I'm looking at a freescale doc for Pulse Oximiter Application at http://cache.freescale.com/files/32bit/doc/app_note/AN4327.pdf?fasp=1&WT_TYPE=Application%20Notes&WT_VENDOR=FREESCALE&WT…. On page 13, it said that the demo is based on the Freescale USB stack. I wondering what part I will need to make it work? Do I need both a microprocessor (may be Kinetis K53) and a seperate USB stack? Thanks!