Intel® Quartus® Prime Standard Edition User Guide: Design Recommendations

ID 683323
Date 9/24/2018
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2.6.6.3. Use Separate CRC Blocks Instead of Allowing Blocks to Merge

Synthesis tools often attempt to optimize CRC designs by sharing resources and extracting duplicates in two different CRC blocks because of the factoring options in the XOR logic.

CRC logic allows significant reductions, but this works best when the Compiler optimizes CRC function separately. Check for duplicate extraction behavior if for designs with different CRC functions that are driven by common data signals or that feed the same destination signals.

For designs with poor quality results that have two CRC functions sharing logic you can ensure that the blocks are synthesized independently with one of the following methods:

  • Define each CRC block as a separate design partition in an incremental compilation design flow.
  • Synthesize each CRC block as a separate project in a third-party synthesis tool and then write a separate Verilog Quartus Mapping (.vqm) or EDIF netlist file for each.