Minutes of Weekly Meeting, 2011-12-05

Meeting called to order: 11:06 AM EST

1. Roll Call

Eric Cormack
Carl Walker
Ian McIntosh
Brad Van Treuren
Peter Horwood
Adam Ley
Patrick Au
Brian Erickson
Richard Foster (joined 11:07)
Harrison Miles (joined 11:28)

Heiko Ehrenberg

2. Review and approve previous minutes:

11/28/2011 minutes:

  • Updated draft circulated on 11/30/2011.
  • No further corrections advised.
  • Brian moved to approve seconded by Brad. No objections or abstentions.

3. Review old action items

  • Adam proposed we cover the following at the next meeting:
    • Establish consensus on goals and constraints
    • What are we trying to achieve?
    • What restrictions are we faced with?
  • All: do we feel SJTAG is requiring a new test language to obtain the information needed for diagnostics or is STAPL/SVF sufficient? see also Gunnar's presentation, in particular the new information he'd be looking for in a test language
  • Ian/Brad: Condense gateway comments and queries into a concise set of questions. - Ongoing
  • All: Forward text file to Ian containing keywords from review of meeting minutes. - Ongoing.
  • Carl/Brad: Get annotated keyword worksheets to Ian by Wednesday Close of Business. - Ongoing
  • All: Consider how a keyword can be used to define the chain configuration for a given test step, and what that keyword might be.
  • Harrison: Prepare slide showing matrix of industry sectors by volume/mix. - Ongoing.
  • Ian: Create new forum discussion topic on attributes of the ideal SJTAG gateway - COMPLETE.
  • All: Respond to forum gateway topic with any opinions on what makes a gateway suitable for use in your application field(s) - COMPLETE.

