1149.4 Working Group Meeting Minutes October 1, 2003 ITC 2003
Attendees:
|
Bill |
Aronson |
National
Semi |
USA |
bill.aronson@nsc.com |
|
Arden |
Bjerkeli |
Asset
Intertech |
UK |
abjerkeli@asset-intertech.com |
|
Jean-Louis |
Carbonero |
ST
Microelectronics |
France |
jean-louis.carbonero@st.com |
|
Pete |
Collins |
JTAG
Technologies |
UK |
petec@jtag.co.uk |
|
Ivan |
Duzevik |
National
Semi |
USA |
ivan.duzevik@nsc.com |
|
Heiko |
Ehrenberg |
Goepel
Electronics |
Germany |
he@goepel.com |
|
Andre |
Fidalgo |
ISEP |
Portugal |
avf@dee.isep.ipp.pt |
|
Ken |
Filliter |
National
Semi |
USA |
ken.filliter@nsc.com |
|
Simon |
Guan |
Lokheed
Martin |
USA |
simon.guan@lmco.com |
|
Graham |
Hollands |
3Com
Europe |
UK |
graham_hollands@3com.com |
|
Carl |
Jeffrey |
Lancaster
Uni |
UK |
c.jeffrey@lancaster.ac.uk |
|
Tapio |
Koivukangas |
Nokia
Mobile Phones |
Finland |
tapio.koivukangas@nokia.com |
|
Veikko |
Loukusa |
Nokia
Mobile Phones |
Finland |
veikko.loukusa@nokia.com |
|
Charles |
Meyerson |
Medtronic |
USA |
charles.meyerson@medtronic.com |
|
Markku |
Moilanen |
Uni of
Oulu |
Finland |
markku.moilanen@ee.oulu.fi |
|
Chuck |
Reid |
Guidant |
USA |
chuck.reid@guidant.com |
|
Teuvo |
Saikkonen |
Uni of
Oulu |
Finland |
ts@ee.oulu.fi |
|
Juha |
Voutilainen |
Uni of
Oulu |
Finland |
vouti@ee.oulu.fi |
|
Markku |
Walmsley |
Guidant |
USA |
mark.walmsley@guidant.com |
|
Jim |
Webster |
BAE
Systems |
UK |
jim.webster@baesystems.com |
|
Working
Group members |
|
|
|
|
|
Adam |
Cron |
Synopsys |
USA |
acron@ieee.org |
|
Frans |
de Jong |
Philips
Research |
the
Netherlands |
frans.de.jong@philips.com |
|
Adam |
Osseiran |
NNTTF |
Australia |
a.osseiran@teletest.org.au |
|
Ken |
Parker |
Agilent |
USA |
kenneth_parker@agilent.com |
|
Steve |
Sunter |
Logicvision |
Canada |
sunter@logicvision.com |
The meeting started at 3:00 pm
There was considerable discussion
about whether 1149.4 information should be coded in an analog extension to BSDL
or to CTL. Ken Parker said that CTL is
too new, and presently has insufficient industry support, whereas “everybody
has a BSDL parser”. Adam Cron said that
at a VTS WG meeting in May 2000, John McDermid presented a first draft of an
analog extension to BSDL – denoted a “straw dog proposal” - it covered 95% of
what could be a complete version. Ken
Parker will follow up on this issue assisted by several members of the WG and
some volunteers present at the meeting.
Steve summarized that a BSDL analog extension seems most appropriate for
describing the analog boundary test access and possibly some core access, and
CTL seems most appropriate for describing the analog core access and possibly
some analog boundary access. Ken said
that users want a single file that lists both digital and analog pins. Parsers for BSDL already exist and could be
adapted to accommodate 1149.4.
Unmodified 1149.1 parsers will simply ignore the analog pins.
A motion was proposed by Frans, and
seconded by Ken Parker: the description
of 1149.4 should be an extension to 1149.1 BSDL. All five WG members voted in favor.
The WG will inform the IEEE of its
decision to adopt BSDL as the 1149.4 description language. BSDL will have an
extension for analog, similar to the extensions for 1149.6 and 1532.
