Serial Ports

How difficult is it to write C/C++ code which works with the serial ports....such as.........you have a serial port cable hooked up to your serial port, and the other end to a small circuit board you made consisting only of an LED....what's the difficulty level of writing code to turn the LED on and off....is that really hard?

Its not too hard. Just operating system dependant. What os?

mmm....most likely WIN ME....

You can use the win32 api function CreateFile() to access the serial port. Look in the documentation at msdn

Not sure if it'll work perfectly under windows, but if you want to try some inline ASM you can use ASM's IN and OUT instructions.