Compile and run

What Run does

Run compiles the active board’s code (if needed) and boots the result on the emulated board. There is no “simulation of your source code” — Velxio builds a real firmware binary with the real toolchain (arduino-cli / ESP-IDF / MicroPython) and executes it instruction by instruction.

• Compile (Ctrl+B) builds without running — useful to check errors fast.
• Stop halts the simulation; Reset reboots the firmware from the start.

The Output console

The bottom-left OUTPUT panel streams the build: library resolution, compiler invocations, memory usage, and finally Compilation successful. It’s the same output the Arduino IDE or idf.py build would give you.

Reading compile errors

Errors arrive exactly as the compiler emits them, with file and line:

• 'foo' was not declared in this scope — typo or missing #include.
• No such file or directory for a header — the library isn’t installed; add it via Libraries (how).
• Linker/section errors on huge sketches — the binary doesn’t fit the selected board’s flash.

Fix, press Run again. Builds after the first are much faster thanks to caching.

Tip: paste a compile error into the AI assistant — explaining errors in context is what its Basic mode is best at.

While it runs

• The status dot next to the board name in the file tree shows Idle / Compiled / Running.
• The serial monitor attaches automatically — see Serial monitor.
• Interact with the circuit live: press buttons, turn potentiometers, change sensor values from their control panels.