题解 | #含有无关项的序列检测#

`timescale 1ns/1ns
module sequence_detect(
	input clk,
	input rst_n,
	input a,
	output reg match
	);

	reg [8:0] buff;
	always @(posedge clk or negedge rst_n) begin
		if (~rst_n) begin
			buff <= 0;
		end else begin
			buff[0] <= a;
			buff[1] <= buff[0];
			buff[2] <= buff[1];
			buff[3] <= buff[2];
			buff[4] <= buff[3];
			buff[5] <= buff[4];
			buff[6] <= buff[5];
			buff[7] <= buff[6];
			buff[8] <= buff[7];
		end
	end

	always @(posedge clk or negedge rst_n) begin
		if (~rst_n) begin
			match <= 0;
		end else begin
			if ({buff[8:6], buff[2:0]} == 6'b011110) begin
				match <= 1;
			end else begin
				match <= 0;
			end
		end
	end
  
endmodule