Kevin Moll scribbled:
> I think you need to enable the pull-up resistors for portb.  IIRC, the
> internal pull-ups are disabled when you change PORTB to output.

Didn't you just contradict yourself here?

Pull-ups should have no effect for pins set as outputs, and no
external pull-ups should be necessary for lighting LED's.

Cheers,
-Neil.



> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Kevin Moll
> Sent: Monday, August 26, 2002 12:22 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [PIC]:Newbie's first attempt
>
>
> Disclaimer: Other newbie trying to answer a question.
>
> I think you need to enable the pull-up resistors for portb.  IIRC, the
> internal pull-ups are disabled when you change PORTB to output.
> Because you
> have the LED bar tied to ground and the PIC can't source any current when
> the output is high (if the pull-ups are disabled), the LED's will never
> light up.  A simple test would be to turn the LED bar around and tie it to
> VCC instead of GND.  You'll get the complement of what you're expecting.
> Otherwise, you can add external pull up resistorts or set an OPTION bit (I
> don't remember which) to enable the internal pullups.
>
> Kevin
>
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