Changing the Tx Power in sdk 15.2.0

[Manu Jain]

Hello,

I am trying to change the tx power for my nRF52-DK which is having nRF52832 chip. I trying the following code to change the tx power to -40 dB.

    int8_t tx_power_level = -40;

    init.advdata.p_tx_power_level = &tx_power_level;

    sd_ble_gap_tx_power_set(BLE_GAP_TX_POWER_ROLE_ADV, m_advertising.adv_handle, tx_power_level);

I have added the following lines of code to the advertising_init() function. 

Please help, I am a beginner.

Thanks in advance. 

[AndreasF]

      Hi.

There is an example which demonstrates how to change the TX power, the example is found in examples\ble_peripheral\ble_app_proximity\main.c

If you look at this example, the TX power is changed in the function tx_power_set(void), which is called after the advertising_start(erase_bonds) function, which again is called after the advertising is initialised in the advertising_init() function.

The tx_power_set(void) function looks like this:

/**@brief Function for changing the tx power.
 */
static void tx_power_set(void)
{
    ret_code_t err_code = sd_ble_gap_tx_power_set(BLE_GAP_TX_POWER_ROLE_ADV, m_advertising.adv_handle, TX_POWER_LEVEL);
    APP_ERROR_CHECK(err_code);
}

You can use this function, and you also need to define the TX_POWER_LEVEL in your main.c file like this:

#define TX_POWER_LEVEL                  (-40)

The main(void) function of the example, examples\ble_peripheral\ble_app_proximity, looks like this:

/**@brief Function for application main entry.
 */
int main(void)
{
    bool erase_bonds;

    // Initialize.
    log_init();
    timers_init();
    buttons_leds_init(&erase_bonds);
    power_management_init();
    ble_stack_init();
    adc_configure();
    gap_params_init();
    gatt_init();
    advertising_init();
    db_discovery_init();
    services_init();
    conn_params_init();
    peer_manager_init();

    // Start execution.
    NRF_LOG_INFO("Proximity example started.");
    advertising_start(erase_bonds);
    tx_power_set();

    // Enter main loop.
    for (;;)
    {
        idle_state_handle();
    }
}

Here you see that the TX power is changed at the bottom before the main loop, by the function call tx_power_set();.

Hope this helps.

Best regards.

Andreas

[Arepa]

Hi Andreas, is there any other option to change the TX power? I mean for that example you posted above you have to call ble_advertising_init adding an advertising instance, what for an example like ble_blinky peripheral?

[AndreasF]

Hi

I'm a bit unsure on what you mean, you can use the same method in the ble_app_blinky project to change the TX Power.

Best regards,

Andreas