nRF52840 stops scanning

RE: nRF52840 stops scanning

bjorn-spockeli — Mon, 12 Aug 2019 15:17:06 GMT

Happy to help. Let me know if you run into any issues.

-Bjørn

RE: nRF52840 stops scanning

Philip — Mon, 12 Aug 2019 13:56:52 GMT

Thanks Bjorn, I will give that a go.

Phil

RE: nRF52840 stops scanning

bjorn-spockeli — Mon, 12 Aug 2019 13:30:27 GMT

Hi Phil,

The status field should be a member of the ble_gap_adv_report_type_t structwhich in turn is a member of the ble_gap_evt_adv_report_t struct in S140 v6.x.x, see S140 SoftDevice v6.1.0: ble_gap_evt_adv_report_t Struct Reference.

So I think it should be

        case BLE_GAP_EVT_ADV_REPORT:
            on_adv_report(&p_gap_evt->params.adv_report);

            if(p_gap_evt->params.adv_report.type.status == BLE_GAP_ADV_DATA_STATUS_INCOMPLETE_MORE_DATA)
            {
                start_scan();
            }
            break;

Best regards

Bjørn

RE: nRF52840 stops scanning

Philip — Mon, 12 Aug 2019 12:44:18 GMT

Hi Bjorn.

Am looking at the last case in your message above. Can't work out how I check the status part of the ADV_REPORT. Can't find 'status' in there??

        case BLE_GAP_EVT_ADV_REPORT:
            on_adv_report(&p_gap_evt->params.adv_report);

            if(p_gap_evt->params.adv_report.?????? == BLE_GAP_ADV_DATA_STATUS_INCOMPLETE_MORE_DATA)
            {
                start_scan();
            }
            break;

Thanks

Phil

RE: nRF52840 stops scanning

bjorn-spockeli — Thu, 11 Jul 2019 21:15:09 GMT

It could be the last case, i.e the status bit is set to BLE_GAP_ADV_DATA_STATUS_INCOMPLETE_MORE_DATA. However, if the workaround solves the issue then I guess we can mark the case as solved.

RE: nRF52840 stops scanning

Philip — Sat, 06 Jul 2019 13:36:11 GMT

Oh I found it. Its set to 0x0000 so no timeout. Must be a glitch that happens with the softdevice sometimes.

My workaround should be ok.

Thanks

Phil

RE: nRF52840 stops scanning

Philip — Sat, 06 Jul 2019 13:34:17 GMT

Thanks Bjørn.

The only one of those cases that could be happening is the timeout, but I can't figure out where that would be set in my project. I searched the whole project (based on multi-link central) for "BLE_GAP_TIMEOUT_SRC_SCAN" and found nothing.

Phil

RE: nRF52840 stops scanning

bjorn-spockeli — Fri, 05 Jul 2019 19:31:38 GMT

Hi Phillip,

Happy to hear that restarting scanning solves the issue.

the SoftDevice API documentation of sd_ble_gap_scan_start scanning will automatically stop in the following cases:

sd_ble_gap_scan_stop is called.
sd_ble_gap_connect is called.
A BLE_GAP_EVT_TIMEOUT with source set to BLE_GAP_TIMEOUT_SRC_SCAN is received.
When a BLE_GAP_EVT_ADV_REPORT event is received and ble_gap_adv_report_type_t::status is not set to BLE_GAP_ADV_DATA_STATUS_INCOMPLETE_MORE_DATA. In this case scanning is only paused to let the application access received data. The application must call this function to continue scanning, or call sd_ble_gap_scan_stop to stop scanning.

Best regards

Bjørn

RE: nRF52840 stops scanning

Philip — Fri, 05 Jul 2019 15:05:12 GMT

Thanks Guys.

I added a command to restart scanning when the issue occurs. It did happen again the other day and restarting scanning solved the issue.

However I still don't understand why it would stop or timeout, after a random period of time. Makes no sense. There is no scanning timeout set in my project.

