biaojue.vhd

这是一个用VHDL语言实现的非常实用的表决器

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_ARITH.all;
use ieee.std_logic_UNSIGNED.all;
ENTITY BIAOJUE IS
  PORT(     FF:IN STD_LOGIC_VECTOR(1 TO 5);
            QQ:OUT BIT;
       QALL:OUT STD_LOGIC_VECTOR(3 DOWNTO 1);
       SHIJIAN:BUFFER STD_LOGIC_VECTOR(3 DOWNTO 0);
       FUWEI,KAISHI,CLK:IN STD_LOGIC);
END BIAOJUE;
ARCHITECTURE FUNG OF BIAOJUE IS
  BEGIN 
    PROCESS(FF,CLK,KAISHI,FUWEI)
     VARIABLE SUO:BOOLEAN;
     VARIABLE SUM:STD_LOGIC_VECTOR(1 TO 3);
     BEGIN
       IF (FUWEI='0') THEN
        QQ<='0';
        SHIJIAN<="1010";
        SUO:=FALSE;
        SUM:="000";
        QALL<="000";
       ELSIF (CLK'EVENT AND CLK='1') THEN 
           IF (KAISHI='1') THEN
             IF (NOT SUO) THEN
              IF SHIJIAN="0000" THEN
                 SUO:=TRUE;
                FOR N IN 1 TO 5 LOOP
                  SUM:=FF(N)+SUM;
                END LOOP;
              ELSE
                SHIJIAN<=SHIJIAN-1; 
              END IF;
             END IF;
             QALL<=SUM;
             IF (SUM >= 3) THEN
               QQ<='1';
             ELSE
               QQ<='0';
             END IF;  
           END IF;
       END IF;
  END PROCESS;
  END FUNG;