Vscode-arduino: identifier "Serial1" is undefined

[clarkbremer]

I have an Arduino Mega 2560. It has 3 serial ports. The standard is "Serial", the others are "Serial1" and "Serial2". VSCode doesn't have a problem with "Serial", but shows an error for "Serial1". Code compiles and uploads just fine, but would be nice not get this error message.

Version: 1.36.1 (user setup)
Commit: 2213894ea0415ee8c85c5eea0d0ff81ecc191529
Date: 2019-07-08T22:59:35.033Z
Electron: 4.2.5
Chrome: 69.0.3497.128
Node.js: 10.11.0
V8: 6.9.427.31-electron.0
OS: Windows_NT x64 10.0.17134

Name: Arduino
Id: vsciot-vscode.vscode-arduino
Description: Arduino for Visual Studio Code
Version: 0.2.27
Publisher: Microsoft
VS Marketplace Link: https://marketplace.visualstudio.com/items?itemName=vsciot-vscode.vscode-arduino

[mMerlin]

Try adding

"defines": ["USBCON"]

to "configurations" in the c_cpp_properties.json file in the .vscode folder. Or adding "USBCON" to the list, if "defines" already exists.

[jimaobian]

If you are using arduino UNO (ATmega328P chip) try:

"defines": [
                "__AVR_ATmega328P__",
                "ARDUINO=10800"
           ]

If you are using arduino Leonardo (ATmega32U4 chip) try:

"defines": [
                "__AVR_ATmega32U4__",
                "ARDUINO=10800"
           ]

If you are using arduino Mega (ATmega2560 chip) try:

"defines": [
                "__AVR_ATmega2560__",
                "ARDUINO=10800"
           ]

Here is the io.h file in AVR library for reference, if you are using other board of AVR.

/* Copyright (c) 2002,2003,2005,2006,2007 Marek Michalkiewicz, Joerg Wunsch
   Copyright (c) 2007 Eric B. Weddington
   All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are met:

   * Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.

   * Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in
     the documentation and/or other materials provided with the
     distribution.

   * Neither the name of the copyright holders nor the names of
     contributors may be used to endorse or promote products derived
     from this software without specific prior written permission.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  POSSIBILITY OF SUCH DAMAGE. */

/* $Id$ */

/** \file */
/** \defgroup avr_io <avr/io.h>: AVR device-specific IO definitions
    \code #include <avr/io.h> \endcode

    This header file includes the apropriate IO definitions for the
    device that has been specified by the <tt>-mmcu=</tt> compiler
    command-line switch.  This is done by diverting to the appropriate
    file <tt>&lt;avr/io</tt><em>XXXX</em><tt>.h&gt;</tt> which should
    never be included directly.  Some register names common to all
    AVR devices are defined directly within <tt>&lt;avr/common.h&gt;</tt>,
    which is included in <tt>&lt;avr/io.h&gt;</tt>,
    but most of the details come from the respective include file.

    Note that this file always includes the following files:
    \code 
    #include <avr/sfr_defs.h>
    #include <avr/portpins.h>
    #include <avr/common.h>
    #include <avr/version.h>
    \endcode
    See \ref avr_sfr for more details about that header file.

    Included are definitions of the IO register set and their
    respective bit values as specified in the Atmel documentation.
    Note that inconsistencies in naming conventions,
    so even identical functions sometimes get different names on
    different devices.

    Also included are the specific names useable for interrupt
    function definitions as documented
    \ref avr_signames "here".

    Finally, the following macros are defined:

    - \b RAMEND
    <br>
    The last on-chip RAM address.
    <br>
    - \b XRAMEND
    <br>
    The last possible RAM location that is addressable. This is equal to 
    RAMEND for devices that do not allow for external RAM. For devices 
    that allow external RAM, this will be larger than RAMEND.
    <br>
    - \b E2END
    <br>
    The last EEPROM address.
    <br>
    - \b FLASHEND
    <br>
    The last byte address in the Flash program space.
    <br>
    - \b SPM_PAGESIZE
    <br>
    For devices with bootloader support, the flash pagesize
    (in bytes) to be used for the \c SPM instruction. 
    - \b E2PAGESIZE
    <br>
    The size of the EEPROM page.

