A simulation that’s an exact copy of a physical device would be ideal. Barring that, developers can choose from a range of simulation techniques that can replicate a device, allowing details such as timing and physical characteristics to be tracked through simulations that simply execute a program with no real interfaces.
Different simulation methodologies provide insight into different aspects of a system. Tradeoffs are normally required to keep the simulation practical, though. For example, simulating an RTL-level design is great for checking timing, electrical interaction, and other circuit-level details, but the amount of processing power is high.
This often reduces runtime speed to a fraction of an actual device. Still, if the insights gained are worthwhile, then reducing the scope of a simulation or taking more time also will be worthwhile. Likewise, improvements in performance permit ever more complex systems to be simulated in real time or near real time.
Some simulations often lack interaction with the outside world, or even simulation of the interfaces that would normally be found in a device. Simulations can be valuable without these interfaces, but including I/O greatly enhances their usefulness.
WANTED: FLEXIBLE I/O Incorporating I/O into a simulation is getting significantly easier for designers. ARM’s processor cores are used in a wide range of standard and custom devices, but they are always surrounded by an array of peripherals. ARM’s latest RealView Simulator lets designers drag and drop peripherals so they can be simulated along with the core (see the figure).
As with most peripheral simulations, digital devices such as serial ports can be fed data streams. But doing the same for analog devices is more difficult. Typically, the developer can provide the digital data stream from an analog peripheral.
Virtutech’s work toward standardizing simulation platforms with organizations such as Eclipse.org, OSCI, and the Spirit Consortium addresses I/O in addition to the broader range of interoparbility models and object reuse across different vendors. Tackling issues such as peripheral support should significantly improve interest in using simulation. ARM • www.arm.com VIRTUTECH • www.virtutech.com
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