How did you make the change from 8 bit to 4 bit? Was there physical moving/
disconnecting or did you just change the software? Can you go back to confirm
that it is really the 4/8 bit change that is causing the problem. Does it
change each time you run the program, as you described, or are there also
changes during the run? It sounds to me more like a bad connection somewhere,
either in your contrast circuit (pot wiper?) or even in the module itself.

For my part, I've used lots of these modules, mainly in 4-bit mode and haven't
seen this problem.

Simon.
---


  On Wed, Aug 14, 2002
at 10:37:15PM -0700, Thomas N wrote:
> Hello Everyone,
>
> My LCD was working fine with 8-bit interface mode.  When I change it to
> 4-bit interface mode, the LCD contrast changes randomly each time I run
> the program (I use ICD).  Sometimes, the display is clear with no dark
> background, but sometimes the background is very dark and it's very hard
> to read the text on the LCD.  Anyone know why it is intermittent like
> this?  There is no improvement between floating the 4 un-used pins and
> grounding them.  Please help!
>
> Thank you in advance!
> Thomas
>
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