I guess that a pretty easy questions but I really couldn't figure it out. I made a design with the Xilinx ISE Design Tools which uses a lookup table which is saved within the BlockRAM. Where do I see the amount of how many BlockRAMs I used and how many are still free?

I guess it must be somewhere within the Design Summary but I really can't find it.

  • 2
    \$\begingroup\$ The Synthesis Report (.syr) file is plain text, you can search it with a text editor. \$\endgroup\$
    – user16324
    Commented Nov 10, 2015 at 13:05

1 Answer 1


After running the step Synthesis the tab Design Summary includes a table with the device utilization. Within this table there should be a line starting with "Number of Block RAM / FIFO" giving the amount of Block RAMs used and avaible. Note these are estimated values.

If there is no such line, then your lookup table has not been synthesized to block RAM. Open the Synthesis Report from the left tree in the Design Summary tab. Search for XST:3218 meaning that your lookup table was to small and has been implemented as LUT-RAM.

After running Implement Design the table is updated to the real values and now includes a line starting with "Number of RAMB18/..." or "Number of RAMB36" (depends on the selected FPGA).


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