> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On
Behalf
> Of Olin Lathrop
> Sent: 19 June 2008 23:29
> To: Microcontroller discussion list - Public.
> Subject: Re: [EE] Tri-state pin with three functions
> 
> Jinx wrote:
> > If Microchip didn't make pins capable of more than one job we'd
> > all be using much bigger chips (and paying for it). No 6-pin, no 8-
> > pin, nothing under 28-pin probably
> 
> There are plenty of projects where 6 and 8 pins are fine.
> 
> The point was that it's often more appropriate to get a bigger PIC
than to
> perform unnatural acts to make I/O pins peform multiple function.
> 
> I got the impression from other questions the OP asked that he is a
> beginner
> and a hobbyist.  So even if a bigger PIC costs a little more than
external
> hardware, it will get the job done reliably with a lot less futzing
around
> trying to figure out why it doesn't work.  This logic makes sense for
all
> but high volume products, or maybe very space constrained products,
> although
> the extra hardware to make pins do double duty probably takes more
space
> than the increment to a bigger PIC.
> 

The OP is using a 40 pin device, almost certainly a DIP if's he's a
beginner.  AFAIK there are no larger PIC available as DIP's, and moving
to surface mount is a big step if you are used to
breadboards/stripboards etc.

One possible solution is some kind of I/O expander, especially if the
PIC already has pins assigned to an I2C master or SPI bus, but Dallas
1-Wire I/O devices are available, or a second PIC could be used.

Regards

Mike

=======================================================================
This e-mail is intended for the person it is addressed to only. The
information contained in it may be confidential and/or protected by
law. If you are not the intended recipient of this message, you must
not make any use of this information, or copy or show it to any
person. Please contact us immediately to tell us that you have
received this e-mail, and return the original to us. Any use,
forwarding, printing or copying of this message is strictly prohibited.
No part of this message can be considered a request for goods or
services.
=======================================================================

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist