verilog- HDL实现流水灯

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用verilog实现流水灯

module flow_deng(

input wire pin_clk_in,

input wire pin_rest_n ,

input wire [1:0] pin_ctrl,

output reg [7:0] pin_led_out

);

wire clk ;

reg [31: 0] counter32;

//fen ping

always @ (posedge pin_clk_in or negedge pin_rest_n) begin

if(pin_rest_n==1'b0) begin

counter32 <= 32'b0;

end

else begin

counter32 <= counter32+1'b1;

end

end

assign clk = counter32[3] ; //16 fen pin

reg [4:0] state;

parameter [4:0] IDLE =5'b0_0001;

parameter [4:0] RIGHT =5'b0_0010;

parameter [4:0] LEFT =5'b0_0100;

parameter [4:0] DOUB_LEFT =5'b0_1000;

parameter [4:0] ERROR =5'b1_0000;

reg [4:0] cur_sta;

always @ (posedge clk or negedge pin_rest_n) begin

if(pin_rest_n==1'b0) begin

state <= IDLE ;

end

else begin

case (state)

IDLE : begin

if (pin_ctrl==2'b00) begin

state <= LEFT ;

end

else if (pin_ctrl==2'b01) begin state <= RIGHT ;

end

else if (pin_ctrl==2'b10) begin

state <= DOUB_LEFT ;

end

else begin

state <= ERROR ;

end

end

LEFT : begin

if (pin_ctrl==2'b00) begin

state <= LEFT ;

end

else if (pin_ctrl==2'b01) begin

state <= RIGHT ;

end

else if (pin_ctrl==2'b10) begin

state <= DOUB_LEFT ;

end

else begin

state <= ERROR ;

end

end

RIGHT : begin

if (pin_ctrl==2'b00) begin

state <= LEFT ;

end

else if (pin_ctrl==2'b01) begin

state <= RIGHT ;

end

else if (pin_ctrl==2'b10) begin

state <= DOUB_LEFT ;

end

else begin

state <= ERROR ;

end

end

DOUB_LEFT : begin

if (pin_ctrl==2'b00) begin

state <= LEFT ;

end else if (pin_ctrl==2'b01) begin

state <= RIGHT ;

end

else if (pin_ctrl==2'b10) begin

state <= DOUB_LEFT ;

end

else begin

state <= ERROR ;

end

end

ERROR : begin

if (pin_ctrl==2'b00) begin

state <= LEFT ;

end

else if (pin_ctrl==2'b01) begin

state <= RIGHT ;

end

else if (pin_ctrl==2'b10) begin

state <= DOUB_LEFT ;

end

else begin

state <= ERROR ;

end

end

default: state <= IDLE ;

endcase

end

end

always @ (posedge clk or negedge pin_rest_n) begin

if (pin_rest_n == 1'b0) begin

pin_led_out[7:0]<=8'b0000_0000 ;

end

else begin

case (state)

IDLE : begin

pin_led_out [7:0] <=8'b0000_0000 ;

end

LEFT : begin

if

((pin_led_out[0]+pin_led_out[1]+pin_led_out[2]+pin_led_out[3]+pin_led_out[4]+pin_led_out[5]+pin_led_out[6]+pin_led_out[7])!=8'd1 ) begin

pin_led_out[7:0] <= 8'b0000_0001;

end

else begin

pin_led_out[7:1] <= pin_led_out[6:0];

pin_led_out[0] <= pin_led_out[7];

end

end

RIGHT : begin

if((pin_led_out[0]+pin_led_out[1]+pin_led_out[2]+pin_led_out[3]+pin_led_out[4]+pin_led_out[5]+pin_led_out[6]+pin_led_out[7])!=8'd1 ) begin