*** WARNING L1: UNRESOLVED EXTERNAL SYMBOL
SYMBOL: LED_OFF
MODULE: .\OutputFiles\Timer.obj (TIMER)
*** WARNING L1: UNRESOLVED EXTERNAL SYMBOL
SYMBOL: LED_ON
MODULE: .\OutputFiles\Timer.obj (TIMER)
*** WARNING L1: UNRESOLVED EXTERNAL SYMBOL
SYMBOL: LED
MODULE: .\OutputFiles\Timer.obj (TIMER)
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
SYMBOL: LED
MODULE: .\OutputFiles\Timer.obj (TIMER)
ADDRESS: 0048H
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
SYMBOL: LED
MODULE: .\OutputFiles\Timer.obj (TIMER)
ADDRESS: 004DH
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
SYMBOL: LED
MODULE: .\OutputFiles\Timer.obj (TIMER)
ADDRESS: 0052H
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
SYMBOL: LED
MODULE: .\OutputFiles\Timer.obj (TIMER)
ADDRESS: 0056H
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
SYMBOL: LED
MODULE: .\OutputFiles\Timer.obj (TIMER)
ADDRESS: 0058H
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
SYMBOL: LED_ON
MODULE: .\OutputFiles\Timer.obj (TIMER)
ADDRESS: 0099H
*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
SYMBOL: LED_OFF
MODULE: .\OutputFiles\Timer.obj (TIMER)
ADDRESS: 00A0H
在用C51编译器出现上面的警告，害我郁闷半天，没道理啊，我仔细检查了两遍 没问题，结果错误出在没有将
一个源文件添加进入工程 ， 看来我还是个初学者 ，居然犯这样的低级错误
