Icom IC-M88 4-5PORT ALLOCATIONS, 4-5-1CPU (LOGIC UNIT; IC661)

4-5 PORT ALLOCATIONS

4-5-1 CPU (LOGIC UNIT; IC661)

Pin PortDescription number name

1BEEP Outputs beep audio signals.

2	VSSTB	Outputs strobe signals for the scrambler
		IC (MAIN unit; IC381, pin 10).
3	EXSTB	Outputs strobe signals			for the
		expander IC (MAIN unit; IC341, pin 1).
4	DASTB	Outputs strobe		signals for	the D/A
		converter (MAIN unit; IC251, pin 6).
5	PLSTB	Outputs strobe signals for the PLL IC
		(MAIN unit; IC1, pin 11).
6	ERXDI	Input port for cloning signals.
7	ETXDO	Outputs cloning signals.
10	SDATA	Outputs serial data for PLL, scrambler
		ICs, etc.
11	SCLK	Outputs serial clock for PLL,
		scrambler ICs, etc.
12	ESCK	Outputs clock signal for the EEPROM
		(IC591, pin 6).
13	ESDA	I/O port for EEPROM data signal
		(IC591, pin 5).
17	CSIFT	Outputs CPU clock shift signal.
		High : While clock is shifted.
27	WDECV	Input port for the WX tone detection.
28	WETIN	Input port for the transceiver’s internal
		inundation detection.
29	EXTSV	Input port	for the external		terminal
		connecting detection.
30	BATTV	Input port	for	the battery	voltage
		detection.
31	TDETV	Input port	for	transmit RF level
		detection.
32	NOISV	Input port for noise level detection.
33	RSSIV	Input port	for	RSSI voltage level
		detection.
34	LOINV	Input port for VCO lock voltage level
		detection.
35	TEMPV	Input port for the transceiver’s internal
		temperature detection.
36	CDECV	Input port for CTCSS/DTCS detection.
38	ATIS	Outputs ATIS wave form.
46–48	COM0–	Output LCD common signals
	COM2
51–70	SEG0–	Output LCD segment signals.
	SEG19
75	CONT1	Output LCD contrast control signals.
76	CONT2
77	LEDS1	Output LCD and key’s back light
78	LEDS2	dimmer control signal.

Pin	Port	Description
number	name
	STXMS	Outputs scrambler mute signal for the
79		AF mute circuit (IC481, pin 3).
		Low : While scrambler is muting.
		Outputs mic mute signal for the AF
80	MICMS	mute circuit (IC481, pin 7).
		Low : While the microphone is
		muting.
		Outputs the internal speaker control
81	ISPMS	signal.
		High : While the speaker is muting.
82	LDTFS	Outputs DTCS’s low-pass filter cut-off
		frequency control signal.
83	W/NS	Outputs Wide/Narrow control signal.
		high : While Narrow is selected.
	AFMS	Outputs the AF mute circuit control
84		signal.
		High : The AF mute circuit is ON.
	AFVS	Outputs AF amplifier’s power supply
85		control signal.
		High : The AF amplifier is ON.
	M5VS	Outputs M5V power supply control
86		signal.
		Low : The common 5V is supplied.
	S5VS	Outputs S5V power supply control
87		signal.
		Low : The common 5V is supplied.
		Outputs V5V power supply control
88	V5VS	signal.
		Low : The common 5V is supplied.
	R5VS	Outputs R5V power supply control
89		signal.
		Low : While receiving.
	T5VS	Outputs T5V power supply control
90		signal.
		Low : While transmitting.
98	CENC1
99	CENC2	Output DTCS/CTCSS wave form.
100	CENC3
102	PTTIN	Input port for [PTT] swtich detection.
		High : While [PTT] switch is pushed.
		Input port for HM-138 (optional
		speaker-microphone)’s [PTT] swtich
103	EPTTIN	detection.
		Low : While HM-138’s [PTT] switch
		is pushed.
	BTYPE	Input port for the connecting battery
104		type detection.
		Low : While using alkaline cells.
109	SQL	Input port for the [SQL] key.
		Low : While [SQL] key is pushed.
110	UP	Input port for the [UP] key.
		Low : While [UP] key is pushed.

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