3.2.4 Overlapping Regions
In advanced use cases and design scenarios, it may be desirable to configure overlapping Flash protection regions. When two or more regions overlap, each permission is set based on the more restrictive permissions of the overlapped regions:
|
Region 1 |
Region 2 |
Effective Permission in Overlap |
|---|---|---|
Read: Enabled | Read: Disabled | Read: Disabled |
Write: Disabled | Write: Enabled | Write: Disabled |
Execute: Enabled | Execute: Disabled | Execute: Disabled |
When two regions overlap, region type specific restrictions still apply. For example:
- When IRT and OTP regions overlap, erase operations are always disabled in the overlapping area. OTP regions do not allow erase operations. IRT regions can enable write/erase permissions. When overlapped, erase operations would be blocked because of the OTP region restrictions.
- When an IRT region overlaps with an OTP or FIRMWARE region, then if the DONE bit is set, other code will not be able to read or execute from section of memory that overlaps with the IRT region.
Region definitions do not need to have the same address alignment when they overlap.