RE: Debugging on NRF52840 Dongle

masterLee — Wed, 13 Mar 2019 13:25:24 GMT

Hi, I would like to see this guide/blog when you finish it since I had similar issues.

I managed to find a solution though, with the help of SB47 next to debug-out connector.

When I couple SB47 the SWD cable I use takes Voltage and the nRF Dongle has power from the cable.

So USB of the dongle is not needed to power the dongle. So you can program the bootloader again in the dongle and thus enabling the USB power of it . Then you can use the nRF connect as before.

Please when you complete the guide send a reply in this post with the link so we can be notified.

Thank you for your time.

RE: Debugging on NRF52840 Dongle

Edvin — Tue, 20 Nov 2018 15:39:34 GMT

Hello Rajendra,

I believe that you haven't removed the bootloader on the dongle, is that correct?

If you just program an application to the chip while still having the bootloader, the bootloader (which is always run on startup) will not recognize the app as a valid application, and it will stay in bootloader mode waiting for a valid app.

The short answer is: It is not possible to debug on the nRF52840 dongle.

The long answer is:

You can't use the DK to program the dongle, because of the voltage difference between the USB (5V) and the DK (3V). If you have a proper Segger programmer with a level shifter this is possible, but the DK programmer doesn't have this.

That being said, you can program the device with the DK, but this is because the bootloader that is programmed on the Dongle includes a part that changes the power registers before it starts the application. The difficult part is that in order to debug your application you need to either remove or replace the bootloader. If you remove it, or replace it without the power register hack, and then reset the device, you will no longer be able to communicate with it using the DK's programmer, and your dongle is bricked until you get hold of a proper segger programmer.

Basically, if you do: "nrfjprog --eraseall && nrfjprog --reset", it is bricked.

We are currently in the making of a guide/blog post that describes how you can use your dongle for developing, but it is not finished yet. I am not quite sure what the blog post will contain, and the guy writing it is out of office this week, so I can't ask him.

We also state that the dongle is not a development kit. If you want to develop on the nRF52840, I really really recommend you to go with the nRF52840 DK.

Best regards,

Edvin