How to configure NRF52840(dk) GPIO voltage to 1.8V on Zephyr

[Volker]

Hi,

I am using the NRF52840DK and would like to configure the GPIOs to have levels of 1,8V by using zephyr 2.4 or zephyr 3.1. By default I am getting 3 V.

Can anybody give me some advise? I did not find anything helpful in the documentation.

Regards,

Volker

[Priyanka]

Hi,

It is possible to set the GPIO level to 1.8V if you put the chip in High voltage mode. NRF_UICCR->REGOUT0  can be used.

Best Regards,

Priyanka

[Volker]

Hi Priyanka,

thank you for this information.
The documentation states, that default value should be 1.8V. As mentioned in my question, I am using zephyr and I am getting 3.0 or 3.3 V. So it seems that some software-compoment does already modify this register.
Do you know, if there is some zephyr-configuration where this can be configured?

Regards,

Volker

[Priyanka]

Hi Volker,

Please note this

-Priyanka

[Volker]

Hi Priyanka,

with your help I am now having a clear understanding of how to configure the GPIO voltage levels based on the nrf registers.

But I am still not able to get this working with zephyr.

I tried to activate the High-Voltage-Mode by configuration CONFIG_BOARD_ENABLE_DCDC_HV=y.

I also tried to activate it by nrf_power_dcdcen_vddh_set(NRF_POWER,true);

But I am still getting nrf_power_mainregstatus_get(NRF_POWER) ==  NORMAL.

As mentioned before I am using the NRF52840DK eval board.

Can you please give me some advise of how to configure this with zephyr using my eval-board?

Volker

[Priyanka]

Hi Volker,

In order to set the device in High Voltage mode you have to connect the supply to the VDDH and do not connect any voltage supply to VDD. You can refer the Main Supply documentation for further details.

-Priyanka

[Volker]

Hi Priyanka,

as mentioned earlier, I am using the nordic nrf82840dk eval board. According to its documentation it should be able to set the GPIO voltage by firmware.

Therefore I am expecting that there is some issue caused by zephyr.

So I would really appreciate some guidance of how to configure the voltage by using zephyr.

-Volker

[Priyanka]

Hi Volker,

You are using the nRF52840DK right? or is it the nRF52840 eval kit?

-Priyanka

[Volker]

https://www.nordicsemi.com/Products/Development-hardware/nrf52840-dk

[Priyanka]

Hi,

You are getting confused by how the high voltage mode is set. It can only be done via hardware connections as mentioned earlier and not possible to do it via software. 

If you use the DK with default config it is in normal voltage mode. If you set SW3 to USB and power the DK from nRF USB (J3), you can change the UICR register and change voltage.

-Priyanka