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How to handle Memory Exceptions on S12Z

Question asked by Axel Hubner on Feb 23, 2016
Latest reply on Feb 26, 2016 by Axel Hubner

I am trying to implement an ECC Error-handling. If an EEPROM ECC Error is detected, the software should try to handle it.

Each double Bit ECC Error causes a Machine Exception.

For debugging purpose, I generate a machine exception by writing a value to the P-Flash, like 01:


Memory Loc. | Commands

01                  *((byte *)0xFE0000) = 0; <-Causes Memory Exception

02                  next Command = 0; <- Next Command


After attending this line of code, a Machine Exception is triggered and the interrupt routine is executed correctly, but

When I return from the ISR, the PC is not set to the next command.

For me it seems that some random code ore some random ISRs will be executed. At the end the Program Counter is loaded with 0x000001.


Do i have to clear the Memory Exception Interrupt?

In the ISR i clear the MMCEC register by writing MMCEC = 0xFFFFFFFF to it.



Thanks Axel