mm9z1-638:machine exception handler question

[gumu]

Dear Sir,

Recently, I encountered an issue in the project where an ECC error occurred while attempting to read EEPROM data. This led to triggering the Machine Exception callback function, and subsequently, the device rebooted. I would like to know if it is possible for the device to continue running without restarting after triggering the Machine Exception.

[gumu]

Dear Sir,

I read about machine exceptions in the S12ZCPU_RM_V1 documentation, and it state:

Machine exceptions are meant to signal severe system problems. Software is expected to re-initialize the system when a machine exception occurs. Unlike interrupts or software exceptions, a machine exception causes the CPU to not perform any stack operations, so it is not possible to return to application code by simply using an RTI (or an RTS)instruction

Does this mean that once a machine exception occurs, the system must be restarted? If so, how can the system recover from the ECC error triggered by EEPROM?

Thanks！

[danielmartynek · Accepted solution]

Hello @gumu,

The mm9z1-639 has the same core as the S12Z series.

Please have a look at this thread:

https://community.nxp.com/t5/S12-MagniV-Microcontrollers/Jump-to-Reset-vector-from-machine-exception...

Regards,

Daniel

[gumu]

Hi @danielmartynek ,

Thank you! As stated in the manual, triggering a machine exception interrupt requires the system to be rebooted.