SJTAG

SJTAG Newsletter
http://www.sjtag.org

 

Issue 21 - Q3-2012

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Any comments on this newsletter can be mailed to admin@sjtag.org.

From the Chair - An Appeal to the Automotive Sector

I'm going to take the unusual step of repeating my "From the Chair" item from the last newsletter: I'm disappointed to report that the appeal I made then produced no interest from anyone involved in the automotive sector.

The SJTAG group recognizes that the auto industry integrates multiple electronic assemblies and demands simple service and diagnostic capabilities from these amalgamated systems. We feel that there are lessons and insight there that would benefit SJTAG and that SJTAG could ultimately benefit the auto industry by providing greater consistency in the way component assemblies could be tested and serviced.

Automotive image

So, our appeal is quite straightforward: If you are working in the automotive electronics industry then please consider joining us. If you know someone in that sector, then please forward this newsletter to them (use the link at the bottom of this mailing).

http://www.sjtag.org/form/contact.html


1149.1 Updates

Some readers may not be aware that the "core" standard for JTAG, IEEE Std. 1149.1 is currently under revision.

IEEE logo

As well as changes to existing concepts, such as introducing excludable segments within a boundary scan register, the proposals for the revised standard will bring in a number of completely new features, such as control of device resets, better control of when a device exits Test Mode, device initialization prior to a test and better recovery to a functional state after test. A major innovation is the introduction of a Procedural Description Language (PDL) to complement the existing BSDL and help describe the dynamic operations that may be required in supporting some of the new features.

SJTAG's vice-chair, Heiko Ehrenberg, has prepared a summary of the changes which is available on the SJTAG website, while more detailed discussion may be found on the 1149.1 Working Group's web pages.

http://files.sjtag.org/Heiko/new in IEEE 1149-2012.pdf
http://grouper.ieee.org/groups/1149/1/


IDCODE and ECID

Ever since the original IEEE Std. 1149.1 standard was first published we've had IDCODE, but it's remained optional throughout, and that looks to continue with the 1149.1-2013 update. Most modern devices seem to implement IDCODE, so do we know why this remains optional? Without advice to the contrary it seems likely that the option was provided to allow old device technologies that simply couldn't provide the 32-bit register to opt out from that while still providing JTAG support. If that's the case then surely that's history now? Having access to a device ID and possibly to a silicon revision mark could be very useful during many JTAG operations and especially at system level where it may be impossible to inspect for markings on a device or board.

Board with Chain

But now 1149.1-2013 looks to be introducing access to the ECID (Electronic Chip ID) that is likely to be less familiar. Again, this will be optional, but perhaps that understandable: The ECID may be several hundred bits long and can contain various details that can, for example, be used to trace an individual die to the wafer it came from. It is unique at the die level and because of this it's likely to appear mainly on higher value silicon product - microprocessors, FPGAs, etc.

There is no defined format or content of the ECID at present and device vendors are likely to be protective of what data their ECIDs actually contain, at least initially. The ECID has the potential to be a tool to combat counterfeiters, but does the fine-grained detail offer other advantages for SJTAG implementers or is it more a convenience for the device vendor? One suggestion is that even without knowing what the ECID data means ECIDs could be logged during board assembly, giving a means to uniquely identify a board at a later date by JTAG interrogation of the devices in the chain. How practical is this? What other uses might there be?

Join the discussion on our forums.

http://forums.sjtag.org/viewtopic.php?f=3&t=162


Next Newsletter

The Q4-2012 edition of this newsletter will be published towards the end of October 2012. Copies of past newsletters are always available on the SJTAG website.

http://www.sjtag.org/newsletters.html


News from the website

A selection of recent RSS/ATOM news items from the website:

Updated Operating Procedures (Issued: Mon, 12 June 2012 20:03:00 GMT)

The meeting of June 11, 2012 agreed a number of revisions to the group's Operating Procedures. This followed the first wholescale review of the procedures since they were established in the Spring of 2009.

URL: http://www.sjtag.org/procedures.html


Meeting Minutes from June 25th (Issued: Wed, 11 July 2012 18:26:00 GMT)

The minutes from the weekly meeting held on June 25th, 2012 have now been published. Featured discussions: a. Proposed changes in IEEE Std. 1149.1-2013.

URL: http://www.sjtag.org/minutes/minutes120625.html


Meeting Minutes from June 18th (Issued: Wed, 27 June 2012 19:27:00 GMT)

The minutes from the weekly meeting held on June 18th, 2012 have now been published. Featured discussions: a. Discussion around Brad's presentation on Embedded JTAG from 2002.

URL: http://www.sjtag.org/minutes/minutes120618.html


Meeting Minutes from June 11th (Issued: Mon, 20 June 2012 20:37:00 GMT)

The minutes from the weekly meeting held on June 11th, 2012 have now been published. Featured discussions: a. Review/approval of updates to Group Operating Procedures, b. What is the current 'state of the art' for SJTAG applications? (concluding a revisit to the SJTAG Proof of Concept demonstration by Asset/Firecron).

URL: http://www.sjtag.org/minutes/minutes120611.html


Meeting Minutes from May 21st (Issued: Mon, 12 June 2012 18:13:00 GMT)

The minutes from the weekly meeting held on May 21st, 2012 have now been published. Featured discussions: a. Review/revalidation of Group Operating Procedures, b. What is the current 'state of the art' for SJTAG applications? (a revisit to the SJTAG Proof of Concept demonstration by Asset/Firecron).

URL: http://www.sjtag.org/minutes/minutes120521.html


Meeting Minutes from May 14th (Issued: Mon, 21 May 2012 20:49:00 GMT)

The minutes from the weekly meeting held on May 14th, 2012 have now been published. Featured discussions: a. Can existing system services provide the identification required by JTAG test?

URL: http://www.sjtag.org/minutes/minutes120514.html


Meeting Minutes from April 30th (Issued: Mon, 15 May 2012 19:49:00 GMT)

The minutes from the weekly meeting held on April 30th, 2012 have now been published. Featured discussions: a. Can existing system services provide the identification as required by JTAG test?

URL: http://www.sjtag.org/minutes/minutes120430.html


Meeting Minutes from April 23rd (Issued: Mon, 07 May 2012 19:26:00 GMT)

The minutes from the weekly meeting held on April 23rd, 2012 have now been published. Featured discussions: a. Q2 Newsletter, b. Board ID: What is the minimum equipment and services needed?

URL: http://www.sjtag.org/minutes/minutes120423.html


Meeting Minutes from April 16th (Issued:Wed, 24 Apr 2012 19:42:00 GMT)

The minutes from the weekly meeting held on April 16th, 2012 have now been published. Featured discussions: a. Board ID: What is the minimum equipment and services needed?.

URL: http://www.sjtag.org/minutes/minutes120416.html