There are two well known method to send data from microcontroller to LCD.
1. 8 bit interface
2. 4 bit interface
But there are some other applications where some new techniques are used to send write/ and read back data from LCD. These methodes involves mainly, 2-wire , 3-wire or even 4-wire interface. In such method some extra hardware is necessary to use with microcontroller and lcd. some people try to use i2c bus interface and ios expanders, some people try to use serial in and parallel out shift rigesters with microcontrollers.
Here we use none of the above said hardware , we will use simple 4-bit technique to control the lcd and write on useful information where and when required.
There are advantages and disadvantages of both of them.
But Normally 4-bit mode of operation is used where Pins of controller (IOs) are to be used for other purposes and if you have enough IOs free you can use 8-bit mode which is faster.
But to chabge the mode operation some necessry changes in code is also required, it depends upon the LCD, so for this datasheet is more important. Normally at the time of inilialzation, mode of operation is decided.
If you people wants the code and other stuff, try the download links,
|circuit diagram of LCD interfacing with Microcontroller 8051, complete circuit including Power supply and crystal and reset circuit and components|
|PIN CONNECTION AND SOLDERING OF LCD TO CIRCUIT BOARD|