41.4.7.4 Register Write Protection

To prevent any single software error from corrupting AESB behavior, certain registers in the address space can be write-protected by setting WPEN (Write Protection Enable), WPITEN (Write Protection Interrupt Enable), and/or WPCREN (Write Protection Control Enable) in the AESB Write Protection Mode register (AESB_WPMR).

If a write access to a write-protected register is detected, the Write Protection Violation Status (WPVS) flag in the AESB Write Protection Status register (AESB_WPSR) is set and the Write Protection Violation Source (WPVSRC) field indicates the register in which the write access has been attempted.

WPVS is automatically cleared after reading AESB_WPSR.

The following registers can be write-protected when WPEN is set in AESB_WPMR:

• AESB Mode Register
• AESB Key Word Register x
• AESB Initialization Vector Register x
• AESB Extended Mode Register

The following registers can be write-protected when WPITEN is set:

• AESB Interrupt Enable Register
• AESB Interrupt Disable Register

The following register can be write-protected when WPCREN is set:

• AESB Control Register