How do you plan to solve it?
/*Write your code here*/ module pwm4_basic(input clk, input rst, input [3:0] duty, output reg pwm_out); reg [3:0] counter; always @(posedge clk) begin pwm_out <= rst ? 1'b0 : (counter < duty); counter <= rst ? 4'b0 : (counter + 4'd1); end endmodule