*/

#ifndef _AVR_IO_H_
#define _AVR_IO_H_

#include <avr/sfr_defs.h>

#if defined (__AVR_AT94K__)
#  include <avr/ioat94k.h>
#elif defined (__AVR_AT43USB320__)
#  include <avr/io43u32x.h>
#elif defined (__AVR_AT43USB355__)
#  include <avr/io43u35x.h>
#elif defined (__AVR_AT76C711__)
#  include <avr/io76c711.h>
#elif defined (__AVR_AT86RF401__)
#  include <avr/io86r401.h>
#elif defined (__AVR_AT90PWM1__)
#  include <avr/io90pwm1.h>
#elif defined (__AVR_AT90PWM2__)
#  include <avr/io90pwmx.h>
#elif defined (__AVR_AT90PWM2B__)
#  include <avr/io90pwm2b.h>
#elif defined (__AVR_AT90PWM3__)
#  include <avr/io90pwmx.h>
#elif defined (__AVR_AT90PWM3B__)
#  include <avr/io90pwm3b.h>
#elif defined (__AVR_AT90PWM216__)
#  include <avr/io90pwm216.h>
#elif defined (__AVR_AT90PWM316__)
#  include <avr/io90pwm316.h>
#elif defined (__AVR_AT90PWM161__)
#  include <avr/io90pwm161.h>
#elif defined (__AVR_AT90PWM81__)
#  include <avr/io90pwm81.h>
#elif defined (__AVR_ATmega8U2__)
#  include <avr/iom8u2.h>
#elif defined (__AVR_ATmega16M1__)
#  include <avr/iom16m1.h>
#elif defined (__AVR_ATmega16U2__)
#  include <avr/iom16u2.h>
#elif defined (__AVR_ATmega16U4__)
#  include <avr/iom16u4.h>
#elif defined (__AVR_ATmega32C1__)
#  include <avr/iom32c1.h>
#elif defined (__AVR_ATmega32M1__)
#  include <avr/iom32m1.h>
#elif defined (__AVR_ATmega32U2__)
#  include <avr/iom32u2.h>
#elif defined (__AVR_ATmega32U4__)
#  include <avr/iom32u4.h>
#elif defined (__AVR_ATmega32U6__)
#  include <avr/iom32u6.h>
#elif defined (__AVR_ATmega64C1__)
#  include <avr/iom64c1.h>
#elif defined (__AVR_ATmega64M1__)
#  include <avr/iom64m1.h>
#elif defined (__AVR_ATmega128__)
#  include <avr/iom128.h>
#elif defined (__AVR_ATmega128A__)
#  include <avr/iom128a.h>
#elif defined (__AVR_ATmega1280__)
#  include <avr/iom1280.h>
#elif defined (__AVR_ATmega1281__)
#  include <avr/iom1281.h>
#elif defined (__AVR_ATmega1284__)
#  include <avr/iom1284.h>
#elif defined (__AVR_ATmega1284P__)
#  include <avr/iom1284p.h>
#elif defined (__AVR_ATmega128RFA1__)
#  include <avr/iom128rfa1.h>
#elif defined (__AVR_ATmega1284RFR2__)
#  include <avr/iom1284rfr2.h>
#elif defined (__AVR_ATmega128RFR2__)
#  include <avr/iom128rfr2.h>
#elif defined (__AVR_ATmega2564RFR2__)
#  include <avr/iom2564rfr2.h>
#elif defined (__AVR_ATmega256RFR2__)
#  include <avr/iom256rfr2.h>
#elif defined (__AVR_ATmega2560__)
#  include <avr/iom2560.h>
#elif defined (__AVR_ATmega2561__)
#  include <avr/iom2561.h>
#elif defined (__AVR_AT90CAN32__)
#  include <avr/iocan32.h>
#elif defined (__AVR_AT90CAN64__)
#  include <avr/iocan64.h>
#elif defined (__AVR_AT90CAN128__)
#  include <avr/iocan128.h>
#elif defined (__AVR_AT90USB82__)
#  include <avr/iousb82.h>
#elif defined (__AVR_AT90USB162__)
#  include <avr/iousb162.h>
#elif defined (__AVR_AT90USB646__)
#  include <avr/iousb646.h>
#elif defined (__AVR_AT90USB647__)
#  include <avr/iousb647.h>
#elif defined (__AVR_AT90USB1286__)
#  include <avr/iousb1286.h>
#elif defined (__AVR_AT90USB1287__)
#  include <avr/iousb1287.h>
#elif defined (__AVR_ATmega644RFR2__)
#  include <avr/iom644rfr2.h>
#elif defined (__AVR_ATmega64RFR2__)
