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looking for advise on connecting to analog model

myonlyscreen

 Hi all

I am looking for advise on the next issue :

i verifiing a  digital design that is coneccted to an analog one , for simulation i was supplied by a vhdl behavioral model of the analog part.

i want to create a loopback in the simulation meaning to sample the output of the analog model which is of type real and after some delay to inject it (with some modification) back to the model input which is of type real as well.

i am using specman 9.2 and my questions are:

1) is there a in/out simple_port of real ?

2) can i use list of real ?

3) do you reccomend on others way to do so not with specman (in the test banch maybe) ?

thanks Eyal.


 

 

  • Here is some example code. You can find more details in the Specman Usage Guide, Ch. 13 Specman/AMS Integration.

     

     <'
    unit verify {
      p1 : out simple_port of real is instance;
      keep p1.hdl_path() == "r1";

      p2 : out simple_port of real is instance;
      keep p2.hdl_path() == "r2";

      the_sum : in simple_port of real is instance;
      keep the_sum.hdl_path() == "sum";

      clk : in simple_port of bit is instance;
      keep clk.hdl_path() == "clk";

      event clk_change is change(clk$)@sim;

      run() is also {
        start ver();
      };

      ver()@clk_change is {
        for i from 1 to 10 {
          var r2 : real = rdist_uniform(-5000,5000);
          var r1 : real = rdist_uniform(-5000,5000);
          p1$ = r1;
          p2$ = r2;
          var exp_sum : real = r1 + r2;
          wait[2];
          // to compare real numbers it is better to check their delta
          // is less than very small value, due to the precision problems
          // of floating points.
          check that abs(exp_sum-the_sum$) < 0.001;
        };
        stop_run();
      };
    };

    extend sys {
      v : verify is instance;
      keep v.hdl_path() == "dut";
    };
    '>

  •  thanks i will go to this ch. you refered to.

    where can i find that document  "Specman Usage Guide" i didnt seem  to find it in the cdnshelp.

    thanks Eyal

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