8.13.5.13 Register Write Protection

To prevent any single software error from corrupting PUF behavior, certain registers in the address space can be write-protected by setting the WPEN and WPITEN bits in the PUF Write Protection Mode Register (PUF_WPMR).

If a write access to a write-protected register is detected, the WPVS flag in the PUF Write Protection Status Register (PUF_WPSR) is set and the field WPSRC indicates the register in which the write access has been attempted.

The WPVS bit is automatically cleared after reading PUF_WPSR.

The following registers can be write-protected when WPEN=1:

• PUF Data Destination Register
• PUF Data Source Register
• PUF Miscellaneous Register

The following registers can be write-protected when WPITEN=1:

• PUF Interrupt Enable Register
• PUF Interrupt Mask Register
• PUF Access Security Interrupt Enable Register