[Cryptech Tech] Status tamper detection and MKM erasure

[Fredrik Thulin]

On fredag 10 juni 2016 kl. 16:21:52 CEST Linus Nordberg wrote:
...
> I just pushed some code to user/ln5/tamper. From commit message:

Thanks for writing this code. I've tested it thoroughly now, and gotten it to 
work with a couple of changes:

0) Had to change -mmcu to attiny828 in the Makefile to get the code to run on 
the ATtiny.

1) Sleep mode seemed not to work - it seemed like the AVR was reset on wakeup 
so if I released the panic button while it was flashing it's LED in the start 
of main() the MKM would not get erased. We need to debug that, but I think 
we'll need to go with busy-waiting for the moment (since it is just a couple 
of days before Berlin). Maybe you and I can read the datasheet together in 
Berlin.

2) The chip needed CS_N to go high to mark the end of the sequential read mode 
select command.

3) Initialization should release control of the MKM to the FPGA.

My work-in progress patch is attached. How do you want to incorporate it? 
Should I just commit and push to your user/ln5/tamper repository?

/Fredrik
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