>What PIC ?   16LF877

> No, because I can drive it fine if I either hard ground it, or drive it from
> portD, so the wiring is correct.  Just seems that portB can't sink it
> enough?

But what *is* there to "sink" ??
The pup is between 250 and 550 KOhm !
And that is the only current tha have to be "sink", if there
isn't anything else connected to the same pin. But then,
you would not get 0V on the pin either. That was when
connected to the MIC, right ?

Are you absolutly sure that the PIC pin is at 0V at the
same time as it's connected to the MIC input pin ?

Jan-Erik.

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics