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I participated in the summer 2003 Bridge Program which is funded by the National Science Foundation. I was one of the twelve students who were chosen to participate in the program. I worked under Dr. Kenneth Johns who is a professor of Physics at the University of Arizona under the immediate supervision of Engineer Joel Steinberg. It was a great opportunity and experience for me to work as an intern in the High Energy Physics Lab. It opens doors for other similar research positions as well as for my future career. I'm very pleased with the guidance I was able to get from my mentors and others in the lab.

Our Assignment

Another Bridge student (Charles Armijo) and I were assigned to design a test board that can test the connections on the MTCXX board using the JTAG boundary-scan technology. The MTCXX is a very sophisticated Printed Circuit Board with more than twenty layers of circuitry. This board attaches through two VMEbus connectors. It is almost impossible to test the connections on such a board that has many layers of circuitry using physical probes. The use of the JTAG boundary-scan technology makes it much easier to do the testing.
The JTAG technology brings back the access to device pins by means of an internal shift register around the boundary of the device, thus it is called boundary scan register. The Boundary Scan Testing allows the capability to efficiently test components on PCBs with tight pin spacing.
We were given a schematic that has the MTCXX VME connectors with the bus connectors. We laid that same schematic on Power Logic, which is a multi-sheet schematic capture, along with four Altera 144 pin chips. The pins on the Altera chips correspond to the pins on the VME connectors. The JTAG signals travel through the four Altera chips, and finally through the VME connectors.
We imported the Schematic to Power PCB from the schematic capture. The Power PCB shows the actual connections on the board. The parts were just dumped in Power PCB; they were piled up together. It took us a great deal of time to lay and position them properly on the board. Routing had to be done to create a metal etch trace of specified width between pads.
The last stage of the design process was to produce a machine readable board description suitable for the PC house to manufacture the board. We used CAM(Computer Aided Manufacturing) in order to return the layout and to view the final design to its final artwork. The commands of the CAM have printing and plotting options. Once the board is made, we will solder the devices on the board and it will be ready for testing.