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OrF's avatar
OrF
Icon for Occasional Contributor rankOccasional Contributor
1 year ago

CDC-50001 - 1-Bit Asynchronous Transfer Not Synchronized

the Quartus STA reports "CDC-50001 - 1-Bit Asynchronous Transfer Not Synchronized" sync-fifo in my design . at this document "AN 919: Improving Quality of Results with Design Assistant" :https://...
Timing
sstrell's avatar
sstrell
Icon for Super Contributor rankSuper Contributor
1 year ago

No, I'm saying to make all your synch chains at least 3 instead of reducing the chain length to 2 so that only chains of 3 get recognized as synch chains. If you reduce the setting to 2, there most likely be many series of 2 registers mis-identified as synch chains.

  • OrF's avatar
    OrF
    Icon for Occasional Contributor rankOccasional Contributor
    1 year ago

    Hi

    Since I can not add another FF to sample for the synchronizers ( inorder to increase the chain to 3) - I have change the setting from 3 to 2 with the next tcl command :

    "set_global_assignment -name SYNCHRONIZATION_REGISTER_CHAIN_LENGTH 2"

    I see that Quartus capture this "setting" , but on the other hand I still get the same warning: " CDC-50001 - 1-Bit Asynchronous Transfer Not Synchronized "

    any other reason for this warning ? any option to for further debug ?