Dynamically enable and disable cdc_acm_uart* devices (instances) on USB connection

RE: Dynamically enable and disable cdc_acm_uart* devices (instances) on USB connection

Jørgen Holmefjord — Fri, 23 Feb 2024 14:59:53 GMT

Hi,

[quote user="puz_md"]By the way, is there a feature where I can upload confidential code? Or can it be seen by everybody?[/quote]

I can convert the ticket to private, then the information is only visible to you, Nordic, and selected distributor.

[quote user="puz_md"]Concerning the "USB_DEVICE_STACK_NEXT", can you tell me in which development state it is? Is it stable? Would you advise switching over to the new stack completely for an industrial product?[/quote]

The new stack is experimental and should not be used in a production firmware at this point. You can use it to explore new features, but it should not be used in production until it is taken out of experimental state.

[quote user="puz_md"]If I understand correctly, with the STACK_NEXT, everything USB-related must be configured in my own code, so no use of prj.conf directives and auto-configuration in the background seems to be possible. Can I access the old configuration values from prj.conf, like device ID or seller name, from my code for the STACK_NEXT? Do you suggest keeping USB related configuration and values in prj.conf, or place it somewhere differently in the code?[/quote]

This will likely change if/when the new stack is in production state and replace the old stack.

[quote user="puz_md"]I think I've seen a USB configuration structure in one of the samples using NEXT_STACK, probably it is related to this one. I have to check again, as I didn't see at first glimpse any configuration number being handled in the code at configuration registration time.[/quote]

All examples I have seen in nRF Connect SDK/Zephyr use 1 for this parameter.

Best regards,
Jørgen

RE: Dynamically enable and disable cdc_acm_uart* devices (instances) on USB connection

puz_md — Wed, 21 Feb 2024 18:29:39 GMT

Hi Jørgen,

thanks a lot for your reply.

[quote userid="14926" url="~/f/nordic-q-a/108138/dynamically-enable-and-disable-cdc_acm_uart-devices-instances-on-usb-connection/469853"]Can you share your project used for testing this?[/quote]

This might be a bit tricky at the moment, I cannot send the whole project because of confidentiality. I have considered reducing my project to the basic framework that shows the problem, but I am very busy with deadlines the coming days... maybe I can find some time in two weeks or so. By the way, is there a feature where I can upload confidential code? Or can it be seen by everybody?

Concerning the "USB_DEVICE_STACK_NEXT", can you tell me in which development state it is? Is it stable? Would you advise switching over to the new stack completely for an industrial product?

If I understand correctly, with the STACK_NEXT, everything USB-related must be configured in my own code, so no use of prj.conf directives and auto-configuration in the background seems to be possible. Can I access the old configuration values from prj.conf, like device ID or seller name, from my code for the STACK_NEXT? Do you suggest keeping USB related configuration and values in prj.conf, or place it somewhere differently in the code?

[quote userid="14926" url="~/f/nordic-q-a/108138/dynamically-enable-and-disable-cdc_acm_uart-devices-instances-on-usb-connection/469853"]bConfigurationValue is described in the USB specifications. This corresponds to the number of the configuration you want to use.[/quote]

I think I've seen a USB configuration structure in one of the samples using NEXT_STACK, probably it is related to this one. I have to check again, as I didn't see at first glimpse any configuration number being handled in the code at configuration registration time.

Best regards,

Michael

RE: Dynamically enable and disable cdc_acm_uart* devices (instances) on USB connection

Jørgen Holmefjord — Tue, 20 Feb 2024 15:12:59 GMT

Hi Michael,

Can you share your project used for testing this?

[quote user="puz_md"]I have some trouble getting the USB contect for the reister/unregister functions, as the sample code seems to require the CONFIG_USB_DEVICE_STACK_NEXT=y option. If I add this option, I get a compile error: gen_isr_tables.py: error: multiple registrations at table_index 55 for irq 55 (0x37).[/quote]

Sounds like both the old and the new USB stack is being included in the project.

[quote user="puz_md"]If I don't use STACK_NEXT, but try to use the macro USBD_DEVICE_DEFINE() like in the example code, I get the following compile error: [...]ld.bfd.exe: app/libapp.a(main.c.obj):(._usbd_contex.static.my_usbd_+0x18): undefined reference to `__device_dts_ord_115'[/quote]

This macro is not available in the old stack API.

[quote user="puz_md"]Is there a way to access/retrieve the "USB device support runtime context" (first parameter of the usbd_[un]register_class() function) when it is defined by the normal system stack?[/quote]

I do not think there is any API to get this, would likely require changing the library sources.

[quote user="puz_md"]And what is the cfg parameter of the usbd_[un]register_class() functions used for? I don't understand what the "(similar to bConfigurationValue)" description means, either... is it a boolean value? What does it affect?[/quote]

bConfigurationValue is described in the USB specifications. This corresponds to the number of the configuration you want to use.

Best regards,
Jørgen

RE: Dynamically enable and disable cdc_acm_uart* devices (instances) on USB connection

puz_md — Tue, 13 Feb 2024 15:39:45 GMT

Hi Jørgen,

I have some trouble getting the USB contect for the reister/unregister functions, as the sample code seems to require the CONFIG_USB_DEVICE_STACK_NEXT=y option. If I add this option, I get a compile error: gen_isr_tables.py: error: multiple registrations at table_index 55 for irq 55 (0x37). I'm currently using the #CONFIG_USB_DEVICE_INITIALIZE_AT_BOOT=y option, but even if I disable it, I still get the irq related link error with STACK_NEXT.

If I don't use STACK_NEXT, but try to use the macro USBD_DEVICE_DEFINE() like in the example code, I get the following compile error: [...]ld.bfd.exe: app/libapp.a(main.c.obj):(._usbd_contex.static.my_usbd_+0x18): undefined reference to `__device_dts_ord_115'

Is there a way to access/retrieve the "USB device support runtime context" (first parameter of the usbd_[un]register_class() function) when it is defined by the normal system stack?

And what is the cfg parameter of the usbd_[un]register_class() functions used for? I don't understand what the "(similar to bConfigurationValue)" description means, either... is it a boolean value? What does it affect?

Best regards,

Michael

RE: Dynamically enable and disable cdc_acm_uart* devices (instances) on USB connection

Jørgen Holmefjord — Thu, 08 Feb 2024 15:16:00 GMT

Hi,

You might use the usbd_register_class() and usbd_unregister_class() APIs to achieve this, but these APIs can only be used when the USB device stack is disabled.

See the USB CDC ACM sample on how the usbd_register_class API is used to register the cdc_acm instance.

Best regards,
Jørgen