Interactive GUI Forms for Verilog Simulation

The following article presents the easiest technique of attaching an interactive GUI to Verilog simulation. Instead of PLI we are using $system task and communication through files. Using simple examples, we demonstrate a bi-directional intercommunication between Verilog domain and Graphical forms.

1. In.tcl : TCL Entry form

The following TC/TK code creates a simple GUI entry form. Using this form, we can pass any information to Verilog domain as well as control simulation run.

#---------------------------------------------------------------------------

#!/usr/local/bin/wish

label .l1 -text "Enter the number:"

pack .l1 -side top -fill x

entry .e1 -bd 1 -textvariable num

pack .e1 -side top -fill x

button .run -text Run -command {save $num; destroy .}

pack .run -fill x -expand 1

button .stop -text Finish -command {finish; destroy .}

pack .stop -fill x -expand 1

proc save {num} {

set IF [open "infile" w]

puts $IF $num

close $IF

}

proc finish {} {

set IF [open "infile" a]

puts $IF 0

close $IF

}

#---------------------------------------------------------------------------

Running in.tcl file, the following window pops up:

Clicking on “Run” buton, we write entered number into the “infile” file.

Clicking on “Stop” button, we write “0” in second line the this file.

2. Out.tcl : TCL display form

The following simple form displays the number written into the “outfile” file:

#---------------------------------------------------------------------------

#!/usr/local/bin/wish

set OF [open "outfile" r]

gets $OF line

close $OF

label .l1 -text "The number is: $line"

pack .l1

button .exit -text Continue -command {destroy .}

pack .exit -fill x -expand 1

#---------------------------------------------------------------------------

This code creates the following window:

3. Test.v : Verilog Test file

Verilog Test file uses $system task to call TCL applications, $readmemb task to read information from the “infile” and $fdisplay task to write information into the “outfile”. See line comments for more descriptions.

#---------------------------------------------------------------------------

module test;

integer i, file;

reg [0:31] num [0:1];

initial

for (i=0; i<5; i=i+1) begin

$system("in.tcl"); // Launch in.tcl application

$readmemh("infile", num); // Read infile data into “num”

if (num[1] == 0) $finish; // if second line contains 0, finish

$display("Number is equal to %x", num[0]);

file = $fopen("outfile"); // Write the same variable into outfile

$fdisplay(file, "%x", num[0]);

$fclose(file);

$system("out.tcl"); // Launch out.tcl application

end

endmodule

#---------------------------------------------------------------------------

4. Instalation and Run

Copy example files from the current article or download in one of compressed file.

In order to run this example, put test.v, in.tcl and out.tcl files into the same directory. Make in.tcl and out.tcl files to be executable and check that their first lines point to existing “wish” command. Then, run test.v example with your favorite simulator.