SWRU626 December 2025 CC3501E , CC3551E
The IDAU defines a background memory map as follows:
If Address bit 26 (hereafter A[26]) is 0 then the address is attributed Non-Secure Callable (NSC).
For Peripherals if A[26] = 1, then the address is attributed as Secure.
If A[26] = 0, then the address is attributed as Non Secure.