30. PWM with 4-bit Resolution

/*Write your code here*/
module pwm4_basic(
    input clk,
    input rst,
    input [3:0] duty,
    output reg pwm_out
);
    reg [3:0] cnt; 
    always @(posedge clk) begin
        if(rst) begin
            pwm_out <= 0;
            cnt <= 0;
        end
        else begin
            cnt <= cnt + 4'b0001;
            if(cnt < duty)
                pwm_out <= 1'b1;
            else
                pwm_out <= 0;
        end
    end
endmodule