5 位奇校验

问题描述

我正在尝试编写一个 5 位 Mealy 奇偶校验器。我编写了一些代码（复位、下一个状态逻辑和输出逻辑），除了检查 5 位输出的部分。如果 1'b1 的个数为奇数，如何检查 5 位变量？

module parity(clk,rst,w,z);

input clk,w; 
reg [1:0] present,next;

output reg z;

parameter s0 = 4'b0000,s1 = 4'b0001,s2 = 4'b0010,s3 = 4'b0011,s4 = 4'b0100,s5 = 4'b0101,s6 = 4'b0110,s7 = 4'b0111,s8 = 4'b1000,s9 = 4'b1001,s10 = 4'b1010;

//Reset
always @(posedge clk,posedge rst)
    
    begin 
        if(rst) 
            present <= s0;
        else 
            present <= next;
    end    


//Next State logic
always @(present,w) 
    begin 
        case(present) 
            s0: if(~w) next = s1; else next = s2;
            s1: if(~w) next = s3; else next = s4;
            s2: if(~w) next = s4; else next = s3;
            s3: if(~w) next = s5; else next = s6;
            s4: if(~w) next = s6; else next = s5;
            s5: if(~w) next = s7; else next = s8;
            s6: if(~w) next = s8; else next = s7;
            s7: if(~w) next = s9; else next = s10;
            s8: if(~w) next = s10; else next = s9;
            s9: if(~w) next = s0; else next = s0;
            s10: if(~w) next = s0; else next = s0;
            default: next = s0;     
        endcase
    end


always @(w,present)
    begin
        if (present == s10 && w == 1)
            z = 1'b1; 
        else 
            z = 1'b0;
    end


endmodule

解决方法

如果你有一个 5 位变量，比如

reg [4:0] data;

您将通过使用一元 ^（XOR 约简）运算符获得奇偶校验：

odd = ^data

parity verilog verilog