【FPGA学习笔记】VL26 含有无关项的序列检测
描述
请编写一个序列检测模块,检测输入信号a是否满足011XXX110序列(长度为9位数据,前三位是011,后三位是110,中间三位不做要求),当信号满足该序列,给出指示信号match。
程序的接口信号图如下:
程序的功能时序图如下:
请使用Verilog HDL实现以上功能,并编写testbench验证模块的功能。 要求代码简洁,功能完整。
输入描述:
clk:系统时钟信号
rst_n:异步复位信号,低电平有效
a:单比特信号,待检测的数据
输出描述:
match:当输入信号a满足目标序列,该信号为1,其余时刻该信号为0
答:
移位寄存器
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module sequence_detect( input clk, input rst_n, input a, output reg match ); reg [ 8 : 0 ] a_r; always@(posedge clk or negedge rst_n) begin if (~rst_n) match <= 1 'b0; else match <= (a_r[ 2 : 0 ] == 3 'b110) && (a_r[8:6] == 3' b011); end always@(posedge clk or negedge rst_n) begin if (~rst_n) a_r <= 9 'b0; else a_r <= {a_r[ 7 : 0 ], a}; end endmodule |
状态机
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module sequence_detect( input clk, input rst_n, input a, output reg match ); parameter ZERO= 0 , ONE= 1 , TWO= 2 , THREE= 3 , FOUR= 4 , FIVE= 5 , SIX= 6 , SEVEN= 7 , EIGHT= 8 , NINE= 9 ; reg [ 3 : 0 ] state, nstate; always@(posedge clk or negedge rst_n) begin if (~rst_n) state <= ZERO; else state <= nstate; end always@(*) begin case (state) ZERO : nstate = a? ZERO : ONE; ONE : nstate = a? TWO : ONE; TWO : nstate = a? THREE: ONE; THREE : nstate = FOUR; FOUR : nstate = FIVE; FIVE : nstate = SIX; SIX : nstate = a? SEVEN: ONE; SEVEN : nstate = a? EIGHT: ONE; EIGHT : nstate = a? ZERO: NINE; NINE : nstate = a? TWO : ONE; default : nstate = ZERO; endcase end always@(posedge clk or negedge rst_n) begin if (~rst_n) match = 0 ; else match = state==NINE; end endmodule |