4. Discussion Topics

  1. January 2012 meeting schedule
    - Agree dates
    - Does the current time slot still work for most people?
    • [Ian] We were suggesting that the first meeting in January 2012 would be 1/9, since 1/2 is going to be a holiday for most people.
    • [Eric] Yes. I think it's a holiday for everyone.
    • [Ian] Yes, with New Year's Day being on the weekend.
    • [Ian] The other question I need to ask is does the current meeting day and time still suit everyone? Does anyone see any changes in their schedules that might mean they'd prefer a change?
    • [Patrick] What is the proposal?
    • [Ian] That the status quo is maintained; we keep to the current day and time.
    • {Brad moved to keep the current day/time, seconded by Eric, no objections}
    • [Ian] There were a couple of things I was going to raise as AOB, but maybe I should deal with them here, while we wait to see if Harrison joins.
  2. Newsletter
    • [Ian] I just realized today that we missed sending out the newsletter that was due at the end of November. I think that we'd really struggle to get the newsletter drafted, reviewed and issued during December.
    • [Ian] I was wondering if we maybe made this an opportunity to shift the timing to make then issue dates in January, April, July and October, more in line with the start of each quarter year.
    • [Brad] That a good idea.
    • [Ian] Are there any objections to that?
    • [Eric] None.
    • [Patrick] It'll be late in the month though, in January?
    • [Ian] Yes, the end of the month. We've always sent out the newsletter on or just before the last day of the month.
  3. Reaffirmation of Officers
    • [Ian] The other item i was reminded of is that it's coming up to a year since the officers were last reaffirmed, so that's something else we need to address during January.
    • [Eric] Is that still required? I thought the IEEE changed that?
    • [Ian] Ah! What they changed was the need to reaffirm existing standards at five-year intervals. WG officers should still be reaffirmed on an annual basis.
    • [Eric] Of course!
  4. Revisit our Primitives discussion
    (Refer to meeting minutes from Q2 2010)
    - Does anything in the forum thread on gateways help us to move forward?
    - Or the structure/control split we touched on last week?
    • [Ian] Maybe we can quickly look at the forum posts that have been made.
    • {Forum shared}
    • [Ian] I see a post by Brad that I haven't read yet. Tim posted much what he said in the meeting, and a lot of that is things I agreed with. Michele posted, which is good to see; I wasn't sure if he was still following us.
    • [Brad] Oh, he's following us, he's just been snowed under with other things!
    • [Ian] That was quite good - it's thinking more at a meta-level.
    • [Brad] It's bridging the gap between P1687, 1149.7, etc., and what we're doing in SJTAG.
    • [Ian] I wrote a lot of words, but there's maybe not all that much substance to it. I meant to go back and add more but never found the time.
    • [Ian] I need to quickly read Brad's post. Yes, parking in a stable state is one of the items I was going to add to my post.
    • [Brad] I didn't have a lot of time. I just quickly added what I immediately thought was missing from the others. My second paragraph is partly covered by some of the other comments, but I thought I should make a particular case for ICT.
    • [Ian] Yes, Tim mentioned discrete pins to enable or link chains, but I think you're giving that another wrinkle by asking a for single pin to link all chains.
    • [Ian] Brad's third paragraph, about disabling the gateway outputs to allow access to the downstream chains is a situation I recognize but had forgotten about. It's a good point.
    • [Ian] Overall, there are a few points in common here, but maybe nothing that we didn't already know.
    • [Brad] We may have talked about some of these things in the past but we didn't have it all recorded in one place; that's the benefit of these posts.
    • {Harrison joined}
    • [Ian] The next thing I'd like to do is to go back to the discussions we had on primitives, maybe 18 months ago, and see if any of the recent ideas give us any new insights on how we can expand those diagrams.
    • {Primitives slide set shared}
    • [Harrison] I had a look at those pictures. You probably went about it the same way as P1687 did. They got diagrams like yours then went back and layered in the control. You could consider that Dot7 can simplify the architectures.
    • [Harrison] The things, and this is what P1687 found hard to wrap its hands around, is the semantics for the control. The hardware is kind of constrained.
    • [Brad] That's something we need to note; that we're deficient in not addressing the 2-wire interface in these slides.
    • [Harrison] The 2-wire interface increases palatability for some.
    • [Adam] I feel I should add that the 2-wire interface implies that there is some addressability function in each chip.
    • [Harrison] Yes, that's part of the control.
    • [Ian] I don't think that's a big issue since most people seem to want their gateways to be addressable anyway.
    • [Brad] Does the addressability of Dot7 give us what we need at board level?
    • [Harrison] What it gives you over what 1149.1 offers so I think it does give you what you want. Dot7 gives you a user defined option, because they were thinking ahead. It's not necessary to be in Test Mode to be in a Dot7 mode.
    • [Ian] Remind what the addressing range is like in Dot7?
    • [Adam] The addressability in the 1149.7 TAP.7.Controller is based on elements which are: 28 bits for a device ID made of manufacturer and device version and 8 bits for node ID that allows you distinguish between instances of the same device on the network. So you could have 256 copies of the same device.
    • [Adam] You could posit an 1149.7 system gateway - it is suggested in the standard although not in any detail - that would theoretically be a valid solution.
    • [Ian] OK, I'm just thinking selfishly about what I might need for some of our systems. I think the largest scheme I know of could use 74 boards in a backplane, so 74 gateways on the one Test Access Connector.
    • [Brad] It's possible that Dot7 may give us something here. We need to ask what is available now from a control aspect. That's why I thought now was maybe a good time to revisit the primitives since our recent discussion was pushing us in the direction of trying to answer that question.
    • [Ian] Are the ones we have here the only games in town?
    • [Brad] They're illustration of the heavier used devices.
    • [Harrison] There are some newcomers, SMBus has been getting some attention. That came up from some of the wireless silicon guys, where speeds were getting to be an issue.
    • [Ian] JTAG can often be considered slow.
    • [Harrison] That's why Dot7 has tried to address that.
    • [Ian] Yeah, well we may often find a more efficient way to do many things, but if it all breaks down we know we can use JTAG to recover say a corrupted board, even if it is slow.
    • [Brad] What may be interesting to ask is what would a Dot7 driven gateway look like?
    • [Harrison] Think of it going forward. The major player will in the next 18 months or so start adopting Dot7. That's where the newer devices will be.
    • [Richard] My question is very simple; will this be compatible with existing standards?
    • [Harrison] Yes, the 4-wire interface.
    • [Brad] That's why I asked what can Dot7 do - Does it do what we want it to do? Does it support our architectures?
    • [Harrison] I think you're going to need hierarchy.
    • [Ian] I picked on hierarchy as a key feature for gateways, because I can see where a third party board may be added to a system after the initial design, and that board may have it's own hierarchy.
    • [Brad] People are using linker devices to manage off-board chains or to daughter boards. But you have the problem of not knowing what board is being plugged in. At some point you may be able to encode some special properties to give insight into what it looks like.
    • [Brad] Ideally, you could purchase a board that contains the tests for that UUT.
    • [Harrison] That's in P1687 - the instrument comes with it's vectors.
    • [Brad] That's assuming you have a repository externally where you store these and fetch then from. What I'm thinking of is the internal situation where you want to know what test you can run on a board, and you don't have access to an external repository.
    • [Harrison] That's where SJTAG fills the void. P1687 has organized a library at the chip level, but no-one is doing that at the chip edge yet.

5. Key Takeaway for today's meeting

  • [Brad] We should consider the applicability of the Dot7 control structure.

6. Schedule next meeting

Next Meeting:
December 12th (11:00 AM EST, 4:00 PM GMT), Patrick, Brad and Carl expect to miss this meeting.

Schedule for December 2011:
19th, Patrick, Ian and Brad will miss this meeting.

First meeting in January 2012 will be Jan 9th.

7. Any other business

Covered under items 4b and 4c.

8. Review new action items

No specific action. It was noted that the discussion of the primitives should be amended to also address 2-wire schemes, per 1149.7.

9. Adjourn

Eric moved to adjourn at 12:03 PM EST, seconded by Patrick.

Respectfully submitted,
Ian McIntosh