At 08:12 AM 1/30/97 -0600, you wrote:
>At 10:44 PM 1/29/97 -0500, you wrote:
>>hey guys & gals
>> How do I eliminate the pot for the contrast adjustment on my lcd
>>display "minimum part count" Thanks in advance. Tony M.
>>
>>
>
>I have an idea that I have not tried yet.  Use the PWM output of the pic to
>adjust the LCD contrast.  Put the output to an RC circuit with a time
>constant that allows the PWM to keep the Cap charged but also allows the
>voltage to be changed.  Connect the + side of the Cap to the adjust pin of
>the LCD.  Like I said, I haven't tried this yet.
>
>Norm

The problem with that technique is that it doesn't have a low enough impedance
to drive the LCD properly.  The normal temp range units require a voltage
in the
range of 0 to .5VDC.  You can use your technique but follow it with an OPAMP.
We have used that technique for years.

Brian