一、 設計目標要求：
【1】 具有“時”、“分”、“秒”計時功能能；
【2】 能進行24|12小時計時模式切換；
【3】 具有校時和清除功能，能夠對“小時”和“分”進行調整；
【4】 具有整點報時功能。在59分51秒、53秒、55秒、57秒發出低音1024Hz信號，在59分59秒發出一次高音2048Hz信號，音響持續1秒鐘，在2048Hz音響結束時刻為整點。
二、 設計原理及效果：
【1】電路原理圖：
【2】設計簡要說明：
本設計在實驗箱上驗證，使用電路模式7，用動態掃描方式顯示，“DS8使能”開關上推；動態位掃描時，時、分、秒之間間隔點亮；
TMODE：12/24進制模式切換，接鍵8；
SCAN：動態掃描時鐘信號，接CLOCK0，跳線選16384Hz；
MINUTE：分校時，接鍵1（單脈沖）；
HOUR：小時時校時，接鍵4（單脈沖）；
EXCHGE：計時/校時切換，接鍵5；
CLK:：時鐘脈沖，接CLOCK2,跳線選1Hz；
RET：清零，接鍵7（單脈沖）；
EN：計數使能，接鍵3；
CLK1024：蜂鳴輸入信號，接CLOCK5,跳線選1024Hz；
SG[6..0]：段選信號，接PIO49到PIO43；
BT[7..0]：位選信號，接PIO41到PIO34；
SPEAKER：蜂鳴輸出信號，接SPEAKER。
【3】實驗效果：
照片描述：晚7點45分07秒（12進制）
照片描述：晚7點45分34秒（24進制）
【1】60進制模塊——CNT60
LIBRARY IEEE; --------CLK時鐘輸入，RET清零，EN計數使能，
USE IEEE.STD_LOGIC_1164.ALL; -------- CQL分或秒的個位輸出，
USE IEEE.STD_LOGIC_UNSIGNED.ALL; --------CQH分或秒的十位輸出,
ENTITY CNT60 IS -------- COUT1進位輸出
PORT (CLK,RST,EN : IN STD_LOGIC;
CQL: OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
CQH: OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
COUT1 : OUT STD_LOGIC); --------向外部的進位
END CNT60;
ARCHITECTURE behav OF CNT60 IS
SIGNAL CQI0: STD_LOGIC_VECTOR (3 DOWNTO 0);
SIGNAL CQI1: STD_LOGIC_VECTOR (3 DOWNTO 0);
SIGNAL COUT0 : STD_LOGIC; ------低位向高位的進位
BEGIN
PROCESS(CLK,RST,EN) -------十進制
BEGIN
IF RST='1' THEN CQI0 <=(OTHERS =>'0');
ELSIF CLK'EVENT AND CLK='1' THEN
IF EN ='1' THEN
IF CQI0 <9 THEN CQI0 <=CQI0+1;
ELSE CQI0 <=(OTHERS=>'0');
END IF;
END IF;
IF CQI0 = 9 THEN COUT0 <= '1';
ELSE COUT0<='0';
END IF;
END IF;
END PROCESS;
CQL<=CQI0;
PROCESS(COUT0,RST) ------六進制
BEGIN
IF RST='1' THEN CQI1 <=(OTHERS =>'0');
ELSIF COUT0'EVENT AND COUT0='1' THEN
IF CQI1<5 THEN CQI1<=CQI1+1;
ELSE CQI1<=(OTHERS=>'0');
END IF;
IF CQI1=5 AND CQI0=9 THEN COUT1<='1';
ELSE COUT1<='0';
END IF;
END IF;
END PROCESS;
CQH<=CQI1;
END behav;
【2】24|12進制模塊——CNT24
LIBRARY IEEE; ---------CLK輸入分的進位信號，RET清零，EN計數使能,
USE IEEE.STD_LOGIC_1164.ALL; ----------MODE為12和24進制的切換，
USE IEEE.STD_LOGIC_UNSIGNED.ALL; --------- CQL小時的個位輸出，CQH小時的十位輸出
ENTITY CNT24 IS
PORT (CLK,RST,EN,MODE: IN STD_LOGIC;
CQL: OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
CQH: OUT STD_LOGIC_VECTOR(3 DOWNTO 0));
END CNT24;
ARCHITECTURE behav OF CNT24 IS
SIGNAL CQI0: STD_LOGIC_VECTOR (3 DOWNTO 0);
