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JTAG cable @ 2.5 V - where?

Started by Markus Zingg October 3, 2006
Hi group

I'm a newbee, so please bear with me if this does not make sense. 

I got a AVNet (MEMEC) Virtex 4 based developper kit based on the
Virtex-4 FX12 Mini Module whoes baseboard JTAG port is documented as
"a 2.5V compatible JTAG chain header". The pinout is identical to what
Xilinx seems to use (14 pins etc.). The docs seem to asume that one
must use the Xilinx parallel cable IV which from what I understand
seems to automatically sense the voltage needs of the target and is
having other nice to have features. However, due to several reasons
which are beond the scope of this post, I can't simply pick up the
phone and order one from a supplier last not least also because I
don't know any that would carry this item here in Switzerland.

The net seems to be full of homebrew JTAG cable websites giving
instructions to build you own. The question is can I use one of those?
I'm a bit afraid that this will not work cause from what I understand
they seem to be designed for 5V or 5V tolerant devices. What other
options do I have? Any links to a schema of the Xilinx paralell cable
IV or such to build my own JTAG cable running at 2.5V?

I would also not mind to shell out the needed $$$ to get that original
cable if I could easily purchase it somewhere online using paypal or a
credit card and get it deliverd quickly. Any ideas?

TIA

Markus

Markus

Our Prog2 cable(ask for narrow head version) is available in the standard 14 
way 2mm connector. Cost GBP�10. It is a Cable III look-alike as most third 
party cables are. Schematics for Cable IV are generally not in public domain 
and generally not replicated by anyone as far as I know.

The only advantage of the Cable IV is the download speed.

Our shop website has those listed under programming solutions for an easy 
order solution.

John Adair
Enterpoint Ltd. - Home of Broaddown2. The Ultimate Spartan3 Development 
Board.
http://www.enterpoint.co.uk

"Markus Zingg" <m.zingg@nct.ch> wrote in message 
news:ahn4i25ir1pnpqbol22na85ggkrjeoam3m@4ax.com...
> Hi group > > I'm a newbee, so please bear with me if this does not make sense. > > I got a AVNet (MEMEC) Virtex 4 based developper kit based on the > Virtex-4 FX12 Mini Module whoes baseboard JTAG port is documented as > "a 2.5V compatible JTAG chain header". The pinout is identical to what > Xilinx seems to use (14 pins etc.). The docs seem to asume that one > must use the Xilinx parallel cable IV which from what I understand > seems to automatically sense the voltage needs of the target and is > having other nice to have features. However, due to several reasons > which are beond the scope of this post, I can't simply pick up the > phone and order one from a supplier last not least also because I > don't know any that would carry this item here in Switzerland. > > The net seems to be full of homebrew JTAG cable websites giving > instructions to build you own. The question is can I use one of those? > I'm a bit afraid that this will not work cause from what I understand > they seem to be designed for 5V or 5V tolerant devices. What other > options do I have? Any links to a schema of the Xilinx paralell cable > IV or such to build my own JTAG cable running at 2.5V? > > I would also not mind to shell out the needed $$$ to get that original > cable if I could easily purchase it somewhere online using paypal or a > credit card and get it deliverd quickly. Any ideas? > > TIA > > Markus >
I don't see where the "Parallel Cable III look-alike" PROG2 is 2.5V 
compliant since the Parallel Cable III doesn't work so well from 2.5V.

I think I've gotten the III to work with a 3.3V supply for 2.5V JTAG but 
the IV or USB versions of the cable are certainly more robust.

Perhaps the Xilinx online store could ship to Switzerland with a simple 
credit card purchase.

The Parallel Cable IV doesn't include schematics but it does show what 
the input and output stages look like, easily replacing the simple 
buffers in the Parallel Cable III which does have full schematics.

