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Simulation error for mod 3 asynchronous in Quartus II

Altera_Forum
Honored Contributor II
‎05-31-2017 03:58 AM
1,951 Views

I have used Quartus II 14.1 (64-bit version). 

I made a mod 3 asynchronous counter as Fig 1. 

 

The functional simulation issues the error message as Fig 2. 

 

And, the timing simulation result is weird. 

I expect the result sequence is 00->01>10->(temporally 11)->00->01->........ 

But, the result is weird as Fig3. 

 

 

Is this a simulator bug? Or, let me know what is a part of mistake. 

Th higher version of Quartus II 14 is as the same.  

 

Thanks, 

Ed
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Altera_Forum
Honored Contributor II
‎05-31-2017 10:20 AM
1,218 Views

Iteration limits occur when you have a logic loop that cause the system to oscillate in 0 time. It's probably something to do with the loop cause by the resets

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Altera_Forum
Honored Contributor II
‎05-31-2017 01:24 PM
1,218 Views

I understand why the error has occurred. 

However as to the solution, I am unsure which parts must be altered or modified in order for the simulator to perform correctly like an actual circuit. 

Actual circuit is working correctly.
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Altera_Forum
Honored Contributor II
‎06-01-2017 05:56 AM
1,218 Views

It works good in version 13.

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