HID and NUS

[Laurent Bourassa]

Hello,

I am attempting to incorporate NUS example (app_uart) into the HID keyboard example. The whole thing compiles with no warning, but when I add {BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE} to m_adv_uuids, the adverstising never starts. I was able to locate where it fails through the debugger. When it enters the line APP_ERROR_CHECK(err_code) it fails.

static void advertising_init(void)
{
    uint32_t               err_code;
    uint8_t                adv_flags;
    ble_advertising_init_t init;

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

    adv_flags                            = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;
    init.advdata.name_type               = BLE_ADVDATA_FULL_NAME;
    init.advdata.include_appearance      = true;
    init.advdata.flags                   = adv_flags;
    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_whitelist_enabled          = true;
    init.config.ble_adv_directed_high_duty_enabled = true;
    init.config.ble_adv_directed_enabled           = false;
    init.config.ble_adv_directed_interval          = 0;
    init.config.ble_adv_directed_timeout           = 0;
    init.config.ble_adv_fast_enabled               = true;
    init.config.ble_adv_fast_interval              = APP_ADV_FAST_INTERVAL;
    init.config.ble_adv_fast_timeout               = APP_ADV_FAST_DURATION;
    init.config.ble_adv_slow_enabled               = true;
    init.config.ble_adv_slow_interval              = APP_ADV_SLOW_INTERVAL;
    init.config.ble_adv_slow_timeout               = APP_ADV_SLOW_DURATION;

    init.evt_handler   = on_adv_evt;
    init.error_handler = ble_advertising_error_handler;

    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);
}

I have tried the same with OTS and altough I wasn't able to communicate trough it I was able to advertise it. I have defined the following in sdk_config.h :

#define BLE_NUS_ENABLED 1

Any idea on what could cause an advertising failure?

[RK]

well you could just debug through to find out where the error is returned or look at the error code to see which one it is. Most likely you've put too much in the advertising packet and overfilled it so you're getting an error that there's no space. 

[Laurent Bourassa]

Hello, the error code is 0x07, which if I get right is NRF_ERROR_INVALID_PARAM. If I am not mistaken, since the NUS is a vendor defined UUID, it has a length of 128 bits, while the HID has 16 bits, right? I'm not quite sure how I am supposed to merge these two.

I attempted to replicate the ble_app_uart example where it uses a NUS profile, and temporarily commented out the HID part to see if I could make it work alone, but with no success. When you say "Too much in the advertising packet", you're talking about the advertising uuid list, correct?

[Laurent Bourassa]

Sorry, I see now what you mean. I have found out here what is the advertising packet. I know how to reduce the size taken by my device name, but it's not enough. I would need to reduce the data field of the NUS, but I'm not sure where to edit that. Probably in ble_nus.h. I will continue to look.

[Einar Thorsrud]

Hi,

Which function returns the error code now? and is it still NRF_ERROR_INVALID_PARAM?

[Laurent Bourassa]

Hello, yes it is still the same error and it is the same function as before that returns it.

I have shortened the advertising packet as much as I think I could :

No device name = 0 byte

-BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE flag = 3 bytes(?)

-HID = 4 bytes (Altough I have two reports for this profile, could it make it longer? Let's assume 8)

-BAS = Not sure about this one, I did not find where it says it is advertised, but I would assume it takes 4 more bytes...

-NUS = For the sake of testing, I have reduced BLE_NUS_MAX_DATA_LEN to 1. I don't know if the fact that there is both RX and TX extends the space taken by the NUS, I assume it does. For my application I don't need TX. (data(1) + manufacturer ID(2) + length(1) + type(2?) = 6 bytes?)

In total I think that would make 17-21 bytes, no? I must be wrong because if so it should work if it's under 31 bytes...

[Einar Thorsrud]

OK, so you get NRF_ERROR_INVALID_PARAM returned from ble_advertising_init()? Which SDK are you using?

Assuming SDK 15.2, this means that the error probably comes from ble_advdata_encode(). That function is responsible for encoding the advertisement packet and is quite easy to understand. Essentially there is an if statement for each field, so you can check with a debugger which fails (which is invalid).