LCD module - Parallel port interface

Connection to a standard PC parallel port is mostly simple. Those displays can handle eight bit input directly. They also need two extra lines to control which kind of data has just arrived and when the data is meant to be stable. Those signals are called RS (Register Select, i.e. instruction or data register) and EN (enable).

So we have to connect ten data lines (8 bits + RS + EN) and one common ground (GND) line, which makes eleven lines to the parallel port. Data read back is not supported by the driver and so we do not need extra lines for this. The follwing table shows the needed connections:

25 pin par.portfunctionLCD pinfunction
2Data 08D0
3Data 19D1
4Data 210D2
5Data 311D3
6Data 412D4
7Data 513D5
8Data 614D6
9Data 715D7

And since we only want to write data another connection is required. Make a permanent connection from GND to pin 5 of the LCD module.

That's it! You may also want to connect the displays power supply pins (1 = GND, 3 = +5V) to your gameport or your favourite +5V source.

This discription is only valid for my version of LCD display module! I will not be responsible for any damage you might do to your display, your computer or anything if your display is wired in another way. Please consult your databook, datasheet or the LCD-module-FAQ for more information.

But anyway the above information should be correct for most display modules.