帧格式头数据检测_VerilogHDL有限状态机

题目1:串行通讯中，经常要检测数据包的开始标志，例如：USB 数据包的起
始数据是8‘b00101010设计一个电路，能够检测串行数据流中的特殊数据串，并在数据串有效时，给出相应的指示信号；
(1)RTL Code
/*信号定义与说明
Clk:同步时钟
rstb: 异步复位信号，低电平复位
up_down: 加/减计数方向控制信号，1为加计数
Din：串行数据输入
pat_det: 检测结果输出
*/
`timescale 1ns/1ns
module serialdata(din,clk,rstb,pat_det);
input clk,rstb;
input din;
output pat_det;
parameter S0='d0,S1='d1,S2='d2,S3='d3,S4='d4,S5='d5,S6='d6,IDLE='d7;
reg[2:0] state;
assign pat_det=(state= =S6&&din= =0)?1:0;
always@(posedge clk or negedge rstb)
begin
if(!rstb) state<=IDLE;
else
begin
case(state)
IDLE:
begin
if(din==0) state<=S0;
else state<=IDLE;
end
S0:
begin
if(din==0) state<=S1;
else state<=IDLE;
end
S1:
begin
if(din==1) state<=S2;
else state<=S1;
end
S2:
begin
if(din==0) state<=S3;
else state<=IDLE;
end
S3:
begin
if(din==1) state<=S4;
else state<=S1;
end
S4:
begin
if(din==0) state<=S5;
else state<=IDLE;
end
S5:
begin
if(din==1) state<=S6;
else state<=S1;
end
S6: state<=IDLE;
default: state<=IDLE;
endcase
end
end
endmodule
(2)Test File
`timescale 1ns/1ns
`include "serialdata.v"
module tb_serialdata;
reg clk,rstb;
wire din;
wire pat_det;
reg[31:0] data;
assign din=data[31];
serialdata t1(din,clk,rstb,pat_det);
initial begin
clk=1'b0;
rstb=1'b0;
data=32'b1001_0010_1010_1100_1010_1000_1010_1010;
#10 rstb=1'b1;
#640 $stop;
end
always@(posedge clk)
begin
data <={data[30:0],data[31]};
end
always #5 clk=~clk;
endmodule
(3)波形与说明
图示标注地方每个上升沿取得数据din，当检测到00101010之后输出pat_det 置为高电平。

整个32位串行输入数据1001_0010_1010_1100_1010_1000_1010_1010，总共640个时间单位stop，即32位输入数据跑两遍，共输出6个高电平脉冲，符合设计!
题目2:设计一个串行数据检测器，输入数据与时钟同步。

要求是：输入连续5
个或5 个以上的1 时输出为1，其他输入情况下输出为0
(1)RTL Code
/*信号定义与说明
clk: 同步输入时钟
nreset: 复位信号，低电平有效
din: 串行数据输入
out:检测结果输出
*/
`timescale 1ns/1ns
module serialfive1(out,din,clk,nreset);
input din;
input clk,nreset;
output out;
parameter M0='d0,M1='d1,M2='d2,M3='d3,M4='d4,IDLE='d5;
reg[2:0] state;
assign out=(state==M4&&din==1)?1:0;
always @(posedge clk)
begin
if(!nreset) state<=IDLE;
else
case(state)
IDLE:
begin
if(din==1) state <= M0;
else state <= IDLE;
end
M0:
begin
if(din==1) state <= M1;
else state <= IDLE;
end
M1:
begin
if(din==1) state <= M2;
else state <= IDLE;
end
M2:
begin
if(din==1) state <= M3;
else state <= IDLE;
end
M3:
begin
if(din==1) state <= M4;
else state <= IDLE;
end
M4:
begin
if(din==1) state <= M4;
else state <= IDLE;
end
default: state <= IDLE;
endcase
end
endmodule
(2)Test File
`include "serialfive1.v"
`timescale 1ns/1ns
module tb_serialfive1;
reg clk,nreset;
wire din,out;
reg[15:0] data;
assign din=data[15];
serialfive1 t1(out,din,clk,nreset);
initial
begin
clk = 1'b0;
nreset = 1'b0;
data = 'b0111_1110_0101_1111;
#8 nreset = 1'b1;
#320 $stop;
end
always #5 clk=~clk;
always @(posedge clk)
data = {data[14:0],data[15]};
endmodule
(3)波形与说明
如图所示，输入16位串行数据0111_1110_0101_1111。

在320个时间单位跑两遍，一共输出4个高电平脉冲输出，其中一个是连续6个1，所以其维持2个clk，如图示，满足设计要求！。