Proteus Virtual System Modelling used for microcontroller education

Engineers working in the embedded system design area using micocontrollers need to resolve some issues not found in desktop environment programming. There is often no standard hardware platform for which the software (firmware) is to be developed. Usually both hardware, and firmware need to be designed, and there are many options to be considered when selecting hardware components. Connections to outside world are made through various interfaces, sensors, and actuators. Those components could be unavailable when firmware development is started. Accurate simulation of such systems would save many hours of prototype development. Provided with some application specific virtual instrumentation, we would have complete embedded virtual laboratory at our disposal. In this paper the Proteus Virtual System Modeller (VSM) software from Labcenter Electronics Ltd is used to provide such simulation environment. This software is used to draw the schematic diagram, but the microcontroller drawn is also able to accept, and execute the code produced with independent compiler. It is even possible to connect Proteus VSM with third party software debugger, and watch animated schematic diagram at work as if it was real hardware. As an example, the operation of small 8-bit microcontroller interrupt handler function will be shown in this article, when there are multiple interrupt sources connected to single interrupt line.