> Van: Michael Hearn <michael.hearn@FALLIBROOME.CHESHIRE.SCH.UK>
> Aan: PICLIST@MITVMA.MIT.EDU
> Onderwerp: Blow only once with not PIC16C84? Is it true?
> Datum: dinsdag 23 juni 1998 15:58
>
> Dear all,
>
> I just want to check whether it is true that the PIC models that can
> deal with analogue ports can only be blown once.
> I am doing a project at school that involves making a robot that can
follow
> a white line made of masking tape (MicroMouse by the IEE) and I was
> wondering what sort of motor we should use. We have a choice between DC
and
> stepper motors but it seems to us that the 16C84 (the chip we use at the
> moment) cannot deal with analogue signals. Is this true and what other
> chips can do this? Also, is it true that the chips that can do this are
> blow once? I just wanted to clear up a few inconsistencies.
>
> Anyone know about this? Anyone? At all?
>
> Michael

Hello Michael,

  The PIC16x84 is one of the few EEPROM -devices (AKA can erased by
electricity).  Most others are EPROM devices (AKA  must be erased with
ultra-violet light).  Because of the fact that most casings are closed
(don't permit any light on the chip) they are called OTP's (One Time
Programmables).  If you blow a fuse there it does not matter, because you
can't erase them anyway. Ok, there are windowed versions of some OTP's, but
the construction _STAYS THE SAME_. This means that if you blow a fuse in a
windowed version you can erase the thing, but you _can't_ reprogram it.
The 16x84 is made to be erased & re-used time & time again.  It's
code-protect -bit can be erased (together with the rest of the PIC that is
:-)

Greetz,
  Rudy Wieser