Icom IC-M87 Service Manual page 14

CPU (continued)
Pin Port
number name
81 ISPMS
82 LDTFS
83 W/NS
84 AFMS
85 AFVS
.
he
86 M5VS
87 S5VS
88 V5VS
89 R5VS
90 T5VS
98– CENC1–
100 CENC3
102 PTTIN
103 EPTTIN
109 SQL
110 UP
111 DOWN
112 CH/WX
113 16/9
114 SCAN
115 H/L
119 UNLCK
Description
Outputs the internal speaker control
signal.
High : While connecting the external
speaker.
Outputs DTCS's low-pass fi lter (Q532)
cut-off frequency control signal.
Outputs Wide/Narrow mode control
signal.
High : W h i l e n a r r o w m o d e i s
selected.
Outputs the AF mute circuit control
signal.
High : While the squelch is closed.
Outputs AF amplifier's power supply
control signal.
High : While noise/tone squelches
are opened or emitting a
beep.
Outputs M5V regulator circuit (Q551–
Q553) control signal.
Low : The common 5V is supplied.
Outputs S5V regulator circuit (Q561)
control signal.
Low : The common 5V is supplied.
Outputs V5V regulator circuit (MAIN
unit; Q321) control signal.
Low : The common 5V is supplied.
Outputs R5V regulator circuit (MAIN
unit; Q322) control signal.
Low : While receiving.
Outputs T5V regulator circuit (MAIN
unit; Q323) control signal.
Low : While transmitting.
Output DTCS/CTCSS wave form.
Input port for [PTT] switch detection.
High : While [PTT] switch is pushed.
Input por t for HM-138 (optional
speaker-microphone)'s [PTT] switch
detection.
Low : While HM-138's [PTT] switch
is pushed.
Input port for [SQL].
Low : While [SQL] is pushed.
Input port for [Y].
Low : While [Y] is pushed.
Input port for [Z].
Low : While [Z] is pushed.
Input port for [DIAL].
Low : While [DIAL] is pushed
Input port for [16•C].
Low : While [16•C] is pushed.
Input port for [SCN•DUAL].
Low : W h i l e [ S C A N • D U A L ] i s
pushed.
Input port for the [H/L•LOCK].
Low : While [H/L•LOCK] is pushed.
Input port for the PLL unlock signal.
High : PLL circuit is unlocked.
4-5-2 EXPANDER (MAIN UNIT; IC341)
Pin Port
number name
Outputs the scrambler switch (IC281,
pin 3) control signal.
5 SRXMS
Outputs the scrambler switch (IC281,
pin 7) control signal.
6 DETMS
Outputs the RF attenuator control sig-
11 ATTS nal.
Outputs the TX mute switch (Q141)
12 TXMS control signal.
Outputs the TX/RX VCO control
13 VCOS
signal.
4-5-3 D/A CONVERTER (MAIN UNIT; IC251)
Pin Port
number name
Output AF signals to the squelch cir-
2 SQCON
cuit (IC231, pin 8).
Output modulation signals to the VCO
3 MOCON
circuit.
10 DTCON Output CTCSS/DTCS signals.
Outputs reference oscillator (X1) con-
11 FRCON
trol signal.
• While receiving
14 T1CON
• While transmitting
Outputs the bandpass filter (D155)
15 T2CON
tuning signal.
Outputs the bandpass filter (D181)
22 T3CON
tuning signal.
Outputs the bandpass filter (D182)
23 T4CON
tuning signal.
4 - 5
Description
Low : While the scrambler function
OFF.
Low : While the scrambler function
ON.
High : While attenuator is ON.
Low : While receiving.
Description
Outputs the bandpass filter (D154)
tuning signal.
Outputs TX power control signal.