At 09:01 AM 10/28/99 -0400, you wrote:
>Well, if you are *really* concerned about radiation, you might inquire
>within microchip to make a few mask rommed parts.  These are parts where
>the code is part of the silicon when the chip is made.
>
>But they might not have the ability (or desire) to make just a few for
>you...

Hi adam!, you are right!.
thanks 4U reply, but I think that I don't have enough time to
do this, because I only need 4 uP (12C508), 2 for the proyect and 2 for
backup, and because I'm living in argentina and here is very difficult
perhaps impossible to get a special part in less than 2 months (I have
to get the unit ready in 30 days!!), thanks anyway :).

some hours ago william wrote:
>>OTP is just normal EPROM without the window.  They're the same dies, so
>>they are no less vulnerable than the windowed EPROM parts.
>
> My top 3 choices are:
> 1- OTP
> 2- OTP
> 3- One Time Programmable (equiv of a prom)
> the memory is nonerasable
> John

Thanks John and William for you reply too.
I thought that OTP was the right choice But I decide to see what will you
piclist people think about, because I'm pretty shure that a lot of you here
have more knowledge and experience than me :).
I didn't know that OTP and EPROM are the same but, no window, may be because
quartz windows are expensive?.
Anyway for high energy particles window o no window they will pass through
anyway :).

                                         :-)
>Well if you can't embedded it in an astronaught, then a metal box should do
>the trick,  if its only 100-150k's up then radiation isn't you main concern,
>I would be more worried about temp extremes and trying to stop the stepper
>from seizing up (I am assuming that this will be exposed to vacuum?  you
>will need to repack the bearings with Fomblin(sp? $$) grease so it wont
>seize up.

Hi Andrew! thanks, no the stepper and controller are part of an experiment
on a G.A.S. canister (G-761) that will fly (we think) in about 5 or 6 month
on the cargo bay of the space shuttle, this controller are one of the seven
experiments on that canister, the enviroment inside the canister is
pressurized at about 10 psi (if I remember correctly), and the temperature
will be in the range of -10 to +70 (inside of the automotive specs for
microchip) so I think that will be no problem.

see you all , thanks bye.


   Leandro J. Laporta (LU2AOQ)
   mail: lu2aoq@yahoo.com
   wrk: Arg. Assoc. for Space Technology.
   ham: TCP/IP high speed group HSG