nRF52840-DK Debugging over 5V USB (SEGGER) with 3.3V sensor

[samuelbaldwin]

Hello,

I am quite new to developing with the nRF52840-DK. Up to this point, I have been flashing the applications (mostly the examples) over USB with the built-in J-Link and SEGGER software (I'm on a Mac). I am trying to create an application to read from a colour sensor over I2C. For now, all I want to do is get the colour data from the sensor over I2C and log it to the Debug Terminal in SEGGER. My problem is that the USB connection that I use for flashing and debugging provides 5V whereas the colour sensor only takes up to 3.6V.

How do I set up the board so that I can flash and debug over USB with SEGGER but also supply an appropriate voltage (~3.3V) to the colour sensor to read the data from it over I2C?

Thanks in advance!

[Jared]

Hi,

The voltage supplied by the USB is regulated down to 3 V by the on-board buck regulator. The 3 V VDD_nRF voltage is supplied to the nRF and the GPIOs and can be adjusted by the firmware of the SoC. See this thread on how to adjust it. 

regards

Jared

[samuelbaldwin]

Hi Jared,

Thanks very much for your reply. That clears everything up!

Best regards,

Sam