Hi Martinj,

This Zephyr example does UART over GPIO:
https://github.com/NXPmicro/zephyr/tree/soft_periph/samples/soft_periph

Here's a picture with the system overview:
https://www.zephyrproject.org/elc-openiot-nxp-demo/

However it receives the data to send via RPMsg from a second core running Linux and vice versa.
It could be possible to remove the RPMsg related part and rewrite the code into a driver and select that peripheral as a debug console in board's DTS file.
The code requires a hardware timer and supports just 8N1 format.

Best regards,
Stana