nrf52-dk: PC reboot issue

[Punk77]

Once I try to connect nrf52-dk development board to a personal computer, using a micro USB cable, once the USB is detected from the PC, it instantly reboot without any reason. I tried with two different PC and with two different USB cable and with two different nrf52-dk board (nrf6827 rev 2.1.0 2020.35). I don't know which is the reason. I tried also using an USB hub (with and without external power supply), and the issue seems not to be related to the power supply itsels but related to the detection of the USB.

Which can be the reason? I already installed the segger embedded studio, but the issue still there. Please let me know.

best regards

[Punk77]

These are two PCs with Windows 8 and without having ne ed USB device issues. The strange thing is not only the reboot issue, but also the fact that the PC does’not boot until the usb Device is removed...I suspect a sort of “cpu” direct access from usb/jtag device...tibia possibile?did you see something similar? One pc is lenovo z500 with i7 cpu, while the other is an HP with Intel cpu

[Punk77]

Finally, after 2 days crashing my head with the board, I find out the issue (which is related to all 3 nrd52dk original boards I bought). I read from another thread that sometimes there are issue with the boot loader and PCs, so I decided to reboot the board holding the reset button. The boards appeared as bootloader into my USB devices, and I drag and drop the latest J-Link OB-SAM3U128-V2-NordicSemi 170724.bin and power-of-power-on the nrf52dk. Finally it appeared as JLINK and com3 port device!

[awneil]

Punk77 said:

I read from another thread

please give a link to that thread, for reference.