24.4.5 Register Access Protection
All registers with write access can be write-protected optionally by the Peripheral Access Controller (PAC), except the following registers:
- Control B register (CTRLB)
- Interrupt Flag Status and Clear register (INTFLAG)
- Status register (STATUS)
Optional write protection by the Peripheral Access Controller (PAC) is denoted by the "PAC Write Protection" property in each individual register description.
Write-protection does not apply to accesses through an external debugger.