boundary scan feature

Duval JP · Joined: 22 Jun 2004 Posts: 1197 Location: France

Hello all,
I am French, and the smoothnesses of the English language are sometimes difficult for me.

For example I would like that somebody explains me if possible simply that wants to say
"JTAG"
"Boundary scan feature"

My dictionnary said Boundary=border border of what ?
Crying or Very sad

Many thanks

DToolan · Posted: Mon Sep 05, 2005 6:57 pm Post subject:

The boundary (or border) on the small scale, refers to the outsides of a chip (the pins). On a larger scale, the boundary (or border) might be the edges (pins / fingers) of a printed circuit board.

The idea of "boundary scan" was devised by PCB manufacturers because of the increasing densities of board design. Board manufacturers used to build a "bed of nails" that touched every pad on a board and tested for continuity, opens or shorts. With pin spacings on chips growing closer together and chip spacings also growing closer, the "bed of nails" technique was more difficult to do.

Boundary-scan, as defined by the IEEE Std. 1149.1 standard, is an integrated method for testing interconnects on printed circuit boards that is implemented at the IC level. The boundary-scan test architecture provides a means to test interconnects between integrated circuits on a board without using physical test probes.

Luciano · Joined: 29 Nov 2004 Posts: 3149 Location: Italy

Boundary-Scan Tutorial

http://www.corelis.com/products/Boundary-Scan_Tutorial.htm

Best regards,

Luciano

Duval JP · Joined: 22 Jun 2004 Posts: 1197 Location: France

Many thanks to Luciano and Dtoolan,

I think, I understand now.
For maintenance it seems to be a very practical toool

Best regards
JP