- John Handwork


John Adair wrote:
> Markus > > Our Prog2 cable(ask for narrow head version) is available in the standard 14 > way 2mm connector. Cost GBP&#4294967295;10. It is a Cable III look-alike as most third > party cables are. Schematics for Cable IV are generally not in public domain > and generally not replicated by anyone as far as I know. > > The only advantage of the Cable IV is the download speed. > > Our shop website has those listed under programming solutions for an easy > order solution. > > John Adair > Enterpoint Ltd. - Home of Broaddown2. The Ultimate Spartan3 Development > Board. > http://www.enterpoint.co.uk > > "Markus Zingg" <m.zingg@nct.ch> wrote in message > news:ahn4i25ir1pnpqbol22na85ggkrjeoam3m@4ax.com... >> Hi group >> >> I'm a newbee, so please bear with me if this does not make sense. >> >> I got a AVNet (MEMEC) Virtex 4 based developper kit based on the >> Virtex-4 FX12 Mini Module whoes baseboard JTAG port is documented as >> "a 2.5V compatible JTAG chain header". The pinout is identical to what >> Xilinx seems to use (14 pins etc.). The docs seem to asume that one >> must use the Xilinx parallel cable IV which from what I understand >> seems to automatically sense the voltage needs of the target and is >> having other nice to have features. However, due to several reasons >> which are beond the scope of this post, I can't simply pick up the >> phone and order one from a supplier last not least also because I >> don't know any that would carry this item here in Switzerland. >> >> The net seems to be full of homebrew JTAG cable websites giving >> instructions to build you own. The question is can I use one of those? >> I'm a bit afraid that this will not work cause from what I understand >> they seem to be designed for 5V or 5V tolerant devices. What other >> options do I have? Any links to a schema of the Xilinx paralell cable >> IV or such to build my own JTAG cable running at 2.5V? >> >> I would also not mind to shell out the needed $$$ to get that original >> cable if I could easily purchase it somewhere online using paypal or a >> credit card and get it deliverd quickly. Any ideas? >> >> TIA >> >> Markus
Well I did say look-alike I didn't say the same. It looks the same to
the Xilinx software so it can use it without issue. Prog2 actually
performs very well against the competition and works in circumstances
where many others fail. We have tried several of these in compatibility
testing with our own boards. Our Prog2 isn't as good as Cable IV but
then it is about 1/5 th of the price when buying and we do give them
away with our own development boards.

John Adair
Enterpoint Ltd.

John_H wrote:
> I don't see where the "Parallel Cable III look-alike" PROG2 is 2.5V > compliant since the Parallel Cable III doesn't work so well from 2.5V. > > I think I've gotten the III to work with a 3.3V supply for 2.5V JTAG but > the IV or USB versions of the cable are certainly more robust. > > Perhaps the Xilinx online store could ship to Switzerland with a simple > credit card purchase. > > The Parallel Cable IV doesn't include schematics but it does show what > the input and output stages look like, easily replacing the simple > buffers in the Parallel Cable III which does have full schematics. > > - John Handwork > > > John Adair wrote: > > Markus > > > > Our Prog2 cable(ask for narrow head version) is available in the standa=
rd 14
> > way 2mm connector. Cost GBP=A310. It is a Cable III look-alike as most =
third
> > party cables are. Schematics for Cable IV are generally not in public d=
omain
> > and generally not replicated by anyone as far as I know. > > > > The only advantage of the Cable IV is the download speed. > > > > Our shop website has those listed under programming solutions for an ea=
sy
> > order solution. > > > > John Adair > > Enterpoint Ltd. - Home of Broaddown2. The Ultimate Spartan3 Development > > Board. > > http://www.enterpoint.co.uk > > > > "Markus Zingg" <m.zingg@nct.ch> wrote in message > > news:ahn4i25ir1pnpqbol22na85ggkrjeoam3m@4ax.com... > >> Hi group > >> > >> I'm a newbee, so please bear with me if this does not make sense. > >> > >> I got a AVNet (MEMEC) Virtex 4 based developper kit based on the > >> Virtex-4 FX12 Mini Module whoes baseboard JTAG port is documented as > >> "a 2.5V compatible JTAG chain header". The pinout is identical to what > >> Xilinx seems to use (14 pins etc.). The docs seem to asume that one > >> must use the Xilinx parallel cable IV which from what I understand > >> seems to automatically sense the voltage needs of the target and is > >> having other nice to have features. However, due to several reasons > >> which are beond the scope of this post, I can't simply pick up the > >> phone and order one from a supplier last not least also because I > >> don't know any that would carry this item here in Switzerland. > >> > >> The net seems to be full of homebrew JTAG cable websites giving > >> instructions to build you own. The question is can I use one of those? > >> I'm a bit afraid that this will not work cause from what I understand > >> they seem to be designed for 5V or 5V tolerant devices. What other > >> options do I have? Any links to a schema of the Xilinx paralell cable > >> IV or such to build my own JTAG cable running at 2.5V? > >> > >> I would also not mind to shell out the needed $$$ to get that original > >> cable if I could easily purchase it somewhere online using paypal or a > >> credit card and get it deliverd quickly. Any ideas? > >> > >> TIA > >> > >> Markus
 John,

