Emulating the CPU is nice, but the trouble has always been emulating the peripherals

Does your editor do this? I tried the example but didn't see e.g. LEDs blinking

Yes,peripherals are fully emulated, not just the CPU. LEDs blink, buttons respond to clicks, Serial Monitor works, servos rotate, displays render (ILI9341 TFT), and we have 48 o more components from the wokwi-elements library. The Blink example should show the built-in LED toggling on pin 13. If it didn't blink for you, it might be a compilation issue

try the example Traffic Light : Simulate a traffic light with red, yellow, and green LEDs

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functional_dev 2 days ago | parent [-]

does this handle the timing differences between browser execution and real time hardware? or is it focused on logic verification?

	▲	dmcrespo 2 days ago \| parent [-]
		Both, with a nuance. The AVR simulator syncs to wall-clock time and each frame calculates cycles from real elapsed deltaMs, so delay(1000) takes 1 real second and timer-dependent code (PWM, millis()) runs at correct real time rates. The RP2040 and ESP32-C3 simulators use a fixed cycles-per-frame budget (125MHz/60 and 160MHz/60 respectively), which targets real time but doesn't compensate for frame drops . if the browser stutters, emulated time stretches slightly. All three are cycle-accurate at the instruction level though, so the logic and peripheral behavior is faithful to real hardware regardless of frame timing

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dmcrespo 2 days ago | parent | prev [-]

You can add peripherals There’s a “+” button on the right side of the circuit editor where you can add components like LEDs