Incorrect link settings to phone and windows pc

RE: Incorrect link settings to phone and windows pc

T IJ — Mon, 20 Jan 2025 10:01:20 GMT

Well after a very long time of debugging and searching possibilities we've finally figured out that our timing is off.

Our min and max connection interval were both set to 8,75ms. Using this between two Nordic microcontrollers worked seamlessly since we were both in control of the central and the peripheral.

The times were set fixed in order to cope with our data throughput.

Connecting to an "OS" we were expecting the same behavior as it worked on our Nordic hardware, but oh boy were we wrong.

We totally missed the part where the OS uses the Bluetooth link to always scan nearby devices and other things. If we would get our 8,75ms + 2120 us time, the OS would have no time to do all the other things.

This is why we only received the 328 us, limiting our bandwith and providing the OS a moment to use the radio for other things.

When we relaxed the connection interval from 8,75-8,75 to 8,75 - 100, we get a maximum of 17040us. I believe the BLE NUS exampled worked but due to Bluetooth caching on the OS it kept the original settings thus always giving us the poor connection bandwidth.

Knowing all this, we've discovered that our device in development phase is unable to offload all data to an OS, thus we have to use a Nodic device to translate Bluetooth to USB.

RE: Incorrect link settings to phone and windows pc

T IJ — Thu, 07 Nov 2024 09:43:35 GMT

I also accept no as an answer if there isnt any

RE: Incorrect link settings to phone and windows pc

T IJ — Mon, 21 Oct 2024 08:08:53 GMT

Can anyone help me with what I am doing wrong here?

RE: Incorrect link settings to phone and windows pc

T IJ — Wed, 16 Oct 2024 11:19:14 GMT

Any information yet?

RE: Incorrect link settings to phone and windows pc

T IJ — Thu, 10 Oct 2024 10:35:29 GMT

Yea, Here is the capture from the nrfConnect SDK. I havent bothered uploading the nrf52 SDK as it was similar to the previous capture I have sent.

devzone.nordicsemi.com/.../sdkConnectBleNus.pcapng

RE: Incorrect link settings to phone and windows pc

Sigurd — Thu, 10 Oct 2024 08:40:13 GMT

Could you upload these 2 sniffer traces ?

RE: Incorrect link settings to phone and windows pc

T IJ — Wed, 09 Oct 2024 13:59:45 GMT

I have tried a nrf connect example from visual code with the Bluetooth uart example and I got this as a response. The top is the length response from the connect sdk (where all is good) and the bottom is from using the nrf52 17.0.2 sdk (where I am having issues with the timing)

Are there major differences between the Bluetooth stack from connect sdk and sdk52?
Our code base is pretty mature and it would be quite the challenge to switch to the connect sdk as no one within our team has any experience with vs code.

RE: Incorrect link settings to phone and windows pc

T IJ — Tue, 08 Oct 2024 12:14:51 GMT

If the LL_LENGTH_RSP for our connection is only limited to 328 us how is it possible that my Stadia controller gets a LL_LENGTH_RSP of 2120 us?

This is the thing that baffles me. Surely there is something different in our way of advertising that causes the host to limit the maximum connection time.

Is there a Nordic BLE example where it is guaranteed to have a connection time longer than 328 us?

RE: Incorrect link settings to phone and windows pc

Sigurd — Tue, 08 Oct 2024 11:06:13 GMT

[quote user="T IJsselmuiden"]So basically there is no way for us to "present us" over Bluetooth to get what we want in timing?[/quote]

You present what values you support in a Data Length Update Procedure(LL_LENGTH_REQ /LL_LENGTH_RSP). Then based on what both sides of the link supports, they will find a common set of what values to use. See e.g. the "How to Enable DLE" chapter in this 3rd party blog post: https://punchthrough.com/maximizing-ble-throughput-part-3-data-length-extension-dle-2/

RE: Incorrect link settings to phone and windows pc

T IJ — Tue, 08 Oct 2024 06:52:14 GMT

So basically there is no way for us to "present us" over Bluetooth to get what we want in timing?
I remember sniffing my Bluetooth headset and Stadia controller and they get the requested data length and timing on both my phone and PC.

RE: Incorrect link settings to phone and windows pc

Sigurd — Mon, 07 Oct 2024 20:47:19 GMT

Hi!

I had a look at the logs. We can't control from the peripheral side what the central supports, so I don't see any ways to change the behavior you are seeing.

RE: Incorrect link settings to phone and windows pc

T IJ — Thu, 03 Oct 2024 06:35:11 GMT

Certainly, here are two captures done one to a pc and one to a phone.devzone.nordicsemi.com/.../BleNUS_5F00_toPc.pcapng devzone.nordicsemi.com/.../BleNUS_5F00_toPhone.pcapng

I hope this helps out

RE: Incorrect link settings to phone and windows pc

Sigurd — Wed, 02 Oct 2024 12:29:46 GMT

Hi!

To investigate this further, please capture sniffer traces for this, so we can see what's happening on-air.

https://www.nordicsemi.com/Products/Development-tools/nrf-sniffer-for-bluetooth-le