module rst_sync( input clk, input rst_n_in, output rst_n_out ); reg [1:0] delay; always @(posedge clk or negedge rst_n_in) begin if(~rst_n_in) begin delay <= 2'b00; end else begin delay <= {delay[0],1'b1}; end end assign rst_n_out = delay[1]; endmodule