47.8.8 SPI Register Write Protection

The FLEXCOM operating mode (FLEX_MR.OPMODE) must be set to FLEX_MR_OPMODE_SPI to enable access to the write protection registers.

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

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

The WPVS bit is automatically cleared after reading FLEX_SPI_WPSR.

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

• SPI Mode Register
• SPI Chip Select Register
• SPI Comparison Register

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

• SPI Interrupt Enable Register
• SPI Interrupt Disable Register

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

• SPI Control Register