[nRF52840 SDK 16.0.0] ble beacon example change TX power level

RE: [nRF52840 SDK 16.0.0] ble beacon example change TX power level

Jørgen Holmefjord — Wed, 13 May 2020 10:05:28 GMT

Please post new questions in a new thread. We want to make the threads follow the topic of the subject, to make information more searchable. Note that many others have asked about long-range advertising before. You should find some examples and suggestions if you use the search-function.

RE: [nRF52840 SDK 16.0.0] ble beacon example change TX power level

alfiero — Wed, 13 May 2020 09:25:42 GMT

Today I also tried to update the parameters m_adv_params of ble_gap_adv_params_t data type, which is declared at the beginning of main.c, by adding in advertising_init() function the last line of the following code:

    m_adv_params.properties.type = BLE_GAP_ADV_TYPE_NONCONNECTABLE_NONSCANNABLE_UNDIRECTED;
    m_adv_params.p_peer_addr     = NULL;    // Undirected advertisement.
    m_adv_params.filter_policy   = BLE_GAP_ADV_FP_ANY;
    m_adv_params.interval        = NON_CONNECTABLE_ADV_INTERVAL;
    m_adv_params.duration        = 0;       // Never time out.
    m_adv_params.primary_phy     = BLE_GAP_PHY_CODED; // added this line,
                                                     // trying to set phy to 125 kbps

But, even in this case, the application doesn't work. By building and debugging, the app_error_fault_heandler is called.

RE: [nRF52840 SDK 16.0.0] ble beacon example change TX power level

alfiero — Tue, 12 May 2020 17:44:24 GMT

I tried to put this code at the end of the advertising_init function, to get the lowest throughput for advertising, which should be 125 kbps (I saw it is supported for advertising non-connectable mode in the latest version of s140):

//set PHY mode: 
    ble_gap_phys_t const myPhys =
            {
                .rx_phys = BLE_GAP_PHY_CODED, //lowest datarate
                .tx_phys = BLE_GAP_PHY_CODED,
            };

    err_code = sd_ble_gap_phy_update(m_adv_handle, &myPhys);
    APP_ERROR_CHECK(err_code);

I get no errors from the compiler, but the application doesn't work.

I would like to set the 125 kbps data rate to achieve the long-range mode for advertising.

Any suggestions? Thank you in advance!!

RE: [nRF52840 SDK 16.0.0] ble beacon example change TX power level

alfiero — Tue, 12 May 2020 15:34:57 GMT

Ok, thank you so much, Jørgen!

Another question (sorry to bother you): I saw that for 'long-range' mode, the data rate should be 125 kbps, so as to reduce receiving errors I guess. What is the default bitrate in this example? 1Mbps? How can I change it to 125 kbps to combine it with the +8 dBm output power, in order to achieve a very long-range transmission? Thank you in advance!!

RE: [nRF52840 SDK 16.0.0] ble beacon example change TX power level

Jørgen Holmefjord — Mon, 11 May 2020 15:01:11 GMT

[quote user="alfiero"]So, do I need only to add your code in the init function, or should I also change the advdata.p_tx_power_level in a different way? I do not full understand the functionality of this latter parameter.[/quote]

No, you do not need to add this. As I said, there is most likely not enough space in the advertising packet to include this anyway. The iBeacon format (which ble_app_beacon closely implements) does not include the parameter.

[quote user="alfiero"]I noticed that in this example project, the function sd_ble_gap_tx_power_set() is not used at all. does it means that the device will keep the default settings of 0 dBm?[/quote]

Yes, the default of 0 dBm will be used when the tx_power is not explicitly set.

RE: [nRF52840 SDK 16.0.0] ble beacon example change TX power level

alfiero — Mon, 11 May 2020 14:55:36 GMT

Ok thank you so much!

So, do I need only to add your code in the init function, or should I also change the advdata.p_tx_power_level in a different way? I do not full understand the functionality of this latter parameter.

I noticed that in this example project, the function sd_ble_gap_tx_power_set() is not used at all. does it means that the device will keep the default settings of 0 dBm?

Thank you again!

RE: [nRF52840 SDK 16.0.0] ble beacon example change TX power level

Jørgen Holmefjord — Mon, 11 May 2020 14:30:32 GMT

Hi,

The code you have added is for including the TX power level that the beacon uses in the advertising packet. It does not change the actual TX power. The reason that the application does not work with these additions is most likely that the advertising packet was already full before you added this additional data field, generating an error when you run the application.

To change the actual TX power level for the advertising, you should call sd_ble_gap_tx_power_set(). You can add this to the end of advertising_init() function to set +8 dBm output power:

err_code = sd_ble_gap_tx_power_set(BLE_GAP_TX_POWER_ROLE_ADV, m_adv_handle, 8);
APP_ERROR_CHECK(err_code);

Best regards,
Jørgen