VL27 不重叠序列检测

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这里最大的问题是：
always @(*) 和 always @(posedge clk or negedge rst_n)的区别
always @(*) 在当前时钟内会变化
always @(posedge clk or negedge rst_n)由时钟驱动，所以会在下一个时钟才发生变化

代码

module sequence_detect(input clk,input rst_n,input data,output reg match,output reg not_match);parameter zero=0,one=1,two=2,three=3,four=4,five=5,six=6,fail=7;reg [2:0] current_stage,next_stage;reg [2:0] cnt;always @(posedge clk or negedge rst_n) beginif(~rst_n)begincnt <= 3'b0 ;endelse begin cnt <= (cnt == 3'd6) ? 3'b1: cnt+ 3'b1 ;endendalways @(posedge clk or negedge rst_n) beginif(~rst_n)begincurrent_stage <= zero;endelse begincurrent_stage <= next_stage;endendalways @(*) beginif(~rst_n)beginnext_stage <= zero;endelse begincase(current_stage)zero  : next_stage = data==1'b0 ? one  : fail;one   : next_stage = data==1'b1 ? two  : fail;two   : next_stage = data==1'b1 ? three: fail;three : next_stage = data==1'b1 ? four : fail;four  : next_stage = data==1'b0 ? five : fail;five  : next_stage = data==1'b0 ? six  : fail;six   : next_stage = data==1'b0 ? one  : fail;fail : next_stage = (cnt == 6 && data == 1'b0) ? one : fail ;default : next_stage = zero;     endcaseendendalways @(*) beginif(~rst_n)beginmatch <= 1'b0 ;not_match <= 1'b0;endelse beginmatch <= (cnt == 6 && current_stage == six) ;not_match <= (cnt == 6 && current_stage == fail);endendendmodule

testbench

  
module testbench_sequence_detect;  reg clk, rst_n, data;  wire match, not_match;  // Instantiate the Unit Under Test (UUT)  sequence_detect uut (  .clk(clk),   .rst_n(rst_n),   .data(data),   .match(match),   .not_match(not_match)  );  // Clock generation  initial begin  clk = 1;  forever #(5) clk = ~clk;  // Generate a 10ns period clock signal  end  // Test stimulus  initial begin   rst_n = 0;  
//        data = 0;  #10;  // Reset the module  rst_n = 1;data = 0;  #10;  // Send a sequence that does not match the expected pattern  
//        data = 1'b0; #10;  data = 1'b1; #10;  data = 1'b1; #10;  data = 1'b1; #10;  data = 1'b0; #10;  data = 1'b0; #10;  data = 1'b0; #10; // Check if not_match is asserted  if (not_match) begin  $display("Sequence did not match at time %t", $time);  end else begin  $display("Test failed: not_match was not asserted when expected");  
//            $finish;  end  //        // Reset the state  
//        #10;  
//        rst_n = 0;  
//        #10;  
//        rst_n = 1;  // Send the correct sequence  data = 1'b0; #10;  data = 1'b1; #10;  data = 1'b1; #10;  data = 1'b1; #10;  data = 1'b0; #10;  data = 1'b0; #10;  data = 1'b0; #10;  // Check if match is asserted  if (match) begin  $display("Sequence matched at time %t", $time);  end else begin  $display("Test failed: match was not asserted when expected");  
//            $finish;  end  // Finish the simulation  $finish;  end  endmodule

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