traffic_light_v2

module TrafficLights_V2(clk,rst,seg_en,seg,R,Y,G);

input clk,rst ;
output reg R,Y,G ;
output reg [3:0]seg_en ;
output [6:0]seg ;


parameter s1 = 1 ,s2 = 2 , s3 = 3 ;
reg [1:0]state ;
reg [30:0]div ;
reg [7:0]count ;
wire scan_clk ;
reg clk_1Hz ;
wire [3:0]scan_code ;

always @(posedge clk or negedge rst)
begin
    if(!rst) begin div <= 0 ; clk_1Hz <= 0 ; end
    else if(div==24999999) begin div <= 0 ; clk_1Hz <= ~clk_1Hz ; end
    else div <= div + 1 ;
end

assign scan_clk = div[16] ;
//assign clk_1Hz = div[15] ;


always @(posedge scan_clk or negedge rst)
begin
    if(!rst) seg_en <= 4'b1110 ;
    else seg_en[3:0] <= {seg_en[0],seg_en[3:1]} ;
end

always @(posedge clk_1Hz or negedge rst)
begin
    if(!rst) state <= s1 ;
    else
     case(state)
        s1:
            begin
            R = 0 ;
            if(!rst)count <= 2'h15 ;
            else if(count[3:0]==0) begin count[3:0] <= 9 ; count[7:4] <= 0 ; end
            else if(count==0) state <= s3 ;
            else count <= count - 1 ;
            end

        s2:
            begin
            Y = 0 ;
            if(!rst)count <= 2'h05 ;
            else if(count==0) state <= s1 ;
            else count <= count - 1 ;
            end

        s3:
            begin
            G = 0 ;
            if(!rst)count <= 2'h10 ;
            else if(count[3:0]==0) begin count[3:0]<=9 ; count[7:4]<=0 ; end
            else if(count==0) state <= s2 ;
            else count <= count - 1 ;
            end
        default:state <= s1 ;
    endcase
end

assign scan_code = (seg_en==4'b1110) ? count[3:0] :
                   (seg_en==4'b1101) ? count[7:4] :
                   (seg_en==4'b1011) ? count[3:0] :
                                       count[7:4] ;// 7's en





assign seg[6:0] = (scan_code==4'h0) ? 7'b0000001 :
                  (scan_code==4'h1) ? 7'b1001111 :
                  (scan_code==4'h2) ? 7'b0010010 :
                  (scan_code==4'h3) ? 7'b0000110 :
                  (scan_code==4'h4) ? 7'b1001100 :
                  (scan_code==4'h5) ? 7'b0100100 :
                  (scan_code==4'h6) ? 7'b0100000 :
                  (scan_code==4'h7) ? 7'b0001111 :
                  (scan_code==4'h8) ? 7'b0000000 :
                  (scan_code==4'h9) ? 7'b0000100 :
                  7'b1111111;//7's number






endmodule