36.5.8 Register Access Protection

All registers with write access are optionally write protected by the PAC, except the following registers:

• Control A (CTRLA) register
• Transmit Data (TXDATA) register
• Interrupt Flag Status and Clear (INTFLAG) register
• Scrambling Key (SCRAMBKEY) register

PAC write protection is denoted by the PAC Write-Protection property in the register description.

Write-protection does not apply to accesses through an external debugger.