gpsim

Simulator for Microchip's PIC microcontrollers
Gpsim is a full-featured software simulator for Microchip PIC microcontrollers.
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Gpsim 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 PIC the same way you would in the real world.
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Gpsim has been designed to be as fast as possible. Real time simulation speeds
of 20Mhz PICs are possible.
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Gpsim has been designed to be as useful as possible. The standard simulation
paradigm including breakpoints, single stepping, disassembling, memory inspect
& change, have been implemented. In addition, gpsim supports many debugging
features that are only available with in-circuit emulators. For example, a
continuous trace buffer tracks every action of the simulator. Also, it's
possible to set read and write break points on values (e.g. break if a specific
value is read from or written to a register).