Why is my device name being truncated?

[Eliot Stock]

Using SDK 14.0.0 with SD 132 v5, the device name I'm advertising with here is "000000DK". But the advertising module is truncating it to "0000". It will do this if I have too much advertising data, but I don't. I should have 31 bytes and that should be fine. It was fine with SDK 12.1 and an earlier SD version.

I've read this post on the same subject, but it doesn't explain this:

devzone.nordicsemi.com/.../

It looks like it's the appearance that's overflowing me. This was never a problem before and if I now omit any call to sd_ble_gap_appearance_set(), I get 0x0000 as the appearance field, whereas I think I used to get no appearance field at all. How do I remove the appearance and get the same behaviour I used to have with the earlier SDK/SD?

[purgoufr]

I wrote function for advertising like that;

static void advertising_init(void)
{
    ret_code_t             err_code;
    ble_advertising_init_t init;

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

    init.advdata.name_type               = BLE_ADVDATA_FULL_NAME;
    init.advdata.include_appearance      = false;
    init.advdata.flags                   = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;
    init.advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    init.advdata.uuids_complete.p_uuids  = m_adv_uuids;

    init.config.ble_adv_fast_enabled  = true;
    init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
    init.config.ble_adv_fast_timeout  = APP_ADV_TIMEOUT_IN_SECONDS;

    init.evt_handler = on_adv_evt;

    err_code = ble_advertising_init(&m_advertising, &init);
    APP_ERROR_CHECK(err_code);

    ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
}

But still I can not see full device name. When include_appearance is true I can see 4 charecter, When include_appearance is false I can see 8 charecter. I understand the data length calculation but I want to see full device name. So, Can I make the length more than 31 bytes? Or is there another way to see full device name?

[Petter Myhre]

31 bytes is maximum. If you want to have a longer device name you need to remove something else, UUID for example.

[Shimon_nohayo]

I have a very similar problem,

Can you explain what do you mean by removing UUID?

Shimon

[Shimon_nohayo]

I have a very similar problem,

Can you explain what do you mean by removing UUID?

Shimon

[Spacha]

This is an old thread but thought to give an update in case someone stumbles upon this problem.

As mentioned before, the advertisement space is limited to 31 bytes including device appearance, name and other advertisement data. To have longer name, you need to get rid of something else (for example appearance, which gives some 4 bytes more space, or UUID, which gives a lot more).

Here's a demonstration of the advertising_init() function that is used to configure the advertisements. The comments show where you can give more space for the device name (appearance and UUID).

static void advertising_init(void)
{
    ret_code_t             err_code;
    ble_advertising_init_t init;

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

    init.advdata.name_type               = BLE_ADVDATA_FULL_NAME;
    init.advdata.include_appearance      = true; //<< To remove appearance, set this to false
    init.advdata.flags                   = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;
    
    //<< Comment out these 2 lines to remove the UUID from the advertisement
    //<< This gives a lot of space for the name.
    init.advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    init.advdata.uuids_complete.p_uuids  = m_adv_uuids;

    init.config.ble_adv_fast_enabled  = true;
    init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
    init.config.ble_adv_fast_timeout  = APP_ADV_DURATION;

    init.evt_handler = on_adv_evt;

    err_code = ble_advertising_init(&m_advertising, &init);
    APP_ERROR_CHECK(err_code);

    ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
}