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Chaining the startKIT

Posted: Wed Jan 22, 2014 2:17 pm
by pstnotpd
The startKIT hardware manual states that header the links on header J8 are meant to chain multiple startkits together.

However I think the JTAG can not be chained as the signals are not pinned out. (correct me if I'm wrong)

So I assume the chained startkits will then not be "visible" on the chain and debugging the chain will not be possible.

Will the tools allow me to chain using the "B" link available on J7 and adjust the xn file?

If so, would this also be possible using the slicekit?

NOTE: for now this is only to use the "visible" core on startKIT

Re: Chaining the startKIT

Posted: Wed Jan 22, 2014 2:51 pm
by sethu_jangala
Does the following Answer for the question in the Q&A section answer you:
http://www.xcore.com/questions/2150/can ... xmos-links

Sethu.

Re: Chaining the startKIT

Posted: Wed Jan 22, 2014 2:58 pm
by segher
Yes, J8 does not contain JTAG signals, so you cannot
daisychain xcores via J8. If you are very adventurous you
could do something with TP1.

J8 contains xlinks; you can connect multiple startkits with
that, and debug them separately, each with its own debugger.
By far the easiest way is to run separate programs on them.

Re: Chaining the startKIT

Posted: Wed Jan 22, 2014 6:34 pm
by pstnotpd
sethu wrote:Does the following Answer for the question in the Q&A section answer you:
http://www.xcore.com/questions/2150/can ... xmos-links
It does, tnx!
segher wrote:If you are very adventurous you
could do something with TP1.
I was lurking the JTAG thread thinking about that, but as I understand it it only has the incoming signals doesn't it?

Re: Chaining the startKIT

Posted: Wed Jan 22, 2014 7:35 pm
by segher
TP1 has all JTAG signals; all are connected properly to the
xcore JTAG pins, and also to 1-bit ports on the debug tile.

Re: Chaining the startKIT

Posted: Thu Jan 23, 2014 6:46 am
by pstnotpd
segher wrote:TP1 has all JTAG signals; all are connected properly to the
xcore JTAG pins, and also to 1-bit ports on the debug tile.
Ok, I must read through that again! So using TP1 it should be possible to setup the JTAG chain to a number of startKITs?

Unfortunately I found that the JTAG signals on the slicekit coreboard are only connected to the PCIe and not to the header. Maybe I can convince Folknology to make a run of proto-slices :o)

I've read in the link documentation that basically the 5 wire link would only be stable using PCB traces, so I assume that's the reason the C & D links are pinnned out like 2 wire links.

While I'm waiting for my shipment of pin headers and jumper cables to come in, does anyone know about proper cable lenght?

I feel a "startCUBE" is in the works....

Re: Chaining the startKIT

Posted: Thu Jan 23, 2014 11:53 am
by Folknology
It's worth reading this small Xmos Links Guide

P.S. this doc is out of date as more topologies are now supported BTW.

P.P.S the XK1 boards provided the simplest implementation of daisy chaining by combining Xtag and channel expansion using the XSYS 20 pin IDC connectors.

P.P.P.S. A sneak peak of the new A series slice kit seems to indicate a return to an IDC XSYS chaining connector to make physically daisy chaining these feasable (due to position of analogue slice)?

regards
Al

Re: Chaining the startKIT

Posted: Thu Jan 23, 2014 12:20 pm
by pstnotpd
Folknology wrote:It's worth reading this small Xmos Links Guide
I've been reading through that one. That mentions 150 mm max for the 2w link but mentions a "driver" which I don't think is on the startKit. So I wonder if a straight connection with jumper cables will work. It also only mentions PCB track as an option for 5w

B.t.w. I can't tempt you into a proto-slice run? ;o)

Re: Chaining the startKIT

Posted: Thu Jan 23, 2014 12:30 pm
by Folknology
B.t.w. I can't tempt you into a proto-slice run? ;o)
This is possible what sort of price would be fair?
And how many would I need to get made?

regards
Al

Re: Chaining the startKIT

Posted: Thu Jan 23, 2014 1:33 pm
by pstnotpd
Folknology wrote:This is possible what sort of price would be fair?
And how many would I need to get made?
I'd personally only want 1 or 2, but I can imagine more people on this forum being interested.

B.t.w. does it also pinout the JTAG, because that's what I actually need.