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Change Vector Table in cortex M4 in a persistent way

EA8 over 7 years ago

Hello,

I need to change the Vector Table but I need it to be persistent through a reset, what I'm trying to do is set a vector table duplicate as a safety measurement for reprogramming the original vector table.

So far I being playing with the VTOR register but it seem that it return to 0 when a reset occurs.

am I messing something?

Regards.

Top replies

42Bastian Schick over 7 years ago +1 suggested

No, there is no way. On Cortex-M VTOR is always set to zero on reset. But since this table is in Flash, why do you want any safety measures? Sure, there is a small likelyhood that the reset-vector gets...
EA8 over 7 years ago in reply to 42Bastian Schick +1

Well, because at the end the reflash of the bootloader (including the vector table) will be done by a peripheral like SPI (or some other), there won't be debug access on the units, and if something goes...
42Bastian Schick over 7 years ago in reply to EA8 +1 verified

OK, you want to update the bootloader? Why not have a two bootloaders. The first stage bootloader is as simple as possible but will never be changed. The second stage bootloader does not have to change...