Name            Subway Turnstile;
        Designer        Rex N. Fisher;
        Device          G16V8; 

        /* Function Specifications */
        
            /*
                Refer to the state diagram on the lab handout.

                State Table  (Assume Gate = 1 when locked):

                COIN   WALK_THRU   GATE   GATE+   GATE.D (D input to GATE)

                0      0           0      0       0
                0      0           1      1       1
                0      1           0      1       1
                0      1           1      1       1
                1      0           0      0       0
                1      0           1      0       0
                1      1           0      1       1
                1      1           1      0       0
            */
                            

        /* Define Logic Operators */
       
            /* 
                AND = &
                OR = # 
                NOT = !  
            */     


        /* Define Output Pin(s) */

            Pin 15 = GATE;
                      

        /* Define Input Pins */
        
            Pin 1  = CLK;   /* Clock Input */
            Pin 2  = WALK_THRU;
            Pin 3  = COIN;
            Pin 11 = !OE;   /* Output Enable Input -- Ground this pin. */


        /* Logic Equations */

            GATE.D = (GATE & !COIN) # (!GATE & WALK_THRU);