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检测101序列的状态机以及verilog代码

已有 2184 次阅读| 2019-7-4 09:43 |个人分类:数字学习笔记|系统分类:芯片设计

s_idle 代表初始状态

s1 代表出现第一个1

s2 代表出现第一个10

s3 代表出现了101

module test101(clk, rst_n, data,flag_101);
input clk, rst_n, data;
output reg flag_101;
reg [1:0] current_state;
reg [1:0] next_state;

parameter s_idle = 2'd0;
parameter s_1 = 2'd1;
parameter s_2 = 2'd2;
parameter s_3 = 2'd3;
always@(posedge clk)begin
if(rst_n==0)begin
  current_state<=s_idle;
end
else begin
  current_state<=next_state;
end
end
always@(*)begin
case(current_state)
s_idle:
  begin
   if(data) next_state = s_1;
   else next_state = s_idle;
  end
s_1:
  begin
   if(data) next_state = s_1;
   else next_state = s_2;
  end
s_2:
  begin
   if(data) next_state = s_3;
   else next_state = s_idle;
  end
s_3:
  begin
   if(data) next_state = s_1;
   else next_state = s_2;
  end
endcase

end
always@(posedge clk)begin
if(rst_n==0)begin
  flag_101<=1'b0;
end
else begin
  case(next_state)
s_idle:
  begin
   flag_101<=1'b0;
  end
s_1:
  begin
   flag_101<=1'b0;
  end
s_2:
  begin
   flag_101<=1'b0;
  end
s_3:
  begin
   flag_101<=1'b1;
  end
  endcase
end

end
endmodule