17.分频器设计拓展练习-任意分频通用模块
(1)Verilog代码：
module divider_n(clk,reset_n,clk_out);input clk;input reset_n;output clk_out;wire clk_out1;wire clk_out2;wire [9:0]n;wire m;assign n = 9;assign m = n % 2;divider_even divider_even_inst(.clk(clk),.reset_n(reset_n),.n(n),.en(!m),.clk_out(clk_out1));divider_odd divider_odd_inst(.clk(clk),.reset_n(reset_n),.n(n),.en(m),.clk_out(clk_out2));assign clk_out = m ? clk_out2 : clk_out1;endmodule
module divider_even(clk,reset_n,n,en,clk_out);input clk;input reset_n;input [9:0]n; //分频数input en;output reg clk_out;reg [9:0]cnt;wire [9:0]MCNT;assign MCNT = (n >> 1) - 10'd1;//计数器模块设计 always@(posedge clk or negedge reset_n)if(!reset_n)cnt <= 10'd0;else if ((cnt == MCNT)&&(en))cnt <= 10'd0;else if(en) cnt <= cnt + 10'd1;else cnt <= 10'd0;//clk_out信号设计always@(posedge clk or negedge reset_n)if(!reset_n)clk_out <= 1'd0;else if (cnt == MCNT)clk_out <= ~clk_out;else clk_out <= clk_out;endmodule
module divider_odd(clk,reset_n,n,en,clk_out);input clk;input reset_n;input [9:0]n; //分频数input en;output clk_out;reg [9:0]cnt;reg clk_1;reg clk_2;wire [9:0]MCNT;wire [9:0]Mid;assign MCNT = n - 10'd1;assign Mid = (n >> 1);//计数器模块设计always@(posedge clk or negedge reset_n)if(!reset_n)cnt <= 10'd0;else if((cnt == MCNT)&&(en))cnt <= 10'd0;else if(en)cnt <= cnt + 10'd1;else cnt <= 10'd0;//clk_1信号设计always@(posedge clk or negedge reset_n)if(!reset_n)clk_1 <= 1'd0;else if(cnt == Mid)clk_1 <= 1'd1;else if(cnt == MCNT)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 == Mid)clk_2 <= 1'd1;else if(cnt == MCNT)clk_2 <= 1'd0;else clk_2 <= clk_2;assign clk_out = (clk_1 | clk_2);endmodule
（2）代码层次：
（3）仿真代码：
`timescale 1ns / 1psmodule divider_n_tb;reg clk;reg reset_n;wire clk_out;divider_n divider_n_inst(.clk(clk),.reset_n(reset_n),.clk_out(clk_out));initial clk = 1'd1;always #10 clk = ~clk;initial beginreset_n = 1'd0;#15;reset_n = 1'd1;#2000$stop;endendmodule
（4）仿真波形
（5）将顶层模块的n改成10，重新进行仿真
（6）引脚绑定：
（7）以下分别是n=10和n=25时的示波器实验现象，时钟频率为50MHz
