nRF52840DK enabling only serial print using USB CDC_ACM

[nagesh.shamnur]

Dear support,

    I am using nRF52840DK board (PCA10056) with SDK version: 17.0.2 version. I am trying out the USB CDC_ACM sample application from the path: <SDK_PATH>/examples/peripheral/usbd_cdc_acm/ . 

   By running the sample as it is, i am able to get the cli prompt on minicom port (ttyACM0) and cli is behaving as expected. However the print in the sample code which prints the message "Hello USB CDC FA demo:" using the interface app_usbd_cdc_acm_write( ) is not be found on minicom serial port. 

Also in the config file <SDK_PATH>/examples/peripheral/usbd_cdc_acm/pca10056/blank/config/sdk_config.h i have disabled CLI (#define NRF_CLI_ENABLED 0) just to get the sample message present in the code which is output using the interface app_usbd_cdc_acm_write( ). So, when i connect the board to either of the USB Port (uart port or usb port) on the board, there are no prints at all. How to get this print displayed on the screen?

 

Basically i am trying to enable USB CDC_ACM driver for my custom application, so that any formatted output from my application gets displayed on my host machine (via minicom/screen) connected via USB cable to board.

Thanks!

Nagesh

[Kenneth]

Hello,

I recommend to connect both USB ports at the same time:

- left USB port: programming and debugging through j-link (SWD), also debugging over serial port, power to nRF52840 is supplied here (switch state: DEFAULT)
- bottom USB port: this is the USB interface of the nRF52840, power can be supplied here (switch state: nRF Only)

Also see documentation for the usbs_cdc_acm example:
https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/usbd_cdc_acm_example.html 

Best regards,
Kenneth

[nagesh.shamnur]

Hi Kenneth,

   Thanks for the reply. I tried again which i am detailing below again for reference. Inspite of this, i am not getting any display on my terminal emulator (minicom)

1) put SW9 switch to default(VDD)

2) connect the PCA10056 board to my ubuntu laptop via USB Connector board (J2)

3) disable CLI in the config file <SDK_PATH>/examples/peripheral/usbd_cdc_acm/pca10056/blank/config/sdk_config.h (#define NRF_CLI_ENABLED 0)

4) Build and flash the image onto board.

5) Now connected one more usb via nRF USB port on board to my laptop via another USB cable

6) Now change nRF only Mode switch to nRF only.

7) run minicom via connected port.

    Since CLI is disabled, no CLI prompt is displayed on the screen and at the same no logs such as  "Hello USB CDC FA demo:" are also not displayed on minicom.

Let me know if i am missing something here. 

Thanks!

[Kenneth]

Have you followed these settings for the terminal window?
https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/lib_cli.html#lib_cli_terminal_settings_uart 

I am using tera term for my testing.

The "Hello USB CDC FA demo: xxxxx" will only be printed while BUTTON_1 is pressed.

Kenneth

[nagesh.shamnur]

Hi Kenneth,

   Thanks for the quick reply. I just realized that the print is coming on pressing button_1 as suggested by you. 

Now my question is, there there a way to remove this limitation and get the print all the time on the terminal, if so, then can you guide me on how to achieve it.

Thanks!

[nagesh.shamnur]

Hi Kenneth,

   Is there a way to achieve this?

[Kenneth]

Honestly speaking you should be able to figure this out by looking at the code.

Kenneth