>Prog2 actually performs very well against the competition and works in
circumstances where many others fail. is this a business secret or can you elaborate a bit on that? Using the right buffers the high level to low level translation should not be a problem anymore. Is it a question of TDO conditioning? Best regards Ulrich Bangert "John Adair" <g1@enterpoint.co.uk> schrieb im Newsbeitrag news:1159907018.668373.267310@i3g2000cwc.googlegroups.com... Well I did say look-alike I didn't say the same. It looks the same to the Xilinx software so it can use it without issue. Prog2 actually performs very well against the competition and works in circumstances where many others fail. We have tried several of these in compatibility testing with our own boards. Our Prog2 isn't as good as Cable IV but then it is about 1/5 th of the price when buying and we do give them away with our own development boards. John Adair Enterpoint Ltd. John_H wrote:
> I don't see where the "Parallel Cable III look-alike" PROG2 is 2.5V > compliant since the Parallel Cable III doesn't work so well from 2.5V. > > I think I've gotten the III to work with a 3.3V supply for 2.5V JTAG but > the IV or USB versions of the cable are certainly more robust. > > Perhaps the Xilinx online store could ship to Switzerland with a simple > credit card purchase. > > The Parallel Cable IV doesn't include schematics but it does show what > the input and output stages look like, easily replacing the simple > buffers in the Parallel Cable III which does have full schematics. > > - John Handwork > > > John Adair wrote: > > Markus > > > > Our Prog2 cable(ask for narrow head version) is available in the
standard 14
> > way 2mm connector. Cost GBP&#4294967295;10. It is a Cable III look-alike as most
third
> > party cables are. Schematics for Cable IV are generally not in public
domain
> > and generally not replicated by anyone as far as I know. > > > > The only advantage of the Cable IV is the download speed. > > > > Our shop website has those listed under programming solutions for an
easy
> > order solution. > > > > John Adair > > Enterpoint Ltd. - Home of Broaddown2. The Ultimate Spartan3 Development > > Board. > > http://www.enterpoint.co.uk > > > > "Markus Zingg" <m.zingg@nct.ch> wrote in message > > news:ahn4i25ir1pnpqbol22na85ggkrjeoam3m@4ax.com... > >> Hi group > >> > >> I'm a newbee, so please bear with me if this does not make sense. > >> > >> I got a AVNet (MEMEC) Virtex 4 based developper kit based on the > >> Virtex-4 FX12 Mini Module whoes baseboard JTAG port is documented as > >> "a 2.5V compatible JTAG chain header". The pinout is identical to what > >> Xilinx seems to use (14 pins etc.). The docs seem to asume that one > >> must use the Xilinx parallel cable IV which from what I understand > >> seems to automatically sense the voltage needs of the target and is > >> having other nice to have features. However, due to several reasons > >> which are beond the scope of this post, I can't simply pick up the > >> phone and order one from a supplier last not least also because I > >> don't know any that would carry this item here in Switzerland. > >> > >> The net seems to be full of homebrew JTAG cable websites giving > >> instructions to build you own. The question is can I use one of those? > >> I'm a bit afraid that this will not work cause from what I understand > >> they seem to be designed for 5V or 5V tolerant devices. What other > >> options do I have? Any links to a schema of the Xilinx paralell cable > >> IV or such to build my own JTAG cable running at 2.5V? > >> > >> I would also not mind to shell out the needed $$$ to get that original > >> cable if I could easily purchase it somewhere online using paypal or a > >> credit card and get it deliverd quickly. Any ideas? > >> > >> TIA > >> > >> Markus
Ulrich

It isn't one thing but a series of things from PCB layout through to choice 
of driver and decoupling. Actually as a cable our Prog1 cable does even 
better but it has the advantage of a Coolrunner-II CPLD and a voltage 
regulator built in. It is some way between what Xilinx do as Cable III and 
their Cable IV. At some stage we may effective take the best bits of Prog1 
and Prog2 and a couple of other things we know will think will make life 
better and make Prog3 but that isn't until we exhaust our current Prog2 
cable stock. We have a few new ideas we are trying out on our new 
development board Tarfessock1 which can double as a programming cable and 
depending if those work they may get fed back into the more general cable 
solutions.

