Parallel interfacing LCD with MCU needs at least 6 I/O pins (4 bit mode) and maximun 11 I/O pins (8 bit mode). The I/O pin’s can be cut down to 3 pin by serial interfacing using shift registers. There are a few shift registers that can be used such as 74HC164, 74HC595, CD4094 and other compatible 8 bit shift register. Before you attempt to do serial interfacing, it helps to get familiar with parallel interfacing, you can find many reference from internet.
May 11th, 2008