Unable to run Zephyr programs on nRF52840DK.

[chrisswinchatt]

Hi,

I am unable to get any programs using Zephyr to run on an nRF52840DK.

• I have tried using the latest DAPlink (from GitHub) and JLink firmware (from Segger) as well as the latest firmware binary available from https://www.nordicsemi.com/Software-and-tools/Development-Kits/nRF52840-DK/Download.
• I can successfully flash binaries of Mbed OS or Zephyr using PyOCD or drag-and-drop with all firmwares, as well as nrfjprog when using JLink firmware (nrfjprog does not detect the board with other firmware)
• With DAPlink firmware LED5 will blink 3 times, and it also blinks whenever serial data is sent to the board
• With JLink firmware, LED5 is lit almost constantly (it blinks off for a fraction of a second about once per second).
• With MBED firmware, LED5 is lit constantly
• With all firmwares, there is no serial output from Zephyr programs. If I try to control LEDs programmatically there is no effect.

I have experienced the same issue on 3x nRF52840DKs which I believe came in a single shipment. As mentioned I am able to reflash the firmware and run mbed OS programs at will.

[chrisswinchatt]

Hi Simon,

I am using upstream Zephyr. The above commands do work. I was evidently using the wrong board spec in the build. A pristine build with the correct spec & JLink firmware fixes the issue. Thanks.