STM32F405: ISR vector table in CCM?

[Yoichi Shinoda]

ISR vector table in SRAM works, but not in CCM. Is this possible? If not, what is the theory behind it? Vector fetching done through I-Bus or S-Bus?

[Tesla DeLorean]

I think it's an I-Bus fetch

[Yoichi Shinoda]

Thanks for the info. Do you have any document pointers?

[waclawek.jan · Accepted solution]

Vectors are fetched through the same bus as instructions, i.e. I-Bus or S-bus depending on the address (0x20000000 being the boundary). I know of no explicit quote for this, but there are hints throughout the documentation (e.g. that vector fetches occurs in parallel with state storing; this literally can occur only if the vector table is mapped at below 0x20000000).

CCM in 'F4xx is on D-bus.

JW

[Yoichi Shinoda]

Got it. The parallelism is the key evidence, I guess. Thanks.