Multiple XK-1s

Technical discussions related to any XMOS development kit or reference design. Eg XK-1A, sliceKIT, etc.
DanB
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Multiple XK-1s

Postby DanB » Mon Jan 31, 2011 9:06 pm

Hi,

It's taken a few days but I now pretty clued up on the differences between the various chips (and package sizes) available, as well as how these are used on the various development kits. Despite this, I am still a little confused with the XK-1:

From my understanding (which may well be wrong), you require an XTAG-2 for debugging and programming an XK-1. Additionally a whole chain of XK-1s can be debugged and programmed using one XTAG-2. Assuming this is correct, why is not possible to purchase the XK-1 alone? One of the major advantages that I can see with the XK-1 is the possibility to chain multiple kits together, through the X-links, and exploit the benefits of the multi-core/threaded architecture. With this in mind I can imagine many people would like to own several XK-1s. From what I can see, though, it is not possible to purchase an XK-1 without an XTAG-2.

Surely this means that there are people out there with more XTAG-2s than they require. Additionally, surely this means that in order to chain multiple XK-1s is reasonably costly considering the inclusion of numerous unwanted/unnecessary XTAG-2s?

From a different angle; If this is the case why are XTAG-2s sold individually if each XK-1 has to be purchased with a corresponding XTAG-2?

Essentially I guess I am trying to confirm if one XTAG-2 can be used on a chain of XK-1s? And if so, is it possible to purchase XK-1s separate from XTAG-2s?

I apologise in advanced if this is a silly question, still new to the platform it is likely I've missed a core concept! :)

Thank you!

Dan.
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leon_heller
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Postby leon_heller » Mon Jan 31, 2011 9:24 pm

It has been asked before. It probably works out cheaper for XMOS and suppliers like Digi-Key to supply an XTAG-2 with each XK-1 than to hold stocks of both units. Sparkfun sells their XS1-L1 board and the XTAG-2 separately, however.
Last edited by leon_heller on Tue Feb 01, 2011 11:28 am, edited 1 time in total.
DanB
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Postby DanB » Mon Jan 31, 2011 9:36 pm

leon_heller wrote:It has been asked before. It probably works out cheaper for XMOS and suppliers like Digi-Key to supply an XTAG2 with each XK-1 than to hold stocks of both units. Sparkfun sells their XS1-L1 board and the XTAG2 separately, however.
Just to confirm; you only need one XTAG-2 for a whole chain of XK-1s? (Want to make sure I'm not missing a trick here!)

And thanks for the heads up about Sparkfun. I do not s'pose you've experience with ordering from them? How does postage and or the various import duties that may be relevant for a UK purchase work out? Trying to determine if it is still better off purchasing elsewhere and getting several "spare" XTAG-2s. Either way, it's only research at the moment as I'm keen to get started on the XC-1A... But just reading about the XMOS is enough to make me want to buy everything :D. Bug much? :)

Dan.

PS. As I write this, another question has popped into my mind. XTAG-2... I assume (from the name) XTAG(-1) may have existed before? How did this differ from -2?
DanB
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Postby DanB » Mon Jan 31, 2011 9:39 pm

Just done a search on Sparkfun (Link: http://www.sparkfun.com/search/results? ... t=products) and I cannot find an XK-1 listed? I can see the XS1-L1 device and a third-party XS1-L1 development board, but no XK-1. What am I doing wrong? :)
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leon_heller
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Postby leon_heller » Mon Jan 31, 2011 9:45 pm

You only need one XTAG-2 for any number of XK-1 boards.

I was referring to Sparkfun's own XS1-L1 board, they don't sell the XK-1.
Last edited by leon_heller on Tue Feb 01, 2011 11:28 am, edited 1 time in total.
DanB
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Postby DanB » Tue Feb 01, 2011 10:15 am

Ah, thanks for the confirmation :).

As an aside, just wondering if you could explain the history of the XTAG-2? I assume, by the naming convention, there was an XTAG-1 in the past... How'd this differ and why did it get replaced? I'm just interested :).

Cheers,

Dan.
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leon_heller
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Postby leon_heller » Tue Feb 01, 2011 11:25 am

Like many other USB JTAG interfaces, the original XTAG used an FTDI chip, and the same device is still used on the XC-1A for the on-board JTAG function. The XTAG-2 uses an XS1-L1 chip to provide the USB connectivity, which has several advantages over the FTDI chip.

Before the original XTAG was developed an Amontec JTAG interface (also based on the FTDI chip) was used. I still have one.
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octal
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Postby octal » Wed Feb 02, 2011 1:27 am

leon_heller wrote:the original XTAG used an FTDI chip
I wonder if we can use an FTDI chip to flash and debug an XS1-L1 board (with either 64 or 128TQFP)?
this would make it easy to make nice devboards with onboard JTAG.
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Bianco
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Postby Bianco » Wed Feb 02, 2011 7:19 am

octal wrote:
leon_heller wrote:the original XTAG used an FTDI chip
I wonder if we can use an FTDI chip to flash and debug an XS1-L1 board (with either 64 or 128TQFP)?
this would make it easy to make nice devboards with onboard JTAG.
Yes you can.
DanB
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Postby DanB » Wed Feb 02, 2011 10:26 am

octal wrote:
leon_heller wrote:the original XTAG used an FTDI chip
I wonder if we can use an FTDI chip to flash and debug an XS1-L1 board (with either 64 or 128TQFP)?
this would make it easy to make nice devboards with onboard JTAG.
I'd be very interested if you did design one, as I'm sure others would to. I presume if lots of people club together we could get a number made to reduce costs and the overall price to everybody :).

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