----- Original Message -----
From: "Jeff DeMaagd" <jeff@DEMAAGD.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, October 08, 2001 10:10 PM
Subject: Re: [PIC]:16F877 ICD/MPLAB TRIS register WEIRDNESS.


> ----- Original Message -----
> From: Bob Ammerman <rammerman@ADELPHIA.NET>
>
>
> > The default is "A/D" on for a very good reason. At powerup, if the pin
> were
> > connected to an analog signal but configured as a digital input then
there
> > would be excessive Idd current because the input was not solidly high or
> > low.
>
> That makes sense- I think.  Do the inputs of TTL gates really create that
> much of a drain in mid-state?  That is all I can see that might cause such
a
> problem.

Well, first, the PICs are CMOS, not TTL; and yes, they can draw quite a bit
of current in mid-state. This can be especially important when the PIC is
spending a good part of its time in reset in a battery-based design.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

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