2 ms·

I assume by "which cannot be cached" he meant "which is in a page configured as non-cacheable in the MMU", i.e. exactly what you said

• adwn 3y ago
  But then why would it have to be a shared counter? Any write to a non-cacheable memory location is transmitted to system RAM, it doesn't have to be shared with other cores, nor does it have to be a counter.
  • tuatoru 3y ago
    Because it is used by a peripheral.