CODEWITHSUNDEEP
diagnosticsautosarnon-volatile
Rafal
Rafal

Reputation: 23

Immediate storage of combined DTC - Dem AUTOSAR

Is it correct behaviour of Dem module if it's saving for combined DTC (with immediate storage enabled) only snapshots and extended data? After power reset and read DTC I'm receiving status of DTC 0x50 but with occurence counter equal to one and with snapshot data. For not-combined DTCs status is different than 0x50. Is it correct?

Upvotes: 2

Views: 8212

Answers (1)

marcin214
marcin214

Reputation: 71

That behavior for sure is incorrect. State 0x50 indicates that DTC is not tested at all, but on the other side, you have stored data for one of the events mapped to this DTC. Below is your DTC status byte: problematic DTC status byte

What we know:

  1. The DEM stores the status bytes for all of DTCs in one block, but extended data and snapshots are stored in a separate block.
  2. The status byte for combined DTCs is evaluated based on the following table: enter image description here
  3. The storage strategy of events are defined by parameter DemEventMemoryEntryStorageTrigger in DEM general options.

I suggest to first check the status of the problematic DTC before reset. If we have in memory snapshot and/or extended data and a status byte which indicates a fail of the DTC, but after reset we have a status 0x50, than it means that the NvM block with the status byte is not triggered to be stored.

But if we also have a status 0x50 before reset, than it means that probably you have only problem with the configuration of DemEventMemoryEntryStorageTrigger.

Upvotes: 2

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