Other domains with their own CPUs can access peripherals, flash and RAM memories. The SPU allows controlling accesses from those bus masters.
The external domains can access application MCU memories and peripherals. External domains are assigned security attributes as described in register EXTDOMAIN[n].PERM.
| Domain | Capability register | Permission register |
|---|---|---|
| Network MCU | EXTDOMAIN[n].PERM (n=0..0), SECUREMAPPING field | EXTDOMAIN[n].PERM (n=0..0), SECATTR field |
The figure below illustrates how the security control units are used to assign security attributes to transfers initiated by the external domains: