VCD – Value Change Dump

📉 VCD – Value Change Dump

#

VCD (Value Change Dump) is a standard waveform file format generated during Verilog simulation. It records signal transitions over time, which can be viewed in tools like GTKWave.

✅ How to Generate VCD:

#

Inside your testbench:

initial begin
  $dumpfile("wave.vcd");       // Output file name
  $dumpvars(0, tb_top);        // Dump all signals in tb_top hierarchy
end

• $dumpfile: sets the filename.
• $dumpvars(level, scope): sets how many levels of signals to record.

📊 View with GTKWave:

#

gtkwave wave.vcd

💡 Additional VCD Tasks

#

✅ Summary

#