ABP why reset frame counter?

[Tom1278]

I'm trying out activation by personalization but the first thing the LoRa stack does is reset the frame counter by calling this function: ResetFCnts
I will be implementing my own non-volatile memory that will store the frame counter and I'm looking for a place in the LoRa stack that I call during the startup to set the frame counter.
Of course I could make my own, for example: CryptoCtx.NvmCtx->FCntList.FCntUp = x;
But I would rather do the correct way if there is one and maybe someone can help me out and point me in the right direction?
Many thanks!

[mluis1]

At stack initialization everything is reset to defaults and this is normal.

After the stack initialization one must restore the previous context from a non volatile memory.
As you can see in below code excerpt the stack is initialized by calling LoRaMacInitialization and then the NVM context is restored by calling NvmDataMgmtRestore.
It is to be noted that in case the restore function didn't succeed then the stack behaves like if it was the first time it was run.

LmHandlerErrorStatus_t LmHandlerInit( LmHandlerCallbacks_t *handlerCallbacks,
                                      LmHandlerParams_t *handlerParams )
{
    //
    uint16_t nbNvmData = 0;
    MibRequestConfirm_t mibReq;
    LmHandlerParams = handlerParams;
    LmHandlerCallbacks = handlerCallbacks;

    LoRaMacPrimitives.MacMcpsConfirm = McpsConfirm;
    LoRaMacPrimitives.MacMcpsIndication = McpsIndication;
    LoRaMacPrimitives.MacMlmeConfirm = MlmeConfirm;
    LoRaMacPrimitives.MacMlmeIndication = MlmeIndication;
    LoRaMacCallbacks.GetBatteryLevel = LmHandlerCallbacks->GetBatteryLevel;
    LoRaMacCallbacks.GetTemperatureLevel = LmHandlerCallbacks->GetTemperature;
    LoRaMacCallbacks.NvmDataChange  = NvmDataMgmtEvent;
    LoRaMacCallbacks.MacProcessNotify = LmHandlerCallbacks->OnMacProcess;

    IsClassBSwitchPending = false;
    IsUplinkTxPending = false;

    if( LoRaMacInitialization( &LoRaMacPrimitives, &LoRaMacCallbacks, LmHandlerParams->Region ) != LORAMAC_STATUS_OK )
    {
        return LORAMAC_HANDLER_ERROR;
    }

    // Restore data if required
    nbNvmData = NvmDataMgmtRestore( );

    // Try to restore from NVM and query the mac if possible.
    if( nbNvmData > 0 )
    {
        LmHandlerCallbacks->OnNvmDataChange( LORAMAC_HANDLER_NVM_RESTORE, nbNvmData );
    }
    else
    {
...
}

In the future it would be nice if you could post this kind of questions on the project Discussions tab. It is a better place to engage discussions and then we can agree if it is an issue or not.
If you don't mind I move this issue to the Discussions tab.

[Tom1278]

Thank you!