Hello Jochen,

 It is still Jean-Yves ...

Beware of the fact that, if your radiations are enough to erase the EPROM, 
they will be likely to affect the functionality of the whole PIC !
I've read results of tests that have been made for the space activity in that 
sense, and the PICs familly is very sensitive to total dose effects 
(functionality loss after current consumption increase) ...

However, if anybody have experience with "plastic EPROM erasure", let me know 
; but it might be very difficult to irradiate enough to erase but not enough 
to destroy it !

Bye

Jean-Yves
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De :  Jochen Feldhaar[SMTP:jfeldhaa@DETEKTOR.DE]
Date : mercredi 9 dˇcembre 1998 11:25
A : pic microcontroller discussion
Cc : Seyler Jean-Yves
Objet : Erasing of EPROM and OTP?

Hello to the list,

I have been wondering if one could use some other kind of radiation to
erase the memory block in a plastic kind of EPROM or OTP microcontrollers,
because UV doen't penetrate plastic...
So I wondered if by using soft (i. e. long-wave) Roentgen radiation it
would be possible to penetrate the IC and transfer the necessary energy to
the memory cells in order to reset them. Of course, too much radiation or
too short a wavelength will damage the crystal structure and the
semiconductor.

So I wonder...did anyone on the list do any trials or do you have knowledge
of such methods??
Or is there another way?

(So it might be a good idea to be well acquainted with your local radiology
department in your hospital if this is workable!)
After erasing, they could be "blank checked" by the programmer, I expect
some ICs not to work after the radiation treatment.

Greetings,

Jochen DH6FAZ