What is Proteus VSM?
Proteus Virtual System Modelling (VSM) combines mixed mode SPICE circuit simulation, animated components and microprocessor models to facilitate co-simulation of complete microcontroller based designs. For the first time ever, it is possible to develop and test such designs before a physical prototype is constructed.
This is possible because you can interact with the design using on screen indicators such as LED and LCD displays and actuators such as switches and buttons. The simulation takes place in real time (or near enough to it): a 300 MHz Pentium II can simulate a basic 8051 system clocking at over 12MHz. Proteus VSM also provides extensive debugging facilities including breakpoints, single stepping and variable display for both assembly code and high level language source.
The VSM architecture allows additional animated models to be created by anyone, including end users. Whilst many types of animated model can be produced without resort to coding, a documented interface has been provided for developers to write their own models packaged as Windows DLLs. These models can implement purely electrical behaviour or combine this with graphical behaviour so that almost any kind of application specific peripheral can be simulated.
ISIS Schematic Capture
Screen shot of the ISIS schematic editor showing an 8051 calculator design that incorporates a numeric keypad and LCD display. The simulation is paused with the 8051 register window and source level debugging window visible.
Schematic Entry
Proteus VSM uses our proven Schematic Capture software to provide the environment for design entry and development. ISIS is a long established product and combines ease of use with powerful editing tools. It is capable of supporting schematic capture for both simulation and PCB design. Designs entered in to Proteus VSM for testing can be netlisted for PCB layout either with our own PCB Design products or with third party PCB layout tools. ISIS also provides a very high degree of control over the drawing appearance, in terms of line widths, fill styles, fonts, etc. These capabilities are used to the full in providing the graphics necessary for circuit animation.
Circuit Simulation

At the heart of Proteus VSM is ProSPICE. This is an established product that combines uses a SPICE3f5 analogue simulator kernel with a fast event-driven digital simulator to provide seamless mixed-mode simulation. The use of a SPICE kernel lets you utilise any of the numerous manufacturer-supplied SPICE models now available and around 6000 of these are included with the package.
Proteus VSM includes a number of virtual instruments including an Oscilloscope, Logic Analyser, Function Generator, Pattern Generator, Counter Timer and Virtual Terminal as well as simple voltmeters and ammeters. In addition, we provide dedicated protocol analysers for SPI and I2C - simply wire them onto the serial lines and monitor the data live during simulation. A truly invaluable (and inexpensive!) way to get your communication software right prior to hardware prototyping.
VSM Logic Analyser - one of several virtual instruments.
Should you wish to take detailed measurements on graphs, or perform other analysis types such as frequency, distortion, noise or sweep analyses of analogue circuits, you can purchase the Advanced Simulation Option. This option also includes Conformance Analysis - a unique and powerful tool for Software Quality Assurance.
Co-Simulation of Microcontroller Software

The most exciting and important feature of Proteus VSM is its ability to simulate the interaction between software running on a microcontroller and any analog or digital electronics connected to it.
The micro-controller model sits on the schematic along with the other elements of your product design. It simulates the execution of your object code (machine code), just like a real chip. If the program code writes to a port, the logic levels in circuit change accordingly, and if the circuit changes the state of the processor's pins, this will be seen by your program code, just as in real life.
The VSM CPU models fully simulate I/O ports, interrupts, timers, USARTs and all other peripherals present on each supported processor. It is anything but a simple software simulator since the interaction of all these peripherals with the external circuit is fully modelled down to waveform level.
VSM can even simulate designs containing multiple CPUs, since it is a simple enough matter to place two or more processors on a schematic and wire them together.
Source Level Debugging
Whilst Proteus VSM is already unique in its capabililty to run near real time simulations of complete micro-controller systems, its real power comes from its ability to perform these simulations in single step mode. This works just like your favourite software debugger, except that as you single step the code, you can observe the effect on the entire design - including all the electronics external to the microcontroller.

VSM achieves this in a number of ways, dependent on the processor family and the tools that you are using. For detailed information on the third party compilers supported by Proteus VSM please see the Third Party Compilers page.
PROSPICE Debugging Windows
Debugging windows for the 8051 calculator design. At the top is the source code showing breakpoints and at the bottom, from left to right, a register window, watch window and 8051 internal memory window.
Model Library
In addition to the microprocessor models for each supported family, each Proteus VSM package includes a library of over 6000 device models such as:
  All manner of standard electronic components including resistors, capacitors, diodes, transistors, SCRs, op-couplers, op-amps, 555 timer etc., etc.
  74 series TTL and 4000 series CMOS devices.
  Memory devices including ROMs, RAMs EEPROMs, I2C device etc.
  Microprocessor support devices such as I/O ports and USARTs.
The Proteus VSM library also contains a number of complex peripheral models including LED/LCD displays, matrix keypad, teletype terminal, DC motors, speaker/sounders and much more These models will allow you to interact with the software running on the simulated microcontroller, much as though you were working with a physical prototype.
 

Animated Graphical LCD panel - this part sits directly on your schematic just like an ordinary component. When you run the simulation, the output from the simulated display controller chip is drawn directly on the screen.

See the calculator picture, above, for further clarification of how the peripheral models work.
For more information on the VSM peripheral library, please click here.

At the time of writing, at least one other company is now developing models for Proteus VSM. Please see our 3rd Party Models page for more information.
You can also create your own models in a variety of ways. A detailed SDK explaining the various ways you can go about this is included with each Proteus VSM package.
Whilst we believe Proteus VSM is functionally so far ahead of any other product that it really has no competition, you may also want to look at our competitive analysis to compare features against other offerings on the market or read some existing customer comments.