Some of the problems people see in programming are actually the target board 
in the main and not necessarily the cable or a combination of them.

John Adair
Enterpoint Ltd. - Home of Tarfessock1. The Cardbus Spartan-3E FPGA 
Development Board.
http://www.enterpoint.co.uk


"Ulrich Bangert" <df6jb@ulrich-bangert.de> wrote in message 
news:eg24sg$h8c$02$1@news.t-online.com...
> John, > >>Prog2 actually performs very well against the competition and works in > circumstances where many others fail. > > is this a business secret or can you elaborate a bit on that? Using the > right buffers the high level to low level translation should not be a > problem anymore. Is it a question of TDO conditioning? > > Best regards > Ulrich Bangert > > "John Adair" <g1@enterpoint.co.uk> schrieb im Newsbeitrag > news:1159907018.668373.267310@i3g2000cwc.googlegroups.com... > Well I did say look-alike I didn't say the same. It looks the same to > the Xilinx software so it can use it without issue. Prog2 actually > performs very well against the competition and works in circumstances > where many others fail. We have tried several of these in compatibility > testing with our own boards. Our Prog2 isn't as good as Cable IV but > then it is about 1/5 th of the price when buying and we do give them > away with our own development boards. > > John Adair > Enterpoint Ltd. > > John_H wrote: >> I don't see where the "Parallel Cable III look-alike" PROG2 is 2.5V >> compliant since the Parallel Cable III doesn't work so well from 2.5V. >> >> I think I've gotten the III to work with a 3.3V supply for 2.5V JTAG but >> the IV or USB versions of the cable are certainly more robust. >> >> Perhaps the Xilinx online store could ship to Switzerland with a simple >> credit card purchase. >> >> The Parallel Cable IV doesn't include schematics but it does show what >> the input and output stages look like, easily replacing the simple >> buffers in the Parallel Cable III which does have full schematics. >> >> - John Handwork >> >> >> John Adair wrote: >> > Markus >> > >> > Our Prog2 cable(ask for narrow head version) is available in the > standard 14 >> > way 2mm connector. Cost GBP&#4294967295;10. It is a Cable III look-alike as most > third >> > party cables are. Schematics for Cable IV are generally not in public > domain >> > and generally not replicated by anyone as far as I know. >> > >> > The only advantage of the Cable IV is the download speed. >> > >> > Our shop website has those listed under programming solutions for an > easy >> > order solution. >> > >> > John Adair >> > Enterpoint Ltd. - Home of Broaddown2. The Ultimate Spartan3 Development >> > Board. >> > http://www.enterpoint.co.uk >> > >> > "Markus Zingg" <m.zingg@nct.ch> wrote in message >> > news:ahn4i25ir1pnpqbol22na85ggkrjeoam3m@4ax.com... >> >> Hi group >> >> >> >> I'm a newbee, so please bear with me if this does not make sense. >> >> >> >> I got a AVNet (MEMEC) Virtex 4 based developper kit based on the >> >> Virtex-4 FX12 Mini Module whoes baseboard JTAG port is documented as >> >> "a 2.5V compatible JTAG chain header". The pinout is identical to what >> >> Xilinx seems to use (14 pins etc.). The docs seem to asume that one >> >> must use the Xilinx parallel cable IV which from what I understand >> >> seems to automatically sense the voltage needs of the target and is >> >> having other nice to have features. However, due to several reasons >> >> which are beond the scope of this post, I can't simply pick up the >> >> phone and order one from a supplier last not least also because I >> >> don't know any that would carry this item here in Switzerland. >> >> >> >> The net seems to be full of homebrew JTAG cable websites giving >> >> instructions to build you own. The question is can I use one of those? >> >> I'm a bit afraid that this will not work cause from what I understand >> >> they seem to be designed for 5V or 5V tolerant devices. What other >> >> options do I have? Any links to a schema of the Xilinx paralell cable >> >> IV or such to build my own JTAG cable running at 2.5V? >> >> >> >> I would also not mind to shell out the needed $$$ to get that original >> >> cable if I could easily purchase it somewhere online using paypal or a >> >> credit card and get it deliverd quickly. Any ideas? >> >> >> >> TIA >> >> >> >> Markus > >