How to set tx_power using sd_ble_gap_tx_power_set() on nrf52832?

[dewal]

Hi everyone,

I want to set TX_POWER using sd_ble_gap_tx_power_set(BLE_GAP_TX_POWER_ROLE_ADV,m_adv_handle,RADIO_TXPOWER_TXPOWER_Pos4dBm);

  m_adv_handle = BLE_GAP_ADV_SET_HANDLE_NOT_SET;

m_adv_handle parameter is wrong passed to the function.

I am refering this link https://devzone.nordicsemi.com/f/nordic-q-a/72412/how-to-set-tx_power-using-sd_ble_gap_tx_power_set-on-nrf52832,

but still problem not solved.

[Vidar Berg]

Hi,

This function must be called after advertising_init() and before advertising start. The reason for this is that the advertisment set is not added prior to that. Also, the handle value will always be '0' as multiple advertisment sets are not supported by the Softdevice.

Best regards,

Vidar

[ande_dewal]

thanks for reply,

I tried as per your response. Tx power is not set it gives always default value.

please help me for solve this problem.

[Vidar Berg]

How do you determine that it's not set? Does sd_ble_gap_tx_power_set() return with an error?

[ande_dewal]

thanks for reply, 

advertising_init();
err_code = sd_ble_gap_tx_power_set(BLE_GAP_TX_POWER_ROLE_ADV, m_adv_handle,RADIO_TXPOWER_TXPOWER_Pos4dBm);
APP_ERROR_CHECK(err_code);
advertising_start();

after that i read  NRF_RADIO->TX_POWER register , it gives always 0dbm.

please help me for change the tx_power in ibecaon code .

[Vidar Berg]

The NRF_RADIO->TX_POWER register is set by the Softdevice at the beginning of the advertising event, and cleared at the end. This is the reason why it always reads as '0'. It does not mean that the setting did not get applied.

You can use the RSSI view in our nRF connect app to see what effect the different output power settings have on the RSSI.

[ande_dewal]

thanks for reply,

I tried to get tx_power  at scanner code, it always gives 0dbm.

I thought i am passing wrong parameter to this function. please tell me exact way to set that properly.

[Vidar Berg]

A scanner does not have any way of knowing the exact TX output power used by the broadcaster, unless the broadcaster is including this TX power setting value in its advertising data. 

You would need dedicated test equipment such as spectrum analyzer if you were to measure the actual output power.

ande_dewal said:

please tell me exact way to set that properly.

It will be set correctly if you use the code you posted earlier .

advertising_init();
err_code = sd_ble_gap_tx_power_set(BLE_GAP_TX_POWER_ROLE_ADV, m_adv_handle,RADIO_TXPOWER_TXPOWER_Pos4dBm);
APP_ERROR_CHECK(err_code);
advertising_start();

[ande_dewal]

thanks for reply,

I did that way also, I tested debugging mode on segger embedded studio . but in Radio TX_power register is is always 0dbm.

[Vidar Berg]

As mentioned earlier, the TX_POWER register will always be read as '0' regardless of the power setting.