#  include <avr/iom64rfr2.h>
#elif defined (__AVR_ATmega64__)
#  include <avr/iom64.h>
#elif defined (__AVR_ATmega64A__)
#  include <avr/iom64a.h>
#elif defined (__AVR_ATmega640__)
#  include <avr/iom640.h>
#elif defined (__AVR_ATmega644__)
#  include <avr/iom644.h>
#elif defined (__AVR_ATmega644A__)
#  include <avr/iom644a.h>
#elif defined (__AVR_ATmega644P__)
#  include <avr/iom644p.h>
#elif defined (__AVR_ATmega644PA__)
#  include <avr/iom644pa.h>
#elif defined (__AVR_ATmega645__)
#  include <avr/iom645.h>
#elif (defined __AVR_ATmega645A__)
#include <avr/iom645a.h>
#elif (defined __AVR_ATmega645P__)
#include <avr/iom645p.h>
#elif defined (__AVR_ATmega6450__)
#  include <avr/iom6450.h>
#elif (defined __AVR_ATmega6450A__)
#include <avr/iom6450a.h>
#elif (defined __AVR_ATmega6450P__)
#include <avr/iom6450p.h>
#elif defined (__AVR_ATmega649__)
#  include <avr/iom649.h>
#elif (defined __AVR_ATmega649A__)
#include <avr/iom649a.h>
#elif defined (__AVR_ATmega6490__)
#  include <avr/iom6490.h>
#elif (defined __AVR_ATmega6490A__)
#include <avr/iom6490a.h>
#elif (defined __AVR_ATmega6490P__)
#include <avr/iom6490p.h>
#elif defined (__AVR_ATmega649P__)
#  include <avr/iom649p.h>
#elif defined (__AVR_ATmega64HVE__)
#  include <avr/iom64hve.h>
#elif defined (__AVR_ATmega64HVE2__)
#  include <avr/iom64hve2.h>
#elif defined (__AVR_ATmega103__)
#  include <avr/iom103.h>
#elif defined (__AVR_ATmega32__)
#  include <avr/iom32.h>
#elif defined (__AVR_ATmega32A__)
#  include <avr/iom32a.h>
#elif defined (__AVR_ATmega323__)
#  include <avr/iom323.h>
#elif defined (__AVR_ATmega324P__)
#  include <avr/iom324p.h>
#elif (defined __AVR_ATmega324A__)
#include <avr/iom324a.h>
#elif defined (__AVR_ATmega324PA__)
#  include <avr/iom324pa.h>
#elif defined (__AVR_ATmega325__)
#  include <avr/iom325.h>
#elif (defined __AVR_ATmega325A__)
#include <avr/iom325a.h>
#elif defined (__AVR_ATmega325P__)
#  include <avr/iom325p.h>
#elif defined (__AVR_ATmega325PA__)
#  include <avr/iom325pa.h>  
#elif defined (__AVR_ATmega3250__) 
#  include <avr/iom3250.h>
#elif (defined __AVR_ATmega3250A__)
#include <avr/iom3250a.h>
#elif defined (__AVR_ATmega3250P__)
#  include <avr/iom3250p.h>
#elif defined (__AVR_ATmega3250PA__)
#  include <avr/iom3250pa.h>  
#elif defined (__AVR_ATmega328P__)
#  include <avr/iom328p.h>
#elif (defined __AVR_ATmega328__)
#include <avr/iom328.h>
#elif defined (__AVR_ATmega329__)
#  include <avr/iom329.h>
#elif (defined __AVR_ATmega329A__)
#include <avr/iom329a.h>
#elif defined (__AVR_ATmega329P__) 
#  include <avr/iom329p.h>
#elif (defined __AVR_ATmega329PA__)
#include <avr/iom329pa.h>
#elif (defined __AVR_ATmega3290PA__)
#include <avr/iom3290pa.h>
#elif defined (__AVR_ATmega3290__)
#  include <avr/iom3290.h>
#elif (defined __AVR_ATmega3290A__)
#include <avr/iom3290a.h>
#elif defined (__AVR_ATmega3290P__)
#  include <avr/iom3290.h>
#elif defined (__AVR_ATmega32HVB__)
#  include <avr/iom32hvb.h>
#elif defined (__AVR_ATmega32HVBREVB__)
#  include <avr/iom32hvbrevb.h>
#elif defined (__AVR_ATmega406__)
#  include <avr/iom406.h>
#elif defined (__AVR_ATmega16__)
