Hi Jim,

the function of the PORTA pins can't be arbitrary choosen, I refer to
the databook pages (p.44 Table5.1)

There are 6 possible configurations which I summarize in the table
below:

RA0 RA1 RA2 RA3 RA4 RA5
A       A     A     A      X     A
A       A     A    ref      X     A
A       A     A     A      X     A
A       A     D     A      X     D
A       A     D    ref     X      D
D       D     D     D     X      D

where A is analog input, D is digital I/O and X is don't care
ref is external reference voltage
RA4 is an OPEN DRAIN type so you need an external pullup resistor to put
the line high.

you're welcome ...

Bart
ON6HF

> -----Original Message-----
> From: Jim Dolson [SMTP:jdolson@ISERV.NET]
> Sent: woensdag 21 april 1999 13:56
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Are ports RA4 and RA5 on 16C73 'Special' ?
>
> I'm obviously missing something here.  I am trying to use ports RA0
> through RA5 as digital I/O lines instead of analog input lines.  RA0 -
> RA3 work fine.  I would like to use RA4 and RA5 for digital output
> only,
> but I can't seem to get them to work.
>
> Can anyone give me a hint as to why RA4 and RA5 might be 'special' in
> some way?  The problem with RA4 may be related to my use of the
> internal
> counter/interrupt.  What about RA5?
>
> Thanks.
>
> Jim
> jdolson@iserv.net