Debug using SWD

Introduction

Cortex-Debug is an extension for Visual Studio Code to streamline the debug process when working with ARM Cortex-M microcontrollers.

Requirements

If you did not install these previously, you need to install now.

• Cortex-Debug

  Install Cortex-Debug extension by marus25 in VSCODE.

• gdb-multiarch

  Install gdb-multiarch by executing command sudo apt install gdb-multiarch.

Setup for ST-Link or JLink

Update or create .vscode/lauch.json file.

lauch.json

    {
     // Use IntelliSense to learn about possible attributes.
     // Hover to view descriptions of existing attributes.
     // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
     "version": "0.2.0",
     "configurations": [
         {
             "name": "Cortex Debug",
             "cwd": "${workspaceFolder}",
             "executable": "${workspaceFolder}/build/BasicSetup.elf",
             "request": "launch",
             "type": "cortex-debug",
             "runToEntryPoint": "main",
             "device": "STM32F407VG",
             "interface": "swd",
             "servertype": "stlink",
             "gdbPath": "/usr/bin/gdb-multiarch"
         }
     ]
    }

Change .elf filename for executable and device name for device (for bluepill, “device”: “STM32F103C8”).For jlink, change “servertype”: “jlink”.

Setup for OpenOCD

OpenOCD server is better than ST-Link server. We also prefer to use OpenOCD instead of ST-Link but it is not neccessary.

Install OpenOCD by executing command sudo apt install openocd. Update .vscode/launch.json.

launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "OpenOCD Debug",
            "cwd": "${workspaceFolder}",
            "executable": "${workspaceFolder}/build/BasicSetup.elf",
            "request": "launch",
            "type": "cortex-debug",
            "runToEntryPoint": "main",
            "device": "STM32F407VG",
            "interface": "swd",
            "servertype": "openocd",
            "configFiles": [
                "interface/stlink-v2-1.cfg",
                "target/stm32f4x.cfg"
            ],
            "gdbPath": "/usr/bin/gdb-multiarch"
        }
    ]
}

Change .elf filename for executable and device name for device. Also you need to chage configFiles (e.g. target/stm32f1x.cfg for bluepill or interface/jlink.cfg for jlink interface). For more about OpenOCD, watch :this.

Run Debugger

• Connet your ST-Link or JLink to your microcontroller and your PC. If you use external debugger like JLink or ST-Link adapter, connect it as:

  • SWCLK of microcontroller to SWCLK of debugger.

  • SWDIO of microcontroller to SWDIO of debugger.

  • SWO of microcontroller to SWO of debugger. (Optional, only if you want to see ITM messages)

  • NRST of microcontroller to NRST of debugger. (Optional, only if you want to hard reset microcontroller using debugger)

  • GND of microcontroller to GND of debugger.

  • 3V3 of microcontroller to 3V3 of debugger.

• Go to Run and Debug section in VSCODE.

• Click Run button.

You will see a floating toolbar which you can use for continue, step over, step into, step out, restart and stop.