题解 | #占空比50%的奇数分频#

````timescale 1ns/1ns
//关键是(N-1)/2和(N-1)翻转，上升沿和下降沿分别计数
module odo_div_or
   (
    input    wire  rst ,
    input    wire  clk_in,
    output   wire  clk_out7
    );

//*************code***********//
    reg[2:0]cnt_p;
    reg[2:0]cnt_n;
    reg     clk_p;
    reg     clk_n;
    
    always @(posedge clk_in or negedge rst)begin
        if(~rst)
            cnt_p <= 0;
        else if(cnt_p == 6)
            cnt_p <= 0;
        else
            cnt_p <= cnt_p + 1'b1;
    end
    
    always @(posedge clk_in or negedge rst)begin
        if(~rst)
            clk_p <= 0;
        else if(cnt_p == 3 || cnt_p ==6)
            clk_p <= ~clk_p;
    end
    
    always @(negedge clk_in or negedge rst)begin
        if(~rst) 
            cnt_n <= 0;
        else if(cnt_n == 6)
            cnt_n <= 0;
        else 
            cnt_n <= cnt_n + 1'b1;
    end
    
    always @(negedge clk_in or negedge rst)begin
        if(~rst)
            clk_n <= 0;
        else if(cnt_n == 3||cnt_n == 6)
            clk_n <= ~clk_n;
    end
    assign clk_out7 = clk_p|clk_n;
//*************code***********//
endmodule