LAUNCHXL-CC2640R2: Simple Observer Not Capturing All Advertising Packets

Part Number: LAUNCHXL-CC2640R2

I am having some reliability issues with the simple_observer_cc2640r2lp_app from the 1_35_00_33 simplelink SDK.  I am trying to capture all advertising packets from a Peripheral device that is sending them every 100mSec (another CC2640R2 LaunchXL running Project_Zero app).  The Peripheral device includes in its advertising data a counter that increments when each ADV packet is sent.  I am inspecting that data in the Observer code and am missing roughly 10% of them.   When I inspect the BLE traffic using TI Packet Sniffer I can see all of the ADV packets sent from the Peripheral, with none missing, so the problem does not seem to lie in the Peripheral device.  I have modified the GAP_DEVICE_INFO_EVENT to filter events to only those that match the Address I am interested in and check that the counter in the mfr. area of the ADV packet is sequential, which indicates that I have not missed a packet.  Code is shown below, along with typical output.  I have DEFAULT_SCAN_DURATION set to 0 to scan indefinitely and DEFAULT_MAX_SCAN_RES set to 8.   I have also set some other GAP parameters as shown below...

//EC - set scan duty cycle to 100%, per e2e.ti.com/.../345382
GAP_SetParamValue( TGAP_GEN_DISC_SCAN_INT, 16);
GAP_SetParamValue( TGAP_GEN_DISC_SCAN_WIND, 16);

//EC - Do not filter by device address.....allow app to receive all ADV packets
GAP_SetParamValue(TGAP_FILTER_ADV_REPORTS, FALSE);

I'm thinking it may be a scan window/interval or timing issue, but am not sure exactly how to attack the problem other than trial and error....any help to solve this is much appreciated.

static void SimpleBLEObserver_processRoleEvent(gapObserverRoleEvent_t *pEvent)
{
    uint8_t event_addr[B_ADDR_LEN];   //!< Address of the advertisement or SCAN_RSP
    uint16_t advDataDifference = 0;
    uint32_t currentTicks = 0;

  switch ( pEvent->gap.opcode )
  {
    case GAP_DEVICE_INIT_DONE_EVENT:
      {
        //Display_print0(dispHandle, 1, 0, Util_convertBdAddr2Str(pEvent->initDone.devAddr));
        //Display_print0(dispHandle, 2, 0, "Initialized");

        // Prompt user to begin scanning.
        //Display_print0(dispHandle, 5, 0, "Discover ->");
      }
      break;

    case GAP_DEVICE_INFO_EVENT:
      {
        //SimpleBLEObserver_addDeviceInfo(pEvent->deviceInfo.addr, pEvent->deviceInfo.addrType);
        advTotEvntCnt++;
        memcpy (event_addr, pEvent->deviceInfo.addr, B_ADDR_LEN);
        currentTicks = Clock_getTicks();

        //check if address matches our matchBuf pattern, so we know it's one of our BLE devices
        if (memcmp(&event_addr[B_ADDR_LEN-ADV_ID_MATCH_LEN], &matchBuf[B_ADDR_LEN-ADV_ID_MATCH_LEN], ADV_ID_MATCH_LEN) == 0)
        {
            advFiltEvntCnt++;
            //store ticks and mfr ADV data to buffers for offline inspection/debuggging.  Perepherial advances counter in mfr.
            //ADV data from with each ADV packet, when it reaches 1000, it wraps back to 0.
            advFiltEvntTicks[advDataBufIndex] = currentTicks;
            memcpy(&advFiltEvntData[advDataBufIndex], pEvent->deviceInfo.pEvtData + 6, sizeof(uint32_t));
            
            //check if the advertising data is sequential...if not log # missed, check for zero ignores when buffer wraps, so not exact, but close enough
            if (advFiltEvntData[advDataBufIndex] > 0)
            {
               advDataDifference = advFiltEvntData[advDataBufIndex] - advFiltLastData;
               if ((advDataDifference > 1) && (advFiltEvntCnt > 1))
               {
                   advFiltMissedEvntCnt += advDataDifference - 1;
               }
            }
            advFiltLastData = advFiltEvntData[advDataBufIndex];
            advDataBufIndex = (advDataBufIndex < ADV_DATA_BUF_LEN) ? advDataBufIndex++ : 0;
        }

        //output performance numbers every 10 seconds
        if (currentTicks - startTicks > 1000000)
        {
            startTicks = currentTicks;
            advFiltMissedEvntPct = ((float)advFiltMissedEvntCnt / (float)advFiltEvntCnt)*100;
            Display_print1(dispHandle, 1, 0, "Time Stamp Ticks: %d", currentTicks);
            Display_print1(dispHandle, 2, 0, "Total Event Count: %d", advTotEvntCnt);
            Display_print1(dispHandle, 3, 0, "Filtered Event Count: %d", advFiltEvntCnt);
            Display_print1(dispHandle, 4, 0, "Missed Event Count: %d", advFiltMissedEvntCnt);
            Display_print1(dispHandle, 5, 0, "Missed Event Percent: %d", advFiltMissedEvntPct);
            advTotEvntCnt = 0;
            advFiltEvntCnt = 0;
            advFiltMissedEvntCnt = 0;
        }
      }
      break;

    case GAP_DEVICE_DISCOVERY_EVENT:
      {
        // Discovery complete.
        scanning = FALSE;

        // Copy results.
        scanRes = pEvent->discCmpl.numDevs;
        memcpy(devList, pEvent->discCmpl.pDevList,
               (sizeof(gapDevRec_t) * pEvent->discCmpl.numDevs));

        Display_print1(dispHandle, 2, 0, "Devices Found %d", scanRes);

        if ( scanRes > 0 )
        {
          Display_print0(dispHandle, 3, 0, "<- To Select");
        }

        // Initialize scan index.
        scanIdx = -1;

        // Prompt user that re-performing scanning at this state is possible.
        Display_print0(dispHandle, 5, 0, "Discover ->");
      }
      break;

    default:
      break;
  }
}

Thank You,

Ed