-- bbc.vhd
-------此模塊對應不同的片選信號，輸出不同的要顯示的數據
library ieee; 
use ieee.std_logic_1164.all; 
---------------------------------
entity bbc is 
port(bai1,bai0,sec1,sec0,min1,min0,h1,h0:in std_logic_vector(3 downto 0); 
sel:in std_logic_vector(2 downto 0); 
q: out std_logic_vector(3 downto 0)); 
end bbc; 
---------------------------------------
architecture bbb_arc of bbc is 
begin 
process(sel) 
begin 
case sel is 
when "000"=>q<=bai0;          ---數碼管1和0選擇ms輸出
when "001"=>q<=bai1;         
when "010"=>q<=sec0;          ---數碼管3和2選擇s輸出 
when "011"=>q<=sec1; 
when "100"=>q<=min0;          ---數碼管5和4選擇minute輸出
when "101"=>q<=min1; 
when "110"=>q<=h0;          ---數碼管7和6選擇hour輸出
when "111"=>q<=h1; 
when others=>q<="111"; 
end case; 
end process; 
end bbb_arc;