Adafruit_USB_Backpack_Plus | Feature enhancements based on fork of CanyonCasa USB

This directory contains the makefile and libraries necessary to build BackpackPlus/BackpackPlus.cpp. If you intend to modify and build the program then the following will be useful information. Note The current revision of the code uses almost 100% of the device so you will need to remove features to add more features. To make space for the audio level meter I had to eliminate some of @CanyonCasa 's debug features and incrementally add things back until I couldn't go any further. For example, if you don't need the audio level meter you can get back a significant amount of space for something else by commenting it out or deleting it.
Make certain you have gnu-make, avr-gcc, avr-libc and avrdude installed. Instructions for setting up your AVR cross-compiler and build system is not in the scope of this README. If you need help for setting up the build system, quick searching reveals hits on many good quality how-to's and tutorials for AVR development. Below instructions assume you are working from a console (cmd.exe, bash, csh, etc.)
Modify BackpackPlus/BackpackPlus.cpp as desired.
Edit the makefile '''PORT = /dev/ttyACM0''' to match the port your USB backpack shows up on (on Windows COM3, for example)
Enter into the build directory and issue make.
Have the command make burn ready to go on the command line.
As with prior instructions, short RESET pin to ground on the USB backpack.
Immediately press enter to issue the make burn command.
Check that avrdude finishes with success.