After last update of PlatformIO, it can’t compilate code even with [Serial.begin()]. Simple code is compilate fine. [image]

Seems to me like your Arduino framework got corrupted (specifically the HardwareSerial code). Can you remove the C:\Userse\Egor_\.platformio\packages\framework-arduino-avr folder and build again?

susaninx October 1, 2022, 2:23pm 6

Thanks for support!
It’s working now

PlatformIO can't compilate any complicate code