30. PWM with 4-bit Resolution

How do you plan to solve it?

/*Write your code here*/
module pwm4_basic(
    input   wire    clk, rst,
    input   wire    [3:0] duty,
    output  reg    pwm_out
);
    reg [3:0]   counter;
    always @(posedge clk or posedge rst) begin
        if(rst) begin
            pwm_out <= 0;
            counter <= 0;
        end
        else begin
            counter <= counter + 1;
            if(counter < duty) pwm_out <= 1;
            else pwm_out <= 0;
        end
    end

endmodule