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

[Jørgen Holmefjord]

The file will not be visible in the explorer window after programming, the file will be flashed correctly, or a file fail.txt that describe the error. Did you put the board in bootloader mode (hold IF BOOT/RESET button while powering the board) before flashing the J-Link OB firmware I linked above? The hex file should not be too big for the nRF52 DK (PCA10040 board), are you sure this is the board you are using? Have you tried a different computer, to eliminate something trying to wrte files to your external drives?