How to make a simple unconnected Broadcaster ?

[Sylvain]

Hello everyone,

I would like to make an unconnected broadcaster to send data to the advertising channels ... I come from a X-NUCLEO-IDB05A1 board and that's has been pretty simple. It is just need to use a function and determine the interval of broadcast and pass the data to this function.

Are there an easy way to do that with the powerful nRF-52840 PDK ?

The "ble_app_alert_notification" example seems to do what I expect. Maybe, it could be a good starting point to understand the Nordic environment.

Thank you,

Sylvain.

[Mttrinh]

Hi,

If you only want to broadcast information and be non-connectable, I think the beacon example is what you are looking for. Yes, you should be able to implement BLE beacons on the nRF52840. Have a look at this post on devzone, there is also a beacon example attached. It is updated for SDK14.1 and should work with the nRF52840. 

 

[Sylvain]

Yes I have used this example as It's said as in other post. But I have few trouble when I try to modify the payload. I juste want to send a payload like that :

#define PAYLOAD_LENGTH  0x04

char payload [PAYLOAD_LENGTH] = {0xFF,0xFF,0xFF,0xFF};

So I modified this function :

static void advertising_init(void)
{
    uint32_t      err_code;
    ble_advdata_t advdata;
    uint8_t       flags = BLE_GAP_ADV_FLAG_BR_EDR_NOT_SUPPORTED;

    ble_advdata_manuf_data_t manuf_specific_data;
    
    memset(&manuf_specific_data, 0, sizeof(manuf_specific_data));

    manuf_specific_data.data.p_data = (char *) payload;
    manuf_specific_data.data.size = PAYLOAD_LENGTH;
 

    //Build and set advertising data.
    memset(&advdata, 0, sizeof(advdata));

    advdata.name_type             = BLE_ADVDATA_NO_NAME;
    advdata.flags                 = flags;
    advdata.p_manuf_specific_data = &manuf_specific_data;

    //Set uniquely the advertising data not the scan response data
    err_code = ble_advdata_set(&advdata, NULL);
    APP_ERROR_CHECK(err_code);

    // Initialize advertising parameters (used when starting advertising).
    memset(&m_adv_params, 0, sizeof(m_adv_params));

    m_adv_params.type        = BLE_GAP_ADV_TYPE_ADV_NONCONN_IND;
    m_adv_params.p_peer_addr = NULL;    // Undirected advertisement.
    m_adv_params.fp          = BLE_GAP_ADV_FP_ANY;
    m_adv_params.interval    = NON_CONNECTABLE_ADV_INTERVAL;
    m_adv_params.timeout     = 0;       // Never time out.
}


I receive the expected data but with other data ... Here's the received data :

[[0x02,0x01,0x04,0x07,0xFF,0x00,0x00,0xFF,0xFF,0xFF,0xFF]]

And I don't find where this data is set ...

Can you help me ?

Sylvain.

[Sylvain]

I found a solution. For any people interested, you need to specify what is the AD type. So, specify the AD type as Manufacturer Specific Data with the following code :

data[0]=0x1E;
data[1]=BLE_GAP_AD_TYPE_MANUFACTURER_SPECIFIC_DATA; //able to have 29 bytes for custom data

After that you can pass all the data you want to sent in this function (with a maximum of 29 Bytes):

sd_ble_gap_adv_data_set(data,strlen(data),NULL,0);

Here's the topics that help me :

https://devzone.nordicsemi.com/f/nordic-q-a/7080/sd_ble_gap_adv_data_set

https://devzone.nordicsemi.com/f/nordic-q-a/8854/fully-custom-advertisement-data/32548#32548

https://devzone.nordicsemi.com/tutorials/b/bluetooth-low-energy/posts/ble-advertising-a-beginners-tutorial

devzone.nordicsemi.com/.../bluetooth-smart-and-the-nordics-softdevices-part-1