Multiple UARTs on nRF5340

[chris_h]

Hi, I wonder if I can get some assistance on an issue I'm having implementing multiple UARTs on my nRF5340 (using the nRF7002DK)?

The Product Specification notes the nRF5340 supports 4 UART's.  I would like to use uart0 for logging, and then uart1 and uart2 as additional UARTs.  I have altered the devicetree to enable all 3 uarts and repurpose DK pins for their use.  What I am struggling with is how to configure this in the prj.conf file. I have already got UART1 working.  The project compiles and the UART messages work as intended on the assigned pins.  I used the following configuration for it to function:

CONFIG_UART_ASYNC_API=y
CONFIG_UART_1_ASYNC=y
CONFIG_UART_1_INTERRUPT_DRIVEN=n
CONFIG_UART_1_NRF_HW_ASYNC=y
CONFIG_UART_1_NRF_HW_ASYNC_TIMER=2
CONFIG_NRFX_TIMER2=y
CONFIG_RESET_ON_FATAL_ERROR=n

However if I add corresponding UART_2 configs, my compiler flags a warning "CONFIG_UART_2_ASYNC was assigned the value y, but got the value n. Missing dependencies: UART_2_NRF_UARTE".  So the below configs do not work

CONFIG_UART_2_ASYNC=y
CONFIG_UART_2_INTERRUPT_DRIVEN=n
CONFIG_UART_2_NRF_HW_ASYNC=y
CONFIG_UART_2_NRF_HW_ASYNC_TIMER=2

Can you please help me find where I am going wrong?  What would be the correct way to enable the uart2?

Chris

[Jared]

Hi,

You're using nRF Connect SDK v.2.5.0 right?

Could you share your project config and devicetree, overlay too if you use it.

regards

Jared 

[chris_h]

Hi Jared,

Thank you for responding.  Yes I am using nRF Connect SDK 2.5.0.  I've attached the requested files. 

Just for clarity on what I'm trying to achieve with the UART's:

• UART0: Debug/logging. Enabled for development, disabled for production
• UART1: Standard UART for comms with another MCU
• UART2: Standard UART for comms with a different MCU

I am able to use both UART0 and UART1 successfully using the custom selected DK pins. I am just unsure of how to set up UART2 so it doesn't flag warnings of missing configuration parameters.  Those config parameters are under the comment "# UART2" in the prj.conf file

3223.prj.conf

4380.nrf7002dk_nrf5340_cpuapp.overlay

Regards,

Chris

[ovrebekk]

Hi Chris

Jared is currently unavailable, and I will help you out in the mean time. 

Where exactly do yo see these warnings? 

I tried to apply your configuration to one of the standard Wi-Fi samples, and while I see some warnings in the editor when reviewing the prj.conf file I don't see any warnings in the build output. 

In the editor I see complaints regarding HAS_HW_NRF_UARTE1 and HAS_HW_NRF_UARTE2 missing, but double checking the .config file in the build/zephyr folder I can see that both of these configurations are included. 

Is this the same issue you are seeing, or is it something else? 

Best regards
Torbjørn

[chris_h]

Hi Torbjørn,

Apologies for the delayed response.  I am seeing the messages in the debug terminal - yes it looks to be the same issue.

I have since used the uart configs from the "connectivity bridge test" sample firmware and that seems to work well - I no longer get the warnings.   Appreciate your help!

[ovrebekk]

Thanks for the update, I will close the ticket then.