Casio CTK-401 manual LCD Driver LSI3 SED1278F0A, Lvcc

Pin No.	Terminal	In/Out	Function
74 ~ 77	DB4 ~ DB7	Out	Data bus for the LCD driver
78	NC9	—	Not used
79	LVCC	In	+5 V source
80 ~ 84	KO8 ~ KO12	Out	Terminals for button scan signal
85 ~ 87	P65 ~ P67	—	Not used
88	RS	Out	Control signal for the LCD driver
89	R/W	Out	Read/Write signal for the LCD driver
90	E	Out	Chip enable signal for the LCD driver
91 ~ 95	P73 ~ P77	—	Not used
96	LGND	In	Ground source
97, 100	MA18, MA15	Out	Address bus

LCD DRIVER (LSI3: SED1278F0A)

The LCD driver can drive a dot matrix LCD having 40 segment and 16 common lines. The LSI contains 240 graphic symbols in the built-in character generator ROM, and stores 80 characters in the built-in display data RAM. In accordance with command from the CPU, the LSI is capable of displaying up to 16 characters simultaneously. The following table shows the pin functions of LSI3.

Pin No.	Terminal	In/Out	Function
1 ~ 22,	SEG1 ~ SEG40	Out	Segment signal output
63 ~ 80
23	VSS	—	GND (0 V) source
24, 25	OSC1, OSC2	In/Out	Terminals for the built-in clock pulse generator. The external
			resistor connected determines the oscillation frequency.
			LCD drive voltage input.
26 ~ 30	V1 ~ V5	In	Those voltages are used for generating the stepped pulse of
			the LCD drive signals.
31, 32	LP, XCLS	—	Not used
33	VDD	In	DVDD (+5 V) source
34, 35	FR, DO	—	Not used
36	RS	In	Data/command determination terminal.
			High: data, Low: command
37	R/W	In	Read/Write terminal. High: read, Low: write
			Chip enable signal.
38	E	In	High: enable, the writing is done at fall edge.
			Low: disenable
39 ~ 42	DB0 ~ DB3	—	Not used. Connected to GND (0 V)
43 ~ 46	DB4 ~ DB7	In/Out	Data bus
47 ~ 62	COM1 ~ COM16	Out	Common signal/output

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