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FFT 8.0 for beginner

Altera_Forum
Honored Contributor II
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Hello everybody, 

 

I am totally new at FPGA-programming (Cyclone III Starter) and especially in understanding the Altera-FFT-core. 

I read the user guide and half of the FFT-threads, but my simulation does not work :( 

 

At first I tried a 64-point burst FFT to see how everything works, later I want to use a 4096-point FFT to transform a signal from an ADC-board. 

 

I generated a random input signal (only real, imag and exp = 0), I set the sink_sop, sink_eop, source_ready and reset_n as shown in the FFT user guide. But there is no source_sop the whole time?! I can imagine that the source_real is always 0, because of the missing source_sop... 

 

But why does not assert the source_sop? EDIT: The source_valid shuold assert before the source_sop can assert, OK! But why doesn't the source_valid assert? :confused: 

 

I think it could be a mistake of beginners :rolleyes:  

Thanks for your help!
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Altera_Forum
Honored Contributor II
561 Views

Ok, I think I didn't simulate long enough. 

 

Now I got results, which make me happier :D 

 

Could somebody watch to my screenshot and perhaps tell me, why the sop, eop get managed wrong?!
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Altera_Forum
Honored Contributor II
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it probably has to do with the source_error codes that are popping up. 

 

check how many packets are making it to the FFT since your sink_ready pin is asserted then deasserted, etc.
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Altera_Forum
Honored Contributor II
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How do you easily enter some meaningful signal to the FFT for simulation?

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