Writing into a file in Verilog-A Model

If the error you got was this:

 Error found by spectre during AHDL read-in.
    ERROR (VACOMP-2212): "fp=$fopen("/home/mac/MAT_CAD/X_MODEL/ref_edge.txt",a)<<--?          "
        "writingfile.va", line 15: Encountered undeclared identifier: a. Declare the identifier before using it.
    ERROR (VACOMP-2259): "end<<--? "
        "writingfile.va", line 17: syntax error.

Then it's because you didn't put quotes around the "a" (the append mode) and you omitted a semi-colon at the end of the line. If I change it to:

      fp=$fopen("/home/mac/MAT_CAD/X_MODEL/ref_edge.txt","a");

(I changed the path to something local so it worked in my location), it worked fine. Here's my complete example:

`include "disciplines.vams"

module writingfile(clk);
input clk;
electrical clk;
parameter real Vth=1.0;
parameter real dir=1.0;
parameter real ttol=1n;

real Cross_point;
integer fp;

analog begin
 @(initial_step) begin
     //fp=$fopen("/home/mac/MAT_CAD/X_MODEL/ref_edge.txt",a)         
     fp=$fopen("./ref_edge.txt","a");
     end

 
  @(cross(V(clk) - Vth, dir, ttol)) begin
                $strobe(" Cross Time = %e  \n", $abstime);
                Cross_point= $abstime ;

                $fwrite(fp,"%e \n",Cross_point);
      end 

end

endmodule

If I run this with this netlist:

//

V1 (clk 0) vsource type=pulse val0=0 val1=2 rise=1n fall=1n period=40n width=20n
W1 (clk) writingfile

ahdl_include "writingfile.va"

tran tran stop=200n

Then I get ref_edge.txt containing:

5.002500e-10
4.050025e-08
8.050025e-08
1.205003e-07
1.605003e-07

Kind Regards,

Andrew.

If the error you got was this:

 Error found by spectre during AHDL read-in.
    ERROR (VACOMP-2212): "fp=$fopen("/home/mac/MAT_CAD/X_MODEL/ref_edge.txt",a)<<--?          "
        "writingfile.va", line 15: Encountered undeclared identifier: a. Declare the identifier before using it.
    ERROR (VACOMP-2259): "end<<--? "
        "writingfile.va", line 17: syntax error.

Then it's because you didn't put quotes around the "a" (the append mode) and you omitted a semi-colon at the end of the line. If I change it to:

      fp=$fopen("/home/mac/MAT_CAD/X_MODEL/ref_edge.txt","a");

(I changed the path to something local so it worked in my location), it worked fine. Here's my complete example:

`include "disciplines.vams"

module writingfile(clk);
input clk;
electrical clk;
parameter real Vth=1.0;
parameter real dir=1.0;
parameter real ttol=1n;

real Cross_point;
integer fp;

analog begin
 @(initial_step) begin
     //fp=$fopen("/home/mac/MAT_CAD/X_MODEL/ref_edge.txt",a)         
     fp=$fopen("./ref_edge.txt","a");
     end

 
  @(cross(V(clk) - Vth, dir, ttol)) begin
                $strobe(" Cross Time = %e  \n", $abstime);
                Cross_point= $abstime ;

                $fwrite(fp,"%e \n",Cross_point);
      end 

end

endmodule

If I run this with this netlist:

//

V1 (clk 0) vsource type=pulse val0=0 val1=2 rise=1n fall=1n period=40n width=20n
W1 (clk) writingfile

ahdl_include "writingfile.va"

tran tran stop=200n

Then I get ref_edge.txt containing:

5.002500e-10
4.050025e-08
8.050025e-08
1.205003e-07
1.605003e-07

Kind Regards,

Andrew.