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16
5.10 LCD Interfacing –
Figure 5: 16x2 LCD Interfacing
Microcontroller
LCD PINS
Description
VCC
VCC
Supply voltage (5V).
GND
GND
Ground
PB0
RS
Register Select
PB1
R/W
READ /WRITE
PB2
EN
Enable
PB4 - PB7
D4 - D7
Bidirectional Data Bus
Table 4: 16X2 LCD Pin Outs
To interface LCD with the microcontroller in default configuration requires 3 control signals and
8 data lines. This is known as 8-bit interfacing mode which requires a total of 11 I/O lines. To
reduce the number of I/O ports required for LCD interfacing we can use 4-bit interfacing mode
which requires 3 control signals with 4 data lines. In this mode higher nibble and lower nibble bits
of commands/data set needs to be sent separately. Figure 5. shows LCD interfacing in 4-bit
Mode.