Gpsim is a full-featured software simulator for Microchip PIC microcontrollers distributed under the GNU General Public License; it has been designed to be as accurate as possible. Accuracy includes the entire PIC, from the core to the I/O pins and including all of the internal peripherals. Thus it’s possible to create stimuli and tie them to the I/O pins and test the PIC the same way you would in the real world and can be controlled from either a graphical user interface (a GUI built in), a command line interface (CLI) or by a remote process. Gpsim has been designed to be as fast as possible. Real time simulation speeds of 20Mhz pics are possible. The major features are;

• Breakpoints; execution, read and write memory, wdt, <ctrl -C>;
• Disassemble o dump memory/eeprom;
• Trace;
• Stimulus files, analog and digital;
• Dynamically loaded modules;
• ...and many many others!

Gpsim supports loadable modules, this means that it is possible to add devices to gpsim that are totally separate from gpsim because they reside in their own libraries and are distributed separately. Basically gpsim provides a basic module library with the following components:

There are, also, two "external" packages;

For more informations click here.

           

JMCAD is an program for the modeling and simulation of dynamic systems. This includes the ability to construct and simulate block diagrams. The visual block diagram interface offers a simple method for constructing, modifying complex system models. The simulation engine provides fast and accurate solutions for linear, nonlinear, continuous time, discrete time, time varying and hybrid system designs. With JMCAD, users can quickly develop software or "virtual" prototypes of systems or processes to demonstrate their behavior prior to building physical prototypes. Some fetaures;

• The user builds his system model by selecting predefined blocks from a block library and simply wiring the blocks together. Each block of the diagram performs a function. Users can also create custom blocks in Java and add them to the JMCAD block library;
• JMCAD is a block diagram language for creating complex nonlinear dynamic systems. Its fast execution speed is perfect for model based operator training, off-line controller tuning, and hardware in the loop testing;
• By combining the simplicity and clarity of a block diagram interface with a high-performance mathematical engine, JMCAD provides fast and accurate solutions for linear, nonlinear, continuous time, discrete time, multi-rate, and hybrid systems;
• For specialized engineering problems, JMCAD offers a comprehensive set of companion products for frequency domain analysis, Java code generation, communications system modeling, DSP and embedded system design, neural networks and real-time analog and digital I/O.

JMCAD is developed and written completely in Java and will run in any certified Java Virtual Machine (JVM).