Sharp MZ-3500 service manual In/Out, RO1B, RO2B

MX 3500
Pin No	Polarity	IN/OUT		Function
	Signal Name
			System reset signal.
57	SYSR	IN	Used to reset I/O port in the MMR.
				(System Reset)
58	FD3	IN	Input from the sytem assignment dip switch.
			"See the dip switch description, provided separately.
			Shared RAM select signal.
59	COAB	IN	Address of the shared RAM is *F800-#FFFF for the main CPU
				(Common RAM Address)
			Select signal for 8KB area allocated to slot 1.
60	RO1B	OUT	Valid when SD2 is active (ROM based BASIC) and SD3 (RAM based BASIC)
				(ROM 1)
61	GND	IN	Ground
62	Vcc	IN	5V supply
63	RO2B		Select signal for 8KB area allocated to slot 2 or 3
		OUT	Valid when SD2 is active (ROM based BASIC) and SD3 (RAM based BASIC).
64	R03B
				(ROM2, 3)
65	RDB	IN	Read signal from the main CPU.
				(Read)
66	CLK		EAIT signal generation clock.
				(Clock)
			Select signal for 8KB area allocated to slot 4.
67	R04B	OUT	Valid when SD2 or SD3 (RAM based BASIC) are active.
				(ROM 4)
			RAS/CAS address switching signal for the main CPU DRAM.
68	MPX	OUT	High: Row address	Low: Column address
				(Multiplex)
69	GND	IN	Ground
			CAS (Column Address) signal for the main CPU 64K DRAM.
70	CASB	OUT	•Refresh for the RAM only.
				(Column Address Select Buffer)
71	GND	IN	Ground
72	INTB	OUT		(Interrupt)
73			Not used

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