vscode-cpptools properties for Arduino Due and Uno

c_cpp_properties.json

{
    "env": {
        "HOME": "/Users/danm"
    },
    "configurations": [
        {
            "name": "Arduino AVR 4.9.2 UNO",
            "includePath": [
                "${HOME}/Library/Arduino15/packages/arduino/hardware/avr/1.6.21/cores/arduino",
                "${HOME}/Library/Arduino15/packages/arduino/hardware/avr/1.6.21/variants/standard",
                "${HOME}/Documents/Arduino/libraries"
            ],
            "browse": {
                "limitSymbolsToIncludedHeaders": false,
                "path": [
                    "${HOME}/Library/Arduino15/packages/arduino/hardware/avr/1.6.21/cores/arduino",
                    "${HOME}/Library/Arduino15/packages/arduino/hardware/avr/1.6.21/variants/standard",
                    "${HOME}/Documents/Arduino/libraries"
                ]
            },
            "defines": [
                "ARDUINO=10804",
                "ARDUINO_AVR_UNO",
                "ARDUINO_ARCH_AVR",
                "F_CPU=16000000L",
                "USBCON"
            ],
            "intelliSenseMode": "clang-x64",
            "compilerPath": "${HOME}/Library/Arduino15/packages/arduino/tools/avr-gcc/4.9.2-atmel3.5.4-arduino2/bin/avr-gcc",
            "cStandard": "c11",
            "cppStandard": "c++11"
        },
        {
            "name": "Arduino SAM 4.8.3 Due",
            "includePath": [
                "${HOME}/Library/Arduino15/packages/arduino/hardware/sam/1.6.11/system/libsam",
                "${HOME}/Library/Arduino15/packages/arduino/hardware/sam/1.6.11/system/CMSIS/CMSIS/Include/",
                "${HOME}/Library/Arduino15/packages/arduino/hardware/sam/1.6.11/system/CMSIS/Device/ATMEL/",
                "${HOME}/Library/Arduino15/packages/arduino/hardware/sam/1.6.11/cores/arduino",
                "${HOME}/Library/Arduino15/packages/arduino/hardware/sam/1.6.11/variants/arduino_due_x",
                "${HOME}/Documents/Arduino/libraries"
            ],
            "browse": {
                "limitSymbolsToIncludedHeaders": false,
                "path": [
                    "${HOME}/Library/Arduino15/packages/arduino/hardware/sam/1.6.11/system/libsam",
                    "${HOME}/Library/Arduino15/packages/arduino/hardware/sam/1.6.11/system/CMSIS/CMSIS/Include/",
                    "${HOME}/Library/Arduino15/packages/arduino/hardware/sam/1.6.11/system/CMSIS/Device/ATMEL/",
                    "${HOME}/Library/Arduino15/packages/arduino/hardware/sam/1.6.11/cores/arduino",
                    "${HOME}/Library/Arduino15/packages/arduino/hardware/sam/1.6.11/variants/arduino_due_x",
                    "${HOME}/Documents/Arduino/libraries"
                ]
            },
            "defines": [
                "F_CPU=84000000L",
                "ARDUINO=10804",
                "ARDUINO_SAM_DUE",
                "ARDUINO_ARCH_SAM ",
                "__SAM3X8E__",
                "USB_VID=0x2341",
                "USB_PID=0x003e",
                "USBCON",
                "USB_MANUFACTURER=\"Arduino LLC\"",
                "USB_PRODUCT=\"Arduino Due\""
            ],
            "intelliSenseMode": "clang-x64",
            "compilerPath": "${HOME}/Library/Arduino15/packages/arduino/tools/arm-none-eabi-gcc/4.8.3-2014q1/bin/arm-none-eabi-gcc",
            "cStandard": "c11",
            "cppStandard": "c++11"
        }
    ],
    "version": 4
}

Defining "USBCON" for Uno maybe incorrect. But it was the only way I could work out how to get Intellisense to recognise the Serial global.