Peter van Hoof wrote:
>
> Yes, I do not have the datasheet of this display but a lot of similar
> displays need a negative voltage for good contrast , most will take a pot
> between -5 and +5 volt

> > I've got two completely unrelated questions for you all:

> > 2. I have a Seiko L2432 2 x 24 char LCD module, which I am having some
> > difficulty getting a decent contrast out of. I am using what appears to be
> > a fairly standard usage of a 10k trimpot to control the LCD drive voltage
> > (pin 3) however the best contrast occurs when this is fully turned towards
> > the ground side. When I connected ground straight to the pin the display
> > was slightly darker but still not upto what I would consider to be a
> > reasonable standard. Anyone have any ideas?
> >
> > Wesley Moore

Get a 1.5 volt battery and connect it positive to pin 3 and negative to
ground. If it darkens the display a lot more, then that is your answer.
It requires a negative bias. In fact it sounds very much like it, as I
have been down this road before.

If you have a max-232 or similar on board, you can steal the negative
supply from that. Still needs a pot for final adjustment, or a voltage
divider pair of resistors.

Don McKenzie  mailto:don@dontronics.com http://www.dontronics.com

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