Icom IC-F33GS Service Manual - page 14
4 - 6
Pin
number
Port
name
Description
13, 15,
16
CENC0–
CENC2
Output the CTCSS/DTCS signals.
29
REF
Outputs the reference oscillator cor-
recting voltage. The voltage is applied
to the buffer amplifi er (IC24, pin 3)
30
PLST
Outputs strobe signals to the PLL IC
(IC21, pin 16).
34
PMFM
O u t p u t s t h e F M / P M m o d u l a t i o n
switching signal to the FM/PM switch
(IC13, pin 5).
35
MDIO
I/O port for the serial data signals
from/to the base band IC (IC14,
pin 11).
36
MSCK
Outputs clock signal for the base
band IC (IC14, pin 13).
37
MDIR
Outputs serial data control signal to
the base band IC (IC14, pin 14).
38
MTCK
Input port for transmitting MSK clock
signal from the base band IC (IC14,
pin 9).
39
MTDT
Outputs MSK data for transmitting to
the base band IC (IC14, pin 10).
40
MRDF
Input port for the receiving MSK de-
tection signal from the base band IC
(IC14, pin 12).
41
DAST
Outputs strobe signals to the D/A
convertor (IC12, pin 6).
43
SENC
Output single tone encoder signal.
44
BEEP
Outputs beep audio signals.
45
SDEC
Input por t for single tone decode
signal from the base band IC (IC14,
pin 21).
46
CDEC
Input port for CTCSS/DTCS signal
from the amplifi er (IC19, pin 1).
48
BATV
Input port for the detect signal for
connecting battery pack’s voltage.
49
LVIN
Input port for the PLL lock voltage.
50
RSSI
Input port for the S-meter signal from
the FM IF IC (IC9, pin 12).
51
TEMP
Input port for the transceiver’s internal
temperature detecting signal.
69
CSFT
Outputs shift signal for reference os-
cillator’s frequency.
70
AFON
Outputs audio control signal.
Low:
While outputs audio signals
from the speaker.
Pin
Number
Port
name
Description
74
PTT
Input port for the PTT switch detec-
tion signal.
Low:
While the PTT switch is
pushed.
75
NOIS
Input port for the noise signal from
the FM IF IC (IC9, pin 13).
76
SO
Outputs serial data to the PLL IC
(IC21, pin 15) and D/A conver tor
(IC12, pin 8).
78
SCK
Outputs serial clock signal to the PLL
IC (IC21 pin 14), D/A convertor (IC12,
pin 7), etc.
79
CLI
Input port for the cloning data signal.
80
CLO
Outputs the cloning data signal.
82
ESDA
I/O port for data signals from/to the
EEPROM (IC10, pin 5).
84
MUTE
Outputs AF control signal .
Low:
While Squelch ON.
85
ESCL
Outputs clock signal to the EEPROM
(IC10, pin 6).
86
S5C
Outputs the S5 regulator (Q26–Q28)
control signal.
Low:
While the S5 regulator out-
puts 5 V voltage.
87
T5C
Outputs the T5 regulator (Q24) con-
trol signal.
Low:
While
transmitting.
88
R5C
Outputs the R5 regulator (Q25) con-
trol signal.
Low:
While
receiving.
89
TMUT
Outputs the transmitting mute switch
control signal to the mute switch
(Q 501).
High:
While
muting.
4-6-2 CPU (MAIN unit; IC22)