Demo code to go along with Hackaday article on Circular Buffers.

Straight out of the box, this will compile for AVR on any platform that's got AVR-GCC and make installed. The code will work with AVR Studio or even Arduino, because it's just C. However you're compiling code, just do that.

To compile / flash C code on Arduino:

1. Create a new sketch, delete everything (the setup and loop functions) from the default .ino file, and quit Arduino
2. Copy the .c and .h files over to the sketch's directory
3. Open the Arduino IDE again and you'll see the code opened up for you in tabs
4. Compile as usual. Edit. Flash. Play around.

There are multiple demo versions hidden in the history of this project. Check them out!

• Naive Demo (a793508): with lots of printing. Good to watch it run and figure out what's going on. Probably too long, sorry.

• Loopback Demo (f33be28): shows how two buffers (one for receiving and one for transmitting) and some interrupt code can handle serial input and output. This is a lot like what the Arduino libraries do under the hood, but written less generally and much more transparently, IMO.

• Words Demo (55ab726): Uses interrupt-driven RX and TX and the bufferPeek() function to print out what you type in only after a complete word has been sent.

Most of the examples depend on having an instantaneous-response serial terminal program. Unfortunately, you Arduino folks are out in the cold here -- Arduino's default serial monitor program only responds when you hit the "Enter" key.

I use a python module (PySerial) that just happens to have a nice built-in serial terminal emulator program. This will work anywhere you've got Python installed: python -m serial.tools.miniterm --cr $PORT $BAUD

On Windows, try Realterm or Tera Term if you're not running XP anymore. (R.I.P. Hyperterminal.)