Quick answer: Proteus VSM can co-simulate supported microcontroller firmware and mixed-mode SPICE circuitry, but the screen shows a model, not a real part. Validate the model, the firmware loading, the pin configuration, and the indicator behaviour, then treat the result as a logic check rather than a physical rating.
What simulation is and is not
Labcenter documents Proteus VSM as co-simulating supported microcontroller firmware together with mixed-mode SPICE circuitry, alongside interactive indicators and debugging facilities, and it separates simulation from physical prototype testing. That separation is the point of this checklist: a lit indicator in a virtual model demonstrates the logic you described, not the current, thermal, or drive behaviour of real hardware.
Pin configuration is a frequent trap
The Arduino digitalWrite() reference states that a pin must be configured as OUTPUT to drive an output voltage, and that on an INPUT pin digitalWrite instead enables or disables the internal pull-up. Those are real hardware semantics. Verify your pin modes explicitly in the sketch rather than assuming something else enforced them, and as a planning caution do not read an active simulated indicator as confirmed electrical behaviour: an indicator in a model is a statement about logic, not proof that a real pin is configured to drive a real load.
Comparison: simulated result versus physical reality
| What simulation shows | What physical hardware instead depends on |
|---|---|
| Logic state (HIGH or LOW) | GPIO drive capability and the load on the pin |
| Indicator lit or unlit | LED forward current and the series resistor |
| Firmware co-simulation | Real timing, clock, and start-up behaviour |
| Interactive indicator | Actual brightness and thermal behaviour |
| Model behaviour | Component tolerances and datasheet ratings |
Ordered validation process
- Confirm the microcontroller model you placed is one Proteus VSM supports for co-simulation.
- Attach your firmware build and confirm it loads, rather than relying on default behaviour.
- Set pin modes explicitly: OUTPUT to drive a pin, pull-up only on INPUT, matching the digitalWrite() rules.
- Choose interactive indicators so node states are visible while you step the logic.
- Treat each current-limiting resistor as a design value, and remember the model value does not prove real LED current.
- Exercise the logic: does the bar graph respond as intended across all intended states?
- Record which results are simulation-only and which still need confirmation on a physical prototype.
Reader questions
Does a successful simulation mean my circuit works on hardware?
No. The vendor distinguishes simulation from physical prototype testing. Simulation validates modelled logic, while hardware adds drive limits, tolerances, and thermal behaviour.
Why does a pin read fine in simulation but not on the board?
A common cause is pin mode. digitalWrite() only drives a voltage when the pin is an OUTPUT; on an INPUT pin it instead controls the internal pull-up. Verify the mode in your own sketch.
Can I trust the LED model series-resistor value?
Treat it as a simulation convenience, not a verified rating. The model does not establish actual LED current, GPIO drive capability, or PCB thermal behaviour.
Menu locations, component names, and software versions change between releases, so confirm them against your own installed version.
Documentation
- Labcenter Proteus Virtual System Modelling documentation
- Arduino digitalWrite() reference (official reference-en source)
Documentation-based reference only: the sources are the vendor simulation documentation and the official Arduino digitalWrite() reference. No simulation was run and no version was checked, so component names, LED model values, menu paths, and the downloadable project still need to be confirmed against your installed release. The same validation discipline applies to the Proteus relay simulation walkthrough, and the PCB making guide is a companion for the physical board that follows.
