PILib is a C++ library that implements an interface for HD44780 based LCD displays for the Raspberry PI. It can be downloaded at PILib . It is pretty easy to use.

The serial link is used as a command/data line (for GP3 pin) and power line (for Vdd pin, through D1 and C1). The filter R2-C2 splits the GP5 pin to two I/O lines. If GP5 outputs a pulse greater than ...