nrf52832 talks to a laptop running v4.2 BT, but not v5

RE: nrf52832 talks to a laptop running v4.2 BT, but not v5

DiBosco — Fri, 19 Jul 2019 09:48:26 GMT

OK, amazingly, we've just had a visitor who has a One Plus 6 phone which has BT5.0 and it works OK. So the problem must lay with Qt.

Many thanks for all the suggestions and help.

RE: nrf52832 talks to a laptop running v4.2 BT, but not v5

DiBosco — Fri, 19 Jul 2019 09:34:20 GMT

Hi and thanks for the reply.

I'm not sure I have worded my question very well really. The nrf works just fine talking to BT4.x computers, so it's not so much backwards compatibility as forwards compatibility. Maybe.

So, I would stress that the nrf talks to computers [and phones] with BT4.2, it's 5.0 that causes problems. So, what I am wondering is whether there is something in the nrf firmware I have to change so that it will talk "properly" to 5.0 devices. Once that is done, I am getting what you're saying that it will then also talk to 4.x devices.

I did kind of suss, eventually, that you needed to have an nrf kit connected to the computer running the nrf Connect to Desktop, but that still didn't seem to do anything as it wouldn't connect to my devkit. Even if it would I am not really sure i's going to help with my issue.

On top of that when I have SES running on the new laptop it crashes. Over and over and over again. To the extent it's unusable - both v4.16 and 4.18 - so I'm having to run SES on my old laptop. I feel like Rick Wakeman with all these keyboards ;-)

So, in summary: nrf device talks to computers with BT4.x. I can sent files using my custom characteristic and all services and characteristics are visible, available and correct.

I connect to this BT5.0 laptop and my Qt program only sees two services not three, and when I connect to my custom service the two custom characteristics' handles are wrong.

Sorry if you already understood that. I fully appreciate that the problem could lay with my Qt program but as things stand I just have no way of proving that. No-one in work has anything else BT5.0, not even a phone. :-/

Many thanks and again sorry if I'm just repeating what you understand!

RE: nrf52832 talks to a laptop running v4.2 BT, but not v5

haakonsh — Fri, 19 Jul 2019 08:24:48 GMT

All BLE 5.0 devices are backwards compatible with 4.2 devices.

When a BLE link is established the central and peripheral devices will query each other with a Feature Request. Each device will then tell the other device exactly what part of the BLE spec it is capable of adhering to, f.ex. 2mbps PHY or Extended MTUs.
Our SoftDevices will then make sure not to use a feature that is not supported by both ends of the link.
This leads me to believe that the issue is in the LG device or the Qt program.

The BLE program in nRF Connect For Desktop requires an nRF52DK attached to the computer to act as a BLE modem, as I understand it you want to use the native BT+wifi multi-modem of your PC and in that case, nRF Connect is not really suited.

I do suggest you capture a sniffer trace of your BLE communication as this will help immensely in debugging BLE problems like this.
See nRF Sniffer User Guide v2.1.

RE: nrf52832 talks to a laptop running v4.2 BT, but not v5

DiBosco — Thu, 18 Jul 2019 16:30:37 GMT

Yeah, Linux actually plays much nicer than Windows with LE.

I'd never come across this method of installing before, but it's cool. You just need to make it executable and it, er, executes.

Program installs but does bot all unfortunately. Hit start scan and nothing happens.

My Qt program works a lot better than this one, it sees my nrf device and connects, it just doesn't see all the services. I'm still not sure whether I'm running true LE5 software on the nrf or not. That's the big question to start with. It could be an issue with the Qt program with some slight difference between LE4.2 and 5.

Thanks for the replies and help, much appreciated.

RE: nrf52832 talks to a laptop running v4.2 BT, but not v5

awneil — Thu, 18 Jul 2019 16:15:48 GMT

You're on Linux? I have no idea about that!

On Windows, you just install it in the normal way.

RE: nrf52832 talks to a laptop running v4.2 BT, but not v5

DiBosco — Thu, 18 Jul 2019 16:08:41 GMT

I didn't even know this existed. I've been Googling LE scanner for Linux and got nowt, so many thanks for that!

Am about to try it. :)

RE: nrf52832 talks to a laptop running v4.2 BT, but not v5

awneil — Thu, 18 Jul 2019 15:53:02 GMT

Yes, BLE 5 should be backwards-compatible with 4.

Does the nRF Connect Desktop work correctly on this new computer?