本帖最后由 le062 于 2010-12-27 17:03 编辑
我要做个智力抢答器，下面是抢答判断的代码
我用了个VARIABLE SC:INTEGER 用来锁存判断
但是仿真的时候 当 CLR=0 AND RST=0,输出A1, B1, C1, D1就都是不定值了- LIBRARY IEEE;
- USE IEEE.STD_LOGIC_1164.ALL;
- ENTITY QDJB IS
- PORT (CLR,RST: IN STD_LOGIC;
- A, B, C, D: IN STD_LOGIC;
- A1, B1, C1, D1: OUT STD_LOGIC;
- G: OUT STD_LOGIC_VECTOR (3 DOWNTO 0));
- END QDJB;
- ARCHITECTURE ART OF QDJB IS
- CONSTANT W1: STD_LOGIC_VECTOR:="1010";
- CONSTANT W2: STD_LOGIC_VECTOR:="1011";
- CONSTANT W3: STD_LOGIC_VECTOR:="1100";
- CONSTANT W4: STD_LOGIC_VECTOR:="1101";
- CONSTANT FOUL: STD_LOGIC_VECTOR:="1111";
- BEGIN
- PROCESS(CLR,RST)
- VARIABLE SC:INTEGER:=00;
- BEGIN
- IF(CLR='1'OR RST='1')THEN
- IF(A='0'AND B='0'AND C='0'AND D='0')THEN
- A1<='0'; B1<='0'; C1<='0'; D1<='0';G<="1110";SC:=01;
- ELSIF((A='1'AND (SC=01))OR (SC=02))THEN
- A1<='1'; B1<='0'; C1<='0'; D1<='0';G<=FOUL;SC:=02;
- ELSIF((B='1'AND (SC=01))OR (SC=03))THEN
- A1<='0'; B1<='1'; C1<='0'; D1<='0';G<=FOUL;SC:=03;
- ELSIF((C='1'AND (SC=01))OR (SC=04))THEN
- A1<='0'; B1<='0'; C1<='1'; D1<='0';G<=FOUL;SC:=04;
- ELSIF((D='1'AND (SC=01))OR (SC=05))THEN
- A1<='0'; B1<='0'; C1<='0'; D1<='1';G<=FOUL;SC:=05;
- END IF;
- ELSE
- IF ((A='1'AND (SC=01))OR (SC=06))THEN
- A1<='1'; B1<='0'; C1<='0'; D1<='0';G<=W1;SC:=06;
- ELSIF((B='1'AND (SC=01))OR (SC=07))THEN
- A1<='0'; B1<='1'; C1<='0'; D1<='0';G<=W2;SC:=07;
- ELSIF((C='1'AND (SC=01))OR (SC=08))THEN
- A1<='0'; B1<='0'; C1<='1'; D1<='0';G<=W3;SC:=08;
- ELSIF((D='1'AND (SC=01))OR (SC=09))THEN
- A1<='0'; B1<='0'; C1<='0'; D1<='1';G<=W4;SC:=09;
- ELSE A1<='0'; B1<='0'; C1<='0'; D1<='0';G<="0000";
- END IF;
- END IF;
- END PROCESS;
- END ART;
谢谢
--
问题搞定 其实没啥问题
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