`timescale 1ns / 1ps

module led_switch(
    output reg led0_r,
    input CLK100MHZ,
    input  btn
    );

    reg tickedLastFrame = 1'b0;

    always@ (posedge CLK100MHZ) begin

    if(btn)
    begin
        if(!tickedLastFrame) begin
        led0_r = ~led0_r;
        tickedLastFrame = 1'b1;
        end
    end
    else begin
    tickedLastFrame = 1'b0;
    end



    end

endmodule