SFFS779 December 2024 TMS320F28P550SJ
Information redundancy techniques can be applied using software as an additional runtime diagnostic. To provide diagnostic coverage for network elements outside the C2000 MCU (wiring harness, connectors, and transceiver) end-to-end safety mechanisms are applied. These mechanisms can also provide diagnostic coverage inside the C2000 MCU.
In the case of processing elements (CPU and CLA), this refers to multiple executions of the code and software-based cross checking to verify correctness. The multiple execution and result comparison can be based on implementations of either the same code executed multiple times or diversified software code. For details regarding the implementation, refer to the ISO26262-5, D.2.3.4.
In the case of the DMA, information redundancy techniques refer to additional information (besides the data payload) that verifies data integrity. For example, SECDED codes, parity codes, CRCs, and so forth enable information redundancy.Typical control applications involve measuring three phase voltage and current. These values are either sampled directly using the on-chip ADC or sent to the TMS320F28P55x MCU by the sensors, which are captured using ECAP and so forth. In such scenarios, the correlation between input signals can be used to check the integrity (for example, if the three-phase voltage, V1, V2, and V3 is being measured, the function V1 + V2 + V3 = 0 can be used to provide diagnostic coverage for input signal integrity).
In the case of SRAM and FLASH memory, the critical data, program, variables, and so forth can be stored redundantly and compared to their active counterparts before being used. Care must be taken to avoid compiler optimizing code containing redundant data or programs.