On Tuesday 06 May 2003 23:13, Ben Jackson scribbled:
> On Tue, May 06, 2003 at 09:19:00PM -0500, Picdude wrote:
> > switched to pnp transistors, and used a common-anode display?  Can I =
save
> > from using the base pull-up resistor?  (I'd still leave the base
> > current-limiting resistor though).
>
> If you do, you'll probably need to change your display loop to update
> TRISB instead of PORTB.  I found that 1 transistor drop (from the PNP)
> was higher than the "on" output of the PIC pins driving the segments,
> so that trying to drive segments I wanted off actually turned them on
> verry faintly.

Not sure what you mean here.  Why TRISB?  I'm assuming the OC output will=
=20
float itself when "off" (high), so I'm not going to float it by making it=
 an=20
input.  I'm a bit confused here.  But I'm going to build the circuits and=
=20
experiment a bit.

Cheers,
-Neil.

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