## Serial Interface

  Instead of polling for input we use an interrupt vector
  to write data to a rx ring buffer when it's available.

  We parse commands using a state machine so we can deal
  with small chunks of characters at a time and spit out
  the parsed command when the transmission has finished.

  TODO: System clock frequency should be a multiple of
  1.8432MHz for perfect USART. This means we would need
  an external crystal oscillator.

### Supported Commands

  - RUN
  - STOP
  - TEMP <num>
  - DEWP <num>

  Decimal point for numbers is currently not supported.
  Make sure you have disabled hardware flow control on
  the client side.

  TODO: Do we need to handle backspaces for interactive
  serial consoles?! Overkill?!

### Web Interface Example

  There is a little example web interface you can check
  out in the opt/webgui directory. The simple php page
  demonstrates how you can create a custom interface for
  your drybox. For more info see the README file there.

  You may need to run the following command to load the
  optional submodules if you can't see the webgui folder:

    git submodule update --init