I read all of the documents I could find about using the JTAG port as a communications interface to the FPGA and implemented my own JTAG controlled logic. The problem is, none of the documents that I read gave a decent solution as to how to get access to the JTAG chain on the PC side of things. I am using the Virtex II-Pro XUP board which has a USB front end to the JTAG interface. Is there an existing software solution available that I can use to send data to the user JTAG registers? If not, then is there a Xilinx API that I need to use to write a program to do it myself or do I need to use a standard USB library? Finally, once I am able to send data to the board's USB interface, is there a protocol that I need to follow to work with the Cypress USB chip or can I just send raw JTAG commands as the data payload?
---Matthew Hicks