Changing pin configuration of Net Core

[aarondashine]

I have an application where I need to use GPIO 1.1 as an SPI pin on the APP core and also use BLE. I ahve configured my project to include BLE however this causes the NET core to take over pin 1.1 for UART0. I have tried to add an overlay file into my project root for the net core to disable UART0 but the build is not picking up the overlay. Can you please confirm the following:

1. Where do i need to put the overlay file? Root directory of project? In a child image folder?
2. How do i configure the project to use the overlay for the net core? Do i need to change the build command?
3. The file is currently called nrf5340dk_nrf5340_cpunet.overlay, is this correct?

Thank you for your help. 

[Sigurd]

Hi!

It's the device-tree nrf-gpio-forwarder node that is used to set which pins will be forwarded to the network core. https://docs.zephyrproject.org/latest/build/dts/api/bindings/gpio/nordic,nrf-gpio-forwarder.html

It's used for the nRF5340DK here: https://github.com/nrfconnect/sdk-zephyr/blob/v3.4.99-ncs1/boards/arm/nrf5340dk_nrf5340/nrf5340_cpuapp_common.dtsi#L113

By default, all pins are assigned to the application core. The app-core controls the allocation of the pins.

Where do i need to put the overlay file? Root directory of project? In a child image folder?

Put it your_app/boards/ folder

Name the file nrf5340dk_nrf5340_cpuapp.overlay , and the content of the file like shown below:

&gpio_fwd {
	status = "disabled";
};

This will disable the pin forwarding to the network core.