In iMPACT 8.1, when generating generic HEX file format, the "swap bits" function is always enabled regardless of the state of the check box. Even after loading a CDF file with "Swap bits" set to FALSE, the HEX file is generated with swapped bits. The PROM file properties shows the box checked, and unchecking the box has no effect.
The problem is that the iMPACT GUI or batch mode will not execute the correct PROMGen command line:
promgen -w -p hex -c FF -o output_file.hex -u 0 input_file.bit
promgen -w -p hex -b -c FF -o output_file.hex -u 0 input_file.bit
The PROMGen command line options are explained further in the PROMGen section of the Development System Reference Guide:
There are two ways to work around this problem:
1. Use iMPACT 7.1.04i
2. Run PROMGen from the command line.
This issue is scheduled to be fixed in ISE 8.2i.
If you need further assistance with this problem, open an online WebCase with Xilinx Customer Support at: http://www.xilinx.com/support/clearexpress/websupport.htm