Hi guys, recently I found out that when you are coding Arduino mega to use its secondary serial ports, it is always “undefined” at Serial1 / Serial2 / Serial3. However the build and verify doesn’t have any issue
The way to resolve this, is to locate this file
.vscode/arduino.json
After locating the file, add a “buildPreferences” at the end of the json
"buildPreferences": [
["build.extra_flags", "-D__AVR_ATmega2560__"]
]
