Page 39 of UG161 talks about compression/decompression and implies that either bitgen or prom compression can be used to shorten the config bit stream size. Most importantly I need to know whether, when using the bitgen compression option this means that I need to use the CLKOUT pin for FPGA configuration as described by UG161 pg 62.
Originally I was trying to load 2 revisions of my design onto one PROM device, however Impact reported that the bit file was too big. After using the bitgen compression option, my bit file was smaller and 2 designs were able to fit on the PROM. However, the Xilinx documentation is unclear as to whether using the bitgen option means that I must use the PROM CLKOUT or not, as pg 39 seems to imply there is a difference between this and PROM compression.
UG161 can be found here http://www.xilinx.com/support/documentation/user_guides/ug161.pdf
I am working with Spartan-6 series XC6SLX45T FPGA and XCF16P PROM if that helps. The tools I'm using are Xilinx ISE 13.4, both the command line and IMPACT.