> ... 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.


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(978) 742-9014, http://www.embedinc.com

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