All registers with write-access are optionally write-protected by the Peripheral Access Controller (PAC), except the following registers:
Optional write-protection by the Peripheral Access Controller (PAC) is denoted by the "PAC Write-Protection" property in each individual register description.
When TrustZone is supported (SAM L11 only), all register reads are allowed. Non-secure writes to APB registers are limited as follows. Illegal writes will be ignored.