When generating a bitstream for a Virtex-4 FX part, I receive the following warning:
"WARNING:Bitstream:135 - Could not determine proper JTAG IDCODE for device name 4VFX60ff1152. The IDCODE will be 0."
This means that the bitstream generated will not configure my device. How can I get a valid bitstream?
This is a known issue which will be fixed in ISE 9.2i Service Pack 2. The issue comes from a problem with the Design Rule Check which is affecting bitstream generation. To work around this, disable the DRC in BitGen. This can be done using the -d (Do not Run DRC) switch. To disable DRC via the ISE GUI, uncheck the "Run Design Rule Check" box in the "Generate Programming File" properties. This work around will not result in DRC errors being missed, as the bug occurs only in the case of a successful DRC check.