#  include <avr/iom16.h>
#elif defined (__AVR_ATmega16A__)
#  include <avr/iom16a.h>
#elif defined (__AVR_ATmega161__)
#  include <avr/iom161.h>
#elif defined (__AVR_ATmega162__)
#  include <avr/iom162.h>
#elif defined (__AVR_ATmega163__)
#  include <avr/iom163.h>
#elif defined (__AVR_ATmega164P__)
#  include <avr/iom164p.h>
#elif (defined __AVR_ATmega164A__)
#include <avr/iom164a.h>
#elif defined (__AVR_ATmega164PA__)
#  include <avr/iom164pa.h>
#elif defined (__AVR_ATmega165__)
#  include <avr/iom165.h>
#elif defined (__AVR_ATmega165A__)
#  include <avr/iom165a.h>
#elif defined (__AVR_ATmega165P__)
#  include <avr/iom165p.h>
#elif defined (__AVR_ATmega165PA__)
#  include <avr/iom165pa.h>
#elif defined (__AVR_ATmega168__)
#  include <avr/iom168.h>
#elif defined (__AVR_ATmega168A__)
#  include <avr/iom168a.h>
#elif defined (__AVR_ATmega168P__)
#  include <avr/iom168p.h>
#elif defined (__AVR_ATmega168PA__)
#  include <avr/iom168pa.h>
#elif defined (__AVR_ATmega168PB__)
#  include <avr/iom168pb.h>
#elif defined (__AVR_ATmega169__)
#  include <avr/iom169.h>
#elif (defined __AVR_ATmega169A__)
#include <avr/iom169a.h>
#elif defined (__AVR_ATmega169P__)
#  include <avr/iom169p.h>
#elif defined (__AVR_ATmega169PA__)
#  include <avr/iom169pa.h>
#elif defined (__AVR_ATmega8HVA__)
#  include <avr/iom8hva.h>
#elif defined (__AVR_ATmega16HVA__)
#  include <avr/iom16hva.h>
#elif defined (__AVR_ATmega16HVA2__)
#  include <avr/iom16hva2.h>
#elif defined (__AVR_ATmega16HVB__)
#  include <avr/iom16hvb.h>
#elif defined (__AVR_ATmega16HVBREVB__)
#  include <avr/iom16hvbrevb.h>
#elif defined (__AVR_ATmega8__)
#  include <avr/iom8.h>
#elif defined (__AVR_ATmega8A__)
#  include <avr/iom8a.h>
#elif defined (__AVR_ATmega48__)
#  include <avr/iom48.h>
#elif defined (__AVR_ATmega48A__)
#  include <avr/iom48a.h>
#elif defined (__AVR_ATmega48PA__)
#  include <avr/iom48pa.h>
#elif defined (__AVR_ATmega48PB__)
#  include <avr/iom48pb.h>
#elif defined (__AVR_ATmega48P__)
#  include <avr/iom48p.h>
#elif defined (__AVR_ATmega88__)
#  include <avr/iom88.h>
#elif defined (__AVR_ATmega88A__)
#  include <avr/iom88a.h>
#elif defined (__AVR_ATmega88P__)
#  include <avr/iom88p.h>
#elif defined (__AVR_ATmega88PA__)
#  include <avr/iom88pa.h>
#elif defined (__AVR_ATmega88PB__)
#  include <avr/iom88pb.h>
#elif defined (__AVR_ATmega8515__)
#  include <avr/iom8515.h>
#elif defined (__AVR_ATmega8535__)
#  include <avr/iom8535.h>
#elif defined (__AVR_AT90S8535__)
#  include <avr/io8535.h>
#elif defined (__AVR_AT90C8534__)
#  include <avr/io8534.h>
#elif defined (__AVR_AT90S8515__)
#  include <avr/io8515.h>
#elif defined (__AVR_AT90S4434__)
#  include <avr/io4434.h>
#elif defined (__AVR_AT90S4433__)
#  include <avr/io4433.h>
#elif defined (__AVR_AT90S4414__)
#  include <avr/io4414.h>
#elif defined (__AVR_ATtiny22__)
#  include <avr/iotn22.h>
#elif defined (__AVR_ATtiny26__)
#  include <avr/iotn26.h>
#elif defined (__AVR_AT90S2343__)
#  include <avr/io2343.h>
#elif defined (__AVR_AT90S2333__)
#  include <avr/io2333.h>
#elif defined (__AVR_AT90S2323__)
#  include <avr/io2323.h>
#elif defined (__AVR_AT90S2313__)
