NRF52840 DK in high voltage mode

[Daniel Reisfeld]

Hi,

I would like to try the DK in a high voltage mode. I tried switching the power source switch to either LIPO or USB (using LIPO battery and USB respectively) but in vain.

Please advise, thanks,

Daniel

[Stian Røed Hafskjold]

Please describe "in vain". Are you getting any voltage on VDD? Remember that the VDD voltage on the board will, after setting the power select switch to either LiPo or USB, be the output of REG0 on the chip, which defaults to 1.8V, so the LEDs will be very dim and hard to see (if that's what you are using for debugging).

In the USB position the board is powered from the USB port closes to the nRF chip. Also, remove the USB cable from the main USB port.

In LiPo position, power the DK from the LiPo battery header not the coin cell battery holder underneath the board. Remove USB cable from the main USB port.

So, step 1 is to check that you are getting 1.8V on VDD. (Check using P1 header)

[Daniel Reisfeld]

Stain,

I understand why I got 3 Volts (wrong USB cable placement). However, if I try using the USB or LiPo (with the switch on the corresponding place), the board doesn't power at all (I tried with two boards).

Did you encounter this situation?

Thanks,

Daniel

[Stian Røed Hafskjold]

The board is not supposed to power up, since VDD is now driven by the output of REG0 on the nRF chip. The nRF chip however is powering up as normal (event though there are no LEDs to indicate this). If you flash a BLE example you should see that the chip is advertising. Set the switch back to the VDD position when flashing, and you might have to power cycle afterwards.

[Daniel Reisfeld]

Thanks Stain! - I'll do so