Phil

RE: nRF52840 stops scanning

bjorn-spockeli — Fri, 05 Jul 2019 13:56:05 GMT

Hi Philip,

Yes, we added a Scanning Module in SDK v15.2.0. In SDK v15.0.0 you can monitor the underlying events that is abstracted by the scanning module. The BLE_GAP_EVT_TIMEOUT event will be sent with the field params.timeout.src set to BLE_GAP_TIMEOUT_SRC_SCAN(0x01), so you can check for this in the ble_evt_handler() in main.c

        case BLE_GAP_EVT_TIMEOUT:
        {
            // Check if scaning times out
            if (p_gap_evt->params.timeout.src == BLE_GAP_TIMEOUT_SRC_SCAN)
            {
                NRF_LOG_DEBUG("Scanning timed out.");
            }
        } break;

Best regards

Bjørn

RE: nRF52840 stops scanning

Philip — Wed, 03 Jul 2019 18:56:05 GMT

Actually in the multi-link central SDK15.0.0 I am using there is no scan_init or scan_evt_handler? Must have been added in SDK15.2.0.

Phil

RE: nRF52840 stops scanning

Philip — Wed, 03 Jul 2019 18:37:37 GMT

Hmm, thanks for the suggestion sounds good.

I will give it a try and monitor the events.

Thanks

Phil

RE: nRF52840 stops scanning

hmolesworth — Wed, 03 Jul 2019 18:22:20 GMT

I find tracing all the scanning events helpful, something like this:

// Scan Events
static char * ble_scan_event_description[] =
{
/* NRF_BLE_SCAN_EVT_FILTER_MATCH",        */ " 0 Filter matched in the multifilter mode",
/* NRF_BLE_SCAN_EVT_WHITELIST_REQUEST:    */ " 1 Request the whitelist from the main application",
/* NRF_BLE_SCAN_EVT_WHITELIST_ADV_REPORT: */ " 2 Device from the whitelist is found",
/* NRF_BLE_SCAN_EVT_NOT_FOUND:            */ " 3 Filter not matched for the scan data",
/* NRF_BLE_SCAN_EVT_SCAN_TIMEOUT:         */ " 4 Scan timeout",
/* NRF_BLE_SCAN_EVT_SCAN_REQ_REPORT:      */ " 5 Scan request report",
/* NRF_BLE_SCAN_EVT_CONNECTING_ERROR:     */ " 6 Error occurred when establishing the connection from sd_ble_gap_connect",
/* NRF_BLE_SCAN_EVT_CONNECTED:            */ " 7 Connected to device"
};
#define NUM_BLE_SCAN_EVENTS (sizeof(ble_scan_event_description)/sizeof(ble_scan_event_description[0]))

/**@brief Function for handling Scanning Module events.
 */
static void scan_evt_handler(scan_evt_t const * p_scan_evt)
{
    ret_code_t err_code;

    switch(p_scan_evt->scan_evt_id)
    {
         case NRF_BLE_SCAN_EVT_CONNECTING_ERROR:     // Error occurred when establishing the connection. In this event, an error is passed from the function call @ref sd_ble_gap_connect
         {
              err_code = p_scan_evt->params.connecting_err.err_code;
              APP_ERROR_CHECK(err_code);
         } break;

         case NRF_BLE_SCAN_EVT_CONNECTED:            // Connected to device
         {
             ble_gap_evt_connected_t const * p_connected = p_scan_evt->params.connected.p_connected;
             // Scan is automatically stopped by the connection.
             NRF_LOG_INFO("Connect to Id %02x%02x%02x%02x%02x%02x",
                      p_connected->peer_addr.addr[0],
                      p_connected->peer_addr.addr[1],
                      p_connected->peer_addr.addr[2],
                      p_connected->peer_addr.addr[3],
                      p_connected->peer_addr.addr[4],
                      p_connected->peer_addr.addr[5]
                      );
         } break;

         case NRF_BLE_SCAN_EVT_SCAN_TIMEOUT:         // Scan timeout
         {
             NRF_LOG_INFO("Scan timed out.");
             scan_start();
         } break;

