launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Debug UTP TM4C",
            "cwd": "${workspaceFolder}",
            "executable": "./target/thumbv7em-none-eabihf/release/utp-tm4c",
            "request": "launch",
            "type": "cortex-debug",
            "runToEntryPoint": "main",
            "internalConsoleOptions": "openOnFirstSessionStart",

            "servertype": "openocd",

            // The default OpenOCD flash procedures yield errors when
            // flashing ("Error erasing flash with vFlashErase packet (from target-download)"),
            // especially on older boards (LM4F).
            //
            // We don't really have a good understanding of why this happens but
            // we have, over the years, built up a battle tested sequence of OpenOCD
            // commands that generally works and keeps the board from getting into
            // bad states.
            //
            // See: https://github.com/ut-ras/Rasware/blob/e5bc8748db8931f742421b1d742d0c330b66d7b6/RASLib/Makefile#L80-L88
            // And: https://github.com/rrbutani/tm4c-llvm-toolchain/blob/bb36dba9d52a9b51350ff8c035fdc91e87cc8b90/common.ninja#L346-L355
            //
            // So, we direct `cortex-m-debug` to feed these commands to the
            // openocd server instead of the default ones on startup, launch,
            // and restart:
            "openOCDLaunchCommands": [
                // "init",
                // "halt",
                // "reset init",
                // "sleep 100",
                // "flash probe 0",
            ],
            "overrideLaunchCommands": [
                // "monitor halt",
                // "monitor reset init",
                // "monitor flash write_image erase target/thumbv7em-none-eabihf/release/utp-tm4c",
                // "monitor sleep 100",
                // "monitor flash verify_image target/thumbv7em-none-eabihf/release/utp-tm4c",
                // "monitor reset init"
                "load"
            ],
            "overrideRestartCommands": [
                "monitor reset init",
            ],

            "preLaunchCommands": ["source .gdbinit"],
            "showDevDebugOutput": "none",

            // Build before launching!
            "preLaunchTask": "Build UTP TM4C",

            // TM4C stuff:
            "configFiles": [
                "board/ti_ek-tm4c123gxl.cfg"
            ],
            "device": "TM4C123GXL",
            "svdFile": ".vscode/TM4C123GH6PM.svd",
        }
    ]
}