Boundry Scan

[vtech]

Does anyone work or have any experience with boundry scan and what brand equipment do you use/prefer?

This is mainly in regard to testing various complex & expensive PCB's.

Thanks

 

[ronsimpson]

Agilent

 

[unclejed613]

Tektronix may still make systems, and Fluke, and i think Zehntel is still around..... and apparently Agilent bought Teradyne, who also used to make them.


or are you referring to testing through a device's JTAG port?

 

[vtech]

Thanks for the info and yes I was referring to testing through JTAG Port. I do realize of availability of several venders and just wondering if anyone was actually using it especially when/if the BSDL file may not be available.

Outfits such as Corelis, Acculogic..etc all have various products claiming to be the tops. We are exploring the possibility of acquiring one at work to expand repair capabilities. Most of the application is rather expensive processor based controllers and mass memory circuits.

 

[unclejed613]

i worked in the ATE industry when everything was done with bed-of-nails fixtures. there still are companies making those systems, but with modern embedded systems, jrag has replaced most of that functionality, although the bed-of-nails systems can say "replace C104" when a shorted cap would keep the jtag from operating at all.

 

[ronsimpson]

For those that don't know; JTAG testing is used with complex ICs, Often on many layer PCBs where most of the traces are not on the top layer. Where there is no room for test points. The ICs are so small probes do not work well or ball grid parts with no leads. JTAG has no problem with parts on both sides of the PCB.

Step one is to put into 'test mode' some or all the ICs. You now have control of all the IO pins. Each pin can be input, output, driven high, driven low, or open and its state red back. You tell IC5, pin 152 go low, go high then look at IC7 pin 309 and see if it got the low/high signal. At the same time you look at all the other pins on the board to see if another input gets the signal when it should not. (testing signals and sort testing)

FLASH memory and micros can be programmed at this time.

Companies like Agilent have huge data bases of test plans. You give a net list to the PC and it generates files for testing.

JTAG ports run 10mhz to 50mhz which is fine for short testing but not good for large memory banks. In the case of mother boards; we load a temporary test program in the computer chips and they in turn walk through the memory at full speed. This way multiple tests are run at the same time.

In short, we turn each IC into a test machine.