library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;

entity sh_machine is
port (           clk: in std_logic;                          --系統(tǒng)時鐘
set,sel,cancel,finish: in std_logic;                        --設定、買、選擇、完成信號
            add,coin0: in bit;                             --增加貨物的數(shù)量及1元硬幣
get,choice_a,choice_b: in bit;                              --貨物類型的選擇跳轉按鈕及選A或選B按鈕
        goods1,goods2: buffer std_logic_vector(3 downto 0);    --貨物號的顯示        
              display: buffer std_logic_vector(15 downto 0);            --十六種貨物的顯示燈
                
       money0,money1 : buffer std_logic_vector(7 downto 0));             --放入的錢數(shù)、返回的錢數(shù)的顯示輸出端
end sh_machine;

architecture xiao of sh_machine is

type  ram_type is array(15 downto 0)of std_logic_vector(7 downto 0); 
signal ram :ram_type;                                           --定義RAM
signal item: std_logic_vector(3 downto 0);                      --商品種類
signal coin: std_logic_vector(7 downto 0);                      --幣數(shù)計數(shù)器
signal pri,qua:std_logic_vector(3 downto 0); 

begin

--數(shù)量和價格的初始化
init:process(set,clk,item)
begin
 if clk 'event and clk='1' then  
    if set='1' then         --設定商品的價格和數(shù)量
        if add='1' then
         qua <=qua+1; 
        else
            if item<"1000" then
                 pri<="0010";
                 ram(conv_integer(item))<=pri & qua;
                 item<=item+1 ;
                 qua <="0000";
            else
                 pri<="0101";
                 ram(conv_integer(item))<=pri & qua;
                 item<=item+1;
                 qua <="0000" ;
           end if;
        end if;
     elsif (finish='1' and sel='0')then      --在購買時相應的商品數(shù)量減少
        if (  (display(conv_integer(goods1))='1' or display(conv_integer(goods2+8))='1')) then
           if get='0' then
               ram(conv_integer(goods1))(3 downto 0)<=ram(conv_integer(goods1))(3 downto 0)-1;
           elsif get='1' then
               ram(conv_integer(goods2+8))(3 downto 0)<=ram(conv_integer(goods2+8))(3 downto 0)-1;
           end if;
        end if;
    end if;
end if;
end process;

--錢數(shù)及貨物的計算
caculate:process
begin
wait until rising_edge(clk);
if set='0' then
     if (coin0='1' and coin<="01100100")then          --投入的錢數(shù)。
               coin<=coin+1;
          if coin>"00010100"  then
               money0<="00010100";     --輸出投入的錢數(shù)
               money1<=(coin - money0);
          
          else
               money0<=coin;
               money1<=(others=>'0');
          end if;
     elsif sel='0' then
         if  cancel='1' then        --取消交易
                  money1<=money0;
                  money0<=(others=>'0');
         elsif   finish='1' then   ----選擇好進行購買時
             if  (get='0' and ram(conv_integer(goods1))(3 downto 0)>"0000" )then
                   money0<=money0-2;
                 if(money0<"00000010") then     --當剩余的錢數(shù)小于最小的貨品單價時退出剩余的錢
                       money1<=money0;            
                       money0<=(others=>'0');
                 end if;
             elsif (get='1' and ram(conv_integer(goods2+8))(3 downto 0)>"0000") then
                      money0<=money0-5;
                  if(money0<"00000110") then      --當剩余的錢數(shù)小于最小的貨品單價時退出剩余的錢
                       money1<=money0;
                       money0<=(others=>'0');
                  end if;
             end if ;
        end if;            
     end if;
end if;
end process;

--檢查指示燈是否滿足點亮的條件
check:process
begin
 wait until rising_edge(clk) ;
 if set='0' then
   if money0<"00000010" then
        display<=(others=>'0');     
   elsif (money0>="00000010" and money0<"00000110") then  
       for i in 0 to 7 loop
           display(i+8)<='0' ;
           if (ram(i)(3 downto 0)>"0000") then
                  display(i)<='1' ;
           else
              display(i)<='0';
           end if;
       end loop;
  elsif  money0>="00000101" then
    for i in 0 to 15 loop  
      if (ram(i)(3 downto 0)>"0000") then
          display(i)<='1';
      else
          display(i)<='0' ;
      end if;
    end loop;
  end if;
  end if;
 end process;


--對商品的選擇
choose:process
begin
 wait until rising_edge(clk) ;
 if coin0='0' then
   if  (sel='1' ) then
      if choice_a='1' then        --選擇a類商品
             goods1<=goods1+1;
         if (display(conv_integer(goods1+1))='0') then
            if goods1<="0111" then
                goods1<=goods1+1;
            else
            goods1<="0000";
            end if;
         end if;
      elsif choice_b='1' then     --選擇b類商品
             goods2<=goods2+1;
        if(display(conv_integer(goods2+8))='0') then
             if goods2<="0111" then
                goods2<=goods2+1;
             else
                goods2<="0000";
            end if;
         end if;
      end if;
   end if;
end if;
end process ;


end xiao;