本程序?qū)崿F(xiàn)的電路是以CycloneII序列之EP2C5Q208C8芯片為例，經(jīng)過特定開發(fā)板電路實際仿真驗證并正確的，程序仿真的時鐘采用12M晶振：
library ieee;
Use ieee.std_logic_1164.all;
Use ieee.std_logic_unsigned.all;
entity DZB1 is
port(cr,min,hor,cp:in std_logic;
q:out std_logic_vector(6 downto 0);
w0,w1,w2,w3,w4,w5:out std_logic);
end DZB1;
architecture dianzi of DZB1 is
signal display,t0,t1,t2:std_logic_vector(8 downto 0);
signal c0,c1,c2,s0,s1,m0,m1,h0,h1,clk1,clk2:std_logic;
signal sq0,sq1,mq0,mq1,hq0,hq1,xs:std_logic_vector(3 downto 0);
begin
process(cr,cp) --分頻開始
begin
if cp'event and cp='1' then
if t0=499 then t0<="000000000";c0<='1';
else t0<=t0+1; c0<='0';
end if;
end if;
if c0'event and c0='1' then
if t1=199 then t1<="000000000";c1<='1';
else t1<=t1+1;c1<='0';
end if;
end if;
if c1'event and c1='1' then
if t2=199 then t2<="000000000";c2<='1';
else t2<=t2+1;c2<='0';
end if;
end if;
end process;
--分頻結(jié)束 --秒計時開始
process(c2,cr,min)
begin
if c2'event and c2='1' then
if sq0=9 then sq0<="0000";s0<='1';
else sq0<=sq0+1;s0<='0';
end if;
end if;
if s0'event and s0='1' then
if sq1=5 then sq1<="0000"; s1<='1';
else sq1<=sq1+1;s1<='0';
end if;
end if;
if cr='0' then sq0<="0000";sq1<="0000";
end if;
if min='0' then sq0<="0000";sq1<="0000";
end if;
end process;--秒計時結(jié)束.
--分開始
process(s1,min)
begin
clk1<=s1 or (not min);--分調(diào)整按鈕，按一下分加1同時將秒清0.
if clk1'event and clk1='1' then
if mq0=9 then mq0<="0000";m0<='1';
else mq0<=mq0+1; m0<='0';
end if;
end if;
if m0'event and m0='1' then
if mq1=5 then mq1<="0000";m1<='1';
else mq1<=mq1+1;m1<='0';
end if;
end if;
if cr='0' then mq1<="0000";mq0<="0000";
end if;--分結(jié)束
end process;
--小時開始
process(m1,hor)
begin
clk2<=m1 or (not hor);--時調(diào)整按鈕，按一下小時加1.
if clk2'event and clk2='1' then
if hq0=9 then hq0<="0000";h0<='1';
else hq0<=hq0+1;h0<='0';
end if;
end if;
if h0'event and h0='1' then
if hq1=5 then hq1<="0000";h1<='1';
else hq1<=hq1+1;h1<='0';
end if;
end if;
if hq1=2 and hq0=4 then
hq0<="0000";hq1<="0000";
end if;
if cr='0' then hq0<="0000";hq1<="0000";
end if;--小時結(jié)束
end process;
--顯示開始
process(xs)
begin
case xs is
when "0000"=>q<="0000001";
when "0001"=>q<="1001111";
when "0010"=>q<="0010010";
when "0011"=>q<="0000110";
when "0100"=>q<="1001100";
when "0101"=>q<="0100100";
when "0110"=>q<="0100000";
when "0111"=>q<="0001111";
when "1000"=>q<="0000000";
when "1001"=>q<="0000100";
when others=>q<="0000001";
end case;
end process;--顯示結(jié)束
--顯示輸出
process(cp)
begin
--顯示計時
if cp'event and cp='1' then
if display<496 then display<=display+1;
else display<="000000000";
end if;
end if;
--秒顯示
if display>0 and display<82 then xs<=sq0;w0<='0';
else w0<='1';
end if;
if display>83 and display<164 then xs<=sq1;w1<='0';
else w1<='1';
end if;
--分顯示
if display>165 and display<247 then xs<=mq0;w2<='0';
else w2<='1';
end if;
if display>248 and display<320 then xs<=mq1;w3<='0';
else w3<='1';
end if;
--時顯示
if display>321 and display<403 then xs<=hq0;w4<='0';
else w4<='1';
end if;
if display>405 and display<496 then xs<=hq1;w5<='0';
else w5<='1';
end if;
end process;
end ;
其中12M時鐘從24腳輸入，七段顯示a,b,c,d,e,f,g對應(yīng)Q0---Q6，綁定管腳依次為171，173，175，164，165，168，169，顯示控制按照從左向右依次為：小時、分、秒（各兩位顯示）的順序，由于6個數(shù)碼管采用總線控制，所以需要分時向總線傳遞顯示信號，分別由位控制腳按照小時、分、秒的順序由176，179，180，181，182和185腳分時點亮，就成了地地道道的電子表。