The Simulator This microcontroller simulator is based on the AQA Electronics A Level specification. The Instruction Set has been expanded slightly over the AQA spec' to make it possible to write timer interrupt code. Getting Started Read this DOC or DOCX or PDF then work through the tutorial links on the left. Bugs There is one significant bug. Some AQA machine instructions take two clock cycles to run. In this simulator, all instructions run in one clock cycle. This problem might get fixed this summer (2009). There are likely to be more undiscovered bugs. Save Your Programs Web-based tools do not have access to the local computer's file system (for security and safety reasons). So to save a program, select the code and copy it (CTRL+C) or mouse right click and choose copy. Then paste the code into a program such as Notepad. Then save the file. Reverse this process to run a saved program. Caution
Tutorial Tasks There are ten (more to come perhaps) examples and tasks. Use the navigation links on the left to get to these. reviseOmatic There are over 60 test/revision questions on assembly code programming and the simulated peripheral devices.
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Some processor details are not specified by AQA so design assumptions had to be made. The processor described in exam questions might differ in some details. For example Pre, Tmr, Porta, b and c and Trisa, b and c are all memory mapped in the simulator. These registers, specified by AQA, might not be memory mapped in exam questions. The processor details could differ in other areas too such as this pinout which is a work of pure imagination. Vpp is used only when programming the chip. PGC is the serial data clock signal used while programming and PGD is the serial program data line. These are for In Circuit Serial Programming (ICSP).
