// try to figure out how iverilog samples edges `timescale 1us/1ns module template_tb ( ); reg clk_i; reg data_i; wire data_o; tst_delay uut( .clk_i(clk_i), .data_i(data_i), .data_o(data_o) ); initial begin $dumpfile("tst_delay.lxt2"); $dumpvars(); clk_i = 0; data_i = 0; end always #10 clk_i = ~clk_i; initial begin #9 data_i = 1; #2 data_i = 0; // note the <= assignment #19 data_i <= 1; #1 data_i = 0; // note the = assignment #19 data_i = 1; #1 data_i = 0; #40 $finish(); end endmodule