Suggestion USB CDC or CLI ?

[shockline]

I am developing a product and there is this situation. My custom board doesn't have UART so I will have to communicate over a Virtual Serial COM Port.

I have a desktop app that sends a challenge (sort of a number) and I need nRF52840 to give a response corresponding to the challenge sent over a serial port.

My question is should I implement a something of my own based on USB CDC Example or should I use Command Line Interface ?

Note that a certain button is first pressed on nRF52840 then it enters this challenge and response mode.

[awneil]

shockline said:

My custom board doesn't have UART

What do you mean by that?

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

shockline said:

should I implement a something of my own based on USB CDC Example or should I use Command Line Interface

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 ...

[shockline]

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

awneil said:

What do you mean by that?

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 ?

[awneil]

shockline said:

I mean that in my custom board I don't have UART Pins

The UART can be assigned to any pins.

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

shockline said:

so I can't use a debugger to communicate with it through nrf log

Not true - you can use RTT instead.

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

shockline said:

should I use basic USB CDC and create some functions of my own or I should build on top of CLI

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.

shockline said:

Which is a wiser choice

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

[awneil]

awneil said:

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

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?' "

[Vipul_Saini]

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