How to change the communication port from USB to UART in OpenThread CLI sample?

[Yuma]

Hi,

I don't know how do I change port from USB to UART in OpenThread CLI sample.

I'd like to connect to the other board with UART TXD/RXD and the other board sends cli command.
I seem the nRF52840-DK communicates using IMCU_USB in nRF5340.

How can I use any free port as a UART and use that UART port for CLI communication?

Best regards,

Yuma

[Sigurd Hellesvik]

Hi,

Which version of the SDK do you use?

Regards,
Sigurd Hellesvik

[Yuma]

Hi,

The SDK I use is nRF Connect SDK v2.3.0.

[Sigurd Hellesvik]

I don't know how do I change port from USB to UART in OpenThread CLI sample.

The OpenThread CLI sample should use UART by default: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/openthread/cli/README.html#snippets.

Which USB do you refer to? (On the nRF52840DK)

How can I use any free port as a UART and use that UART port for CLI communication?

I suggest that you see https://academy.nordicsemi.com/courses/nrf-connect-sdk-fundamentals/, and learn how to use the DeviceTree and pinctrl. I think those are what you need.

[Yuma]

I got a new understanding from what you're saying and the schematic.

- OpenThread CLI sample uses UART.
- The UART used in the sample is "nRF52_UART" of nRF52840, and it communicates with the PC via the USB connector (J2) through VCOM of nRF5340.
- When the board directly communicates with another device using the RX pin and TX pin of "nRF52_UART", it can connect by wiring from the P0.06/P0.08 pin header by turning SW11 OFF.

Is there any mistake in the above understanding?

[Sigurd Hellesvik]

Yuma said:

- When the board directly communicates with another device using the RX pin and TX pin of "nRF52_UART", it can connect by wiring from the P0.06/P0.08 pin header by turning SW11 OFF.

Correct.

Yuma said:

- When the board directly communicates with another device using the RX pin and TX pin of "nRF52_UART", it can connect by wiring from the P0.06/P0.08 pin header by turning SW11 OFF.

Yep.

Yuma said:

- When the board directly communicates with another device using the RX pin and TX pin of "nRF52_UART", it can connect by wiring from the P0.06/P0.08 pin header by turning SW11 OFF.

SW11 only turns of flow control.

You can still connect P0.06 and 0.08 to something even when the Interface MCU is connected.
The cleaner method for getting UART to pins would be to re-route the UART to some other pins in your software for the developement nRF, using pinctrl.