At 11:51 AM 11/5/00 -0000, you wrote:
>Thanks Andrew - I'll have a play with this.  I also liked Alexandre's
>suggestion of a digital pot - advantage  there would be  non-volatility of
>the wiper position + not having to increase the frequency of the interrupt.
>
>Jim M

I've got a sketched design using a simple R-2R network on 4 port pins,
plus an emitter follower (6parts in total, counting 2  quad resistor
networks).
Total cost less than one thin dime in quantity.  It's optimized for TN
displays.

Best regards,
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Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Contributions invited->The AVR-gcc FAQ is at: http://www.bluecollarlinux.com
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