8 Bit mode and 4 bit mode differs in how data is send to LCD.
In 8 Bit Mode, character data (8 bit ASCII) and LCD commands are send through data lines D0 – D7 of the LCD. Enable Pin (E) of the LCD is used to provide data strobe…
But 4 Bit Mode uses only 4 data lines D4 – D7. In this the 8 bit data and commands are divided into two parts and sent sequentially through the 4 data lines.
The idea of 4 bit mode is introduced to save pins of microcontroller (serial communication LCD saves more pins). 4 bit mode interfaced lcd will be a bit slower than 8 bit mode. But this speed difference is not significant as LCDs are slow speed devices.
Due to these reasons 4 bit mode is commonly used…