SIGNAL CQI1: STD_LOGIC_VECTOR (3 DOWNTO 0);
SIGNAL CQI2: STD_LOGIC_VECTOR (3 DOWNTO 0);
SIGNAL CQI3: STD_LOGIC_VECTOR (3 DOWNTO 0);
BEGIN
P1: PROCESS(CLK,RST,EN) --------24進制模式
BEGIN
IF RST='1' THEN
CQI0 <=(OTHERS =>'0');CQI1 <=(OTHERS =>'0');
ELSIF CLK'EVENT AND CLK='1' THEN
IF EN ='1' THEN
IF CQI1<2 THEN
IF CQI0<9 THEN
CQI0<=CQI0+1;
ELSE CQI0<=(OTHERS=>'0');
CQI1<=CQI1+1;
END IF;
ELSIF CQI0<3 THEN
CQI0<=CQI0+1;
ELSE CQI0<=(OTHERS=>'0');
CQI1<=(OTHERS=>'0');
END IF;
END IF;
END IF;
END PROCESS P1;
P2: PROCESS(CLK,RST,EN) ------12進制模式
BEGIN
IF RST='1' THEN
CQI2 <=(OTHERS =>'0');CQI3 <=(OTHERS =>'0');
ELSIF CLK'EVENT AND CLK='1' THEN
IF EN ='1' THEN
IF CQI3<1 THEN
IF CQI2<9 THEN
CQI2<=CQI2+1;
ELSE CQI2<=(OTHERS=>'0');
CQI3<=CQI3+1;
END IF;
ELSIF CQI2<2 THEN
CQI2<=CQI2+1;
ELSE CQI2<="0001";
CQI3<=(OTHERS=>'0');
END IF;
END IF;
END IF;
END PROCESS P2;
P3: PROCESS(MODE) ------MODE=’1’為24進制，MODE=’0’為12進制
BEGIN
CASE MODE IS
WHEN '1'=> CQL<=CQI0;CQH<=CQI1;
WHEN '0'=> CQL<=CQI2;CQH<=CQI3;
WHEN OTHERS=>NULL;
END CASE;
END PROCESS P3;
END behav;
【3】控制邏輯模塊——CONTROL
LIBRARY IEEE; -------EXCHGE校時與計時模式控制，
USE IEEE.STD_LOGIC_1164.ALL; -------MINUTE手動分校時
USE IEEE.STD_LOGIC_UNSIGNED.ALL; -------HOUR手動時校時
ENTITY CONTROL IS -------CY0,CY1分別接受秒和分的進位信號
PORT (MINUTE,HOUR,EXCHGE,CY0,CY1: IN STD_LOGIC; ------CLK0,CLK1分別控制分和小時的時鐘脈沖
CLK0: OUT STD_LOGIC;
CLK1: OUT STD_LOGIC);
END CONTROL;
ARCHITECTURE behav OF CONTROL IS
SIGNAL A0: STD_LOGIC;
SIGNAL A1: STD_LOGIC;
BEGIN
P1: PROCESS(EXCHGE,MINUTE,HOUR)
BEGIN
IF EXCHGE='1' THEN
A0<=MINUTE;
A1<=HOUR;
END IF;
END PROCESS P1;
P2: PROCESS(EXCHGE,CY0,CY1) -------EXCHGE=’1’校時模式，EXCHGE=’0’為計時模式
BEGIN
IF EXCHGE='1' THEN
CLK0<=A0;CLK1<=A1;
ELSE CLK0<=CY0;CLK1<=CY1;
END IF;
END PROCESS P2;
END ARCHITECTURE behav;
【4】動態掃描模塊——SCAN_LED
LIBRARY IEEE; -------SCAN動態掃描時鐘信號
USE IEEE.STD_LOGIC_1164.ALL; -------DIN接受時、分、秒數據
USE IEEE.STD_LOGIC_UNSIGNED.ALL; -------SG輸出段選信號
ENTITY SCAN_LED IS -------ＢＴ輸出位選信號
PORT(SCAN : IN STD_LOGIC;
DIN:IN STD_LOGIC_VECTOR(23 DOWNTO 0);
SG:OUT STD_LOGIC_VECTOR(6 DOWNTO 0);
BT:OUT STD_LOGIC_VECTOR(7 DOWNTO 0));
END;
ARCHITECTURE one OF SCAN_LED IS
SIGNAL CNT6:STD_LOGIC_VECTOR(2 DOWNTO 0);
