Question of ECMS(MPC5674F)

[Luke_Chun]

Hello Team

Could you check about the question of ECMS(MPC5674F)?

As the RM's Chapter 16  ECSM introduction, it was written like following;

There are two types of ECC errors: correctable and non-correctable. A correctable ECC error is generated when only one bit is wrong in a 64-bit doubleword. In this case, it is corrected automatically by hardware and no flags or other indication is set that the error occurred. A non-correctable ECC error is generated when two or more bits in a 64-bit doubleword are incorrect. Non-correctable ECC errors cause an interrupt, and if enabled, additional error details are available in the ECSM.

As my understanding, it is “no flags” in case of 1bit error.

However it can be reported by ECSM_ESR. I think that 1 bit error is possible to report by ECSM_ECR enable and can be checked ECSM_ESR....

Could you let me know the meaning of “no flags” ?

Thank you.

[davidtosenovjan · Accepted solution]

Thanks for your question. It’ll be relic from previous generation of ECSM module used on MPC55xx devices, where there was no reporting capability for single bit errors.

I would note that ECC detection/correction module is enabled always regardless ECSM setting. ECSM only offers additional reporting capability.

For details see my document

http://www.nxp.com/assets/documents/data/en/application-notes/AN5200.pdf

To sum it up - single bit errors are always automatically corrected, but they may be also reported in case it is enabled in ECSM module.