基于USB总线的边界扫描测试仪的研制-模式识别与智能系统专业论文.docx

英文摘要ABSTRACT 英文摘要 ABSTRACT Currently,the digital system is composed of large anaount of highly fine packeted ICs，such PGAs，BGAs，SMTs，and MCMs．It could lead to the narrower space between the connections on the PCB and the closer distance between the test points，and it could even make some test points inaccessible．So，the aaditional test methods based on probes nails beds are no longer available． As design for test technology,the boundary—SCan test fixes special element called boundary-scan cell(BSC)between the deviee input pins and the logic inputs，or between the core logic outputs and the device output pins．Thus，the BSC acts as the virtual test probe that carries out the test stimulus，and captures the test respondences．So，when the digital system is completely made up of the boundary- scan devices，the testability ofthe system would be improved greatly and test problem we confronted with would be settled easily． For this purpose，we should employ the new test instrument fit for boundary-scan test．So，I developed boundary-scan tester with the USB interface in this dissertation． Users set the test instructions test vectors by the tester software．Then the tester applies the test instructions test vectors to the circuit under test(CUT)．Last．the tester receives the test respondence from the CUT and sends back to the tester sothvare running 011 the PC． The design be divided into the following parts： ①Hardware design for the boundary-scan tester． ②Firmware design for the boundary-scan tester． ③USB driver design for the boundary-scan tester, ④Application software design for the boundary-scan tester． The design result indicates that the whole test system works smoothly．Benefitted from the USB interface，the tester has the following advanced characteristics： ①Ability for PnP． ②Bus powered characteristics． ③Completely external attachment t0 the PC，without fear of the EMI，the unreliable physical attachment to the PC，and the unpredictable crash of the PC for overheating． Keyword：