SIGNAL D:STD_LOGIC_VECTOR(3 DOWNTO 0);
BEGIN
P1:PROCESS(SCAN)
BEGIN
IF SCAN'EVENT AND SCAN='1' THEN
IF CNT6<5 THEN
CNT6<=CNT6+1;
ELSE CNT6<="000";
END IF;
END IF;
END PROCESS P1;
P2:PROCESS(CNT6) --------位選
BEGIN
CASE CNT6 IS
WHEN"000"=> BT <="00000001"; --------時、分、秒之間隔一個數碼管顯示
WHEN"001"=> BT <="00000010";
WHEN"010"=> BT <="00001000";
WHEN"011"=> BT <="00010000";
WHEN"100"=> BT <="01000000";
WHEN"101"=> BT <="10000000";
WHEN OTHERS => NULL;
END CASE;
END PROCESS P2;
P4: PROCESS(CNT6)
BEGIN
CASE CNT6 IS
WHEN"000"=> D <=DIN(3 DOWNTO 0);
WHEN"001"=> D <=DIN(7 DOWNTO 4);
WHEN"010"=> D <=DIN(11 DOWNTO 8);
WHEN"011"=> D <=DIN(15 DOWNTO 12);
WHEN"100"=> D <=DIN(19 DOWNTO 16);
WHEN"101"=> D <=DIN(23 DOWNTO 20);
WHEN OTHERS=>NULL;
END CASE;
END PROCESS P4;
P3:PROCESS(D) -------段選
BEGIN
CASE D IS
WHEN "0000" =>SG<="0111111";WHEN "0001" =>SG<="0000110";
WHEN "0010" =>SG<="1011011";WHEN "0011" =>SG<="1001111";
WHEN "0100" =>SG<="1100110";WHEN "0101"=>SG<="1101101";
WHEN "0110" =>SG<="1111101";WHEN "0111" =>SG<="0000111";
WHEN "1000" =>SG<="1111111";WHEN "1001" =>SG<="1101111";
WHEN OTHERS=>NULL;
END CASE;
END PROCESS P3;
END ARCHITECTURE one;
【5】整點報時模塊——ALARM
LIBRARY IEEE; ------ML輸入分個位，MH輸入分十位
USE IEEE.STD_LOGIC_1164.ALL; ------SL輸入秒個位，SH輸入秒十位
USE IEEE.STD_LOGIC_UNSIGNED.ALL; ------CLK輸入1024Hz時鐘脈沖
ENTITY ALARM IS ------SPEAKER輸出報時信號
PORT (ML: IN STD_LOGIC_VECTOR(3 DOWNTO 0);
MH: IN STD_LOGIC_VECTOR(3 DOWNTO 0);
SL: IN STD_LOGIC_VECTOR(3 DOWNTO 0);
SH: IN STD_LOGIC_VECTOR(3 DOWNTO 0);
CLK: IN STD_LOGIC;
SPEAKER: OUT STD_LOGIC);
END ALARM;
ARCHITECTURE behav OF ALARM IS
SIGNAL DIV2CLK: STD_LOGIC;
BEGIN
PROCESS(CLK)
BEGIN ----------實驗箱的可用時鐘有限，1024Hz作高音信號
IF CLK'EVENT AND CLK='1' THEN -----------1024Hz時鐘脈沖2分頻，產生蜂鳴低音信號
DIV2CLK<=NOT DIV2CLK;
END IF;
END PROCESS;
PROCESS(MH,ML,SH,SL)
BEGIN
IF MH=5 AND ML=9 THEN
IF SH=5 THEN
IF (SL=1 OR SL=3 OR SL=5 OR SL=7) THEN -------51、53、55、57秒輸出低音信號
SPEAKER<=DIV2CLK;
ELSIF (SL=9) THEN --------59秒輸出高音信號
SPEAKER<=CLK;
ELSE SPEAKER<='0';
END IF;
ELSE SPEAKER<='0';
END IF;
ELSE SPEAKER<='0';
END IF;
END PROCESS;
END ARCHITECTURE behav;
【6】頂層實體——CLOCK
LIBRARY IEEE; ------CLK接1Hz時鐘脈沖，
USE IEEE.STD_LOGIC_1164.ALL; ------ RET接清零鍵，EN接計數使能鍵，
