Issue link: https://iconnect007.uberflip.com/i/520182
22 SMT Magazine • June 2015 changes to the board file and regenerating (and hence needing to re-debug) test vectors. Libraries developed in a higher level device centric language are also more reusable and can be migrated project to project without modi- fication. DDR3, PHY, SPI, I 2 C, and much more become easily testable and the libraries are not specific to the devices. In addition, specialist boundary-scan tools tend to have better signal integrity and can push bits into the scan chain at a much faster rate than most ICT hardware, allowing more de- vices to be tested more quickly. Integrating Specialist Boundary-Scan Integrating a specialist boundary-scan sys- tem such as XJTAG with the ICT equipment provides a convenient means of performing boundary-scan test without changing to a dif- ferent test-execution environment or remov- ing the unit under test from the ICT fix- ture. Combining ICT and external boundary-scan in one efficient process step can help improve efficiency, minimise demand for additional items of test equipment on the produc- tion line, and protect sensitive hardware from physical dam- age, loss or misplacement. The Keysight 3070 util- ity card and similar Teradyne multi-function application board simplifies integrating the user's choice of external electronics. Users can plug-in custom modules to perform spe- cific test functions. Specialty boundary-scan controllers take advantage of this extensibility. They are ap- proved by the respective ICT vendors, and plug directly into the expansion board to provide access to specialist boundary-scan test and pro- gramming tools. Multiple instances of the con- troller can be installed into each board, which can boost throughput significantly without cus- tom fixturing. Specialty controllers can connect to a maxi- mum of four boundary-scan chains on the unit under test, and multiple controllers can be fit- ted to each utility card or multi-function appli- cation board. This gives users the flexibility to test boards with more than one boundary-scan chain, or to test multiple panellised boards si- multaneously. The controller also allows in- system programming of devices at close to their theoretical maximum programming speeds. Multiple controllers can program multiple boards simultaneously, so all boards in a pan- elised assembly can be programmed in the same time needed to program a single board. Paired with the throughput multiplier effect that comes from combining ICT, boundary-scan and programming in a single step, this can become a tremendous time saver. Test Re-use Boosts Productivity Integrating specialist boundary-scan in this way can not only simplify test generation, but also helps when it comes to diagnosing and repairing boards. The increased test coverage of previously inac- cessible nets and devices saves the need to interpret failure messages that can be ambigu- ous, thereby reducing the time to identify the cause of a de- fect. The same boundary-scan tests can be used in bench-top repair as are used in produc- tion ICT since they are not de- pendent on access granted to the circuits by a fixture which increases throughput of the ICT station and test fixture by mini- mising the time devoted to rework. Production equipment can be used for produc- tion more often. Test engineers can utilise the same bound- ary-scan tests used by the board designers when creating tests to be run on the production test platform, which minimises duplicated effort. Moreover, boundary-scan tests can be de- bugged on the bench rather than on the tester, minimising the time test engineers must spend using the production test equipment to trouble- shoot tests. The boundary-scan application can be completely validated before being integrat- TeST MATCH—PARTneRInG SPeCIALIST BOunDARy-SCAn WITH ICT continues Multiple controllers can program multiple boards simultaneously, so all boards in a panelised assembly can be programmed in the same time needed to program a single board. " " Feature