Hitachi HD44780 contrast control

Community General Discussion
1

Hitachi HD44780
Hitachi HD44780533×722 83.2 KB

I often read comments on here that it is a common mistake to connect the contrast control pot to +5V.

The image above is a scan from Hitachi's data sheet for the HD44780. I've had a paper copy of the data sheet from, I don't know, maybe 1990, not really sure.

So, if Hitachi put in their data sheet about their product instructions to connect the pot to +5V how is doing so a mistake? It is what the manufacturer said should be done. Were Hitachi mistaken about this? Is there some history to this I am not aware of?

3

Hi

A an early HD44780 displays player I always followed HItachi's data sheet.

Good contrast is often found for 4V < (Vdd -V0) <4.5V , a potentiometer is not a so bad idea to adjust (Vdd-V0) !!

Potentiometer gives you the way to set the best contrast (temperature changes, different angles of view....)