LCD Module Pin Assignment

Pin assignment

The pin assignment shown below is an industry standard for small (80 characters or less) alphanumeric LCD-modules. To be sure always check the manufacturers datasheet!
To locate pin 1 on a module check the manufacturers datasheet!

Table 1, Pin assignment
Pin number Symbol I/O Function

1 Vss - Power supply (GND)

2 Vcc - Power supply (+5V)

3 Vee - Contrast adjust

4 RS I 0 = Command input/output
1 = Data input/output

5 R/W I 0 = Write to LCD module
1 = Read from LCD module

6 E I Enable signal (Data strobe)

7 DB0 I/O Data bus line 0 (LSB)

8 DB1 I/O Data bus line 1

9 DB2 I/O Data bus line 2

10 DB3 I/O Data bus line 3

11 DB4 I/O Data bus line 4

12 DB5 I/O Data bus line 5

13 DB6 I/O Data bus line 6

14 DB7 I/O Data bus line 7 (MSB)

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

4-bit Interface

Data bus lines 0 through 3 are not used when the module is operated in 4-bit mode. Commands and data are still 8 bits long, but are transferred as two 4-bit nibbles on data bus lines 4 through 7. The most significant nibble (bits 4 through 7) is transferred first, followed by the least-significant nibble (bits 0 through 3).