16.分频器设计—奇分频

（1）Visio视图：

（2）Verilog代码：

module divider_five(clk,reset_n,clk_out);
 
    input clk;
    input reset_n;
    
    output clk_out;
    
    reg [2:0]cnt;
    reg clk_1;
    reg clk_2;
 
//计数器模块设计
    always@(posedge clk or negedge reset_n)
        if(!reset_n)
            cnt <= 3'd0;
        else if(cnt == 3'd4)
            cnt <= 3'd0;
        else 
            cnt <= cnt + 3'd1;
            
//clk_1信号设计
    always@(posedge clk or negedge reset_n)
        if(!reset_n)
            clk_1 <= 1'd0;
        else if(cnt == 3'd2)
            clk_1 <= 1'd1;
        else if(cnt == 3'd4)
            clk_1 <= 1'd0;
        else 
            clk_1 <= clk_1;
//clk_2信号设计
    always@(negedge clk or negedge reset_n)
        if(!reset_n)
            clk_2 <= 1'd0;
        else if(cnt == 3'd2)
            clk_2 <= 1'd1;
        else if(cnt == 3'd4)
            clk_2 <= 1'd0;
        else 
            clk_2 <= clk_2;
 
    assign clk_out = (clk_1 | clk_2);
 
endmodule

（3）RTL视图：

（4）仿真文件代码：

`timescale 1ns / 1ps
 
module divider_five_tb;
 
    reg clk;
    reg reset_n;
    
    wire clk_out;
 
    divider_five divider_five_inst(
        .clk(clk),
        .reset_n(reset_n),
        .clk_out(clk_out)
    );
    
    initial clk = 1'd1;
    always #10 clk = ~clk;
    
    initial begin
        reset_n = 1'd0;
        #20;
        reset_n = 1'd1;
        #2000
        $stop;
    end
endmodule

（5）仿真波形：

（6）引脚绑定：

set_property IOSTANDARD LVCMOS33 [get_ports clk_out]
set_property IOSTANDARD LVCMOS33 [get_ports reset_n]
set_property IOSTANDARD LVCMOS33 [get_ports clk]
set_property PACKAGE_PIN M13 [get_ports clk_out]
set_property PACKAGE_PIN N15 [get_ports reset_n]
set_property PACKAGE_PIN W19 [get_ports clk]

（7）实验现象：