LCD and contrast (HD44780)

I want to issue a word of caution about the contrast pin wiring on HD44780 compatible liquid crystal displays.

All my diagrams show the contrast pin going directly to ground: that's how my display works. Any voltage level higher than that makes the contrast too light and display unreadable.

Other displays need an intermediate voltage, so you better check out how yours works before soldering it in place! The datasheet might be a good starting point.


These displays will be used on my FT-817 Frequency Reader and Interactive Frequency Reader projects, so I will have to be careful too. ;-)