William "Chops" Westfield <westfw <at> mac.com> writes:

> On Apr 1, 2007, at 8:14 AM, Vasile Surducan wrote:
> 
> > It's not 0.3V.
> 
> It is according to assorted datasheets.  Not just microchip, either.
> (although the 16F54 that Peter specifically complains about still says
> -0.6 to Vcc+0.6)

Actually it says Vss and Vdd (exactly). See the Vil and Vih specs in table 11.2
in the datasheet of the pic16f5x, as I wrote in another email in this thread.
 
> Still, it seems to me that MOST pins in any circuit are not going to
> need additional protection, and the pins that DO need protection were
> likely to have needed it even with the old specs.  I suspect Peter's
> problems are due more to a particularly sensitive chip/batch/unit than
> the change in the specs; as he says, I would have expected more noise
> if expensive external protection networks had suddenly become necessary
> on most microcontroller pins.

Yes, but in fact they have become necessary at least according to the specs in
the datasheet (even if my case was a marginal batch).

And, I am not complaining, I would like to see a) that the specs in the data
sheet  are not going to stay the way they are now (since they cannot be worked
with) and b) that some sort of inexpensive solution exists for clamping (i.e.
not 5 cents per pin + double sided board with plated vias instead of single 
sided).

Peter P.


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