VHDL实例化定义错误

[qq_42326374]

b2v_inst1: LS74160_1
PORT MAP(CLK => SYNTHESIZED_WIRE_135,
ENT => SYNTHESIZED_WIRE_136,
A => SYNTHESIZED_WIRE_137,
B => SYNTHESIZED_WIRE_137,
C => SYNTHESIZED_WIRE_137,
D => SYNTHESIZED_WIRE_137,
LDN => SYNTHESIZED_WIRE_136,
ENP => SYNTHESIZED_WIRE_136,
CLRN => SYNTHESIZED_WIRE_136,
RCO => SYNTHESIZED_WIRE_139);
Error (12006): Node instance "b2v_inst1" instantiates undefined entity "LS74160_1"

[laidaihua]

意思就是LS74160_1未定义啊，原因不外乎以下两种：
1、设计未包含必要的库(即包含有LS74160的元件库)；
2、例化的元件名称与库中不符；