#  include <avr/io2313.h>
#elif defined (__AVR_ATtiny4__)
#  include <avr/iotn4.h>
#elif defined (__AVR_ATtiny5__)
#  include <avr/iotn5.h>
#elif defined (__AVR_ATtiny9__)
#  include <avr/iotn9.h>
#elif defined (__AVR_ATtiny10__)
#  include <avr/iotn10.h>
#elif defined (__AVR_ATtiny20__)
#  include <avr/iotn20.h>
#elif defined (__AVR_ATtiny40__)
#  include <avr/iotn40.h>
#elif defined (__AVR_ATtiny2313__)
#  include <avr/iotn2313.h>
#elif defined (__AVR_ATtiny2313A__)
#  include <avr/iotn2313a.h>
#elif defined (__AVR_ATtiny13__)
#  include <avr/iotn13.h>
#elif defined (__AVR_ATtiny13A__)
#  include <avr/iotn13a.h>
#elif defined (__AVR_ATtiny25__)
#  include <avr/iotn25.h>
#elif defined (__AVR_ATtiny4313__)
#  include <avr/iotn4313.h>
#elif defined (__AVR_ATtiny45__)
#  include <avr/iotn45.h>
#elif defined (__AVR_ATtiny85__)
#  include <avr/iotn85.h>
#elif defined (__AVR_ATtiny24__)
#  include <avr/iotn24.h>
#elif defined (__AVR_ATtiny24A__)
#  include <avr/iotn24a.h>
#elif defined (__AVR_ATtiny44__)
#  include <avr/iotn44.h>
#elif defined (__AVR_ATtiny44A__)
#  include <avr/iotn44a.h>
#elif defined (__AVR_ATtiny441__)
#  include <avr/iotn441.h>
#elif defined (__AVR_ATtiny84__)
#  include <avr/iotn84.h>
#elif defined (__AVR_ATtiny84A__)
#  include <avr/iotn84a.h> 
#elif defined (__AVR_ATtiny841__)
#  include <avr/iotn841.h> 
#elif defined (__AVR_ATtiny261__)
#  include <avr/iotn261.h>
#elif defined (__AVR_ATtiny261A__)
#  include <avr/iotn261a.h>
#elif defined (__AVR_ATtiny461__)
#  include <avr/iotn461.h>
#elif defined (__AVR_ATtiny461A__)
#  include <avr/iotn461a.h>
#elif defined (__AVR_ATtiny861__)
#  include <avr/iotn861.h>
#elif defined (__AVR_ATtiny861A__)
#  include <avr/iotn861a.h>
#elif defined (__AVR_ATtiny43U__)
#  include <avr/iotn43u.h>
#elif defined (__AVR_ATtiny48__)
#  include <avr/iotn48.h>
#elif defined (__AVR_ATtiny88__)
#  include <avr/iotn88.h>
#elif defined (__AVR_ATtiny828__)
#  include <avr/iotn828.h>
#elif defined (__AVR_ATtiny87__)
#  include <avr/iotn87.h>
#elif defined (__AVR_ATtiny167__)
#  include <avr/iotn167.h>
#elif defined (__AVR_ATtiny1634__)
#  include <avr/iotn1634.h>
#elif defined (__AVR_AT90SCR100__)
#  include <avr/io90scr100.h>
#elif defined (__AVR_ATxmega8E5__)
#  include <avr/iox8e5.h>
#elif defined (__AVR_ATxmega16A4__)
#  include <avr/iox16a4.h>
#elif defined (__AVR_ATxmega16A4U__)
#  include <avr/iox16a4u.h>
#elif defined (__AVR_ATxmega16C4__)
#  include <avr/iox16c4.h>
#elif defined (__AVR_ATxmega16D4__)
#  include <avr/iox16d4.h>
#elif defined (__AVR_ATxmega16E5__)
#  include <avr/iox16e5.h>
#elif defined (__AVR_ATxmega32A4__)
#  include <avr/iox32a4.h>
#elif defined (__AVR_ATxmega32A4U__)
#  include <avr/iox32a4u.h>
#elif defined (__AVR_ATxmega32C3__)
#  include <avr/iox32c3.h>
#elif defined (__AVR_ATxmega32C4__)
#  include <avr/iox32c4.h>
#elif defined (__AVR_ATxmega32D3__)
#  include <avr/iox32d3.h>
#elif defined (__AVR_ATxmega32D4__)
#  include <avr/iox32d4.h>
#elif defined (__AVR_ATxmega32E5__)
#  include <avr/iox32e5.h>
#elif defined (__AVR_ATxmega64A1__)
#  include <avr/iox64a1.h>
#elif defined (__AVR_ATxmega64A1U__)
