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Altera_Forum's avatar
Altera_Forum
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15 years ago

CLOCKS_ARE_SYNCHRONIZED Warning

I have this warning

Warning: Assertion warning: Number of metastability protection registers is not specified. Based on the parameter value CLOCKS_ARE_SYNCHRONIZED=FALSE, the synchronization register chain length between read and write clock domains will be 2

I don't know where to set the synchronization chain number in the GUI, I did set the Synchronization Register Chain length to 2 in the Analysis & Synthesis Settings window but it doesn't seem to be OK...:confused::confused:

Thank you for your help!

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    I presume that warning refers to a specific module/function you're using.

    It's a bit hard to give any advice without knowing what it is.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    When locating it in design file, it appears that the warning refers to a dcfifo_hrd1 subdesign file which has a set of "local" altera options on top ( OPTIONS ALTERA_INTERNAL_OPTION = "AUTO_SHIFT_REGISTER_RECOGNITION=OFF;REMOVE_DUPLICATE_REGISTERS=OFF;suppress_da_rule_internal=d101;suppress_da_rule_internal=d102;suppress_da_rule_internal=s102;{-to p0addr} POWER_UP_LEVEL=LOW;{-to rdptr_g} suppress_da_rule_internal=r105"; ).

    Thank you