nRF5340 VREQCTRL for Additional 3 dB TX Power

[Akash Patel]

Hi team,

I am working with the nRF5340 PDK v0.8.0 and I am trying to request the additional voltage for the VREGRADIO to support the additional 3 dB TX power on the RADIO. I am using the radio_test example in the SDK (nrf\samples\peripheral\radio_test) for this. To facilitate this, the only changes I made were to the main.c file as seen below. Is this the correct way to request the higher voltage? When debugging I am not seeing the bit value in the register change but I am printing out the correct value of the register (see screenshot below).

Unfortunately, I do not have the proper RF equipment to measure the extra 3 dB change in output power. I only have the RSSI Viewer with the nRF52840 Dongle which doesn't look to be changing from having this to not having this.

Added:

#include <nrfx/hal/nrf_vreqctrl.h>

nrf_vreqctrl_radio_high_voltage_set(NRF_VREQCTRL_NS, true); 

while(!nrf_vreqctrl_radio_high_voltage_check(NRF_VREQCTRL_NS));

Also some printk statements. Here is my final main.c file:

/*
 * Copyright (c) 2020 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-BSD-5-Clause-Nordic
 */

#include <sys/printk.h>
#include <drivers/clock_control.h>
#include <drivers/clock_control/nrf_clock_control.h>
#include <nrfx/hal/nrf_vreqctrl.h>

static void clock_init(void)
{
	int err;
	struct device *clock;
	enum clock_control_status clock_status;

	clock = device_get_binding(DT_INST_0_NORDIC_NRF_CLOCK_LABEL);
	if (!clock) {
		printk("Unable to find clock device binding\n");
		return;
	}

	err = clock_control_on(clock, CLOCK_CONTROL_NRF_SUBSYS_HF);
	if (err) {
		printk("Unable to turn on the clock: %d", err);
	}

	do {
		clock_status = clock_control_get_status(clock,
			CLOCK_CONTROL_NRF_SUBSYS_HF);
	} while (clock_status != CLOCK_CONTROL_STATUS_ON);

	printk("Clock has started\n");
}

void main(void)
{
	printk("Starting Radio Test example\n");

	clock_init();

    nrf_vreqctrl_radio_high_voltage_set(NRF_VREQCTRL_NS, true); 

    while(!nrf_vreqctrl_radio_high_voltage_check(NRF_VREQCTRL_NS));

//        NRF_VREQCTRL->VREGRADIO.VREQH = 1;

//        while (!VREGRADIO.VREQHREADY);

    printk("Register value is %d\n", NRF_VREQCTRL->VREGRADIO.VREQHREADY);
    printk("RADIO is ready to operate on high voltage\n");

}

Regards,

Akash Patel

[haakonsh]

Hmm, This will be a bit tricky without measuring. Can you send me the hex files for the network and application cores? 

You can test whether the RSSI measurements are accurate enough by lowering the TX power by 3dB. If there's no difference in RSSI value then you cannot rely on RSSI to test for the +3dBm mode. 

nrf_radio_txpower_set(NRF_RADIO, 0xFD); // Neg3dBm

[Akash Patel]

Hello,

I am finding it hard to measure the difference in the RSSI value. I have kept the board in the same position and programmed the board with radio_test without requesting the higher voltage and choosing TX carrier. I then programmed the board with radio_test with requesting the higher voltage and chose TX carrier on the same channel but I do not see a difference in RSSI.

I am using git commit 42730175544661f06371efb0c49bde39969dc5b8 for the NRF repo.

Here is the radio_test hex for the network core: /cfs-file/__key/communityserver-discussions-components-files/4/0207.zephyr.hex

Here is the hello_world application that I am running on the application core (This is a non-secure merged hex): /cfs-file/__key/communityserver-discussions-components-files/4/0312.merged.hex

Regards,

Akash Patel

[haakonsh]

Hmm, the device does not advertise. 

I get the following in the uart log:

There's no additional logging at this point, I assume that the NS image never booted, or it does not use logging.

I'm using a PCA10095 rev 0.7 DK. What do you use? 

[Akash Patel]

Hello,

Please make sure you are connecting TxD pin to P0.26 and RxD pin to P0.25 to enable logging of the network core. This can be found at the bottom of the page here. Application core will have log output to a different COM port than the network core. For me, I have COM 11, 12, and 13 enumerate when using the DK. COM11 is where the network core logs are coming and COM12 is where the application core logs are coming.

I am using PCA10095 v0.8.0. 

I am also providing the radio_test hex for the network core which does not include the request for additional voltage so that you can compare the output power from this one to the one from my previous post: /cfs-file/__key/communityserver-discussions-components-files/4/2364.zephyr.hex

Regards,

Akash

[haakonsh]

Hey Akash, sorry for the late reply. I've been in a sort of quarantine and I have not had any access to our Office/Labs. 

I'me struggling to get the nRF5340 to advertise, network log:

*** Booting Zephyr OS build v2.1.99-ncs1-3-g7ddab664b04b ***
Starting Radio Test example
Clock has started
Register value is 1
RADIO is ready to operate on high voltage

What kind of advertising data are you using? I'm trying to identify the device based on name, address type, Manu. spec. data, etc, because there's so many devices with similar RSSI near me. 

[Akash Patel]

Hello,

This is the radio_test example so it is not doing any sort of advertising. I was using the UART CLI to start TX carrier on a specific channel. If you have access to a spectrum analyzer where you can directly connect the output of the radio via J1 to the spectrum analyzer, that would be great.

Regards,

Akash

[haakonsh]

Aah!

Then I need to head to the lab tomorrow!