         case NRF_BLE_SCAN_EVT_FILTER_MATCH:         // A filter is matched or all filters are matched in the multifilter mode
             {
               ble_gap_evt_adv_report_t const *p_adv_report = p_scan_evt->params.filter_match.p_adv_report;
               NRF_LOG_INFO("Scan Match Id: %02x%02x%02x%02x%02x%02x",
                      p_adv_report->peer_addr.addr[0],
                      p_adv_report->peer_addr.addr[1],
                      p_adv_report->peer_addr.addr[2],
                      p_adv_report->peer_addr.addr[3],
                      p_adv_report->peer_addr.addr[4],
                      p_adv_report->peer_addr.addr[5]
                      );
             }
             break;

         case NRF_BLE_SCAN_EVT_NOT_FOUND:            // The filter was not matched for the scan data
             {
               ble_gap_evt_adv_report_t const *p_not_found = p_scan_evt->params.p_not_found;
               NRF_LOG_INFO("Deny Id: %02x%02x%02x%02x%02x%02x",
                      p_not_found->peer_addr.addr[0],
                      p_not_found->peer_addr.addr[1],
                      p_not_found->peer_addr.addr[2],
                      p_not_found->peer_addr.addr[3],
                      p_not_found->peer_addr.addr[4],
                      p_not_found->peer_addr.addr[5]
                      );
             }
             break;

         default:
//       case NRF_BLE_SCAN_EVT_FILTER_MATCH:         // A filter is matched or all filters are matched in the multifilter mode
         case NRF_BLE_SCAN_EVT_WHITELIST_REQUEST:    // Request the whitelist from the main application. For whitelist scanning to work, the whitelist must be set when this event occurs
         case NRF_BLE_SCAN_EVT_WHITELIST_ADV_REPORT: // Send notification to the main application when a device from the whitelist is found
//       case NRF_BLE_SCAN_EVT_NOT_FOUND:            // The filter was not matched for the scan data
         case NRF_BLE_SCAN_EVT_SCAN_REQ_REPORT:      // Scan request report
            if (p_scan_evt->scan_evt_id < NUM_BLE_SCAN_EVENTS)
            {
               NRF_LOG_INFO("scan_evt_id: %d %s", p_scan_evt->scan_evt_id, ble_scan_event_description[p_scan_evt->scan_evt_id]);
            }
            else
            {
               NRF_LOG_INFO("Unhandled scan_evt_id: %d", p_scan_evt->scan_evt_id);
            }
             break;
    }
}

Selectively enable/disable the event reports, but ensure everything generates a trace in case something wierd happes .. if any event happens that is ..

RE: nRF52840 stops scanning

Philip — Wed, 03 Jul 2019 18:02:29 GMT

Hi Bjørn.

When it has had the problem it is only scanning, it is not connected to any of the nRF52832 devices.

What could cause the scanning to randomly stop?

I could add a watchdog timer, but would be better to figure out what the issue.

Is there any variables / functions I can monitor regarding scanning that I could log? e.g. is there a function that tells you if scanning is running, or has failed?

Thanks

Phil

RE: nRF52840 stops scanning

bjorn-spockeli — Wed, 03 Jul 2019 11:13:26 GMT

Hi Phillip,

[quote user=""][/quote]

The system can be running fine like this for 1 / 2 weeks 24 hours a day, then out of the blue the nRF52840 stops picking up any peripherals. It could be in the middle of the night, when the system isn't doing anything complicated like connecting / mass data transfer etc.

The fact that all the peripherals 'disappear' at the same time suggests the central is at fault. The peripherals have all been started at different times and have power etc.

It sounds like the nRF52840 stops scanning. Is the nRF52840 only scanning for the nRF52832 devices or or is it connected to all the nRF52832 devices? You could start a "watchdog" timer that is reset every time you receive an advertisment packet from one of the nRF52832 devices. If the timer times out, then you can call the SD-api to restart scanning.

Do you log any debug information through the CDC USB interface?

Best regards

Bjørn