nRF52DK does not advertise when NUS is combined with custom service.

[Rishi]

Hello, I am trying to implement my custom service with NUS. I have gone through almost all the solutions presented on this forum.

Observations:

• The board does not advertise.

• On debugging, the board keeps resetting.

• ble_advertising_init() generates error code 0x0C i.e. NRF_ERROR_DATA_SIZE. This means that the data is overflowing in the packet.

Procedures performed:

• Changed p_ble_enable_params->common_enable_params.vs_uuid_count = 1; to p_ble_enable_params->common_enable_params.vs_uuid_count = 2; in softdevice_handler.c

• Defined static ble_uuid_t m_adv_uuids[] = {{BLE_UUID_NUS_SERVICE, BLE_UUID_TYPE_VENDOR_BEGIN}, {BLE_UUID_OUR_SERVICE_UUID, BLE_UUID_TYPE_VENDOR_BEGIN}};

I have enabled scan response packet as:

static void advertising_init(void)
{
	uint32_t      err_code;
	ble_advdata_t advdata;

	// Build advertising data struct to pass into ble_advertising_init().

	memset(&advdata, 0, sizeof(advdata));

	advdata.name_type               = BLE_ADVDATA_FULL_NAME;
	advdata.include_appearance      = false;
	advdata.flags                   = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;

	ble_adv_modes_config_t options = {0};
	options.ble_adv_fast_enabled  = BLE_ADV_FAST_ENABLED;
	options.ble_adv_fast_interval = APP_ADV_INTERVAL;
	options.ble_adv_fast_timeout  = APP_ADV_TIMEOUT_IN_SECONDS;

	// OUR_JOB: Create a scan response packet and include the list of UUIDs
	ble_advdata_t srdata;

	memset(&srdata, 0, sizeof(srdata));

	srdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
	srdata.uuids_complete.p_uuids = m_adv_uuids;
	
	err_code = ble_advertising_init(&advdata, &srdata, &options, on_adv_evt, NULL);
	APP_ERROR_CHECK(err_code);
}

With both advertising and scan response packet we should have a total size of 496 bits and should easily accommodate 256 bits from two base UUIDs. Still I am getting NRF_ERROR_DATA_SIZE.

• I have also tried using a single base UUID from NUS with my custom 16 bit service ID. The problem persists even then.

Any suggestions or link would be much appreciated.

Thank you.

[Jørgen Holmefjord]

Hi,

It looks like you are putting both UUIDs in the scan response package. This will make the scan reponse package 32 byte, which is more than the allowed 31 bytes. You will have to put one UUID in the advertising data and one UUID in the scan response data.

advdata.uuids_more_available.uuid_cnt = 1;
advdata.uuids_more_available.p_uuids = &m_adv_uuids[0];

srdata.uuids_more_available.uuid_cnt = 1;
srdata.uuids_more_available.p_uuids = &m_adv_uuids[1];

Best regards,

Jørgen

[Rishi]

Hey Jorgen, Your suggestion worked out perfectly.

Thanks.