FPGA状态机

一、状态机实现

1. 状态机：实现一个测试过程，该过程包括启动准备状态、启动测试、停止测试、查询测试结果、显示测试结果、测试结束返回初始化6个状态；用时间来控制该过程，90秒内完成该过程

2. 描述状态跳转时间

   • 状态机状态
     • s0：准备状态
     • s1：启动状态
     • s2：停止状态
     • s3：查询测试结果
     • s4：显示测试结果
     • s5：测试结束返回初始态
   • 阶段性跳转
     • s0 -> s1 第1s跳转到s1
     • s1 -> s2 第25s跳转到s2
     • s2 -> s3 第55s跳转到s3
     • s3 -> s4 第60s跳转到s4
     • s4 -> s5 第75s跳转到s5
     • s5 -> s0 第90s跳转回初始状态

3. 编码实现。

module fsm(
	input clk,
	input rst_n,
	output result
);
reg[5:0] state;
reg[27:0] ctn;
parameter max_time=28'd49_999_999;
wire[63:0] timer;
parameter s0 = 6'b100000;
parameter s1 = 6'b010000;
parameter s2 = 6'b001000;
parameter s3 = 6'b000100;
parameter s4 = 6'b000010;
parameter s5 = 6'b000001;

//计数器
always@(posedge clk or negedge rst_n)begin
	if(!rst_n)begin
		ctn <= 28'd0;
	end
	else if(ctn == max_time)begin
		ctn <= 28'd0;
	end
	else ctn <= ctn +1'b1;
end 
always @(posedge clk or negedge rst_n)begin
	if(rst_n)begin
		state <= s0;
	end	
	else
		case(state)
			s0:begin
				if(timer == 1)
					state <= s1;
				else state <= s0;			
			end
			s1:begin
				if(timer == 25)
					state <= s2;
				else state <= state;
			end
			s2:begin
				if(timer == 55)
					state <= s3;
				else state <= state;
			end
			s3:begin
				if(timer == 60)
					state <= s4;
				else state <= state;
			end
			s4:begin
				if(timer == 75)
					state <= s5;
				else state <= state;
			end
			s5:begin
				if(timer == 90)
					state <= s0;
				else state <= state;
			end
			default:sr=state <= s0;	
		endcase
end
endmodule 

二、检测10010串

1. 画出可以检测10010串的状态图
   
2. verilog编程实现

module Ce_Top(
	input clk,
	input rst_n,
	input data,
	output result
);
reg result_r;
reg[4:0] state;
parameter IDLE = 5'b10000;
parameter S1   = 5'b01000;
parameter S10  = 5'b00100;
parameter S100 = 5'b00010;
parameter S1001= 5'b00001;
always@(posedge clk or negedge rst_n)begin
	if(!rst_n)begin
		state <= IDLE;
		result_r <= 1'b0;
	end	
	else	
		case(state)		
		IDLE: begin
			if(data==0)begin
				state <= IDLE;
				result_r <= 0;
			end	
			else begin
				state <= S1;
				result_r <= 0;
			end
		end
		S1:begin		
			if(data ==0)begin
				state <= S10;
				result_r <= 0;
			end			
			else begin
				state <=S1;
				result_r <= 0;
			end
		end
		S10:begin	
			if(data ==0)begin
				state <= S100;
				result_r <= 0;
			end			
			else begin
				state <=S1;
				result_r <= 0;
			end
		end		
		S100:begin
			if(data==0)begin		
				state <= IDLE;
				result_r <= 0;
			end			
			else begin
				state <= S1001;
				result_r <= 0;
			end
		end		
		S1001:begin
			if(data==0)begin		
				state <= IDLE;
				result_r <= 1;
			end
			else begin
				state <= S1;
				result_r <= 0;
			end
		end
		default: state <= 5'bx;
		endcase
end
assign result =result_r;
endmodule 

三、总结

主体实验通过状态机对实验进行状态跳转，进入不同逻辑时序，在代码是线上只做了思路书写，未上板验证实验。