Using uart0 and uart1 in the app cpu with BT enabled on the nrf5340dk?

RE: Using uart0 and uart1 in the app cpu with BT enabled on the nrf5340dk?

Kazi Afroza Sultana — Fri, 25 Aug 2023 12:13:01 GMT

Hello Daniel,

I have been looking into your queries. I think your DK version is V1. If this swapping is for nRF5340 DK, it could be possible what you are asking about. Do you want to swap the COM port during runtime or in different build? I think it is on different build time.

[quote user="danielhira"]Is there a way to use the "The second (middle) COM routed to the P24 connector" to communicate with the application core without external wiring?[/quote]

We think in this case, you need external wire.

[quote user="danielhira"]Alternatively, is there a way to re-map the pins such that gpio_fwd is able to use other GPIO pins instead of the UART ones, and if so could you please give an example of how to do this?[/quote]

You can use overlay to change this:

You could set status = ''disabled'' or change the pins that are forwarded to the network core in an overlay.

''Lastly, or also alternatively, is there a way to remap the pins to change "The first COM port outputs the log from the network core (if available)." such that it also outputs logs from the app cpu? If this is possible, could you please provide an example of how to do this?''

It is not possible as network core and application core has their different instances. These instances can not share the pins.

RE: Using uart0 and uart1 in the app cpu with BT enabled on the nrf5340dk?

danielhira — Tue, 22 Aug 2023 20:36:55 GMT

Hi Kazi,

Thank you for the response. A few followup questions:

Is there a way to use the "The second (middle) COM routed to the P24 connector" to communicate with the application core without external wiring? (I see https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/device_guides/working_with_nrf/nrf53/nrf5340.html#nrf5340-dk-v1-0-0-com-ports mentioning adding wiring)
- If external wiring is required, what would be the best way to route those back to the app cpu? If pin mapping is required, could you share an example overlay for accomplishing this?
Alternatively, is there a way to re-map the pins such that gpio_fwd is able to use other GPIO pins instead of the UART ones, and if so could you please give an example of how to do this?
Lastly, or also alternatively, is there a way to remap the pins to change "The first COM port outputs the log from the network core (if available)." such that it also outputs logs from the app cpu? If this is possible, could you please provide an example of how to do this?

Thank you,

-Daniel

RE: Using uart0 and uart1 in the app cpu with BT enabled on the nrf5340dk?

Kazi Afroza Sultana — Tue, 22 Aug 2023 13:54:46 GMT

Hello,

When connected to a computer, the nRF5340 DK v1.0.0 emulates three virtual COM ports (https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/device_guides/working_with_nrf/nrf53/nrf5340.html#id40). In the default configuration, they are set up as follows:

The first COM port outputs the log from the network core (if available).
The second (middle) COM port is routed to the P24 connector of the nRF5340 DK.
The third (last) COM port outputs the log from the application core.

Probably one of this COM port is used by network core when you add CONFIG_BT = y.

You can see here https://github.com/nrfconnect/sdk-zephyr/blob/2119df306f5c9104d479f96c4c8af00857094f83/boards/arm/nrf5340dk_nrf5340/nrf5340_cpuapp_common.dtsi#L108 how this is forwarded to network core.

Thanks.

Kazi