--文件名：shop.vhd。
--功能：貨物信息存儲，進程控制，硬幣處理，余額計算，顯示等功能。
--說明：顯示的錢數coin的 以5角為單位。
library ieee;
use ieee.std_logic_arith.all;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity shop is
port ( clk:in std_logic;-----系統時鐘20mhz
       set,get,sel,finish: in std_logic;-----設定、買、選擇、完成信號
       coin0,coin1: in std_logic; -----------5角硬幣、1元硬幣
       price,quantity  :in std_logic_vector(3 downto 0);-------價格、數量數據
	   item0 , act:out std_logic_vector(3 downto 0);---------顯示、開關信號
	   seg7:out std_logic_vector(6 downto 0);--------------錢數、商品數量顯示數據
	   scan:out std_logic_vector(2 downto 0);--------------數碼管地址選擇
	   act10,act5   :out std_logic);-------------------------1元硬幣、5角硬幣
end ;
architecture one of shop is
	type  ram_type is array(3 downto 0)of std_logic_vector(7 downto 0); 
	signal ram :ram_type; ------------------定義RAM
	signal clk1khz,clk1hz:std_logic;
	signal item: std_logic_vector(1 downto 0);------商品種類
	signal coin: std_logic_vector(3 downto 0);------幣數計數器
	signal pri,qua:std_logic_vector(3 downto 0);----商品單價、數量
	signal clk1hzhz: std_logic; ------------------------控制系統的時鐘信號
	signal y0,y1,y2:std_logic_vector(6 downto 0);----錢數、商品數量
begin
-------------------------------------1khz分頻
process(clk)                            
variable cnt: integer range 0 to 0;
begin
   if clk'event and clk='1' then 
      if cnt=0 then clk1khz<= not clk1khz;cnt:=0;
      else cnt:=cnt+1;
      end if;
   end if;
end process ;
-------------------------------------1hz分頻
process(clk1khz)                            
variable cnt: integer range 0 to 0;
begin
   if clk1khz'event and clk1khz='1' then 
      if cnt=0 then clk1hz<= not clk1hz;cnt:=0;
      else cnt:=cnt+1;
      end if;
   end if;
end process ;
----------------------------------
process(set,clk1hz,price,quantity,item)
begin
  if set='1' then 
      ram(conv_integer(item))<=price & quantity;------把商品的單價、數量置入到RAM
      act<="0000";
  elsif clk1hz'event and clk1hz='1' then 
		 act5<='0'; 
		 act10<='0';
      if coin0='1' then ----------投入5角硬幣，coin自加
	      if coin<"1001"then 
	         coin<=coin+1; 
		  else coin<="0000";
		  end if;
      elsif coin1='1' then -------投入1元硬幣，coin自加2
		  if coin<"1001"then 
		     coin<=coin+2;           
		  else coin<="0000";
		  end if;
      elsif sel='1' then  ----------對商品進行循環選擇
            item<=item+1;                 
      elsif get='1' then -----------對商品進行購買
         if qua>"0000" and coin>=pri then 
             coin<=coin-pri;
             qua<=qua-1;
			 ram(conv_integer(item))<=pri & qua;
            if item="00" then act<="1000";-------購買時，自動售貨機對4種商品的操作
			elsif item="01" then act<="0100";
		    elsif item="10" then act<="0010";
		    elsif item="11" then act<="0001";
			end if;
		end if;
      elsif  finish='1' then -----------------結束交易，退幣（找幣）
         if coin>"0001" then --此IF語句完成找幣操作
			act10<='1';
			coin<=coin-2;     
         elsif coin>"0000" then 
			 act5<='1'; 
			 coin<=coin-1;
         else 
             act5<='0'; 
             act10<='0';
         end if;
      elsif get='0' then 
            act<="0000";                  
         for i in 0 to 3 loop
         pri(i)<=ram(conv_integer(item))(4+i);-------商品價格的讀取       
         qua(i)<=ram(conv_integer(item))(i);---------商品數量的讀取
         end loop; 
      end if;
  end if;
end process ;
-----------------------------------------商品指示燈譯碼------
process(item)                          
begin
case item is
	when "00"=>item0<="0111";
	when "01"=>item0<="1011";
	when "10"=>item0<="1101";
	when others=>item0<="1110";
end case;
end process;
--------------------------------------錢數的BCD到七段碼的譯碼
process (coin)                       
begin
  case coin is
    when"0000"=>y0<="1111110";
	when"0001"=>y0<="0110000";
	when"0010"=>y0<="1101101";
	when"0011"=>y0<="1111001";
	when"0100"=>y0<="0110011";
	when"0101"=>y0<="1011011";
	when"0110"=>y0<="1011111";
	when"0111"=>y0<="1110000";
	when"1000"=>y0<="1111111";
	when"1001"=>y0<="1111011";
    when others=>y0<="0000000";
  end case;
end process;
------------------------------------數量的BCD到七段碼的譯碼
process (qua)                       
begin
  case qua is
    when"0000"=>y1<="1111110";
	when"0001"=>y1<="0110000";
	when"0010"=>y1<="1101101";
	when"0011"=>y1<="1111001";
	when"0100"=>y1<="0110011";
	when"0101"=>y1<="1011011";
	when"0110"=>y1<="1011111";
	when"0111"=>y1<="1110000";
	when"1000"=>y1<="1111111";
	when"1001"=>y1<="1111011";
    when others=>y1<="0000000";
  end case;
end process;
------------------------------------單價的BCD到七段碼的譯碼
process (pri)                       
begin
  case pri is
    when"0000"=>y2<="1111110";
	when"0001"=>y2<="0110000";
	when"0010"=>y2<="1101101";
	when"0011"=>y2<="1111001";
	when"0100"=>y2<="0110011";
	when"0101"=>y2<="1011011";
	when"0110"=>y2<="1011111";
	when"0111"=>y2<="1110000";
	when"1000"=>y2<="1111111";
	when"1001"=>y2<="1111011";
    when others=>y2<="0000000";
  end case;
end process;
----------------------------------數碼管動態掃描
process(clk1khz,y0,y1,y2)
variable cnt:integer range 0 to 2;
begin
if clk1khz'event and clk1khz='1' then
	cnt:=cnt+1;
end if;
case cnt is
	when 0=>scan<="001";seg7<=y0;
	when 1=>scan<="010";seg7<=y1;
	when 2=>scan<="100";seg7<=y2;
when others=>null;
end case;
end process;
end ;