CDC COM Port Stops Working Without J-Link RTT Viewer on Custom nRF52840 Board

RE: CDC COM Port Stops Working Without J-Link RTT Viewer on Custom nRF52840 Board

manoj_patil — Sat, 18 Jan 2025 09:30:28 GMT

I got my solution by using the following prj.conf configurations:

# CONFIG_CLOCK_CONTROL_NRF_K32SRC_SYNTH=y
# OR
CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=y
# CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n
# OR
CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=n
CONFIG_BOARD_ENABLE_DCDC=n

CONFIG_SERIAL=y
CONFIG_CONSOLE=y
CONFIG_UART_CONSOLE=y
CONFIG_UART_LINE_CTRL=n

These settings worked for me. Thank you for supporting.

RE: CDC COM Port Stops Working Without J-Link RTT Viewer on Custom nRF52840 Board

Einar Thorsrud — Thu, 16 Jan 2025 11:44:47 GMT

Hi,

I think you can ignore my comment about configuring VDDH. As long as VDDH is shorted to VDD, andy VDDH related config should be irrelevant. But it could be worth making sure BOARD_ENABLE_DCDC_HV is not enabled (for instance by explicity setting CONFIG_BOARD_ENABLE_DCDC_HV=n. If that does not help, we should look at other potential causes of this issue.

RE: CDC COM Port Stops Working Without J-Link RTT Viewer on Custom nRF52840 Board

manoj_patil — Thu, 16 Jan 2025 05:18:20 GMT

We have checked all the peripherals and the application, and they are running well. However, we are still facing the same problem as before. Could you guide us on how to enable VDDH in NCS v2.6.1?

RE: CDC COM Port Stops Working Without J-Link RTT Viewer on Custom nRF52840 Board

Einar Thorsrud — Tue, 14 Jan 2025 15:02:23 GMT

Hi,

Is it only USB CDC that does not work when not debugging, or does the device not seem to be oprrating at all? (for instance, if you toggle the LED in the application, do you see it toggling)? If debugging is needed in order to run the application, is it worth checking that you have not enabled VDDH in the board files. Also, consider disabling the RTT console / shell backend.

Also, which SDK version are you using, and is it this console sample you are refering to, or another?