To follow up on this issue with
volunteers, these minutes will be sent to the reflector with the dot4 URL
(http://grouper.ieee.org/groups/1149/4/) and the WG meeting minutes of May 2000
in which analog BSDL is discussed (
http://grouper.ieee.org/groups/1149/4/min0500.html#language )
When the attendees were asked who
would look at the analog extension proposal, 8 people raised their hands.
Tapio noted that they need dot1 and
dot4 because their boards are mostly mixed-signal. Pete said that he’s hearing lots of customer interest in dot4.
Next year, likely before the next WG
meeting, the published 1149.4 standard becomes 5 years old, and there is an
opportunity to edit it before then.
An email will be sent and include
the list of editorial changes. A note
in the minutes of May 2000 already mentioned these modifications – as listed
here for convenience (thanks to Adam Cron):
Steve said he provided a descriptive
note of how to connect an ABM to a digital pin (so that it meets 1149.1 and
1149.4 rules for digital pins). This is
shown in an ITC’02 paper by Sunter et al.
We will need to add a note to Rule
10.2.2 referring to the analog extension, when the extension has been created.
We need to update 1149.4 to reflect
the changes that were made in the latest version of 1149.1.
Rcom must typically be << 10
ohms, not 1 kohm as it may say in the present version of 1149.4.
Charles raised a concern that if
on-chip stimulus and response capture exists on-chip, and uses the analog
buses, there are no rules governing this situation. Steve noted that the rule regarding internal scan chains not
interfering with boundary scan measurements is the most applicable rule, and
the other applicable rule is the one regarding 1% measurement accuracy. He said that being more specific than those
two rules would be difficult, but welcomed suggestions.
Steve noted that for deep sub-micron
CMOS technologies, as was first noted several years ago by Matsushita,
transistor leakage may limit the number of transmission gates per bus to around
30. This was one reason that the analog
bus is permitted to have one level of hierarchy on-chip. Thirty transistors place an upper limit of
30x30 = 900 on the maximum number of nodes that can be accessed. To go beyond this, and to make layout more
distributed and less of a star configuration, we could consider permitting more
levels of hierarchy.
Charles said his company was using
only two bits per pin to save gate area, by omitting the D and C bits – only
using the analog bus access bits. This
permitted analog access and the ability to drive logic 1 and 0 (via each bus),
but it prevent measuring impedance at the same time. Steve noted that using 2 boundary scan bits, with 4 latches would
permit all variations and reduce boundary scan length – however it would
require two boundary scan loads: one to set the digital state, and the second
to select pins for analog access.
Steve noted that the switches which
deliver Vmin and Vmax to a pin are permitted to have an impedance as large as
10 kohm. If the pin must always have,
for example, a 50 ohm load off-chip then the Vmin and Vmax switches are useless
– we have no rule to address this. We
should either say that the drivers are not needed for this case, or that the
function driver must be used.
Carl asked where the 1149.4
bandwidth limitation originated. Steve
replied that the limitation comes from assuming use of near-minimal size
transmission gates, each with 500 ohm resistance, one in the ABM and one in the
TBIC to total 1 kohm, and a few hundred picofarads of off-chip bus
capacitance. If analog buffers are used
in the TBIC, the bandwidth can increase by more than an order of magnitude.
Steve said that we should consider
permitting ABMs to be used as an ATAP.
It permits all existing switch combinations of the TBIC, but allows the
same pad cells and boundary scan cells to be used. When this was proposed several years ago, it was rejected to
ensure that the ATAP pins were used for only test. However, 1149.1 permits the use of a compliance enable pin which
allows even the digital TAP pins to be used for non-test purposes.
Charles asked whether an ABM could
be used and documented for a power pin.
These pins are normally listed as Linkage pins, and an ABM is certainly
not required, but monitoring a power pin’s voltage can be quite useful. Presently, this would be described as
internal access.
Steve noted that we need a more
efficient solution for differential pins.
Presently, we require 4 scan bits per pin, and 8 bits per differential
pair. It might be possible to allow all
existing test capabilities with only 4 bits per pair whenever a fully
differential ATAP is used (AT1, AT1N, AT2, AT2N). Differential is likely going to be a popular way to implement
dot4. Steve (and possibly others) will
investigate further.
Considering a date for the next WG
meeting, Adam Osseiran asked the attendees to raise their hand if they plan to
attend VTS – no one raised their hand.
Six raised their hands for DATE.
Meeting adjourned at 4:40 pm.