Making changes in "Server Setup" for "nRF52840 Dongle" in "nRF Connect for Desktop Bluetooth Low Energy" doesn't save changes to dongle.

[GameCodingNinja]

The "nRF52840 Dongle" defaults to a max length of 20 in all of the "General Access" characteristics and I'm trying to change that to a higher number. I change it to 60 for each of the characteristics, save each characteristic and then apply the changes to the device. Reload the dongle and the values are back to 20. I tried creating a new service and once again, the new service not saved.

I'm trying to get the dongle to transmit and receive more then just 20 bytes at a time.

Any idea of how to do this?

[Amanda Hsieh]

Hi, 

You can save the setup and load it when you need. See Configuring server setup. 

Regards,
Amanda H.

[GameCodingNinja]

Yep, I've done that but that's not the problem. The changes don't seem to be getting saved to the dongle. Even though I changed the max data length to 60, the BLE code in my 52840 still reports 20 when making a connection to the dongle.

Also, see the attached screen shot above.

//
// BLE connected callback
//
static void connected_cb(struct bt_conn *conn, uint8_t err)
{
    char addr[BT_ADDR_LE_STR_LEN];

    if (err)
    {
        LOG_DBG("Connection failed (err %u)", err);
        return;
    }

    bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    current_conn = bt_conn_ref(conn);

    LOG_INF("Connected %s; Max data length: %u", addr, bt_nus_get_mtu(current_conn));
}

[GameCodingNinja]

Looks like the defaults are already set to the max.
https://github.com/NordicSemiconductor/pc-ble-driver-py/blob/master/pc_ble_driver_py/ble_driver.py#L1776

There's two observes for the data length but they are not being called. I added the observers but my break points are not getting hit. I can't override the function you highlighted. Not sure where this fixed size of 20 bytes is coming from.
github.com/.../observers.py

[Amanda Hsieh]

Hi, 

Maybe you can do a sniffer trace to see if the MTU is actually updated? That should also show if there are other configurations that can cause the limitation. If you could provide the nRF Sniffer log, it could help to investigate the issue. 

-Amanda H.

[GameCodingNinja]

I installed WireShark and downloaded the sniffer. I've never worked with these tools before and the instructions are written for people with experience. I have no clue what I'm even looking at. No clue how your python app works with WireShark.

I'm surprised there's nothing to this effect already built into your "Bluetooth Low Energy" app in nRF Connect for Desktop.

[Amanda Hsieh]

Hi, 

You can follow the guide to Installing the nRF Sniffer and Running the nRF Sniffer. The nRF Sniffer usage doc would show you how to use it.

-Amanda H. 

[GameCodingNinja]

That's what I'm reading and not getting much out of it. I'll try again tomorrow morning.

[Amanda Hsieh]

Hope this tutorial could help. 

[GameCodingNinja]

That tutorial was what I needed but unfortunately, WireShark becomes unresponsive when trying to load the nrf_sniffer interface. I even tried using the previous stable version. Not sure what to do now.

[Amanda Hsieh]

Which DK and HW version are you using to run the nRF Sniffer? If you are using nRF52840 DK v3.0.0, please use the USB port. 

Could you check the steps in Installing the nRF Sniffer capture tool and Adding a Wireshark profile for the nRF Sniffer? 

-Amanda H.

[GameCodingNinja]

Even though I removed the nrf sniffer from the extcap folder, it freezes when the app loads. It's trying to laod an external plugin I deleted. It did the same thing when the external plugin was installed. I've uninstalled WireShark and reinstalled it numerous times. Even deleted the program folder after uninstall. I can't even run the program at this point.

[Amanda Hsieh]

I would suggest to uninstall WireShark, and delet the Wireshark folder under C:\Program Files\Wireshark and C:\Users\YourUserName\AppData\Roaming\Wireshark, and then refer to this guide to install again. 

-Amanda H.