Simulator

The simulator shows a picture of the programmers model of a 6811 so that a programmer may observe the changes in the registers as each opcode is executed. The simulator allows a programmer to view memory, alter any register, to single step and to set breakpoints. I have used the simulator in a Macintosh environment. It is very good. To start the simulator on a Mac only requires double clicking the sim68 icon. Once the simulator is started, an s19 file may be loaded for simulating. After loading an s19 record, the PC is automatically set to the next instruction to execute and the simulator shows the disassembled mnemonic of what instruction will execute next. There is a "step" button and a "go" button. The "step" button is clicked once per single step through the code. Menu options allow for the setting of break points, displaying of memory, and modifying of registers.

Debugging code is certainly best done on the simulator. If your program is not doing what you expect on the Miniboard, then you have very little feedback about what is happening on the Miniboard. In the simulator, you have exacting feedback about every thing that is going on in the MCU and in memory.

The simulator is easily applied to programs that were developed in assembly language. Simulating the code which came from a compiler will prove much more challenging since compilers may not include interrupt vector information (like the reset vector) or completely dereference all symbols in its assembly dump.

Since the simulator will not be able to simulate interrupts, programmers will quickly find the limits of where the simulator is useful. Developing a useful robot control program will require the use of interrupts.

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