SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
In order to protect the FLASH device, a software controlled write protection feature is supported. Any data write detected (by using DAC), pointing to an area of the FLASH that is protected, is not permitted.
A programmable region of the FLASH device, defined as a number of FLASH 'blocks' starting from a particular block number can be protected. Three programmable registers are provided. The first OSPI_LOWER_WR_PROT_REG register defines the FLASH block that is located at the bottom of the region to be protected. The second OSPI_UPPER_WR_PROT_REG register defines the FLASH block that is located at the top of the region to be protected. The third OSPI_WR_PROT_CTRL_REG register is a control register consisting of 2 bits. The OSPI_WR_PROT_CTRL_REG[0] INV_FLD bit allows software to invert the region that is being protected, causing the programmed region to become the only areas of FLASH memory that is not protected from writes. The OSPI_WR_PROT_CTRL_REG[1] ENB_FLD bit is the write protection enable bit. When this bit is set to 0, the FLASH device is unprotected.
For implementation, the data interface must map the incoming address into its associated FLASH block. A block can be between 1 and 65 KB, programmed via the OSPI_DEV_SIZE_CONFIG_REG register.