BCD計數器 0-9 顯示於7-segment

輸入 :　clock :=48Mhz
              reset := push button
輸出：1 digit 7-segment


48Mhz -> 1Hz ->0..9 BCD conuter -> 7segment

----
--VHDL code for BCD to 7-segment display converter
----
--------------------------------------------------------

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

entity cnt_9 is
port (
      Clk : in std_logic;
      Rst : in std_logic;
      segment7 : out std_logic_vector(6 downto 0)  -- 7 bit decoded output.
    );
end cnt_9;
--'a' corresponds to MSB of segment7 and g corresponds to LSB of segment7.
architecture Behavioral of cnt_9 is

   signal temp: std_logic_vector(0 to 3);
   signal Fre_1hz : std_logic ; --1Hz 基頻
   signal Pulse : std_logic ; --按鍵防彈跳頻率
 
begin

Clk_generator:  process(Clk)
variable Delay : std_logic_vector(24 downto 0); begin
if rising_edge(Clk) then
if Delay=24000000 then Delay := "0000000000000000000000000" ; --–-將輸入頻率除頻成 1Hz
Fre_1hz <= not Fre_1hz ; else Delay := Delay+1 ; end if ;
Pulse <= Delay(14); ---產生防彈跳頻率
end if ;
 end process Clk_generator ;

 
 BCD_CNT: process(Fre_1hz,Rst)
  begin
      if Rst='1' then
         temp <= "0000";
      elsif(rising_edge(Fre_1hz)) then
        if temp="1001" then
      temp<="0000";
   else
      temp <= temp + 1;
   end if;
      end if;
 
   end process;
------------------------------------------------------  
bcd_7seg: process (clk,temp)
BEGIN
if (Clk'event and Clk='1') then
case  temp is
when "0000"=> segment7 <="0000001";  -- '0'
when "0001"=> segment7 <="1001111";  -- '1'
when "0010"=> segment7 <="0010010";  -- '2'
when "0011"=> segment7 <="0000110";  -- '3'
when "0100"=> segment7 <="1001100";  -- '4'
when "0101"=> segment7 <="0100100";  -- '5'
when "0110"=> segment7 <="0100000";  -- '6'
when "0111"=> segment7 <="0001111";  -- '7'
when "1000"=> segment7 <="0000000";  -- '8'
when "1001"=> segment7 <="0000100";  -- '9'
--nothing is displayed when a number more than 9 is given as input.
when others=> segment7 <="1111111";
end case;
end if;
end process;


end Behavioral;