quartus2编译中的问题

Error: Can't route source node "DB[2]" of type max_io to destination node "Mux8~136" of type max_mcell
Error: Can't route source node "DB[10]" of type max_io to destination node "Mux11~43" of type max_mcell
Error: Can't find fit
出现上面的问题是怎么回事啊?

DB[10] 和DB[2]都是怎么定义和约束的?

DB:in std_logic_vector(11 downto 0);

请问在不?我的qq是531291208

上面的问题已经解决，改了一下源代码！