4 - 6
4-6 PORT ALLOCATIONS
4-6-1 MAIN CPU (MAIN UNIT; IC23)
Pin
number
Port
name
Description
1
DSDA
I/O port for data signal to the D/A con-
verter (IC30 pin 6).
2
DAST
Outputs strobe signals to the D/A
converter (IC8, pin 6).
10
SSO
Outputs serial data to the PLL IC (IC4,
pin 15) and D/A converter (IC8, pin 8).
11
SCK
Outputs clock signal to the PLL IC (IC4
pin 14), D/A converter (IC8, pin 7),
etc.
13
PLST
Outputs strobe signals to the PLL IC
(IC4, pin 16).
15
DASW
Outputs control signal to the digital
/analog switch (IC42).
Low:
While analog mode is se-
lected.
16
TXC
Outputs the T8V regulator circuit
(Q34) control signal.
Low:
During transmit.
17
TMUT
Outputs the R8V regulator circuit
(Q30) control signal.
Low:
During receive.
18
AFON
Outputs control signal for AF mute
circuit (Q28, Q29).
High:
While AF amplifi er (IC38) is
activated.
19
NWC
Outputs wide/narrow switch (D2, D4)
control signal.
High:
When narrow band is se-
lected.
20
DDSD
Input port for serial data from the
DTMF decoder IC (IC6, pin 9).
21
DDAC
Outputs clock signals to the DTMF
decoder IC (IC6, pin 10).
32
RMUT
Input port for the AF mute signal from
the optional unit via J2.
Low:
While RX audio is muted.
33
MMUT
Input port for the microphone mute
signal from the optional unit via J2.
Low:
While microphone audio is
muted.
34–36
OPT1–
OPT3
I/O ports for optional unit.
37
NOIS
Input port for the noise signal from the
FM IF IC (IC9, pin 13).
38
POSW
Input port for the [ ] switch.
Low:
While [ ] switch is pushed.
39
DDST
Input port for DTMF detection signal
from the DTMF decoder IC (IC6,
pin 11).
40
IGSW
Input port for the remote power con-
trol signal from external connector, J7.
41
PWON
Outputs control signal for the power
switch circuit (Q41, Q42).
Low: While power ON.
43
SENC
Outputs single tone encoder signal.
Pin
number
Port
name
Description
44
BEEP
Outputs beep audio signals.
45
SDEC
Input por t for single tone decode
signal from the base band IC (IC2,
pin 21).
46
CDEC
Input port for CTCSS/DTCS signal
from the LPF (IC1, pin 7).
47
ULCK
Input port for the PLL unlock signal.
Low: The PLL circuit is unlocked.
48
BATV
Input port for the connected battery
for the low battery detection.
49
LVIN
Input port for the PLL lock voltage.
50
RSSI
Input port for the S-meter signal from
the FM IF IC (IC12, pin 12).
51
TEMP
Input port for the transceiver’s internal
temperature detecting signal.
68
CLO
Outputs the data signal to the FRONT
CPU (FRONT UNIT; IC3).
69
CLI
Input port for the data signal from the
FRONT CPU (FRONT UNIT; IC3).
72
HORN
Outputs external device control signal.
High:
When matched 5/2 tone sig-
nals are received.
78
MTCK
Input port for transmitting MSK clock
signal from the base band IC (IC2,
pin 9).
79
NTXD
Outputs NMEA data signals for the
connected unit via external connector
(J7).
80
NRXD
Input port for NMEA data signals from
the connected unit via external con-
nector (J7).
88
DIM
Input port for the LCD backlight con-
trol signal from the external connector
(J8).
Low:
W h i l e L C D b a c k l i g h t i s
dimmed.
89–91
CENC0–
CENC2
Output the CTCSS/DTCS signals.
93
MTDT
Outputs the MSK data to the base
band IC (IC2, pin 10).
94
MDIR
Outputs serial data control signal to
the base band IC (IC2, pin 14 ).
95
MDIO
I/O port for the serial data signals
f r o m / t o t h e b a s e b a n d I C ( I C 2 ,
pin 11).
96
MSCK
Outputs clock signal for the base
band IC (IC2, pin 13).
97
PMFM
Outputs the the FM/PM switch (IC43,
pin 11) control signal.
High:
While PM is selected.
98
ESDA
I/O port for data signals from/to the
EEPROM (IC26, pin 5).
