Sony XR-4803 service manual Pin No, Pin Name, Function

Pin No.		Pin Name	I/O							Function
69		UNISO	O	Serial data output terminal for the unilink						Not used (open)
70		UNISI	I	Serial data input terminal for the unilink						Not used (fixed at “L”)
71		UNICKO	O	Serial data transfer clock signal output terminal for the unilink Not used (connected to pin ^¥)
72		BUSON	O	Bus on/off control signal output terminal						Not used (pull up)
73		SYSRST	O	Reset signal output terminal			“L”: reset			Not used (pull up)
74		VREG	O	CPU regulator output terminal				Connected to capacitor
75		GND	—	Ground terminal
76		X OUT	O	Main system clock output terminal (4.5 MHz)
77		X IN	I	Main system clock input terminal (4.5 MHz)
78		CE	I	CPU chip enable signal input (fixed at “H”)
79		VDD1	—	Power supply terminal (+5V)
80		RESET	I	System reset signal input from the reset signal generator (IC551) and reset switch (S551)
				“L” is input for several 100 msec after power on, then it changes to “H”
*1 loading/tape operation motor control
		MODE	STOP		LOADING/	EJECT/			BRAKE
TERMINAL					FORWARD	REVERSE
	LM LOD (pin 8)		“L”		“H”	“L”			“H”
	LM EJ (pin 9)		“L”		“L”	“H”			“H”

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