| 摘要 |
PURPOSE:To diagnose a fault of an LSI in a mounted state by supplying the same information as input information to the LSI to be diagnozed to an input pin of a good-quality LSI and putting it in operation, and comparing its output information with the output of the LSI to be diagnosed. CONSTITUTION:While the LSI2 to be diagnosed is mounted in a system 1 to be diagnosed, pieces of input and output pin information of the LSI2 is led out by an adapter 5. Only input pin information is supplied to an input pin of the good- quality LSI8 as it is, and output pin information is compared by an information comparison part 9 with output pin information of the conforming LSI8 on real- time basis. At this time, pieces of input and output pin information are stored continuously in an information storage part 10 all the time, and the storing operation is stopped when the comparing part 9 detects dissidence of output pin information between both LSIs 2 and 8. Consequently, history information up to just before the occurrence of a fault remains in the information storage part 10 and is checked to make a fault analysis easily. |
