Motorola IC-T81A, IC-T81E service manual CPU Logic Unit IC1

4-5-3 CPU (LOGIC UNIT; IC1)

Pin	Port	Description
number	name
		Input port for the over-voltage detec-
1	VIN	tion from connected battery pack or
		external power supply.
		Input port for remote control signals
2	REMOTE	from an optional HM-75A microphone
		via the [MIC] jack.
3	SD	Input port for the S-meter voltage.
4	CTCIN	Input port for CTCSS decoded sig-
		nals.
5	LOCKV	Input port for the PLL lock voltage.
6	THERMC	Input port for the tranceiver’s internal
		temparature.
7	SBATT	Input port for the VCC voltage (con-
		nected battery voltage).
		Outputs control signal for the LCD
8	CONT	contrast.
		High : The LCD contrast is deep.
9	CTCOUT	Outputs CTCSS signals while trans-
		mitting.
		Output port for:
		• Beep audio signals while receiving.
10	BEEP	• DTMF signals or 1750 Hz Europe
		tone signal while transmitting.
		[EUR], [ITA], [UK]
		Input port for the bias control voltage
11	BPCPI	to judge kinds of battery types.
		High : Supply the bias control volt-
		age.
		Input port for the noise signal (pulse-
12	NOISE	type) from the IF IC (RF unit; IC 701,
		pin 13).
		Outputs data signals to the PLL IC2
		(RF unit; IC802, pin 4).
13	PDA2/UL	Input port for the PLL unlock signal
		from the PLL IC2 (RF unit; IC802, pin
		4).
		Outputs data signals to the PLL IC1
		(RF unit; IC801, pin 5).
14	PDA1/UL	Input port for the PLL unlock signal
		from the PLL IC1 (RF unit; IC801, pin
		5).
15	DAST	Outputs strobe signals to the D/A IC
		(LOGIC unit; IC5, pin2).
16	IOST	Outputs strobe signals to the I/O IC
		(RF unit; IC2, pin 1 and IC3, pin 1).
17	PLST2	Outputs strobe signals to the PLL IC2
		(RF unit, IC802, pin5).
18	PLST1	Outputs strobe signals to the PLL IC1
		(RF unit, IC801, pin 3).
19	CLONEOUT	Output port for the cloning signal.

Pin	Port	Description
number	name
20	CLONEIN	Input port for the cloning signal.
21	TXC	Outputs T4 regulator control signal.
		High : While transmitting.
22	R3C	Outputs R3 regulator control signal.
		High : While receiving.
23	CPUHV	Input port for the reset signal from
		Q151 (LOGIC unit).
		Outputs control signal for charger cir-
24	CHGC	cuit (RF unit; Q5).
		High : While battery is charging.
		Outputs control signal for the AF
25	AFON	amplifier requlator circuit.
		High : Activates the AF amplifier cir-
		cuit.
26	PCON	Outputs +3C regulator control signal
		(LOGIC unit; Q142 and Q145).
		Outputs control signal for the Europe
27	TCON	tone and DTMF.
		Low : Activates the Europe tone.
		High : Activates DTMF.
28	BLED	Outputs BUSY LED control singal.
		Low : The BUSY LED is ON.
29	LIGHT	Outputs LCD backlight control signal.
		High : Lights ON.
		Outputs control signal for the regulator
30	MICC	secton of MIC amplifier (LOGIC unit;
		IC301).
		Low : Activates the MIC amplifier
		circuit.
		Outputs AF mute and MIC mute con-
31	RM/MM	trol signals.
		High : Mute is ON.
32	POWER	Input port for the [POWER] switch.
33	RESET	Input port for the RESET signal from
		IC142, pin 1 (LOGIC unit).
39	PTT	Input port for the [PTT] switch.
		Outputs clock signal to the PLL IC1
41	CK	(IC801), PLL IC2 (IC802), D/A IC (IC5)
		, I/O IC (IC2, IC3) on the RF unit and
		EEPROM IC (LOGIC unit; IC2).
42	ESIO	Data bus line for the EEPROM
		(LOGIC unit; IC2).
43–46	KR3–KR0	Input ports for key matrix.
47, 48	I1, I2	Input ports for Initial matrix.
49–54	KS5–KS0	Outputs port for key matrix.
55, 56	DICK,	Input port for the up/down signal from
	DIUK	the main dial (LOGIC unit; S1).

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