PIC12C5XX, page 80, note 5.

I am working on a low power battery project, and it so happens this topic
has peaked my interest.....so maybe, the "application" is what dictates how
the I/O and pins are configured.  Could this be the confusion?




> I think its taken out of context....when they say that, its for testing
> conditions I believe.  For worst case power consumption's and such, or to
> measure prop delays, they must state those conditions such that a designer
> could duplicate it.
>
> What page of the data sheet did you read that on?
>
> -----Original Message-----
> From: David Covick [mailto:dac@WEST.NET]
> Sent: Wednesday, September 22, 1999 7:56 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: What to do with PINs not used
>
>
> Harrison,
>
> What do I do with the statement in the Microchip data sheet that says
"with
> all I/O pins in hi-impedance state and tied to Vdd or Vss"??
>
> David
>
>
>
> > Why does this come up every 6 months or so???
> >
> > NO!!!  Don't tie them to anything!  Define them as OUTPUTS, and set them
> to
> > default as low.
> >
> > Why?  Because, these are I/O pins.  Unless its a dedicated input pin,
> don't
> > tie it because at somepoint two things might happen.  First, an
> unprogrammed
> > chip might be put into the circuit, and I don't recall if by default the
> > pins are input or outputs.  If tied either way, they could might drive
Vcc
> > to Vss, or the other way around.
> >
> > Second, if you need to use that pin for something else down the road,
you
> > have to then isolate it first and wire it up.
> >
> > Most programmable logic devices define unused pins as no connects, as
they
> > tristate or isolate the pins when they burn them.
> >
> > Just my .02 worth.  Everyone has their own ideas on what to do....
> >
>