nRF52840 USB example crash

[ilia]

Hi. I've just received my nRF52840-PDK and now I am trying to run usb examples from SDK 13.1.0.

I have started with VisualGDB using arm-eabi toolchain and USB HID Generic example from the SDK. The project built and flashed without errors. But when I connect second USB I get SIGTRAP exception in reent.c on NVIC_Enable_IRQ() in core_cm4.h. Pretty the same as here. The solution in that thread was to change startup files, but don't know how to make it. So this is a question number 1.

I have also tried to flash precompiled .hex files from the SDK, but for every USB example none of my PCs could recognize this USB device. So maybe I need to install some drivers for HID examples?

Other options I have checked, without success:

• build with GNUARM toolchain from command line as well as from VisualGDB (in case of VisualGDB I had to select software FP instead of hardware, and disable softdevice);
• build with arm-eabi from VisualGBD using SDK 13.0.0 and 13.1.0.
• build projects from examples in IAR, not succeeded.

What do I need to do to get working USB on nRF52840?

[ilia]

Hi @hungbui,

Situation #1:

I use HID_Generic example code from the SDK with VisualGDB on Windows PC. I flash and run the code with debugging. Everything is working - the board is just waiting for USB connection. Then I connect the second USB cable and project crashes with exception SIGTRAP in the exact same location as in the referenced thread. And I don't see how to change startup file because in project references there is ".c" startup file and not ".s".

Situation #2:

Flash precompiled .hex -> the PC will not recognize the device.