Interfacing a Liquid Crystal Display Module

Interfacing a Liquid Crystal Module

The following tables show pin assignments for typical LCD modules. There are two tables, the first for modules with less than 80 characters, the second for modules with more than 80 characters.

Finally, a typical electrical interface circuit is shown at the bottom of the page.

Pin assignment for <= 80 character displays
Pin number	Symbol	Level	I/O	Function
1	Vss	-	-	Power supply (GND)
2	Vcc	-	-	Power supply (+5V)
3	Vee	-	-	Contrast adjust
4	RS	0/1	I	0 = Instruction input 1 = Data input
5	R/W	0/1	I	0 = Write to LCD module 1 = Read from LCD module
6	E	1, 1-->0	I	Enable signal
7	DB0	0/1	I/O	Data bus line 0 (LSB)
8	DB1	0/1	I/O	Data bus line 1
9	DB2	0/1	I/O	Data bus line 2
10	DB3	0/1	I/O	Data bus line 3
11	DB4	0/1	I/O	Data bus line 4
12	DB5	0/1	I/O	Data bus line 5
13	DB6	0/1	I/O	Data bus line 6
14	DB7	0/1	I/O	Data bus line 7 (MSB)


Pin assignment for > 80 character displays
Pin number	Symbol	Level	I/O	Function
1	DB7	0/1	I/O	Data bus line 7 (MSB)
2	DB6	0/1	I/O	Data bus line 6
3	DB5	0/1	I/O	Data bus line 5
4	DB4	0/1	I/O	Data bus line 4
5	DB3	0/1	I/O	Data bus line 3
6	DB2	0/1	I/O	Data bus line 2
7	DB1	0/1	I/O	Data bus line 1
8	DB0	0/1	I/O	Data bus line 0 (LSB)
9	E1	1, 1->0	I	Enable signal row 0 & 1
10	R/W	0/1	I	0 = Write to LCD module 1 = Read from LCD module
11	RS	0/1	I	0 = Instruction input 1 = Data input
12	Vee	-	-	Contrast adjust
13	Vss	-	-	Power supply (GND)
14	Vcc	-	-	Power supply (+5V)
15	E2	1, 1->0	I	Enable signal row 2 & 3
16	n.c.

A typical electrical interface, along with pin assignments is shown below: