TMS570LC4357: EFU1 and EFU2 test for diagnostics

Another related question: For eFuse ECC Logic Self Test (38.3.2.5), the reference manual says:
"This test should only be performed once for every device PORRST cycle."

Will the test be invalid after other types or resets? What downside is there to executing this test every reset?

Thank you.

Hello Colleen,

There are correct in your assertion that you should check the EFUSE ESM channels after power up to insure no issues have occurred. For EFU5, this is test that gets ran at boot time as part of the autoload sequence. Note that it is indicated as auto coverage because it happens without intervention from you. You need only check the status of the EFUSE auto load using ESM Grp1 Ch40 to see the result of the auto load.

For EFU6, the ECC of the EFUSE data is automatically checked when the data is read and loaded on each power on reset. However, it is recommended that you also run the EFUSE ECC Logic Self-Test to insure there are no latent faults in the ECC logic that could have resulted in a false positive. This doesn't indicate that the EFUSE data that was loaded is necessarily incorrect, it merely indicates that the ECC logic was flawed so there is the potential that it could be.

Also, it is possible to instantiate the EFUSE auto load self test outside of a power on reset. The value in this is to flag any potential latent faults for the next power cycle. i.e., if you are using the device in a High Demand application such as industrial where the device is ON for very long periods of time, there is some probability that faults could occur in parts of the device that are not being used (such as EFUSE auto load). By execution of the self test you could flag the issue and notify to prevent a point of use or on demand fault during the next power cycle. This usually isn't a necessity for automotive use cases or use cases where the ratio of ON time to OFF is very low.

Thanks Chuck.

Can you please also clarify this point: 'EFU6 is "Efuse ECC Logic Self Test". To implement this test correctly, do I follow "38.3.2.5 eFuse ECC Logic Self Test" in the reference manual? Or is EFU6 all of Figure 38-1 in the reference manual?'

Also, under what test (EFU1, EFU2, etc) does the Stuck at Zero test (38.3.2.4 in the reference manual) does not fall into?

To clarify my last question, into what test (EFU1, EFU2, etc) does the Stuck at Zero test fall?