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Altered Hub & a Crossbar ? — Parallax Forums

Altered Hub & a Crossbar ?

DDgDDg Posts: 2
edited 2014-05-29 02:31 in General Discussion
Hi,
As a newbie to the Propeller, I have a couple of absurd questions:

1> Is there any way at all, that the Hub can be programmed Not to Round Robin ?

(Assuming my application can handle the consequences...)

Could I (for instance) Randomize the Hub? (selection of the Cogs)

2> Perhaps just a little less absurd... Any precedent with multiple Propellers on either side of a crossbar?

I'm hoping someone out there who might have used the Transputer and the C004 switch decades ago might sympathize.

Thanks!

Comments

  • Duane DegnDuane Degn Posts: 10,588
    edited 2014-05-26 11:01
    There are people around who used the Transputer. I think Leon did a lot of work with it.

    To answer your first question, no, there is not a way to change the round robin hub access. It's hard wired into the chip.

    I don't understand your question about "either side of the crossbar". There are many multiple Propeller projects. Clock Loop had 55 Propeller setup which he could program all at once.

    I'm sure I could find links if you're interested in some of the multi-Propeller projects (I'm sure several are listed in my index (see signature)).

    Welcome to the forum.
  • LeonLeon Posts: 7,620
    edited 2014-05-26 12:36
    Yes. I designed a transputer module with 1 Mbyte of DRAM and a motherboard that could hold up to 16 of them, with two C004 switch chips controlled by a Z8 MCU with an RS-232 I/F to a host system. It was rather expensive but I sold a lot of them.
  • DDgDDg Posts: 2
    edited 2014-05-28 19:27
    Oh, this is plesantly unexpected. I was afraid I might have become a Rip Van Winkle!

    Duane, Leon glad to have found you right away,
    Now the reason behind those questions... (if you'll allow some leeway with the terminology...)
    From the time of the T800, I'v been contemplating the possibility of a neural(!) architecture, not so much at the individual neuron level but at the level of functional neuclei. If one were to consider them to be a massively parallel bunch of coprocessors. Each one of them is doing their own thing at the 'subconscious' level until the 'executive' directs conscious attention to it.
    I suppose now you might begin to appreciate my question about a 'Non Round Robin' Hub.

    Since the Prop does not support interrupts but offers the immensly useful counters and a bunch of I/Os it would be great if the Hub could be governed by certain external or internal parameters to transfer control to a specific Cog. Any suggestions?

    I understand that Prop2 is on the drawing board and CG is discussing potential new designs of the Hub with experts on this forum. Would a 'Non Round Robin' Hub merit CG's attention? While I don’t expect it to be a trivial modification, If its possible at all, such a system might open up some very interesting possibilities indeed.

    If selecting Cogs through an alternative system is not going to be possible at all, then one is left with (a much more expensive and complex) alternative of implementing such a system across multiple propellers with a C004 like crossbar selecting a specific prop based on some algo/criteria.
    Leon, What would be the equivalent of a C004 to use with propellers? I'd really appreciate your thoughts on the above.
  • LeonLeon Posts: 7,620
    edited 2014-05-29 02:31
    A 'C004' for the Propeller? I don't think it is feasible, because the Propeller doesn't have anything like the transputer link hardware.
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