ENTITY CLOCK IS ------SCAN接CLK0時鐘掃描信號
PORT(CLK,EN,RST,SCAN,TMODE,EXCHGE:IN STD_LOGIC; ------TMODE12|24進制切換
HOUR,MINUTE,CLK1024:IN STD_LOGIC; -------EXCHGE計時|校時模式控制
SPEAKER: OUT STD_LOGIC; -------HOUR手動時校時
SG:OUT STD_LOGIC_VECTOR(6 DOWNTO 0); -------MINUTE手動分校時
BT:OUT STD_LOGIC_VECTOR(7 DOWNTO 0)); ------CLK1024接1024Hz時鐘脈沖
END ENTITY; -------SG輸出段選信號
ARCHITECTURE STRUC OF CLOCK IS -------BT輸出位選信號
COMPONENT CNT60 ------SPEAKER接蜂鳴器
PORT (CLK,RST,EN : IN STD_LOGIC;
CQL: OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
CQH: OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
COUT1 : OUT STD_LOGIC);
END COMPONENT;
COMPONENT CNT24
PORT (CLK,RST,EN,MODE: IN STD_LOGIC;
CQL: OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
CQH: OUT STD_LOGIC_VECTOR(3 DOWNTO 0));
END COMPONENT;
COMPONENT CONTROL
PORT (MINUTE,HOUR,EXCHGE,CY0,CY1: IN STD_LOGIC;
CLK0: OUT STD_LOGIC;
CLK1: OUT STD_LOGIC);
END COMPONENT;
COMPONENT SCAN_LED
PORT(SCAN : IN STD_LOGIC;
DIN:IN STD_LOGIC_VECTOR(23 DOWNTO 0);
SG:OUT STD_LOGIC_VECTOR(6 DOWNTO 0);
BT:OUT STD_LOGIC_VECTOR(7 DOWNTO 0));
END COMPONENT;
COMPONENT ALARM IS
PORT (ML: IN STD_LOGIC_VECTOR(3 DOWNTO 0);
MH: IN STD_LOGIC_VECTOR(3 DOWNTO 0);
SL: IN STD_LOGIC_VECTOR(3 DOWNTO 0);
SH: IN STD_LOGIC_VECTOR(3 DOWNTO 0);
CLK: IN STD_LOGIC;
SPEAKER: OUT STD_LOGIC);
END COMPONENT;
SIGNAL D :STD_LOGIC_VECTOR(23 DOWNTO 0);
SIGNAL M0,M1,M2,M3 :STD_LOGIC;
SIGNAL M4,M5,M6,M7 :STD_LOGIC_VECTOR(3 DOWNTO 0);
BEGIN
u1: CNT60 PORT MAP(CLK=>CLK,RST=>RST,EN=>EN,COUT1=>M0,
CQH=>D(7 DOWNTO 4),CQL=>D(3 DOWNTO 0));
u2: CNT60 PORT MAP(CLK=>M2,RST=>RST,EN=>EN,COUT1=>M1,
CQH=>D(15 DOWNTO 12),CQL=>D(11 DOWNTO 8));
u3: CNT24 PORT MAP(CLK=>M3,RST=>RST,EN=>EN,MODE=>TMODE,
CQH=>D(23 DOWNTO 20),CQL=>D(19 DOWNTO 16));
u4: CONTROL PORT MAP(EXCHGE=>EXCHGE,HOUR=>HOUR,MINUTE=>MINUTE,
CLK0=>M2,CLK1=>M3,CY0=>M0,CY1=>M1);
u5: SCAN_LED PORT MAP(SCAN=>SCAN,SG=>SG,BT=>BT,
DIN(3 DOWNTO 0)=>D(3 DOWNTO 0),
DIN(7 DOWNTO 4)=>D(7 DOWNTO 4),
DIN(11 DOWNTO 8)=>D(11 DOWNTO 8),
DIN(15 DOWNTO 12)=>D(15 DOWNTO 12),
DIN(19 DOWNTO 16)=>D(19 DOWNTO 16),
DIN(23 DOWNTO 20)=>D(23 DOWNTO 20));
U6: ALARM PORT MAP(ML=>M6,MH=>M7,SL=>M4,SH=>M5,CLK=>CLK1024,
SPEAKER=>SPEAKER);
END STRUC;