Free Parallella Porcupine breakout boards!!

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Re: Free Parallella Porcupine breakout boards!!

Postby aolofsson » Mon Dec 15, 2014 10:32 pm

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Re: Free Parallella Porcupine breakout boards!!

Postby jharp » Thu Dec 18, 2014 4:20 pm

Thanks so much. Great news.

Ordered one as soon as I read the post, and it arrived yesterday.

Now I know what I'll be doing this weekend! :D

Jeff
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Re: Free Parallella Porcupine breakout boards!!

Postby udif » Tue Jan 13, 2015 6:51 am

Is it possible to use the porcupine board to link two parallella boards via the eLinks?
I understand the eLinks are also connected to a 0.1" grid pins.
Can a typical IDC cable (lets say a very short one, a few CM long) good enough to carry these signals?
How about 80 wire IDC cables used for 133MHz IDE where every other wire is a shield/ground?
http://ptgmedia.pearsoncmg.com/images/c ... 05_alt.jpg
What if I cut the cable and leave only the two close connectors?

Wait - will a 1:1 connector even work, or do I need to cross Tx/Rx pairs?
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Re: Free Parallella Porcupine breakout boards!!

Postby FHuettig » Tue Jan 13, 2015 5:57 pm

Hi udif,

udif wrote:Is it possible to use the porcupine board to link two parallella boards via the eLinks?

Yes it is, that's the intent of the North and South connectors.

udif wrote:I understand the eLinks are also connected to a 0.1" grid pins.

For space I had to use 2mm connectors instead of 0.1", but the IDC connectors and ribbon cables are readily available.

udif wrote:Can a typical IDC cable (lets say a very short one, a few CM long) good enough to carry these signals?

I haven't tested the maximum speed, but the eLinks use LVDS signals which are pretty robust. And the Epiphany allows reducing the clock speed by 1/2 or 1/4 on a per-link basis if needed.

udif wrote:How about 80 wire IDC cables used for 133MHz IDE where every other wire is a shield/ground?
http://ptgmedia.pearsoncmg.com/images/c ... 05_alt.jpg
What if I cut the cable and leave only the two close connectors?

Interesting idea, the differential signaling does not need as many grounds as single-ended, but having the extra grounds between each pair might be good for isolation. I'm not sure if you can find that sort of thing for a 30-conductor 2mm pitch header though, the resulting ribbon pitch would be 0.5mm. My thought instead is to split each pair of the cable after it leaves the ICD connectors, so the bulk of the cable is 15 individual pairs. That should cut down on crosstalk. Haven't tried it though.

udif wrote:Wait - will a 1:1 connector even work, or do I need to cross Tx/Rx pairs?

The Porcupine is set up to do all the re-arrangement for you, so just connect the TX connector on one side to the RX connector on the other side, and v.v. and you're all set.

This is what it looks like:
DSC02815s.JPG
Parallella + Porcupine w/eLink cables.
DSC02815s.JPG (250.07 KiB) Viewed 17406 times


DSC02815s.JPG
Parallella + Porcupine w/eLink cables.
DSC02815s.JPG (250.07 KiB) Viewed 17406 times


-Fred
Attachments
DSC02816s.JPG
Same thing from the Porcupine side.
DSC02816s.JPG (266.96 KiB) Viewed 17406 times
-- Fred -- Hardware Guy --
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Re: Free Parallella Porcupine breakout boards!!

Postby udif » Tue Jan 20, 2015 10:07 am

Great! But now they are out of stock :-(
When can we expect them to be available again?
Can we trust the Digikey date (~8 weeks from now)?
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Re: Free Parallella Porcupine breakout boards!!

Postby djhuft » Tue Feb 03, 2015 4:40 am

I'm interested too. I'd really like to put one of these to use in a robotics project.
Just having a PCB like that for throwing some prototypes together would be extremely handy.

I see that the end of March is Digikey's backorder estimate. If that's right, I'll wait for it. Otherwise, I might spin my own.
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Re: Free Parallella Porcupine breakout boards!!

Postby kriegalex » Fri May 22, 2015 12:38 pm

Hi,

I just saw those pictures of two boards interconnected and that's one of the things I wanted to do with the two boards I have here in my school. We just have the boards, so in order to make a mini-cluster, we would have to buy 2 Porcupines daughter cards right ? After that, I'm not sure where to go, I guess we have to be able to build a short IDE cable by ourselves.

I also am not sure how to adapt one of the example to run on two boards. From what I understood, the two cards would be seen as a single 32-core system just by using NORTH and SOUTH connectors. But then, how to configure a program, let's say matmul_optimized :

Code: Select all
#define _Nhchips 1 --> 2 ?
#define _Nside    4 --> 4
#define _Ncores  (_Nside * _Nside) --> (2*_Nside*_Nside) ?


Is all this right ? Nothing more than building a cable and interconnecting the two boards and changing some consts ?

Best regards
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Re: Free Parallella Porcupine breakout boards!!

Postby 9600 » Fri May 22, 2015 2:16 pm

kriegalex wrote:I just saw those pictures of two boards interconnected and that's one of the things I wanted to do with the two boards I have here in my school. We just have the boards, so in order to make a mini-cluster, we would have to buy 2 Porcupines daughter cards right ? After that, I'm not sure where to go, I guess we have to be able to build a short IDE cable by ourselves.


Yes, but note that it's not IDE cables that you would need. What is required is 2x15 (30-pin) cables with 2.0mm pitch (not the more common 2.54mm pitch) connectors. See the Porcupine documentation in the parallella-hw repo for the Molex part number.

Regards,

Andrew
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Re: Free Parallella Porcupine breakout boards!!

Postby Amiejay » Thu Jun 04, 2015 2:58 am

Hi all...

Are these boards ever to be produced commercially again?

My AI project is coming along amazingly well, and I'm approaching the point where some form of distributed processing might be useful. I'd love to directly interface two 7020 boards using Porcupines. Directly interfacing four 7010 boards might be an option as well, assuming I can find four Porcupine boards.

Failing that, I might need to explore some kind of Ethernet-based distribution.

I have two of the Zebax-produced breakout boards, but I'm concerned about the amount of noise in that type of connection.

If the Porcupines will be produced commercially again, any idea when?

Thanks...
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Re: Free Parallella Porcupine breakout boards!!

Postby aolofsson » Thu Jun 04, 2015 10:02 am

1 batch of 1,000 now being built up. PCBs just arrived, assembly starting this week.
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