30. PWM with 4-bit Resolution

/*Write your code here*/

module pwm4_basic(
    input clk,
    input rst,
    input wire[3:0] duty,
    output reg pwm_out
);
reg[3:0] counter;

always @(posedge clk) begin
    pwm_out <= rst ? 1'b0:(counter < duty);
    counter <= rst ? 4'b0000:(counter + 1);
end
endmodule

module pwm4_basic(
    input clk,
    input rst,
    input wire [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

        if (counter < duty)
            pwm_out <= 1'b1;
        else
            pwm_out <= 1'b0;


        counter <= (counter == 4'b1111) ? 4'b0000 : (counter + 1'b1);
    end
end

endmodule