Recommended approach for radio_test-like firmware on custom nRF52840 board

[Venu Madhav Murapaka]

We are working with a custom nRF52840 PCB and would like guidance on the correct and supported way to build a firmware equivalent to the radio_test sample on the nRF52840 DK, specifically for RF testing with command-based control (TX/RX/carrier/sweep).

On the DK, radio_test works out of the box via UART/USB, but on custom hardware we are running into multiple dependencies and assumptions that make radio_test difficult to reuse reliably.

Before continuing further, we would like to clarify:

1. Is radio_test_sample intended to be reused on custom boards, or is it DK-specific?

2. If not, what is the Nordic-recommended and supported approach for creating a radio_test hex firmware for a custom nRF52840 pcb design.

3. We also would like to have UART serial commands access where we can pass commands like: parameters_print, start)tx_sweep etc......ALL in a custom PCB

   
   
   We are happy to share the PCB schematic and pin mappings if required. We are mainly looking for direction on the correct approach, rather than ad-hoc fixes.

Any guidance from the Nordic team would be greatly appreciated.

[Håkon Alseth]

Hi,

 

Is radio_test_sample intended to be reused on custom boards, or is it DK-specific?

Yes, you can use this on any custom nRF5x design.

• If not, what is the Nordic-recommended and supported approach for creating a radio_test hex firmware for a custom nRF52840 pcb design.

• We also would like to have UART serial commands access where we can pass commands like: parameters_print, start)tx_sweep etc......ALL in a custom PCB

You will need to setup the pins to your desired GPIOs, as well as any other hardware related configuration specific to your board.

Typical things:

* DCDC present? If not, add this to your board overlay:

&reg1 {
	regulator-initial-mode = <NRF5X_REG_MODE_LDO>;
};

 

* external 32.768 kHz xtal present? If not, enable internal 32k RC oscillator:

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

 

And here is a example overlay for uart0. Feel free to take this and change as desired:

&pinctrl {
	uart0_default_alt: uart0_default_alt {
		group1 {
			psels = <NRF_PSEL(UART_TX, 1, 1)>,
				<NRF_PSEL(UART_RX, 1, 2)>,
				<NRF_PSEL(UART_RTS, 1, 3)>,
				<NRF_PSEL(UART_CTS, 1, 4)>;
		};
	};

	uart0_sleep_alt: uart0_sleep_alt {
		group1 {
			psels = <NRF_PSEL(UART_TX, 1, 1)>,
				<NRF_PSEL(UART_RX, 1, 2)>,
				<NRF_PSEL(UART_RTS, 1, 3)>,
				<NRF_PSEL(UART_CTS, 1, 4)>;
			low-power-enable;
		};
	};
};


&uart0 {
	compatible = "nordic,nrf-uarte";
	current-speed = <115200>;
	status = "okay";
	pinctrl-0 = <&uart0_default_alt>;
	pinctrl-1 = <&uart0_sleep_alt>;
	pinctrl-names = "default", "sleep";
};

 

Kind regards,

Håkon

[Venu Madhav Murapaka]

Thanks for this Håkon Alseth  

I have 2 questions in my mind:

1. Whatever you changes regarding overlays etc that you have suggested, can I add or modify in the already existing radio_test firmware?
2. Do we have anything to do with the schematic diagram of the PCB board ? I mean, considering the TX and RX pins etc.

[Håkon Alseth]

Hi,

 

Venu Madhav Murapaka said:

1. Whatever you changes regarding overlays etc that you have suggested, can I add or modify in the already existing radio_test firmware?

Yes, you can add a overlay with your specified pins or other settings. See our ncs dev academy for more details, specifically lesson 3 here:

https://academy.nordicsemi.com/courses/nrf-connect-sdk-fundamentals/

 

Venu Madhav Murapaka said:

2. Do we have anything to do with the schematic diagram of the PCB board ? I mean, considering the TX and RX pins etc.

Yes, the chosen UART pins must match how your custom board has been routed.

 

Kind regards,

Håkon

[Venu Madhav Murapaka]

It worked!!

Just added an overlay nrf52840dk_nrf52840.overlay
and did some changes to the prj.conf file

Now I'm able to send commands to my custom PCB just like the nrf52840 DK using the radio_test firmware.

[Håkon Alseth]

Hi,

 

I am glad to hear that this worked as intended! Hope you have a wonderful day!

 

Kind regards,

Håkon