设计一个六分频时钟信号

（1）visio视图：

（2）Verilog代码：

module divider_six(clk,reset_n,clk_out);

    input clk;
    input reset_n;
    
    output reg clk_out;
    
    reg [1:0]cnt;

//计数器模块设计   
    always@(posedge clk or negedge reset_n)
        if(!reset_n)
            cnt <= 2'd0;
        else if (cnt == 2'd2)
            cnt <= 2'd0;
        else    
            cnt <= cnt + 2'd1;

//clk_out信号设计
    always@(posedge clk or negedge reset_n)
        if(!reset_n)
            clk_out <= 1'd0;
        else if (cnt == 2'd2)
            clk_out <= ~clk_out;
        else 
            clk_out <= clk_out;
            

endmodule 

（3）RTL视图：

（4）仿真文件代码：

`timescale 1ns / 1ps

module divider_six_tb;

    reg clk;
    reg reset_n;
    
    wire clk_out;

    divider_six divider_six_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 N15 [get_ports reset_n]
set_property PACKAGE_PIN W19 [get_ports clk]
set_property PACKAGE_PIN M13 [get_ports clk_out]

（7）实验现象：

（8）使用降频的方法实现八分频：

module ex_divider_eiht(clk,reset_n,clk_flag);

    input clk;
    input reset_n;
    
    output reg clk_flag;
    
    reg [2:0]cnt;
    
//计数器设计
    always@(posedge clk or negedge reset_n)
        if(!reset_n)
            cnt <= 3'd0;
        else 
            cnt <= cnt + 3'd1;

//clk_flag信号设计
    always@(posedge clk or negedge reset_n)
        if(!reset_n)
            clk_flag <= 1'd0;
        else if(cnt == 3'd6)
            clk_flag <= 1'd1;
        else 
            clk_flag <= 1'd0;
        

endmodule

`timescale 1ns / 1ps

module ex_divider_eiht_tb;

    reg clk;
    reg reset_n;
    
    wire clk_flag;

    ex_divider_eiht  ex_divider_eiht0(
        .clk(clk),
        .reset_n(reset_n),
        .clk_flag(clk_flag)
    );
    
    initial clk = 1'd1;
    always #10 clk = ~clk;
    
    initial begin
        reset_n <= 1'd0;
        #20
        reset_n <= 1'd1;
        #2000
        $stop;
    end
    
    
endmodule

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