Input port for the PLL lock voltage.
Description
4-5-2 OUTPUT EXPANDER (MAIN UNIT; IC17)
Pin Port
number name
4 RXC
5 AFON
6 NWC
7 RMUT
11 BUSY
13 TMUT
14 MMUT
4-5-3 LCD DRIVER (FRONT UNIT; IC6)
Pin Port
number name
1 LIGT1
2 LIGT2
SEG32–
3–34
SEG1
COM4–
35–38
COM1
4-5-4 D/A CONVERTER IC (MAIN UNIT; IC6)
Pin Port
number name
2 SQIN
4 TENC
11 BAL
14 T1
22 T2
23 REF
4 - 5
Description
Outputs transmit/receive control signal.
High: While receiving.
Outputs audio output control signal.
High: While receiving.
Outputs wide/narrow control signal.
High: Wide is selected.
Outputs receiving mute control signal.
Low: While receiving is muting.
Outputs busy detecting signal to the
optional unit.
Outputs transmitting mute control sig-
nal.
Low: While transmitting is muting.
Outputs the microphone mute control
signal.
Low: While the microphone is muting.
Description
Outputs dimmer control signal.
High: Dimmer is ON.
Outputs backlight control signal.
High: Backlight is ON.
Output LCD segment signals.
Output LCD common signals.
Description
Outputs the detection level control sig-
nal for the squelch circuit.
Outputs the TENC level control signal.
Outputs the modulation balance con-
trol signal.
Outputs the tuning voltage for band-
pass filters
• Outputs the tuning voltage for band-
pass filters.
• Outputs transmitting power control
signal.
Outputs the reference oscillator cor-
recting voltage.