USB : USB Classes    Packing and Unpacking  
Even if you plan to have your device talk only to a PC program of your own, you will still want to send bit variables at times, or bit fields: groups of data items having one bit, with maybe some items being 2-7 bits in size, because that is all the space they need. (Why waste packet space?)
 
  

2 of 14
Copyright Notice and Author Information