Unable to Send Messages NRF52 BLE Central Custom Device

RE: Unable to Send Messages NRF52 BLE Central Custom Device

endnode — Thu, 25 May 2017 11:10:34 GMT

Glad to help and good to hear that peer_manager works well for you!

RE: Unable to Send Messages NRF52 BLE Central Custom Device

P879 — Wed, 24 May 2017 22:19:50 GMT

Thank you for all of your help endnode. I solved the issue several minutes ago.

The issue was solved by adding all of the peer_manager code that was included in the HRS demo. With this the bonding would occur quite easily. Once bonded the commands worked immediately.

I will note that if anyone has trouble bonding you have to make sure to remove the handling of

BLE_GAP_EVT_SEC_PARAMS_REQUEST by the on_ble_evt event handler. Both the event handler and peer_manager were trying to respond to the event causing the processor to reset. This took me several hours to figure out. The peer manager handles all of the security requests.

RE: Unable to Send Messages NRF52 BLE Central Custom Device

P879 — Tue, 23 May 2017 20:46:58 GMT

After more trial and error I believe that the problem is that the connection is paired, but not bonded. The custom device requires bonding. The iOS and Android phones all bond automatically. I am going to move forward with attempting to implement the peer_manager to handle the bonding.

RE: Unable to Send Messages NRF52 BLE Central Custom Device

endnode — Tue, 23 May 2017 19:39:20 GMT

//..

case BLE_GATTC_EVT_WRITE_RSP:
            if ((p_ble_evt->evt.gattc_evt.gatt_status == BLE_GATT_STATUS_ATTERR_INSUF_AUTHENTICATION) ||
                (p_ble_evt->evt.gattc_evt.gatt_status == BLE_GATT_STATUS_ATTERR_INSUF_ENCRYPTION))
            {
                uint32_t err_code = dm_security_setup_req(&p_client->handle);
                APP_ERROR_CHECK(err_code);
            }
            on_evt_write_rsp(p_ble_evt, p_client);
            break;

So if you are using Device Manager module or your own code to manage link security it should be solved there. But as I said it's hard to debug something through the forum posts just based on few lines of code and UART debug (not saying I do want your full project, I don't have time to run it and debug for you anyway;)

RE: Unable to Send Messages NRF52 BLE Central Custom Device

endnode — Tue, 23 May 2017 19:37:55 GMT

Well my assumption that GATT object you are targeting requires some pairing step which you haven't pass is based on BLE_GATT_STATUS_ATTERR_INSUF_AUTHENTICATION error you get as Write result. The fact that mobile apps are OK can be simply caused by proper pairing of your device with that phone. Now when I look into nRF5 SDK v13 there is an example .\examples\ble_central\ble_app_multilink_central\client_handling.c where BLE event handler contains following code:

//...

RE: Unable to Send Messages NRF52 BLE Central Custom Device

P879 — Tue, 23 May 2017 19:18:44 GMT

Since both the LightBlue app and the nRF connect app can immediately discover all of the services and perform any operation I don't believe that a security issue is occurring. I don't think that I need anything in that realm.

I have discovered two services, but I have not called:

uint32_t characteristic_add(uint16_t service_handle, ble_add_char_params_t * p_char_props, ble_gatts_char_handles_t * p_char_handle)

with either of them. Is this a step that has to occur before I can start writing to the characteristics? It just seems like I have discovered them, but as you said they are not 'open'. It has to be something on my end.

RE: Unable to Send Messages NRF52 BLE Central Custom Device

endnode — Tue, 23 May 2017 16:26:38 GMT

Hard to say when not seeing what is really happening on BLE radio but if you are not sure if pairing is completed in your custom code then using peer_manager module from SDK might help. I personally don't us it but if you are starting from scratch it might be the fastest route.

RE: Unable to Send Messages NRF52 BLE Central Custom Device

P879 — Tue, 23 May 2017 16:24:28 GMT

I am working on solving the permission issue, but I am not having any luck. I am trying to call:

error = sd_ble_gap_authenticate(p_ble_evt->evt.gattc_evt.conn_handle, &security_params);

When I receive the security failure. I am leaning towards implementing the Peer Manager software. It appears that the peer manager performs the security and bonding that is not included in the UART BLE example. Does this seem like good route to take?

RE: Unable to Send Messages NRF52 BLE Central Custom Device

endnode — Tue, 23 May 2017 09:34:51 GMT

It looks like your characteristics are not "open" but they have certain permissions set on ATT/GATT layer and your connection doesn't have authorization (typically didn't pass some Security Manager pairing/bonding procedure).