--using textio.allEntity Soda_Machine is port( --would need maximum of 30 nickles NICKEL_IN : std_logic_vector(4 downto 0); --would need maximum of 15 dimes DIME_IN : std_logic_vector(3 downto 0); --would need maxium of 6 quarters QUARTER_IN: std_logic_vector(2 downto 0); SELECTION: std_logic_vector(15 downto 0); PRICE: out std_logic_vector(15 downto 0); RESET: BOOLEAN; CLK: BIT; --return change and soda NICKEL_OUT, DIME_OUT, DISPENSE: out BOOLEAN );End Soda_Machine;

architecture BEHAVIOR of Soda_Machine is signal Current_Coin_Count, Next_Coin_Count: INTEGER range 0 to 30; -- 30 nickles is $1.50 signal Current_Return_Change, Next_Return_Change : BOOLEAN;beginprocess(NICKEL_IN, DIME_IN, QUARTER_IN, RESET, CLK, Current_Coin_Count, Current_Return_Change)--maximum amount of coins--possible is 30 niickles variable Temp_Coin_Count: INTEGER range 0 to 30;begin-- Set all Change Returned to 0 NICKEL_OUT <= FALSE; DIME_OUT <= FALSE; DISPENSE <= FALSE; Next_Coin_Count <= 0; NEXT_Return_Change <= FALSE;-- Synchronous resetif (not RESET) then Temp_Coin_Count := Current_Coin_Count; Case SELECTION is when "000" => PRICE := "110010";End Case; -- Check whether change was put in the Machineif (NICKEL_IN) then Temp_Coin_Count := Temp_Coin_Count + 1; --counting number of nickles inputed

elsif(DIME_IN) then Temp_Coin_Count := Temp_Coin_Count + 2; --counting number of dimes inputedelsif(QUARTER_IN) then Temp_Coin_Count := Temp_Coin_Count + 5; --counting number of quarters inputedend if;-- Keeps track if enough change was put in machine

--Macine Requires 25 Nicklesif(Temp_Coin_Count >= 25) then Temp_Coin_Count := Temp_Coin_Count - 25;--soda given to customer DISPENSE <= TRUE;end if;

--If too many nickles change is returnedif(Temp_Coin_Count >= 1 or Current_Return_Change) thenif(Temp_Coin_Count >= 2) then --dime returned DIME_OUT <= TRUE; Temp_Coin_Count := Temp_Coin_Count - 2; --stil return more change Next_Return_Change <= TRUE;end if;if(Temp_Coin_Count = 1) then --nickle returned NICKEL_OUT <= TRUE; Temp_Coin_Count := Temp_Coin_Count - 1;end if;end if;Next_Coin_Count <= Temp_Coin_Count;end if;end process;

processbegin--returns change on positive clock edegewait until CLK' event and CLK = '1';Current_Return_Change <= NEXT_Return_Change;Current_Coin_Count <= Next_Coin_Count;end process;end BEHAVIOR;