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;
always@(posedge clk)
begin
    if(rst)
    begin
        counter <= 0 ;
        pwm_out <= 0;
    end
    else
    begin
        counter <= counter + 1 ;
        if(counter < duty)
         pwm_out <= 1;
        else
         pwm_out <= 0;
    end
end
endmodule