> > ... and the PIC can't source any current when
> > the output is high (if the pull-ups are disabled),
>
> Yes, it can.  Port B has full totem pole drivers.  The pullups are
disabled
> for output pins because they don't make any sense then.  The pullups can
be
> useful when the pin is an input, because inputs are high impedence.  This
> allows, for example, a switch to be sensed by the PIC by connecting it
> between a port B input pin and ground.
>

Thanks for pointing that out.  I miscounted all the NOT symbols floating
around on the logic diagram of the PORTB pins in the datasheet, and I've
been under the impression that the reason for the pull-ups was to change
PORTB output between open-collector and push-pull.  By the datasheet saying
that the pullups were disabled when PORTB was changed to output, I thought
it meant that it defaulted back to open-collector.  Luckily none of my
projects so far have relied on the pullups :)

Kevin

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