Nordic nRF52-DK disconnects from computer when uploading compiled BIN files from mbed

[Keith Hammock]

I have a Nordic nRF52-DK that I am using to create and run programs written using the mbed compiler. I have followed the instructions outlined here on the mbed website( os.mbed.com/.../) for uploading the current firmware also provided on that website. Now, whenever I try to upload a compiled BIN file that I have written and compiled using the mbed compiler, the board disconnects from my computer and immediately reconnects, whilst having no compiled BIN file on the board. Also, at random points while the board is connected and I am doing things not related to the board, like traversing the internet, the board will also disconnect and reconnect.

[Jørgen Holmefjord]

Hi,

It is normal that the board disconnects and reconnects when you are flashing using "Drag-and-drop" method. Are you sure that the application is working?

The random disconnects sounds like an issue with the cable or power to the board. Do you have any serial output from your application that can indicate if the chip is reset in these cases?

Did you flash the mbed firmware to the interface chip on the nRF52-DK, or are you using the default Segger J-Link OB firmware?

Best regards,

Jørgen

[Keith Hammock]

I used the mbed-os-example-blinky template program, and compiled the main.cpp file. I dragged the compiled file onto the board. Then I pressed the RESET button, and nothing happened. If I hold the RESET button down, then the LED blinks, and after holding it down for 5 seconds, the LED blinks even faster for a second then goes back to not blinking, whether or not I am still holding down the RESET button. Also, while typing this, the board disconnected and reconnected to my laptop 3 times.