TheLegace

module Lab2(
                input CLOCK_50,             //50Mhz input clock
                input [3:0] KEY,                //4 Pushbuttons
                output reg [7:0] HEX0,      //7-seg display 0
                output reg [7:0] HEX1,      //7-seg display 0
                output reg [17:0] LEDR
);

    reg [7:0] count;                //8-bit counter
    reg [7:0] push2;                //count when pushbutton 3/KEY[2] is pushed
    reg flag;                       //set once pushbutton3/KEY[2] is pushed
    reg [7:0] elapsed;              //elapsed time between pushbutton3/KEY[2] and pushbutton2/KEY[1]
    wire [7:0] h0,h1;
    seg7 s1(elapsed[7:4], h1);
    seg7 s0(elapsed[3:0], h0);

    always @ (posedge CLOCK_50)
        begin
            if(count==16'b1100001101010000) //divider by 50 000 -->resulting count ever 1ms
                count <= 4'b0000;   //reset to 0
            else count <= count+1;  //increment counter
            if(KEY[2]) begin
                push2 <= count;
                flag = 1;
            end
            if(flag && KEY[1]) begin
                elapsed <= count-push2;
                HEX1=h1;
                HEX0=h0;
            end
            if(~flag && KEY[1]) begin   //KEY[1] enabled first
                LEDR[0] = 1;                //error LED
                HEX0 = 8'b0;                //output 0
                HEX1 = 8'b0;                //output 0
            end
        end
endmodule

module seg7(input [3:0] DEC,                //4-bit decimal value to output on LED
                output reg [7:0] LED            //8-bit Value of value of LED
);
    always @(DEC)
        case(DEC)
            0: LED = 7'b1111110;
        1: LED = 7'b0110000;
            2: LED = 7'b1101101;
            3: LED = 7'b1111001;
            4: LED = 7'b0110011;
            5: LED = 7'b1011011;
            6: LED = 7'b1011111;
            7: LED = 7'b1110000;
            8: LED = 7'b1111111;
            9: LED = 7'b1111011;
            10: LED = 7'b1110111;
            11: LED = 7'b0011111;
            12: LED = 7'b1001110;
            13: LED = 7'b0111101;
            14: LED = 7'b1001111;
            15: LED = 7'b1000111;
            default: LED = 7'bx;
        endcase
endmodule