UART Communication with NRF52840 Xiao Ble

[MrsIoT]

Hello,

I need assistance with establishing communication between two microcontrollers using UART. Specifically, I am using the NRF52840-based XIAO microcontroller. My goal is to send data to the other microcontroller via the RX/TX pins.

I attempted to achieve this using the NRF Connect SDK and Zephyr, following the instructions provided in this link: academy.nordicsemi.com/.../. Unfortunately, I was unable to obtain the desired outcome.

Could you please suggest a solution to this issue? Is it possible to utilize the XIAO for this purpose? Additionally, I would like to know if it is feasible to control the XIAO's individual GPIOs. I would greatly appreciate your guidance and recommendations on what steps should be taken.

Thank you kindly for your assistance.

Best regards

[Jared]

Hi,

Any XIAO specific questions needs to be directed to the creators of that module, I'm not that familiar with that module but I don't see any issues with communicating over UART as long as the pins that you're using has been routed out on the board and is not already used by something else. Could you explain in more detail what exactly you have tried and what you observe? Do you see any activity on the UART lines? 

regards

Jared 

[MrsIoT]

I'm using openthread to receive UDP packets on the Xiao and want to pass the received message to the host MCU through UART. Similarly, I want to receive UART messages from the host MCU and send them via UDP. 

I have tried simply sending a hello world message to the host MCU but the message is not received. The tx and rx pins are indeed mapped out on the physical board as shown below.

Could the issue be because I'm using openthread? Can I map the tx pin to some other pin using the zephyr device tree or proj.conf file? 

This should be simple, but doesn't seem to work. 

[Jared]

Hi,

I think it would be much easier to debug this if you started with a simpler application. Can you for instance run the Zephyr UART driver sample successfully on your board?

regards

Jared