nRF52840 PDK debugging with 1.8V periphery

RE: nRF52840 PDK debugging with 1.8V periphery

Sebi1128 — Mon, 19 Sep 2022 14:18:44 GMT

Hello,

I have the exact same problem:

Even though I followed the instructions (1.8V external voltage connected to P21, VEXT->nRF switch is in the ON position, USB connected on J2, SW9 on VDD, SW6 on default), I still measure a VDD voltage of 3V at P1.

Is there anything else that I should change? Any jumpers?

Thank you for the help,

Sebastian

RE: nRF52840 PDK debugging with 1.8V periphery

Reto — Wed, 05 Jul 2017 11:57:48 GMT

Thank you Sigurd. It all works very well now.

RE: nRF52840 PDK debugging with 1.8V periphery

Sigurd — Mon, 26 Jun 2017 12:46:06 GMT

The VDD_nRF pins should have the same voltage as VEXT(when VEXT->nRF switch is in the ON position). Depending on how much current you sensor need, you could also configure a GPIO to output-mode (and high drive), and supply the sensor from the GPIO pin.

RE: nRF52840 PDK debugging with 1.8V periphery

Reto — Fri, 23 Jun 2017 06:30:12 GMT

Even though debugging works fine. I still have a problem:

VDD=3.0V I2C-pull-up-resistors (R52, R53) for SCL and SCK are pulled up to VDD=3.0V.

This would destroy my sensor which runs only on 1.8V. How can I set VDD to 1.8V (Vext)?

Thank you very much! Reto

RE: nRF52840 PDK debugging with 1.8V periphery

Reto — Fri, 23 Jun 2017 05:05:19 GMT

Thank you Sigurd. It works very well. By the way, I do work with Eclipse. Fantastic tutorial you have here. You all do a great job at Nordic Semiconductor!

Reto

RE: nRF52840 PDK debugging with 1.8V periphery

Sigurd — Mon, 19 Jun 2017 14:06:50 GMT

Hi,

Yes, this is possible. You will need to put the VEXT->nRF switch in the ON position.

In this position you can power the nRF52840 SoC directly from the external supply connector (P21) without powering the rest of the board from the same source. I.e. the interface MCU will be powered from the J2 USB connector, while the nRF52840 is powered from the P21 connector.

See this infocenter page for more information.

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