Engine stops on burn, even for dual bank devices

[mck1117]

STM32H743 is dual bank, and you should be able to execute from one bank while erasing/writing the other.

But sometimes, you push burn and the engine dies because the ECU was locked up for ~1 second. What's up with that?

[mck1117]

good case:
0.97 second wall clock time, 974 main loop calls
bad case:
0.97 second wall clock time, 212 main loop calls
so something got jammed after ~212ms then unstuck once the erase was done
and this log line agrees
Reset sync as time since last trigger event is 0.757s, threshold 0.100
0.757 + 0.212 ~= 0.97

[mck1117]

Tried configuring the MPU to disallow access to the second bank (in case some other code was trying to read it?). Confirmed that it causes a memory protection fault if you try to access that flash bank, but it never trips during the erase!

[mck1117]

Turning off the instruction cache makes it go away