Swiss-based international machine-vision specialist Leutron Vision AG is using XJTAG boundary scan to screen circuit boards before functional testing. Compared to optical inspection, XJTAG is enabling higher test coverage, increased productivity and faster rework, and is contributing to continuous improvement of the company’s camera units, interface cards and frame grabbers.
The developers and production engineers at Leutron are using XJTAG boundary scan to speed up debugging of prototype designs, and to increase the productivity of production testing by quickly identifying boards with manufacturing defects.
In the past the company has used optical inspection to identify boards with soldering defects so that repairable faults can be rectified before passing the board forward for functional testing. “Since our functional test routines are relatively time consuming, it makes no sense to test boards carrying defects that we could identify using faster methods,” comments Mathias Leumann of Leutron. “However, many of our boards now contain a significant number of BGA devices, such as RISC processors, DDR-SDRAMs, serial flash, parallel flash and FPGAs. We are unable to verify connections to these using optical inspection. Going forwards, we identified boundary scan as the fastest and most effective way to screen boards and hence maximise overall test productivity.”
Mathias Leumann and his team evaluated several boundary scan test systems. XJTAG offered the best value. “We selected the XJTAG system for its outstanding price/performance ratio and the high level of support, both through direct contact with the manufacturer as well as local support from their distributor partner,” he says. “Some of the alternatives were offering expensive features that were unnecessary for our purposes, but XJTAG has delivered high-value capabilities, at the best price.”
With its advanced graphical interface and features including automatic scan-chain detection, built-in netlist explorer and high-level test-description language, XJTAG provides intuitive tools to define the circuit to be tested and then to perform the tests. “The XJTAG user interface allows me to see clearly what the software will do with the board,” agrees Pawel Studler, Hardware Engineer at Leutron. “This gives me valuable freedom to create tests that will do what I want.”
Tests are developed at Leutron’s headquarters and delivered to the company’s manufacturing partner, which is using the XJRunner run-time environment to screen production units. Where a unit fails screening, XJRunner helps track down faults to enable faster rework. XJRunner is also able to program components in boards passing boundary scan tests. “This is an efficient strategy,” comments Mathias Leumann. “XJRunner can be deployed at no additional cost and saves us dealing with defective boards ourselves.”
In addition to successfully screening for defects, XJTAG boundary scan has also enabled Leutron to achieve higher test coverage than is typically possible using functional test alone. Mathias Leumann concludes, “XJTAG is an effective tool that has helped us increase quality as well as productivity”.