Calculate clock settings for Papilio DCM/PLL timer system. This is a Spartan6 FPGA. Derived from http://www.xilinx.com/support/documentation/user_guides/ug382.pdf
Presents a basic GUI unless invoked with two args (in MHz). E.g. papilio_clock 32 24.576
Basic GUI prompts for these values and displays as pictured. The clocks are also printed to console or cmd line. If invoked with two args - does not show GUI.
Currently only computes possibilities for one single, or two cascaded, DCMs. PLLs may follow...