Research On Technology Of Boundary-Scan Test Of Mixed-Signal Circuit Based On IEEE1149.4 Standard

With the rapid development of electronic technology, VLSI(Very Large Scale Itegrate Circuits) is widely applied in the electronic equipments . The structure of VLSI is complex, and the density of tube feet is intensive, logic is complicated. Especially a large number of mixed-signal integrated circuits are used in the electronic equipments, such as radar, communication, navigation, computer etc. Traditional test means are already unable to meet the needs of electronic equipments. Boundary-scan technology, improves mix-signal circuit observability and controllability greatly, reduces difficulty of test of electronic system. As a kind of new developing BIT technology, Boundary scan technology is widely used in industry.In this paper,IEEE1149.4 Std mixed-signal test bus and its characteristic are studied. According to the structure defined in this standard, test methods of mixed-signal circuits are studied. The mixed-signal boundary-scan test system, which is complianted to IEEE1149.4 Std, is designed. The main contents are as follows:The structure of mixed-signal circuit which newly-defined in IEEE1149.4 Std is analyzed in detail, especially anolog boundary module and test bus interface circuit.On the basis of mixed-signal Boundary scan technology, a scheme of mixed-signal Boundary-scan test system is presented and the hardwares are implemented, including the controller and display unit. Finally methods of testing in mixed-signal circuits are researched.The results show that the design is feasible and the study is successful.