Main dumbreader

main_dumbreader is a fairly simplistic RFID reader firmware. All it does is to export a number of primitives and give the host PC direct access to the RC632. Because it doesn't actually do something useful rather than shifting bytes from SPI to USB (and back), we call it "dumb".

The reason for first providing the main_dumbreader firmware is mainly because its easy to do, and because the already existing librfid project supported such readers fairly good.

The access primitives provided by main_dumbreader are:


 * read RC632 register
 * write RC632 register
 * read RC632 fifo
 * write RC632 fifo

In addition, there is some experimental support for:


 * signalling RC632 interrupts on the USB interrupt endpoint