long range

[Michael]

Hello All,

I am having trouble changing the 'ble_app_multiperipheral_pca1056_s140' example to work with long range. I have read a few of the blog posts and similar devzone posts but I can't seem to find an answer that works. 

Here is my code for configuring the gap advertising set:

   // only extended advertising will allow primary phy to be coded
    NRF_LOG_INFO("Advertising type set to EXTENDED_CONNECTABLE_NONSCANNABLE_UNDIRECTED ");
    //adv_params.properties.type = BLE_GAP_ADV_TYPE_CONNECTABLE_SCANNABLE_UNDIRECTED;
    adv_params.properties.type = BLE_GAP_ADV_TYPE_EXTENDED_CONNECTABLE_NONSCANNABLE_UNDIRECTED;
              
    err_code = ble_advdata_encode(&advdata, m_adv_data.adv_data.p_data, &m_adv_data.adv_data.len);
    APP_ERROR_CHECK(err_code);

    // Start advertising.
    memset(&adv_params, 0, sizeof(adv_params));
    adv_params.p_peer_addr   = NULL;
    adv_params.filter_policy = BLE_GAP_ADV_FP_ANY;
    adv_params.interval      = APP_ADV_INTERVAL;
    adv_params.duration      = 0;//APP_ADV_DURATION;

    NRF_LOG_INFO("Setting adv params phy to coded phy .. ");
    adv_params.primary_phy     = BLE_GAP_PHY_CODED;
    //adv_params.secondary_phy   = BLE_GAP_PHY_CODED;

    err_code = sd_ble_gap_adv_set_configure(&m_adv_handle, &m_adv_data, &adv_params);
    APP_ERROR_CHECK(err_code);
}

The error I get is :

<info> app: Setting adv params phy to coded phy ..

<error> app: ERROR 7 [NRF_ERROR_INVALID_PARAM] at :0

PC at: 0x00000000

<error> app: End of error report

Any help where I am going wrong or anything that I have missed would really be appreciated.

Cheers

Michael

[Håvard]

Hi Michael, for extended advertising to work, it must use the secondary phy.

When using extended advertising, the primary phy is only used to "point" over to the secondary phy, where the much longer data can exist.

So you probably don't want to comment out the secondary phy. :)

[Michael]

Hi Håvard 

Thanks for the input. I have tried it with and without priory to submitting the ticket and it didn't make any difference (the error 7 was still reported). 

Also;

Do you know what the 'adv_params.duration'  should be set too? (I have tried both 0 and APP_ADV_DURATION)  ??

Do I need to add the line (i'm not sure what the srdata is used for) - 

err_code = ble_advdata_encode(&srdata, m_adv_data.scan_rsp_data.p_data, &m_adv_data.scan_rsp_data.len);  ??

I can't seem to find a large amount of information on the setting requirements for long range so I'm shooting in the dark 

Any help appreciated

Cheers

Michael

[Michael]

Hi Håvard 

Yes that has cleared up the error. Do you know if there is a white paper or similar document from Nordic that describes the setting requirements to enable some of these modes (and there dependencies)??

I understand that the Infocenter document holds a lot of information about the SoftDevice API (including defines, Enumerations, functions and structures) .... but as far as I can see it doesn't tell you a lot of information for the requirements to enable a particular connection type (in my case the long range). 

For example a search of 'long range' in the Infocentrer it returns no results. 

If I search 'BLE_GAP_PHY_CODED' one of the returned functions is for the  sd_ble_gap_phy_update function, which has a note :

"Note: BLE_GAP_PHY_CODED is only supported as an experimental feature in this SoftDevice."

None of the returned information is of any real help into what I need to set as opposed to what I can set - I guess that is why this is a common question on the devzone site?? 

Thanks for your help 

Cheers

Michael

[Håvard]

I'm glad you got it working Michael. :)

I am not aware of any whitepaper, or step by step tutorial for long range or other "modes", that clearly list the dependencies. But there are some examples that use long range:

https://github.com/NordicPlayground/nRF52-ble-long-range-demo

https://github.com/NordicPlayground/nrf52-ble-app-uart-long-range

ATT_MTU Throughput Example (For the connection, not advertising or scanning)

There are several resources to give a more general understanding of long range (I know that is not what you are asking for, but for completeness, I want to add links for others to see):

https://www.nordicsemi.com/eng/Products/Bluetooth-5

https://blog.nordicsemi.com/getconnected/tested-by-nordic-bluetooth-long-range

https://blog.nordicsemi.com/getconnected/things-you-should-know-about-bluetooth-range

https://devzone.nordicsemi.com/b/blog/posts/testing-long-range-coded-phy-with-nordic-solution-it-simply-works-922075585

I agree that it could be more explicitly stated in the API that the scan response data must be NULL when the advertising type is non-scannable.

It is said more implicitly under GAP Advertising types

"Scan response data can only be specified for a @ref ble_gap_adv_properties_t::type
that is scannable."

and under GAP advertising data buffers:
"non-scannable types do not support scan response data."

And when you add too many implicit parameters on top of each other mistakes get easy to make.

I will check internally if someone wants to clean up the API a bit or make a blog post about advertising- and connection phys. (I assume this is what you mean by "modes" but feel free to specify it more).

Good luck with your project.

 -Håvard

[Michael]

Hi Håvard 

I'm sure a blog post would be welcomed and appreciated by the community as more people  use these newly introduced modes, feature and functions. 

Thank you very much for your help and support

Kind regards

Michael

[kathleenlai]

Hi @Michael,

 According to the code, may I know why there is a memset (line 12) to clear the adv_params before it start advertising?

Im a bit confuse as the adv_params already set in advertising_init, then comes to advertising_start it was clear and set again?

Because I'm facing the same problem as you , so I wondering why it is so. 

Hope u can help. Thank you so much .

Regards,

Kathleen

[kathleenlai]

Hi Håvard ,

I have similar problem face while using BLE_GAP_PHY_CODED just to do simple advertising. (using nRF5_SDK_15.3.0_59ac345)

The code I compiled can run well without error, however the nrf52840 PDK didn't advertising as my sniffer can't get any advertise packet . I double check with the oscilloscope, the scope display show no advertise packet.  

I set the .scan_rsp_data.p_data = NULL and .scan_rsp_data.len=0 . however still no advertise packet was advertise. 

I wonder how it could happen. Can you help?

Thank you .

Best regards,

Kathleen