1、1、要求：設計一個四位二進制計數器，將計數結果由數碼管顯示，顯示結果為十進制數。數碼管選通為低電平有效，段碼為高電平有效。分析：VHDL 描述包含五部分：計數器、將四位二進制數拆分成十進制數的個位和十位、二選一的數據選擇器、七段譯碼、數碼管選通控制信號 線定義為信號library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL; entity counter3 is Port ( clk:in STD_LOGIC; clk1 : in STD_LOG

2、IC; clr : in STD_LOGIC; en : in STD_LOGIC; co : out STD_LOGIC; scanout:out std_logic_vector(1 downto 0; ledout:out std_logic_vector(6 downto 0; end counter3; architecture Behavioral of counter3 is signal cnt:std_logic_vector(3 downto 0; signal cnt1:std_logic_vector(3 downto 0; signal cnt2:std_logic_

3、vector(3 downto 0; signal hex:std_logic_vector(3 downto 0; signal scan:std_logic_vector(1 downto 0;enclrsignal led:std_logic_vector(6 downto 0; begin -四位二進制計數器 process(clk begin if clkevent and clk=1 then if clr=1 then cnt0; co=0; elsif en=1 then if cnt=1111 then cnt=0000; co=1; else cnt=cnt+1; co=0

4、; end if; end if; end if; end process; -將二進制數拆分成十進制數的個位和十位 cnt1=cnt when cnt=1001 else cnt-1010; cnt2=0000 when cnt=1001 else 0001; -七段數碼管選通控制信號產生 process(clk1,clr begin if clr=1 then scan=10 then scan=01; else scan=scan+1;end if;end if;end process; scanout=scan; -二選一數據選擇器with scan select hex=cnt1 w

5、hen 01, cnt2 when others;ledout=not led; -七段譯碼with hex select led=1111001 when 0001, 0100100 when 0010,0110000 when 0011,0011001 when 0100,0010010 when 0101,0000010 when 0110,1111000 when 0111, 0000000 when 1000,0010000 when 1001, 0001000 when 1010,0000011 when 1011,1000110 when 1100,0100001 when 11

6、01, 0000110 when 1110,0001110 when 1111,1000000 when others;end Behavioral; 2、八位二進制計數器結果有兩位七段數碼管顯示 library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL; - Uncomment the following library declaration ifinstantiating - any Xilinx primitives in this c

7、ode. -library UNISIM; -use UNISIM.VComponents.all; entity counter8 isPort ( clk:in std_logic; clk1 : in STD_LOGIC;clr : in STD_LOGIC; en : in STD_LOGIC; co : out STD_LOGIC;scanout:out std_logic_vector(1 downto 0; ledout : out STD_LOGIC_VECTOR (6 downto 0; end counter8; architecture Behavioral of cou

8、nter8 is signal cnt:std_logic_vector(7 downto 0; signal hex:std_logic_vector(3 downto 0; signal scan:std_logic_vector(1 downto 0; signal led:std_logic_vector(6 downto 0; begin process(clk begin if clkevent and clk=1 thenif clr=1 thencnt0; co=0;elsif en=1 thenif cnt=11111111 then cnt=00000000;co=1;el

9、secnt=cnt+1;co=0;end if; end if;end if; end process; process(clk1,clr begin if clr=1 then scan=10 then scan=01; else scan=scan+1; end if; end if; end process; scanout=scan; with scan select hex=cnt(3 downto 0 when 01, cnt(7 downto 4 when others; ledout=not led; with hex select led=1111001 when 0001, 0100100 when 0010, 0110000 when 0011, 0011001 when 0100, 0010010 when 0101, 0000010 when 0110, 1111000 when 0111, 0000000 when 1000, 0010000 when 1001,