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Initial value setting error

Er7Cho1gU
Novice
345 Views

Hello:

    I'm new in verilog.  Hopping that it's not a very stupid problem.

    I'm tring to buid a FSM system using register "state" to perform the state now.  There is no error hint or any functional problem on FSM insted of the initial problem on reg "state".  The waveform shows that reg "state" keeping high at the begining, untill  the stop signal arrives.  Alought I had setting the initial value at begin, I can't fix it and I have no idea what could I do.  Hopping that someone can help me.

 

Here is my code:

module state(start,stop,state);
input start,stop;
output reg state;

initial state = 1'b0;

always@(posedge start or posedge stop)begin
if(start == 1) state = 1;
else if(stop == 1) state = 0;
else state = state;
end
endmodule

 

螢幕擷取畫面 2022-10-10 184732.png

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1 Solution
ShengN_Intel
Employee
285 Views

Hi,


Try to use devices Cyclone III, Cyclone IV, Max II, Max V or Arria II instead of Cyclone V. New devices are not supported on vwf waveform simulator because this is legacy simulator which only supported legacy devices and mainly for university program purpose. Or may be you can use modelsim simulator instead of vwf waveform simulator.


Best Regards,

Sheng

p/s: If any answer from the community or Intel Support are helpful, please feel free to give best answer or rate 4/5 survey.


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4 Replies
ShengN_Intel
Employee
310 Views

Hi,

 

I'm getting the desired vwf waveform for the code posted above. Check image below:

ShengN_Intel_0-1665463043264.png

I think there is no problem with the code given.

File attached: fsm.zip

Quartus version: Prime 21.1 Standard Edition

 

Best Regards,

Sheng

p/s: If any answer from the community or Intel Support are helpful, please feel free to give best answer or rate 4/5 survey.

 

Er7Cho1gU
Novice
295 Views

Sorry, I upload a wrong picture above.  Here is my vwf waveform.螢幕擷取畫面 2022-10-11 160354.png

The "state" pin perform high at the begining.  However, you said that the waveform simulation on your computer is correct.  I'm wondering if it is because of the setting of my quartus.  I just install Quartus these days.  By the way, my quartus is version 13.1 web edition.  I found that even I use timing simulation insted of functional simulation, there has no delay on the waveform.  I'm not sure if there is a problem on the result and I'm figuring out the solution.

螢幕擷取畫面 2022-10-11 161636.png螢幕擷取畫面 2022-10-11 161808.png

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ShengN_Intel
Employee
286 Views

Hi,


Try to use devices Cyclone III, Cyclone IV, Max II, Max V or Arria II instead of Cyclone V. New devices are not supported on vwf waveform simulator because this is legacy simulator which only supported legacy devices and mainly for university program purpose. Or may be you can use modelsim simulator instead of vwf waveform simulator.


Best Regards,

Sheng

p/s: If any answer from the community or Intel Support are helpful, please feel free to give best answer or rate 4/5 survey.


Er7Cho1gU
Novice
271 Views

I understand.  Thanks of the reply!!

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