pic readout despite code protect because of x-ray radiation

[andresteff]

Hello,
is there a possibility to read the flash from the PIC (PIC16F1619), despite code pritect?

I have irradiated a prototype with x-ray radiation. approx. 1-3 Gray/h.
After 2 minutes the PIC went off.
The 2 prototype worked. No failure.

Now I want to read out the memory to see if the program was disturbed by the radiation, or if there is a regular hardware bug.

[temtronic]

Probably not... and now you know WHY you should not use 'code protect' until the HOUR you ship out the FINAL product.

I have to assume that Microchip has altered the 'code protection' methods since the 16C84 days. Those could be read even when 'protected'....

ah the good old days.....

[Ttelmah]

Basically no.
That is the whole point of protection.

However you can verify the memory, using a trick. If you program another
chip with the same code, and protection, then read it, the values you get
back should be the same as those from the irradiated chip if the memory
hasn't changed.

Some of the PIC's do say they use NOR flash. This is much less likely to
be affected by XRays than NAND flash.

[andresteff]

[andresteff]

the pic can not be programmed.

big....

[Ttelmah]

Remember if a chip has a protection bit set, it can only be programmed
after a full erase using full programming voltages, not LVP.

[andresteff]

[Ttelmah]

EMC is much more likely.
However that is why equipment in locations where it is likely to be exposed
to such problems has to be properly designed and protected.
I have some kit that is right adjacent to a couple of high power radiation
sources. They are inside lead Faraday cages. The connections for power
have multiple isolation and protection layers. Spark gap. EMC chokes.
Transorbs, then normal supply filtering and protection.