Suggestion USB CDC or CLI ?

RE: Suggestion USB CDC or CLI ?

Vipul_Saini — Fri, 27 Sep 2019 09:54:05 GMT

Hey awneil, I have this similar question.

Thing is, I want to communicate my nrf52840 to PC through USB. Can you suggest some mechanism to access the USB receive buffer in main() in this example: https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.3.0/usbd_cdc_acm_example.html?cp=5_1_4_6_50_3.

The end goal is to make 2 functions that could be used in main() to read and write data to a USB host through virtual serial com port.

Thanks

RE: Suggestion USB CDC or CLI ?

awneil — Fri, 27 Sep 2019 09:32:05 GMT

[quote userid="6462" url="~/f/nordic-q-a/52650/suggestion-usb-cdc-or-cli/212222"]The wise choice would have been to have an accessible UART![/quote]

See this thread for a whole load of suggestions on debug facilities to include in a design:

https://www.avrfreaks.net/forum/how-do-i-check-life-signs-scope-atmega2560-standalone

"A key consideration of your design from the outset should be, 'how will I debug this?' "

RE: Suggestion USB CDC or CLI ?

awneil — Fri, 27 Sep 2019 09:19:33 GMT

[quote userid="82168" url="~/f/nordic-q-a/52650/suggestion-usb-cdc-or-cli/212213"]I mean that in my custom board I don't have UART Pins[/quote]

The UART can be assigned to any pins.

As a standard design practice, always have a UART accessible - it is invaluable for debug!

[quote userid="82168" url="~/f/nordic-q-a/52650/suggestion-usb-cdc-or-cli/212213"]so I can't use a debugger to communicate with it through nrf log[/quote]

Not true - you can use RTT instead.

infocenter.nordicsemi.com/.../communicate.html

[quote userid="82168" url="~/f/nordic-q-a/52650/suggestion-usb-cdc-or-cli/212213"]should I use basic USB CDC and create some functions of my own or I should build on top of CLI[/quote]

That's really a design decision that only you can make in the light of your particular requirements, resources, and constraints.

Nobody else knows your particular requirements, resources, and constraints.

[quote userid="82168" url="~/f/nordic-q-a/52650/suggestion-usb-cdc-or-cli/212213"]Which is a wiser choice[/quote]

The wise choice would have been to have an accessible UART!

😉

RE: Suggestion USB CDC or CLI ?

shockline — Fri, 27 Sep 2019 09:01:54 GMT

I am sorry if I didn't make it more clearer.

[quote userid="6462" url="~/f/nordic-q-a/52650/suggestion-usb-cdc-or-cli/212134"]What do you mean by that?[/quote]

I mean that in my custom board I don't have UART Pins so I can't use a debugger to communicate with it through nrf log.

I know CLI uses USB CDC as an underlying transport but I was asking should I use basic USB CDC and create some functions of my own or I should build on top of CLI. Which is a wiser choice ?

RE: Suggestion USB CDC or CLI ?

awneil — Thu, 26 Sep 2019 19:46:11 GMT

[quote userid="82168" url="~/f/nordic-q-a/52650/suggestion-usb-cdc-or-cli"]My custom board doesn't have UART[/quote]

What do you mean by that?

The UART is part of the chip - your board can't remove it!

[quote userid="82168" url="~/f/nordic-q-a/52650/suggestion-usb-cdc-or-cli"]should I implement a something of my own based on USB CDC Example or should I use Command Line Interface[/quote]

That's not an either/or choice!

The USB CDC is just a transport - so you will also need either the CLI or some other "handler" for the application comms ...