Of course you all know that there are 44780 clone displays that do NOT support 4 bit mode. Having said this, At the time I found building a parallel port interface for the LCD and debugging the protocol like this, using turbo C under DOS, invaluable. Schematics are on the web or DIY (just wires from a parallel port to a LCD module and a power supply). Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.