6.1.2.8 DIAG_SRAM_MARCH_SEC_OVERLAP

#define DIAG_SRAM_MARCH_SEC_OVERLAP (0x80U)

Determines the overlap between each SRAM section when calling DIAG_SRAM_MarchPeriodic(). Due to the physical layout of the SRAM on the device, the smallest value for this macro is 0x10. Choose a value divisible by 0x10 to get the best possible coverage, unless no overlap is required in which case the value can be set to zero. Using no overlap is not recommended, as coupling faults between SRAM sections will not be detected. Moreover, configure the value so that DIAG_SRAM_DATA_REGION_LEN - DIAG_SRAM_MARCH_SEC_OVERLAP is divisible by DIAG_SRAM_MARCH_SEC_SIZE - DIAG_SRAM_MARCH_SEC_OVERLAP. The value must be smaller than DIAG_SRAM_MARCH_SEC_SIZE. Increasing the overlap size will increase the coupling fault coverage at the cost of an increase in the number of SRAM sections. In turn, this increases the total number of times the API must be called before the entire SRAM is tested once, which increases the FDTI.

For each address in the SRAM used by the application, coupling faults between that address and at least the DIAG_SRAM_MARCH_SEC_OVERLAP closest addresses in each direction are covered by the DIAG_SRAM_MarchPeriodic() diagnostic. For most addresses and values of DIAG_SRAM_MARCH_SEC_OVERLAP and DIAG_SRAM_MARCH_SEC_SIZE, the number of neighbouring addresses covered is larger than DIAG_SRAM_MARCH_SEC_OVERLAP in one or both directions.

As an example, using a section size of 0x100 and 75% overlap, so that DIAG_SRAM_MARCH_SEC_SIZE = 0x100 = 256 and DIAG_SRAM_MARCH_SEC_OVERLAP = 0xC0 = 192, has the effect that for each address in the SRAM used by the application, coupling faults between that address and at least the 192 closests addresses in each direction are covered.