30. PWM with 4-bit Resolution

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 [4:0] counter;
    always @(posedge clk) begin
        if(rst) begin
            pwm_out <= 1'b0;
            counter <= 4'd0;
        end else begin
            if(counter < duty) begin
                pwm_out <= 1'b1;
            end else begin
                pwm_out <= 1'b0;
            end
            if(counter == 4'd15) begin
                counter <= 4'd0;
            end else begin
                counter <= counter + 1'b1;
            end
        end
    end
endmodule