FPGA 学习10 状态机的理解

╰半夏微凉° 2022-12-12 04:33 182阅读 0赞

# FPGA 学习10 状态机的理解 #

Hello.v 文件

module Hello(Clk,Rst_n,data,led);
    
    	input Clk;//50M
    	input Rst_n;//低电平复位
    	
    	input [7:0]data;
    	
    	output reg led;
    	
    	localparam
    		CHECK_H	= 5'b0_0001,
    		CHECK_e 	= 5'b0_0010,
    		CHECK_la	= 5'b0_0100,
    		CHECK_lb	= 5'b0_1000,
    		CHECK_o	= 5'b1_0000;
    
    	reg[4:0]state;
    	
    	always@(posedge Clk or negedge Rst_n)
    	if(!Rst_n)begin
    		led <= 1'b1;
    		state <= CHECK_H;
    	end
    	else begin
    		case(state)
    			CHECK_H:
    				if(data == "H") 
    					state <= CHECK_e;
    				else
    					state <= CHECK_H;
    			
    			CHECK_e:
    				if(data == "e")
    					state <= CHECK_la;
    				else
    					state <= CHECK_H;
    					
    			CHECK_la:
    				if(data == "l")
    					state <= CHECK_lb;
    				else
    					state <= CHECK_H;
    					
    			CHECK_lb:
    				if(data == "l")
    					state <= CHECK_o;
    				else	
    					state <= CHECK_H;
    					
    			CHECK_o:
    				begin
    					state <= CHECK_H;
    					if(data == "o")
    						led <= ~led;
    					else
    						led <= led;
    				end
    				
    			default:state <= CHECK_H;
    		endcase		
    	end
    
    endmodule
    	
    	/* CHECK_o : //进入第5个状态条件 if(data == "o") begin led <= ~led ; state <= CHECK_H ; end else state <= CHECK_H ; default : //其它非正常状态 state <= CHECK_H ; */

Hello\_tb.v 文件

`timescale 1ns/1ns
    `define clock_period 20
    module Hello_tb ;
    
    	reg Clk ;
    	reg Rst_n ;
    	reg [7:0]ASCII;
    	
    	wire led;
    
    	Hello Hello_0(
    		.Clk(Clk) ,
    		.Rst_n(Rst_n) ,
    		.data(ASCII) ,
    		
    		.led(led) 
    	);
    
    	initial Clk = 1 ;
    	always#(`clock_period/2) Clk = ~Clk ;
    	
    	initial begin
    	//信号初始化
    		Rst_n = 0;
    		ASCII = 0;
    		#(`clock_period * 200);
    		Rst_n = 1;
    		#(`clock_period * 200 +1);
    		
    		
    	// forever : 循环调用，在仿真的时候设置仿真时间即可
    		forever begin
    			ASCII = "I";
    			#(`clock_period);
    			ASCII = "A";
    			#(`clock_period);
    			ASCII = "M";
    			#(`clock_period);
    			ASCII = "X";
    			#(`clock_period);
    			ASCII = "i";
    			#(`clock_period);
    			ASCII = "a";
    			#(`clock_period);
    			ASCII = "o";	
    			#(`clock_period);
    			ASCII = "M";
    			#(`clock_period);
    			ASCII = "e";
    			#(`clock_period);
    			ASCII = "i";
    			#(`clock_period);
    			ASCII = "g";
    			#(`clock_period);
    			ASCII = "e";	
    			
    			#(`clock_period);
    			ASCII = "H";
    			#(`clock_period);
    			ASCII = "E";
    			
    			#(`clock_period);
    			ASCII = "M";
    			#(`clock_period);
    			ASCII = "l";
    			
    			#(`clock_period);
    			ASCII = "H";
    			#(`clock_period);
    			ASCII = "E";
    			#(`clock_period);
    			ASCII = "L";
    			#(`clock_period);
    			ASCII = "L";
    			#(`clock_period);
    			ASCII = "O";
    			#(`clock_period);
    			
    			ASCII = "H";
    			#(`clock_period);
    			ASCII = "e";
    			#(`clock_period);
    			ASCII = "l";
    			#(`clock_period);
    			ASCII = "l";
    			#(`clock_period);
    			ASCII = "o";
    			
    			#(`clock_period);
    			ASCII = "l";
    		end
    	end
    		
    endmodule