multiple nRF52840's USB CDC ACM instances

RE: multiple nRF52840's USB CDC ACM instances

ovrebekk — Wed, 29 Jan 2020 11:26:42 GMT

Hi Rob

Now that MS effectively deprecated W7 it's definitely not a recommended platform ;)

The best of luck with your project 🙂

Best regards
Torbjørn

RE: multiple nRF52840's USB CDC ACM instances

Rob Philip — Tue, 28 Jan 2020 15:12:18 GMT

No problem. W7 is something I use less and less. I'm finding Linux to be more useful as a test platform these days.

Thanks for the example - I'll be able to do good things with it!

RE: multiple nRF52840's USB CDC ACM instances

ovrebekk — Tue, 28 Jan 2020 13:29:13 GMT

Hi Rob

I had a similar question earlier in Devzone, but unfortunately I was unable to find a good way to label the comports.

I have a suspicion it is related to the .inf file in Windows 7, but I haven't been able to confirm it.

"CDC test" is the product string, which you should be able to reference separately from each CDC instance, but we don't have any examples showing how to do this unfortunately (nor have we tested if this would work on Windows 7).

Best regards
Torbjørn

RE: multiple nRF52840's USB CDC ACM instances

Rob Philip — Mon, 27 Jan 2020 19:33:54 GMT

That worked quite well. But it confused Windows 7 a lot - W7 could only assign a driver to one of the CDC ports. W10 and Mac OS did fine, though. I wonder if W7 is confused because both are "CDC Test". Any idea how one would label one of them "CDC Data" and the other "CDC Commands"?

RE: multiple nRF52840's USB CDC ACM instances

Rob Philip — Mon, 27 Jan 2020 16:14:29 GMT

Thank you, good sir.

I will try it today.

RE: multiple nRF52840's USB CDC ACM instances

ovrebekk — Mon, 27 Jan 2020 13:56:17 GMT

Hi Rob

You will find the full example attached:
devzone.nordicsemi.com/.../238013_5F00_usbd_5F00_cdc_5F00_acm_5F00_dual_5F00_cdc.zip

Hopefully you will have more success with it.

Best regards
Torbjørn

RE: multiple nRF52840's USB CDC ACM instances

Rob Philip — Sat, 25 Jan 2020 07:35:06 GMT

Torbjörn:

I grabbed your example main file but alas it did not compile out of the box with the default parameters in the "CLI" demo. I added in app_usbd_serial_num.c and bsp_cli.c and removed "while (app_usbd_event_queue_process())" because first the function wasn't being built and then when I turned on APP_USBD_CONFIG_EVENT_QUEUE_ENABLE I got a compile error indicating

#error "Current CLI CDC implementation supports only USB with event queue disabled (see APP_USBD_CONFIG_EVENT_QUEUE_ENABLE)"

so I modded it not to do that call and do nrf_cli_process instead, for each instance. But alas things did not work properly.

Is there any chance you could zip up and attache complete working project? I would like (although don't *need*) to have two virtual comports between my PC and dongle for some debugging I need to do.

RE: multiple nRF52840's USB CDC ACM instances

ovrebekk — Thu, 31 Oct 2019 08:50:34 GMT

Good to hear you solved the SoftDevice issue.

Regarding the USB serial display name I am starting to think you would have to modify the .inf file in order to set the display name of the CDC interfaces.

On Windows 8 and earlier this is quite straight forward, but on Windows 10 you can not provide an .inf file unless it is tested by Microsoft through the HLK framework.

Which Windows version are you using yourself?

Best regards
Torbjørn

RE: multiple nRF52840's USB CDC ACM instances

OceanS — Tue, 29 Oct 2019 03:23:17 GMT

Hi,

I have got a workaround for the issue that USBD would conflict with Softdevice. I swap to the example under the folder /example/peripheral/usbd_ble_uart and integrated a CLI CDC ACM instance over it. Job done although I still take more time to drill up how this example gets USBD along with Softdevice.

Still in pursuing to modify the USB serial display name.

RE: multiple nRF52840's USB CDC ACM instances

OceanS — Mon, 28 Oct 2019 13:37:13 GMT

Hi,

Thanks for your quick response. Another question, it seems that USBD would not work properly with Softdevice. As you would be able to see in nrf_drv_power.c. Any thought? Thanks.

#ifdef SOFTDEVICE_PRESENT
if (nrf_sdh_is_enabled())
{
return NRF_ERROR_INVALID_STATE;
}
#endif

RE: multiple nRF52840's USB CDC ACM instances

ovrebekk — Fri, 25 Oct 2019 07:41:07 GMT

Good question. I have been digging into the code for a while without finding a way to do this, and the developer didn't know either.

It might be possible to link to a user string in the interface descriptor iInterface field, but I need some more time to try this out. I will try to get back to you on this by Monday next week.

Best regards
Torbjørn

RE: multiple nRF52840's USB CDC ACM instances

OceanS — Wed, 23 Oct 2019 12:08:02 GMT

Hi ovrebekk,

Thanks. Got it. Actually today I also figured it out just like what you are instructing. Anyway appreciate.

Btw, could we let the windows/linux enumerate the virtual com ports with some customised name, but not as below? Because, in my situation, there would be one serial port(device) acting as AT command interface and the other working with CLI&Log. Some bit silly thought, for example, could I have the displaying name as "USB Serial Device_AT (COM10)", "USB Serial Device_CLIandLog(COM9).

RE: multiple nRF52840's USB CDC ACM instances

ovrebekk — Wed, 23 Oct 2019 11:55:32 GMT

Yes, the USBD driver uses a modular structure that allows you to instantiate multiple different classes, the only limitation being the number of IN/OUT endpoints supported by the USBD interface.

I made a quick version of the usbd_cdc_acm example in nRF5 SDK v15.3.0 to demonstrate this, setting up two unique CDC instances, and you will find the main file below:

devzone.nordicsemi.com/.../main.c

Best regards
Torbjørn