#  include <avr/iox64a1u.h>
#elif defined (__AVR_ATxmega64A3__)
#  include <avr/iox64a3.h>
#elif defined (__AVR_ATxmega64A3U__)
#  include <avr/iox64a3u.h>
#elif defined (__AVR_ATxmega64A4U__)
#  include <avr/iox64a4u.h>
#elif defined (__AVR_ATxmega64B1__)
#  include <avr/iox64b1.h>
#elif defined (__AVR_ATxmega64B3__)
#  include <avr/iox64b3.h>
#elif defined (__AVR_ATxmega64C3__)
#  include <avr/iox64c3.h>
#elif defined (__AVR_ATxmega64D3__)
#  include <avr/iox64d3.h>
#elif defined (__AVR_ATxmega64D4__)
#  include <avr/iox64d4.h>
#elif defined (__AVR_ATxmega128A1__)
#  include <avr/iox128a1.h>
#elif defined (__AVR_ATxmega128A1U__)
#  include <avr/iox128a1u.h>
#elif defined (__AVR_ATxmega128A4U__)
#  include <avr/iox128a4u.h>
#elif defined (__AVR_ATxmega128A3__)
#  include <avr/iox128a3.h>
#elif defined (__AVR_ATxmega128A3U__)
#  include <avr/iox128a3u.h>
#elif defined (__AVR_ATxmega128B1__)
#  include <avr/iox128b1.h>
#elif defined (__AVR_ATxmega128B3__)
#  include <avr/iox128b3.h>
#elif defined (__AVR_ATxmega128C3__)
#  include <avr/iox128c3.h>
#elif defined (__AVR_ATxmega128D3__)
#  include <avr/iox128d3.h>
#elif defined (__AVR_ATxmega128D4__)
#  include <avr/iox128d4.h>
#elif defined (__AVR_ATxmega192A3__)
#  include <avr/iox192a3.h>
#elif defined (__AVR_ATxmega192A3U__)
#  include <avr/iox192a3u.h>
#elif defined (__AVR_ATxmega192C3__)
#  include <avr/iox192c3.h>
#elif defined (__AVR_ATxmega192D3__)
#  include <avr/iox192d3.h>
#elif defined (__AVR_ATxmega256A3__)
#  include <avr/iox256a3.h>
#elif defined (__AVR_ATxmega256A3U__)
#  include <avr/iox256a3u.h>
#elif defined (__AVR_ATxmega256A3B__)
#  include <avr/iox256a3b.h>
#elif defined (__AVR_ATxmega256A3BU__)
#  include <avr/iox256a3bu.h>
#elif defined (__AVR_ATxmega256C3__)
#  include <avr/iox256c3.h>
#elif defined (__AVR_ATxmega256D3__)
#  include <avr/iox256d3.h>
#elif defined (__AVR_ATxmega384C3__)
#  include <avr/iox384c3.h>
#elif defined (__AVR_ATxmega384D3__)
#  include <avr/iox384d3.h>
#elif defined (__AVR_ATA5702M322__)
#  include <avr/ioa5702m322.h>
#elif defined (__AVR_ATA5782__)
#  include <avr/ioa5782.h>
#elif defined (__AVR_ATA5790__)
#  include <avr/ioa5790.h>
#elif defined (__AVR_ATA5790N__)
#  include <avr/ioa5790n.h>
#elif defined (__AVR_ATA5791__)
#  include <avr/ioa5791.h>
#elif defined (__AVR_ATA5831__)
#  include <avr/ioa5831.h>
#elif defined (__AVR_ATA5272__)
#  include <avr/ioa5272.h>
#elif defined (__AVR_ATA5505__)
#  include <avr/ioa5505.h>
#elif defined (__AVR_ATA5795__)
#  include <avr/ioa5795.h>
#elif defined (__AVR_ATA6285__)
#  include <avr/ioa6285.h>
#elif defined (__AVR_ATA6286__)
#  include <avr/ioa6286.h>
#elif defined (__AVR_ATA6289__)
#  include <avr/ioa6289.h>
#elif defined (__AVR_ATA6612C__)
#  include <avr/ioa6612c.h>
#elif defined (__AVR_ATA6613C__)
#  include <avr/ioa6613c.h>
#elif defined (__AVR_ATA6614Q__)
#  include <avr/ioa6614q.h>
#elif defined (__AVR_ATA6616C__)
#  include <avr/ioa6616c.h>
#elif defined (__AVR_ATA6617C__)
#  include <avr/ioa6617c.h>
#elif defined (__AVR_ATA664251__)
#  include <avr/ioa664251.h>
#elif defined (__AVR_ATA8210__)
#  include <avr/ioa8210.h>
#elif defined (__AVR_ATA8510__)
