how to trace channels

[mohanraj360]

i am using nrf52840 sdk 14.2 s140

i want to advertise in a single channel and which app is used to trace on which channel is advertising

[AndreasF]

Hi.

Bluetooth Low Energy advertises by hopping between three different channels, that is channel 37, 38, and 39.

If you want to advertise on a single channel, you simply have to turn off two of the three channels.

You can find this in the infocenter here.

Example:

    ble_gap_adv_params_t adv_params;


    adv_params.channel_mask.ch_37_off = 1;
    adv_params.channel_mask.ch_38_off = 1;

- Andreas

[mohanraj360]

i tried and how to check whether ble is transmitting on the particular channel

[AndreasF]

Hi.
Well as i said, BLE is always advertising on 3 channels, and skips between the 3 channels.

This means that BLE does not advertise on a particular channel.

If you want to advertise on a particular channel, you have to turn off two channels, like I showed in my previous reply.

- Andreas

[mohanraj360]

ok is there any application which shows  the ble is advertising on particular chaNNEL

[AndreasF]

Hi.

No, there is not any example applications where advertising happens on a particular channel.
But you can add the code in my previous reply to any example found in the \ble_peripheral folder.
Let me show you here:

Open the ble_app_blinky project in the folder \nRF5_SDK_14.2.0_17b948a\examples\ble_peripheral\ble_app_blinky\pca10056\s140 in your prefered IDE.

Find the static void advertising_start(void) function in main.c


If you want to turn of channel 37, add the code:

adv_params.channel_mask.ch_37_off = 1;

If you want to turn of channel 38, add the code:

adv_params.channel_mask.ch_38_off = 1;

If you want to turn of channel 39, add the code:

adv_params.channel_mask.ch_39_off = 1;

Here is what my static void advertising_start(void) function looks like when I have turned off channel 37 and 38.

static void advertising_start(void)
{
    ret_code_t           err_code;
    ble_gap_adv_params_t adv_params;

    // Start advertising
    memset(&adv_params, 0, sizeof(adv_params));

    adv_params.type        = BLE_GAP_ADV_TYPE_ADV_IND;
    adv_params.p_peer_addr = NULL;
    adv_params.fp          = BLE_GAP_ADV_FP_ANY;
    adv_params.interval    = APP_ADV_INTERVAL;
    adv_params.timeout     = APP_ADV_TIMEOUT_IN_SECONDS;

    adv_params.channel_mask.ch_37_off = 1;
    adv_params.channel_mask.ch_38_off = 1;

    err_code = sd_ble_gap_adv_start(&adv_params, APP_BLE_CONN_CFG_TAG);
    APP_ERROR_CHECK(err_code);
    bsp_board_led_on(ADVERTISING_LED);

   
}

This is done just like the infocenter explained, in the link i added in my previous reply.

- Andreas