[NTLK] A new ROM board
m.melcher at robowerk.de
Thu Feb 24 05:32:26 PST 2022
And here is the first question to core devs:
Is there a way to get the CPU into Supervisor mode from a native function inside a normal script? I am trying to circumvent the MMU that blocks me from reading from and writing to the ROM area. The ROM function LoadPhysicalByte seems to fail on physical devices.
Even better than disabling the entire MMU, would be to change permissions on accessing the first 16MB. To program the Flash ROM, my code must run in RAM, so I can give the correct command sequences for flashing the devices without any ROM access interrupting them. However, if I disable the MMU, my RAM vanishes at its virtual location and pops up at its physical location, which is somewhat unpredictable without reversing the MMU table.
If everything fails, I can patch the ROM to provide such a function before flashing it to the ROM board, but that patch would have to work on all possible future ROMs, so it's not an optimal approach.
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