Answers Database

bitgen 7.0: Does bitgen 7.0 do a length count alignment of the bitstream?


Record #1786

Product Family:  Software

Product Line:  Merged Core

Problem Title:
bitgen 7.0: Does bitgen 7.0 do a length count alignment of the
bitstream?



Problem Description:
keywords:
bitgen,length count,length count alignment,bitstream,makebits, done

urgency:
standard

general description:
In XACT 5.2.1, makebits automatically does a length count
alignment.  By default, makebits uses the -lc=aligned_done.  This
ensures that if the FPGA under configuration is in a byte-wide
configuration mode, there will be enough CCLK's to finish
the configuration.  Under some circumstances, if there are not
if the bitstream is not 'DONE length count aligned' the /INIT
pin will be high, but DONE will never go high, and/or the
FPGA will not respond to inputs.


Solution 1:

bitgen 7.0, like makebits 5.2.1, aligns the length count
 of the bitstream.



End of Record #1786