#  include <avr/ioa8510.h>
/* avr1: the following only supported for assembler programs */
#elif defined (__AVR_ATtiny28__)
#  include <avr/iotn28.h>
#elif defined (__AVR_AT90S1200__)
#  include <avr/io1200.h>
#elif defined (__AVR_ATtiny15__)
#  include <avr/iotn15.h>
#elif defined (__AVR_ATtiny12__)
#  include <avr/iotn12.h>
#elif defined (__AVR_ATtiny11__)
#  include <avr/iotn11.h>
#elif defined (__AVR_M3000__)
#  include <avr/iom3000.h>
#elif defined (__AVR_ATtiny817__)
#  include <avr/iotn817.h>
#elif defined (__AVR_ATtiny816__)
#  include <avr/iotn816.h>
#elif defined (__AVR_ATtiny814__)
#  include <avr/iotn814.h>
#elif defined (__AVR_ATtiny807__)
#  include <avr/iotn807.h>
#elif defined (__AVR_ATtiny806__)
#  include <avr/iotn806.h>
#elif defined (__AVR_ATtiny804__)
#  include <avr/iotn804.h>
#elif defined (__AVR_ATtiny417__)
#  include <avr/iotn417.h>
#elif defined (__AVR_ATtiny416__)
#  include <avr/iotn416.h>
#elif defined (__AVR_ATtiny414__)
#  include <avr/iotn414.h>
#elif defined (__AVR_ATtiny412__)
#  include <avr/iotn412.h>
#elif defined (__AVR_ATtiny406__)
#  include <avr/iotn406.h>
#elif defined (__AVR_ATtiny404__)
#  include <avr/iotn404.h>
#elif defined (__AVR_ATtiny402__)
#  include <avr/iotn402.h>
#elif defined (__AVR_ATtiny3217__)
#  include <avr/iotn3217.h>
#elif defined (__AVR_ATtiny3216__)
#  include <avr/iotn3216.h>
#elif defined (__AVR_ATtiny3214__)
#  include <avr/iotn3214.h>
#elif defined (__AVR_ATtiny214__)
#  include <avr/iotn214.h>
#elif defined (__AVR_ATtiny212__)
#  include <avr/iotn212.h>
#elif defined (__AVR_ATtiny204__)
#  include <avr/iotn204.h>
#elif defined (__AVR_ATtiny202__)
#  include <avr/iotn202.h>
#elif defined (__AVR_ATtiny1617__)
#  include <avr/iotn1617.h>
#elif defined (__AVR_ATtiny1616__)
#  include <avr/iotn1616.h>
#elif defined (__AVR_ATtiny1614__)
#  include <avr/iotn1614.h>
#elif defined (__AVR_ATtiny1607__)
#  include <avr/iotn1607.h>
#elif defined (__AVR_ATtiny1606__)
#  include <avr/iotn1606.h>
#elif defined (__AVR_ATtiny1604__)
#  include <avr/iotn1604.h>
#elif defined (__AVR_ATtiny104__)
#  include <avr/iotn104.h>
#elif defined (__AVR_ATtiny102__)
#  include <avr/iotn102.h>
#elif defined (__AVR_ATmega809__)
#  include <avr/iom809.h>
#elif defined (__AVR_ATmega808__)
#  include <avr/iom808.h>
#elif defined (__AVR_ATmega4809__)
#  include <avr/iom4809.h>
#elif defined (__AVR_ATmega4808__)
#  include <avr/iom4808.h>
#elif defined (__AVR_ATmega328PB__)
#  include <avr/iom328pb.h>
#elif defined (__AVR_ATmega324PB__)
#  include <avr/iom324pb.h>
#elif defined (__AVR_ATmega3209__)
#  include <avr/iom3209.h>
#elif defined (__AVR_ATmega3208__)
#  include <avr/iom3208.h>
#elif defined (__AVR_ATmega1609__)
#  include <avr/iom1609.h>
#elif defined (__AVR_ATmega1608__)
#  include <avr/iom1608.h>
#elif defined (__AVR_DEV_LIB_NAME__)
#  define __concat__(a,b) a##b
#  define __header1__(a,b) __concat__(a,b)
#  define __AVR_DEVICE_HEADER__ <avr/__header1__(io,__AVR_DEV_LIB_NAME__).h>
#  include __AVR_DEVICE_HEADER__
#else
#  if !defined(__COMPILING_AVR_LIBC__)
#    warning "device type not defined"
#  endif
#endif

