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Re: GA144 article

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On Tuesday, July 31, 2012 12:33:22 AM UTC-4, Paul Rubin wrote:
> > If they took out half the cores to provide more complex routing, would
> > that make you happier?  Unfortunately this would also slow down the
> > comms as there would need to be more muxing, switching and who knows what.  
> 
> I asked Jeff Fox on this newsgroup about adding more comm channels to
> the cores and he seemed to think it would not have been a big deal in
> terms of chip area.  My idea was simply to add diagonal connections
> between the cores to go with the existing orthogonal ones, a fairly
> minor design tweak intended to make it easier to route signals around.

Maybe you should build your own chip then?  Maybe this is a minor design tweek, I don't think it would add much to the comms on the chip.  If you are going to improve the internode comms I would suggest a cube arrangement.  


...snip...

> > The time between the @ and the !b is about 1.5 ns. ..
> > go @ !b go ;
> 
> I don't think it's that fast, per the databook
>  http://www.greenarraychips.com/home/documents/greg/DB001-110412-F18A.pdf
> pages 9 and 12.  The @ and the !b and the jump are each 5.1 ns so
> that whole loop takes over 15 ns per word moved.  You might be able to
> get it to 12ns with unext instead of jump.  And I guess for some
> purposes you don't have to count the jump as part of the latency
> for the data, but 10ns is still pretty bad, especially if you have
> to incur it through several nodes.  

The F18A databook page 9, "5.1 nanoseconds when reading or writing internal memory".  These ops are not to or from "internal memory".  The simulator will tell how much time code takes I believe.  When I get to that point I'll give it a try. 

The loop time is not so important as is the latency.  The cycle time does not need to be any faster than a node can generate or process data so there is no real issue there.  The latency determines the delay in getting from one point in the chip to another and may be important, especially if you need to calibrate and/or match the delay.  In fact I have some concerns about syncing delays between separate paths for multiple ADC inputs. 


> > My current step is to figure out how to run with SDRAM and
> > why GA abandoned using SDRAM on their eval board.  There must have
> > been a reason because the GA144 has ROM code for SDRAM.
> 
> You could ask them...

Yes, but so far it has been a difficult process to get useful answers.  The answers only provoke more questions really.  So far they have said that the SDRAM interface was only tried on the S40 and was a failure because it was "too specific".  So why is this in the ROM code on the GA144?  Also, the GA144 data sheet says the ROM code is for "an external SDRAM using 18-bit data."  I can't find any 18 bit SDRAM chips these days.  I think they were using a 32 bit part and ignoring 14 bits.  Also, I just realized the part number they gave me was for a DDR part which requires a differential clock.  This is just a complication with no value in my opinion.  An SDRAM using a single wire clock will work just as well since it will be exceedingly hard to run these devices at 100 MHz, much less 166 or 200 MHz.  Also, the SDR device I am looking at is lower power than the DDR device they used. 

Rick

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GA144 article Mark Wills <markrobertwills@yahoo.co.uk> - 2012-07-18 03:48 -0700
  Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-19 10:51 -0700
    Re: GA144 article Mark Wills <markrobertwills@yahoo.co.uk> - 2012-07-20 01:30 -0700
      Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-20 01:48 -0700
        Re: GA144 article Mark Wills <markrobertwills@yahoo.co.uk> - 2012-07-20 03:25 -0700
        Re: GA144 article Syd Rumpo <usenet@neonica.co.uk> - 2012-07-20 11:59 +0100
      Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-22 18:59 -0700
        Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-22 19:16 -0700
          Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-22 19:31 -0700
            Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-22 20:08 -0700
              Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-23 16:24 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-23 22:33 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-24 14:04 -0700
            Re: GA144 article vandys@vsta.org - 2012-07-23 03:34 +0000
            Re: GA144 article Bernd Paysan <bernd.paysan@gmx.de> - 2012-07-23 14:11 +0200
              Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-23 16:47 -0700
              Re: GA144 article "Clyde W. Phillips Jr." <cwpjr02@gmail.com> - 2012-07-24 20:11 -0700
          Re: GA144 article Richard Owlett <rowlett@pcnetinc.com> - 2012-07-23 02:04 -0500
  Re: GA144 article Daniel Kalny <dkalny@seznam.cz> - 2012-07-24 02:37 -0700
    Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-24 03:12 -0700
      Re: GA144 article stephenXXX@mpeforth.com (Stephen Pelc) - 2012-07-24 10:36 +0000
        Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-24 10:28 -0700
          Re: GA144 article Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-07-24 22:12 +0000
      Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-24 14:49 -0700
        Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-26 13:25 -0700
          Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-27 13:17 -0700
            Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-27 14:31 -0700
              Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-27 22:02 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-28 23:03 -0700
                Re: GA144 article marko <marko@marko.marko> - 2012-07-30 09:12 +1000
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-31 01:09 -0700
                Re: GA144 article marko <marko@marko.marko> - 2012-08-01 00:19 +1000
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-31 09:59 -0700
                Re: GA144 article marko <marko@marko.marko> - 2012-08-01 10:13 +1000
                Re: GA144 article Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-01 00:59 +0200
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-31 16:54 -0700
                Re: GA144 article Luca Saiu <positron@gnu.org> - 2012-08-04 10:46 +0200
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-05 11:04 -0700
                Re: GA144 article Luca Saiu <positron@gnu.org> - 2012-08-06 02:02 +0200
                Re: GA144 article Mark Wills <markrobertwills@yahoo.co.uk> - 2012-08-06 02:16 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-30 08:23 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-30 21:33 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-31 01:51 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-31 11:48 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-07-31 14:54 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-07-31 16:09 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-01 12:57 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-01 14:16 -0700
                Re: GA144 article vandys@vsta.org - 2012-08-01 22:32 +0000
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-01 16:03 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-01 16:13 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-01 16:10 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-01 22:18 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-02 11:47 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-02 14:32 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-02 16:01 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-02 16:38 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-03 08:40 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-03 09:19 -0700
                Re: GA144 article rickman <gnuarm@gmail.com> - 2012-08-03 11:15 -0700
                Re: GA144 article Paul Rubin <no.email@nospam.invalid> - 2012-08-05 15:50 -0700
                Re: GA144 article Mark Wills <markrobertwills@yahoo.co.uk> - 2012-08-06 02:21 -0700

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