unable to debug nrf52840 USB CDC ACM built on BLE client application

[RVA]

I'm facing an issue to debug nrf52840 using usb cdc acm application on top of ble client application . Same result when using Fanstel based on nrf52840 connected via usb to the host as well.

1. In most cases resetting the target force a recovery after flashing the application. - Why the target needs recovery ?
2. When running the debugger it returns with exception, 

Core registers:

Disassembly viewer:

Using Cortex-Debug extension for vscode. launch.jason as follows:

{
    "version": "0.2.0",
    "configurations": [


        {
            "name": "Cortex Debug",
            "cwd": "${workspaceRoot}",
            "executable": "${workspaceRoot}/_build/nrf52840_xxaa.out",
            "request": "launch",
            "type": "cortex-debug",
            "servertype": "jlink",
            "device": "nrf52",
            "interface": "swd",
            "serialNumber": "",
            "armToolchainPath": "/usr/local/gcc-arm-none-eabi-6-2017-q2-update/bin",
            "svdFile": "${workspaceRoot}/modules/nrfx/mdk/nrf52840.svd",
        }
    ]
}

When I use BLE client application or USB CDC ACM application, the debugger runs without any problems



Please help !

[Simonr]

Hi

Just wanted to let you know that I tried to reproduce this on my end with an nRF52840 Dongle running the USB CDC ACM project, but connecting to the COM port worked fine both with and without a debugger connected to the device.

So again, could it be related to voltage levels on your dongle specifically? USB probably activates REG0 with 1.8V output, but perhaps the debugger forces the VDD voltage to 3V or something on your end. It should work anyways though, but can you check the VDD voltage level on your Dongle with and without the debugger connected?

Best regards,

Simon