EDA Playground EPWave $dumpfile error: no vcd file found

Question

I am trying to simulate my design in EDA Playground. I tested my design file and testbench file in my local computer using ModelSim (not from EDA), and it was successful. However, I tried to do the same with EDA Playground. It is successfully compiled and run without EPWave.

When I try click the 'Open EPWave' option, it gives me an error called

No *.vcd file found. EPWave will not open. Did you use '$dumpfile("dump.vcd"); $dumpvars;'?

How can I solve this issue?

Here is the link to my design https://www.edaplayground.com/x/A9Rb

Answer 1

This is the world's most helpful error message; it tells you what code to write. Basically, Verilog simulators need you to

• open a file to store the waveform information in and this is what $dumpfile("dump.vcd"); does;
• specify waveform information about which parts of the design you want to store in the file and this is what $dumpvars; does (store eveything, in this case).

You need to add both these lines of code to the beginning of an initial block, either a completely separate one or an existing one, eg line 21:

initial begin
    $dumpfile("dump.vcd"); $dumpvars;
    //ADDITION
    ALU_CONTROL = 5'b00100;