[MPC5744P] Ecc Event Err

[fyw]

i'm using data flash(0x00800000-0x00817fff) as eeprom,  i want to ask if i read somthing form data flash and get the C55FMC_MCR.EER bit set, the value i read are sure to be all ff?

for example:

      value =*( (unsigned int*)0x00800000)   //at the same time C55FMC_MCR.EER change from 0-->1

then the value read are 0xffffffff? Is that sure?

At the same time if i read the data flash and find that the value!=0xffffffff, can i be sure that the C55FMC_MCR.EER  didn't set?

Thank you very much!

[davidtosenovjan]

Hi,

reading of location with double bit ECC error by the core leads in exception. No data is returned. Exception handler must manage this erroneous condition.

If you see this data in dump window in debugger, typically you will see ‘????????’ what’s indicating bus error.

[fyw]

what i say is the eeprom flash not the code flash. The code Flash is exactly like what you say, the eeprom flash looks different. When you read the eeprom where there are double bit ECC error, no exception seems happen and it seems FF returned.  Can you tell me about the ecc characteristics of eeprom flash? Thank you very much!

[davidtosenovjan]

OK, I have understood it wrong way. Honestly I haven’t know it all FFs are returned because other MPC57xx device return different value (0x1555_1555). But MPC5744P returns 0xFFFF_FFFF.

If returned value is 0xFFFF_FFFF, check C55FMC_MCR.EER, if it is 1 then it is ECC error. If not, it is valid data of value 0xFFFF_FFFF.