CDC-50001 - 1-Bit Asynchronous Transfer Not Synchronized

Bottom line: After all the trial and error in these threads, I need to do two things:

1.Set the global assignment with -name SYNCHRONIZER_IDENTIFICATION "FORCED IF ASYNCHRONOUS".
2.Remove the reset from the synchronizers.

But I’m wondering if this is a bug in Quartus or if there’s a technical explanation for why this is necessary.

Regarding the synchronizer, in ASIC design, synchronizers do have an async reset.

What about FORCED IF ASYNCHRONOUS?

Thanks,
Or

Hi Or,

Sometimes the flip-flop with async clear will not be identified as synchronizer due to other considerations of the tool. Some of the reasons mentioned before. If that happens, try to avoid async clear. You'll find that the synchronizer template code all without the async clear.

thanks

what about the meaning , FORCED IF ASYNCHRONOUS ? or why cant I use the Forced option

Hi Or,

Those flip-flop with async clear can't be identified as synchronizer even after enable FORCED IF ASYNCHRONOUS means can't be forced. This is the tool consideration for the functionality. In this case, better avoid the async clear.

Thanks,

Regards,

Sheng