学了一段时间的Verilog总结一

有关模块代码的学习

本人将根据教材《Verilog数字系统教程》-----（夏宇闻）学习总结
本文章为实例主题（一）

1.16位半加器

module halfadd(A,B,sum,cout);
input [15:0] A,B;
output [15:0] sum;
output cout ;
wire [15:0] sum;
wire cout ;
assign {
     cout,sum} = A+B;
endmodule

2.测试电路一

module Test(Error,Wait,Valid,Clear,Out);
input Error,Wait,Valid,Clear;
output Out ;
wire T1,T2,Out;
assign T1 = ~(Error&Wait);
assign T2 = ~(Valid|Clear);
assign Out = T1&T2;
endmodule 

3.4bit 相等比较器

code:

module Equalcheck(A,B,Result);
input [3:0]A,B;
output Result;
//assign Result=(A==B);//这句话也可
assign Result = (A==B)?1:0;
endmodule

testbench

`timescale 1 ps/ 1 ps
module Equalcheck_vlg_tst();
reg [3:0] A;
reg [3:0] B;
// wires                                               
wire Result;                        
Equalcheck i1 (
	.A(A),
	.B(B),
	.Result(Result)
);
initial                                                
begin                                                  
#100 A=4'b0000;B=4'b1111;
#100 A=4'b1010;B=4'b1010;
#100 A=4'b0111;B=4'b0101;
#100 A=4'b1011;B=4'b1011;
#100 $stop;                                         
end                                                                                                   
endmodule

4.1bit 全加器

module add_1bit(A,B,Cin,sum,cout);
	input A,B,Cin;
    output sum,cout;
    assign {
     cout,sum} = A+B+Cin;
endmodule

5. 8bit单向总线缓冲器

code

module tri_buf(Dout,Din,en);
input en;
input [7:0] Din;
output [7:0] Dout;
assign Dout = (en)?Din:8'bz;
endmodule

testbench

`timescale 1 ps/ 1 ps
module t();
reg [7:0] Din;
reg en;                                            
wire [7:0]  Dout;                          
tri_buf i1 (   
	.Din(Din),
	.Dout(Dout),
	.en(en)
);
initial                                                
begin                                                  

 en=0;
 Din=0;
 #100 en=1;
 #100 Din=8'b10110110;
 #100 Din=8'b11111111;
 #100 Din=8'b10101010;
 #100 Din=8'b01010101;
 #100 Din=8'b11010111;
 #100 $stop;
end                                                    
                                               
endmodule

6.带同步清零的约翰逊移位计数器

module SHIFT (A,clr,clk);
input clk,clr;
output [2:0]A;
reg[2:0] A ;
always@(posedge clk)
if(clr)
  A <= 3'b000;
else 
begin 
A[0] <= ~A[2];
A[2:1] <= A[1:0];
end
endmodule

7.Case实现4选1多路选择器

module mux4_1(in1,in2,in3,in4,sel,dout);
input in1,in2,in3,in4;
input [1:0]sel;
output dout;
reg dout;
always@(*)
case (sel)
2'b00: dout =in1;
2'b01: dout =in2;
2'b10: dout =in3;
2'b11: dout =in4;
default dout = 1'bx;
endcase
endmodule

8.Case实现3-8译码器

module decode3_8(in,out);
input [2:0]in;
output [7:0] out;
reg [7:0] out;
always@(in)
case (in)
3'b000: out=8'b1111_1110;
3'b001: out=8'b1111_1101;
3'b010: out=8'b1111_1011;
3'b011: out=8'b1111_0111;
3'b100: out=8'b1110_1111;
3'b101: out=8'b1101_1111;
3'b110: out=8'b1011_1111;
3'b111: out=8'b0111_1111;
default out = 8'bz;
endcase
endmodule

9. 异步清零，异步置数触发器

module DEF1(q,out,clk,clr,set);
input q,clk,clr,set;
output out;
reg out;
always@(posedge clk )
begin
if(!clr)
out <= 1'b0;
else if(set)
out <= 1'b1;
else 
out <= q;
end
endmodule

10.异步清零，同步置数8bit计数器

module count (clk,rst,load,datain,out);
input clk,rst,load;
input [7:0]datain;
output [7:0] out;
reg [7:0] out;
always@(posedge clk or negedge rst)
begin 
if(!rst)
out <= 8'h00;
else if(load)
out <= datain;
else 
out <= out +8'h1;
end
endmodule

11.带输入输出缓冲的16bit半加器

module bufadd (A,B,C,clk,rst);
input [15:0]A,B;
input clk,rst;
output[16:0]C;
reg [15:0]a,b;
reg [16:0]c;
always @(posedge clk)
if (!rst)begin
a <= 16'b0;
b <= 16'b0;
end
else 
begin
a<=A;
b<=B;
end

/*always @(posedge clk)
if(!rst)
c<=17'b0;
else 
c<=a+b;*/
//上面注释的话可代替下面的话。

assign C=a+b;
always @(posedge clk)
if(!rst)
c<=17'b0;
else 
c<= C;
endmodule

12.不同占空比的分频器

code:

module DivFreq （clkin,clkout,rst);
input clkin,rst;
output clkout ;
reg [1:0] out ;
reg clkout;
always @(posedge clk)
if (!rst)
out <= 2'b00;
else if (out ==2'b10)
out <=2'b00;
else 
out <=out +2'b01;
always @(posedge clk)
if (out == 2'b00)
clkout <=1'b1; 
else if (out == 2'b10)
clkout <=1'b0; 
endmodule

testbench:

`timescale 1 ps/ 1 ps
module DivFreq_t();
reg clkin;
reg rst;                                             
wire clkout;                          
DivFreq i1 (   
	.clkin(clkin),
	.clkout(clkout),
	.rst(rst)
);
always #50 clkin = ~clkin;
initial                                                
begin                                                  
		clkin = 0;
		rst = 1;
		#10 rst = 0;
		#110 rst = 1;
		#10000 $stop;                      
end                                                                                                     
endmodule

13. 8bit 并入串出寄存器

module paratoserial(clk,load,parain,serialout);
input clk,load;
input [7:0]parain;
output serialout;
reg serialout;
reg [7:0]data;
always @(posedge clk)
if(load )
data <= parain;
else 
data <= (data<<1);
always @(posedge clk)
if (load)
serialout <=7'b0;
else
serialout <=data[7];
endmodule

14. 4bit 串入串出寄存器

module sisoreg(clk,din,dout);
input clk,din;
output dout;
reg dout;
reg [3:0]q;
always @(posedge clk)
begin
q[0]<= din;
q[3:1]<=q[2:0];
dout <= q[3];
end
endmodule

15.上升沿捕捉电路

module btn(clk,rst,Signal, pos_btn);
input clk, rst,Signal;
output pos_btn;
reg buf1,buf2;
always@(posedge clk)
begin
   if(!rst)
     begin
       buf1 <= 1'b0;
       buf2 <= 1'b0;
     end
   else
    begin
       buf1 <= Signal;
       buf2 <= buf1; 
    end
end
assign pos_btn = (buf1)&(~buf2);
endmodule

作者寄语

本文章大多为电路模板代码，有少许测试代码。
这些程序大同小异，理解为主即可。
最后，如有问题，可评论，私信。
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