How to use both uart0 and uart1 on nrf5340

RE: How to use both uart0 and uart1 on nrf5340

Hung Bui — Tue, 13 May 2025 11:16:01 GMT

Hi Mary,

[quote user=""]I get this message: UART_RX_BUF_REQUEST event, but not the error. I have also tried to pass another buffer but it keeps sending that message.[/quote]

Could you explain this a little bit more ? As far as I know having UART_RX_BUF_REQUEST is normal as you need to provide the UART library buffer.

How do you use UART0 , is it ASYNC or INTERRUPT_DRIVEN ?

Please give more info about your application.

RE: How to use both uart0 and uart1 on nrf5340

Marika Di Martino — Fri, 09 May 2025 10:39:49 GMT

It is also disabled in zephyr.dts. I can see the message sent through uart1 using uart_poll_out, but when I try to send an input message, it is not sent.

RE: How to use both uart0 and uart1 on nrf5340

Turbo J — Fri, 09 May 2025 10:11:45 GMT

Check the generated DTS (build/zephyr directory). There might be a default gpio forwarding active..

RE: How to use both uart0 and uart1 on nrf5340

Marika Di Martino — Fri, 09 May 2025 10:07:05 GMT

Thank you. I have disabled gpio_fwd, but uart1 is still not working. Any ideas?

RE: How to use both uart0 and uart1 on nrf5340

Turbo J — Fri, 09 May 2025 09:58:27 GMT

That DTS overlay forwards the P1.0 and P1.1 pins to the network coprocessor.

Those cannot be controlled by the application processor peripherial unless you disable/change that forwarding in gpio_fwd section.