The simulation below is running 256 NOP (no operation) commands. Look at the examples for something more interesting.
You can type your code directly into the code editing area of the simulator but there is no save faclity.
A better idea is to use a text editor such as Notepad to create and save your code.
When entering code, please remember that, within this simulation, all numbers are hexadecimal. Eventually you will need to use the 0xFF notation but for now just enter FF.
Then copy and paste your code from your text editor into the simulator code editor.
Press the "F8" key to assemble your code and load the machine code into the processor. (Make sure your cursor is in the code editor region when you press F8)
This also resets the processor and starts code execution from address zero.
To run the code one line at a time, press the "S" button (Stop / Step).
To run the code continuously, click the "Increase Processor Speed" button.
Be careful not to refresh your web page. This is equivalent to a cold boot and your simulation re-starts without any code.
This simulator is being built by Neil Bauers and is a "best effort" attempt to match the microcontroller outlined in the new United Kingdom AQA Exam Board specification. Please use it with this in mind. This early version is useable but there are still unfinished modules and most likely lots of bugs. Ian Kemp has already helped with some useful technical details. Further constructive criticism is hoped for.
As well as introducing microcontroller programming, the plan is to simulate devices such as stepper motors and H Bridge controllers, promoting understanding of these devices.
System Requirements
A web browser with the latest Adobe Flash Player (V9) plugin installed.
A text editor such as Notepad.
A mouse or other pointing device.
For very smooth animations, good machine and graphics performance are needed.
Known Bugs
Labels have not been implemented yet.
The processor stops and sulks if it encounters an invalid op code. You need to fix the coding error and re-assemble the code.
Wish List
Labels and Literals have not yet been implemented.
More simulated peripherals are needed.
Input peripherals as well as output.
A better screen layout.
Code highlighting animated as the code executes.
Adobe are promoting a free cross-platform run-time environment called Adobe Air.
This allows Flash applications such as this simulator to be installed as if they were normal native applications. This would also allow the file-open and file-save actions to be performed. The web-based version does not allow access to the file system. This limitation would be removed.
My plan is to develop both the web based simulator and also an Adobe Air version.