C1541 drive emulation debug on DE2

Adding my own VHDL work to some other people work to get FPGA reading D64 directly from sd card. Project is already able to load many games but still bugs to find out. Debug is going on with DE2 board.

DE0 Nano low cost Multi IO schematic and BOM

DE0 Nano low cost Multi I/O (audio/video/kbd/sd_card/digital IO) schematic and BOM available at https://sourceforge.net/projects/darfpga/files/hardware/io_sd_board