USB CDC ACM:uart tx unable to trigger interrupt

RE: USB CDC ACM:uart tx unable to trigger interrupt

Susheel Nuguru — Wed, 04 Oct 2023 11:35:30 GMT

Hi Reskyllr,

Thanks for your patience while I was gone.

It is possible that the current async uarte usage with USB CDC ACM be written in a way that is relying on the rx aswell to complete the first transaction. Maybe you can rewrite the application that the order of initialization and the first transaction does not rely on rx being enabled?

Do you see that his is something specific to how the drivers are handling the initialization?

RE: USB CDC ACM:uart tx unable to trigger interrupt

Reskyllr — Mon, 25 Sep 2023 06:16:35 GMT

Hi, Maria

I have conducted reproducible experiments and read relevant documents, and learned that USB CDC ACM works in interrupt mode by default.
No changes are required, my requirement is to receive data from uart_tx without sending any uart instructions, as long as this can be achieved (so that uart information can be received when our reset starts).

Thanks,

Reskyllr

RE: USB CDC ACM:uart tx unable to trigger interrupt

Maria Gilje — Wed, 20 Sep 2023 15:34:35 GMT

Hi Reskyllr,

I have started to look at this, but I am unsure if I have all the requirements to reproduce.

Have you reproduced on the nRF5340 DK?

Which modifications have you done for the Peripheral UART sample? I assume you build with prj_cdc.conf and adding usb.overlay, but are there others changes?

BR,

Maria

RE: USB CDC ACM:uart tx unable to trigger interrupt

Reskyllr — Thu, 14 Sep 2023 05:49:20 GMT

Hi,

emm,There is one more url above).

https://github.com/nrfconnect/sdk-nrf/tree/main/samples/bluetooth/peripheral_uart

just try it,You just need to run cdc uart in it.

Thanks,

Reskyllr

RE: USB CDC ACM:uart tx unable to trigger interrupt

Susheel Nuguru — Tue, 12 Sep 2023 10:36:41 GMT

Reskylir,

I am not able to access the git repo you linked. It says access is denied.

Can you please fix the access to AryanNordic and give me steps to reproduce this with the USB CDC ACM. I can then try to see what the actual block here is and suggest you something.

RE: USB CDC ACM:uart tx unable to trigger interrupt

Reskyllr — Sat, 09 Sep 2023 03:45:37 GMT

Hi,

Sorry, my English is not very good.
Please refer to this sample (github.com/.../peripheral_uart). There is a uart_async_adapter that converts usb cdc acm to the same API as asynchronous uart.
But it seems that it cannot be separated from the interruption. When my com is open, the tx data does not appear on my terminal. Only if I send a message (uart rx) from the terminal, the tx data can be displayed on the terminal.
But this will not be the case with asynchronous uart. As long as my com is open, the tx data will be output directly.
My purpose is to make USB CDC ACM work like other asynchronous UART.
If you need more information, I can provide relevant test demos.

Thanks,

Reskyllr

RE: USB CDC ACM:uart tx unable to trigger interrupt

Susheel Nuguru — Fri, 08 Sep 2023 10:24:26 GMT

Hi Reskyllr,

I am having a bit of a struggle to understand the below thing you wrote.

[quote user=""]However, cdc acm is interrupted and cannot be used for asynchronous work. I can only store the information that needs to be output in the buffer, and then manually get the initialization information from the console when the terminal rx triggers an interrupt.[/quote]

I do not know what this limitation is. Why do you have to buffer the data before it is sent to the output. Can you show me which API you are using so that I can try to understand the limitations that comes with it.