15.4.9 SAM L11 TrustZone Specific Register Access Protection

All PAC registers can only be accessed in the secure alias, with the following exceptions:

• Write Control (WRCTRL) register is also accessible in the Non-Secure Alias, but only for write protection requests on non-secured peripherals.
• Peripheral Write Protection Status (STATUSn) registers are also accessible in the Non-Secure Alias, but they will only report information on non-secured peripherals.