#include <avr/portpins.h>

#include <avr/common.h>

#include <avr/version.h>

#if __AVR_ARCH__ >= 100
#  include <avr/xmega.h>
#endif

/* Include fuse.h after individual IO header files. */
#include <avr/fuse.h>

/* Include lock.h after individual IO header files. */
#include <avr/lock.h>

#endif /* _AVR_IO_H_ */

[Xring-git]

The same for me, but with:

TCCR2A
TCCR2B
TCNT2
OCR2A
WGM21
CS22
CS20

Code compiles and uploads just fine, but with "Not defined" error.

With F12 appear multiple .h files, seems that "__AVR_ATmega328P__" define is ignored.

[thomasio101]

The problem

I had a similar issue, the issue with Serial was indeed resolved by adding "USBCON" to defines, but I still had issues with identifiers such as DDRD being undefined. (After writing this answer, I discovered that @jimaobian's answer has the same effect.)

TLDR

Add the following properties to c_cpp_properties.json:

"compilerArgs": ["-mmcu=atmega328"],
"defines": ["USBCON"]

Explanation

After some research, I discovered that the definition for DDRD can be found in multiple files (each of which is for a different MCU version). For example, this is a definition from C:\Program Files (x86)\Arduino\hardware\tools\avr\avr\include\avr\iom328p.h;

#define DDRD _SFR_IO8(0x0A)

At the top of that file, I found this comment;

/* This file should only be included from <avr/io.h>, never directly. */

Thus, I took a look at C:\Program Files (x86)\Arduino\hardware\tools\avr\avr\include\avr\io.h. That file included the following comment;

This header file includes the apropriate IO definitions for the
device that has been specified by the -mmcu= compiler
command-line switch. This is done by diverting to the appropriate
file <avr/ioXXXX.h> which should
never be included directly. Some register names common to all
AVR devices are defined directly within <avr/common.h>,
which is included in <avr/io.h>,
but most of the details come from the respective include file.

After finding this, I managed to find the -mmcu argument in this documentation. Based on that documentation I concluded that I need to pass -mmcu=atmega328 to the compiler for it to work with an Arduino with an ATmega328 MCU.

Now, my c_cpp_properties.json looks like this;

{
    "configurations": [
        {
            "name": "Win32",
            "includePath": [
                "${workspaceFolder}/**",
                "C:/Program Files (x86)/Arduino/hardware/arduino/avr/cores/arduino",
                "C:/Program Files (x86)/Arduino/libraries/**",
                "C:/Program Files (x86)/Arduino/hardware/arduino/avr/libraries/EEPROM/src",
                "C:/Program Files (x86)/Arduino/hardware/arduino/avr/libraries/HID/src",
                "C:/Program Files (x86)/Arduino/hardware/arduino/avr/libraries/SoftwareSerial/src",
                "C:/Program Files (x86)/Arduino/hardware/arduino/avr/libraries/SPI/src",
                "C:/Program Files (x86)/Arduino/hardware/arduino/avr/libraries/Wire/src",
                "C:/Program Files (x86)/Arduino/tools/**",
                "C:/Program Files (x86)/Arduino/hardware/arduino/avr/**",
                "C:/Program Files (x86)/Arduino/hardware/tools/avr/avr/include",
                "C:/Program Files (x86)/Arduino/hardware/tools/avr/lib/gcc/avr/7.3.0/include"
            ],
            "forcedInclude": [
                "C:/Program Files (x86)/Arduino/hardware/arduino/avr/cores/arduino/Arduino.h"
            ],
            "compilerArgs": ["-mmcu=atmega328"],
            "intelliSenseMode": "clang-x64",
            "compilerPath": "C:/Program Files (x86)/Arduino/hardware/tools/avr/bin/avr-gcc.exe",
            "cStandard": "c17",
            "cppStandard": "c++17",
            "defines": ["USBCON"]
        }
    ],
    "version": 4
}

[YakovL]

I had problems similar to those of @Xring-git :
OUTPUT, PORTC,
TCCR1A, (but not TCCR1B!), TCNT1, OCR1A, WGM12, CS10, TIMSK1, OCIE1A, TIMER1_COMPA_vect
all give errors like

identifier "DDRC" is undefined

which don't prevent sketch from compiling/uploading.

When I opened ./vscode/c_cpp_properties.json and changed

        "defines": [
            "USBCON"
        ],

to

        "defines": [
            "__AVR_ATmega328P__",
            "ARDUINO=10800",
            "USBCON"
        ],

All those errors went away.

However, I still have errors for noInterrupts, interrupts and ISR functions. They tell specifically:

#define noInterrupts() cli()
Expands to:

__asm__ __volatile__ ("cli" ::: "memory")
identifier "__asm__" is undefined C/C++(20)

and

#define noInterrupts() sei()
Expands to:

__asm__ __volatile__ ("sei" ::: "memory")
identifier "__asm__" is undefined C/C++(20)

and

#define ISR(vector,...) extern "C" void vector (void) __attribute__ ((signal,__INTR_ATTRS)) __VA_ARGS__; void vector (void)
Expands to:

extern "C" void __vector_11 (void) __attribute__ ((signal,used)) ; void __vector_11 (void)
expected a '{'C/C++ (130)

I wonder if there's a more systematic approach to fix these, also without editing c_cpp_properties.json per each sketch.

[adiazulay]

Thanks everyone for the feedback here! #1141 should fix these issues, and it's very close to being ready to merge. I'll post here again when we have a release candidate that's ready for testing.