Honored ContributorI ran my Cyclone 3 design with and without compressed config file
generation & in both cases the .sof file came out to be 350KB. No change with compression. Did I miss some Quartus setting or do I just have an uncompressible design ? How much compression are people seeing ?
Honored ContributorOk, I see the uncompressed .jic ends at 368KB & the compressed .jic ends
at 131KB, with the file size remaining fixed at 512KB for both cases. Thanks for the help. Is this info in any Altera app note ? I've read a number of pdfs and didn't see any of the info in this thread presented.Honored ContributorIt should be.. somewhere. :)
- .SOF files are always the same size for a given FPGA device, because they're never compressed. - .POF files are always the same size for a given ROM device because they specify the contents of the entire ROM, even if it's blanks. Compression, however, lets you cram more stuff into a smaller ROM, as you just found out. - .JIC files are always the same size for a given FPGA and ROM combination due to the above. - .RBF files are the only ones that become smaller with compression, because they contain the raw compressed bitstream.Honored ContributorIn my calculation, an EPCS4 image (4 MBit) has a size of 512 kB. The *.pof or *.jic file, although using compression, will be filled up with 0xff up to the image size.
So apparently, there's no problem at all. I guess, you didn't try yet to program the file to the EPCS4 device? P.S.: You didn't previously mention the intention of combining two images. This can be done in the programming file converter. The individual images must still fit to the device when blocked into pages. 'Honored ContributorHonored ContributorHonored ContributorThe latter is right, configuration bitstream load stops after the real data and a few terminating '1' s. Decompression takes place on the fly, there's no additional delay. Some configuration schemes, e.g. FPP are using a reduced bit rate to compensate the decompression overhead.
Honored ContributorWhy the same project if targeted to EP4CGX150+EPCS128 results in larger *.pof then if targeted to EP4CGX22+EPCS4?
Larger means according to *.map file.Honored ContributorThere are more cells in the EP4CGX150, so the uncompressed bitstream will be bigger, even if you aren't using most of them. As a result the compressed bitstream will be a bit bigger too.
Honored ContributorHonored ContributorIt's probable that Quartus spreads the design in all the FPGA and as a result the configuration stream for the EP4CGX150 doesn't compress that good because you don't have big bunches of zeros all around. I don't know if there is any workaround to make the configuration time shorter...
