64.6.12 Register Write Protection

To prevent any single software error from corrupting QSPI behavior, certain registers can be write-protected by setting the WPEN bit in the Write Protection Mode register (QSPI_WPMR).

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

The WPVS bit is automatically cleared after reading QSPI_WPSR.

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

• QSPI Mode Register
• QSPI Serial Clock Register
• QSPI Scrambling Mode Register
• QSPI Scrambling Key Register
• QSPI Write Instruction Code Register
• QSPI Read Instruction Code Register
• QSPI Instruction Address Register
• QSPI Instruction Frame Register
• QSPI Refresh Register
• QSPI Write Access Counter Register
• QSPI Pad Calibration Configuration Register
• QSPI Pad Calibration Bypass Register
• QSPI Timeout Register
• QSPI DLL Configuration Register

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

• QSPI Control Register

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

• QSPI Interrupt Enable Register
• QSPI Interrupt Disable Register