Icom IC-M88 Service Manual page 11

4-5 PORT ALLOCATIONS
4-5-1 CPU (LOGIC UNIT; IC661)
Pin Port
number name
1 BEEP
Outputs beep audio signals.
Outputs strobe signals for the scrambler
2 VSSTB
IC (MAIN unit; IC381, pin 10).
Outputs strobe signals for the
3 EXSTB
expander IC (MAIN unit; IC341, pin 1).
Outputs strobe signals for the D/A
4 DASTB
converter (MAIN unit; IC251, pin 6).
Outputs strobe signals for the PLL IC
5 PLSTB
(MAIN unit; IC1, pin 11).
Input port for cloning signals.
6 ERXDI
Outputs cloning signals.
7 ETXDO
Outputs serial data for PLL, scrambler
10 SDATA
ICs, etc.
O u t p u t s s e r i a l c l o ck fo r P L L ,
11 SCLK
scrambler ICs, etc.
Outputs clock signal for the EEPROM
12 ESCK
(IC591, pin 6).
I/O port for EEPROM data signal
13 ESDA
(IC591, pin 5).
Outputs CPU clock shift signal.
17 CSIFT
High : While clock is shifted.
Input port for the WX tone detection.
27 WDECV
Input port for the transceiver's internal
28 WETIN
inundation detection.
Input port for the external terminal
29 EXTSV
connecting detection.
Input port for the battery voltage
30 BATTV
detection.
Input port for transmit RF level
31 TDETV
detection.
Input port for noise level detection.
32 NOISV
Input port for RSSI voltage level
33 RSSIV
detection.
Input port for VCO lock voltage level
34 LOINV
detection.
Input port for the transceiver's internal
35 TEMPV
temperature detection.
Input port for CTCSS/DTCS detection.
36 CDECV
Outputs ATIS wave form.
38 ATIS
COM0–
Output LCD common signals
46–48
COM2
SEG0–
Output LCD segment signals.
51–70
SEG19
CONT1
75
Output LCD contrast control signals.
76 CONT2
Output LCD and key's back light
77 LEDS1
dimmer control signal.
78 LEDS2
Description
Pin
Port
number
name
STXMS
79
MICMS
80
81
ISPMS
82
LDTFS
83
W/NS
AFMS
84
AFVS
85
M5VS
86
S5VS
87
88
V5VS
R5VS
89
T5VS
90
98
CENC1
99
CENC2
100
CENC3
PTTIN
102
103 EPTTIN
BTYPE
104
109
SQL
UP
110
4 - 4
Description
Outputs scrambler mute signal for the
AF mute circuit (IC481, pin 3).
Low : While scrambler is muting.
Outputs mic mute signal for the AF
mute circuit (IC481, pin 7).
Low : While the microphone is
muting.
Outputs the internal speaker control
signal.
High : While the speaker is muting.
Outputs DTCS's low-pass filter cut-off
frequency control signal.
Outputs Wide/Narrow control signal.
high : While Narrow is selected.
Outputs the AF mute circuit control
signal.
High : The AF mute circuit is ON.
Outputs AF amplifier's power supply
control signal.
High : The AF amplifier is ON.
Outputs M5V power supply control
signal.
Low : The common 5V is supplied.
Outputs S5V power supply control
signal.
Low : The common 5V is supplied.
Outputs V5V power supply control
signal.
Low : The common 5V is supplied.
Outputs R5V power supply control
signal.
Low : While receiving.
Outputs T5V power supply control
signal.
Low : While transmitting.
Output DTCS/CTCSS wave form.
Input port for [PTT] swtich detection.
High : While [PTT] switch is pushed.
Input port for HM-138 (optional
speaker-microphone)'s [PTT] swtich
detection.
Low : While HM-138's [PTT] switch
is pushed.
Input port for the connecting battery
type detection.
Low : While using alkaline cells.
Input port for the [SQL] key.
Low : While [SQL] key is pushed.
Input port for the [UP] key.
Low : While [UP] key is pushed.