mux21a.vhd

二选一多路选择开关

ENTITY mux21a IS
     PORT(a,b,s:IN BIT;
               y:OUT BIT);
END ENTITY mux21a;
ARCHITECTURE one OF mux21a IS
BEGIN
     PROCESS(a,b,s)
     BEGIN

        IF s='0'THEN
             y<=a;
        ELSE
             y<=b;
        END IF;
     END PROCESS;
END ARCHITECTURE one;