30. PWM with 4-bit Resolution

How do you plan to solve it?

/*Write your code here*/
module pwm4_basic(input clk,rst,input [3:0] duty,output reg pwm_out);
    reg [3:0] counter=4'b0000;
    always @(posedge clk) begin
        if(rst) begin
            pwm_out<=1'b0;
            counter<=4'b0000;
        end
        else begin
            counter<=counter+1;
            if(counter<duty)
                pwm_out <= 1'b1;
            else
                pwm_out<=1'b0;
            if(counter==4'b1111) 
                counter<=4'b0000;
        end
    end
endmodule