Usage instructions

SC is a language with a C-like syntax. An SC program consists of the .sc source files in the current directory, along with the source files in any specified module search paths. Each .sc source file contains the code for the module with the same name. .. TODO details: modules, what compiles, etc

This is a simple SC program showing the syntax:

byte foo = 4;

void main()
{
    byte bar;

    bar = 3;

    while (foo != 2)
    {
        foo = bar;
        bar--;
    }

    doTheFoo(5);
}

void doTheFoo(byte bar)
{
    foo = bar + 2;
}

To use functions and data fields from other modules, prefix their name with the module name and a period. For example, foo.bar = 42; assigns 42 to the bar data field in the foo module.

To compile the program, run scc.py. If you want to specify a module search path, use the -m option. -m can be used multiple times to specify more search paths. Use the --help option to see all options.

Assembling

The compiler writes the output assembly to output.asm. Use as504 output.asm (or as504.py output.asm on Windows) to assemble the output and create output.hex.

Uploading

The uploader uses a subset of the functionality of the debugger. It’s intended to quickly upload a program to the board.

Run uploader.py SERIALPORT output.hex, where SERIALPORT is the serial port on which the board is connected. To see which ports are available on your system, run uploader.py --list-ports. If you use an USB serial port, please install the driver if the port is not visible.

Sometimes, the hardware is in an incorrect state to receive commands, sometimes even directly after a powering on. If this is the case, the uploader will warn that the board is not responding. Press the reset button on the board to continue.

Debugging

The debugger is an interactive command-line program that can show the current program execution location, memory and register contents and allows single stepping.

Start the debugger with debugger.py SERIALPORT. Like the uploader, debugger.py --list-ports shows the available ports on your system. (For listing ports, there’s no difference between the two.)

These commands are available in the debugger:

list: Shows the previous, current and next instructions located around the program counter. If you add an address (like list 04A1), it shows the instructions around that location. This command requires debug information loaded with the load command.

show <variable>: Shows the contents of the specified variable. The variable name must contain the module name, like show main.counter.

mem <location> <address>: Shows the contents of a memory block. The location must be one of direct, indirect, external and code, and may be abbreviated. Example: mem direct 3b. The 32 byte block containing that address is shown.

step: Executes one instruction. If you add a number (like step 12), that number of instructions are executed.

load <filename>: Uploads a program to the board and loads associated debug information, if present. Uploading a program does only changes memory that will contain the program. Other memory (including registers) is not reset.

loaddebug <filename>: Loads the debug information for a program. This is useful if the program has already been uploaded but the debug information hasn’t been loaded yet.

run: Starts execution of the program.

stop: Stops execution of the program. In certain conditions, the monitor program on the board does not process the stop command. In that case, you have to reset the board to stop execution. Note that resetting the board modifies the program counter and the special function registers.

reset: Sets the program counter to 0. This does not reset memory or special function registers.

exit: Quits the debugger.