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Unique Propeller Functional Abilities? - Page 2 — Parallax Forums

Unique Propeller Functional Abilities?

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Comments

  • LeonLeon Posts: 7,620
    edited 2011-05-18 07:42
    He should have just looked at the XMOS web site, it's all explained very clearly there! :)
  • davidsaundersdavidsaunders Posts: 1,559
    edited 2011-05-18 07:44
    I am out of this discussion. Leon: Enjoy your argument in support of your preferred MCU that you always tell us can do anything better than the Prop. Different MCUs have different strengths PERIOD. And thus said I say GOOD BY to this thread (it seems clear to me where it is headed).
  • LeonLeon Posts: 7,620
    edited 2011-05-18 07:45
    You should have checked your facts before making unjustifiable claims! I actually like and use both devices, as well as many others. It all depends on the application.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2011-05-18 07:47
    Another unique Prop feature: a nearly-VLIW instruction set, somewhat akin to microcode, including programmed flag setting and conditional execution for each instruction.

    -Phil
  • LeonLeon Posts: 7,620
    edited 2011-05-18 07:54
    Sorry, but that isn't unique. The XMOS instruction set has instruction prefixes which do some clever stuff:
    Instruction prefixes are used to extend the range of immediate operands and to provide more inter-register operations (and inter-register operations with more operands).

    The Inmos transputer instruction set included up to two prefixes.
  • ericballericball Posts: 774
    edited 2011-05-18 08:08
    I think Leon has shown that some, maybe all, of the features which might be considered "unique" to the Propeller exists, or are achievable, by other hardware. However, this doesn't take anything away from the Propeller or the other hardware, nor those who may not be aware of the other hardware. It's a big world and it's impossible to know everything. Quite frankly, I doubt if any features ever remain unique for long.

    The question really is - does (or can) the Propeller meet the requirements I have? These requirements may be certain features, might be a price point or even form factor. A requirement may even be simple knowledge of existence or comfort level.

    What we, as Propeller enthusiasts, can do is to highlight the features of the Propeller which we have found to be advantageous in our projects and help others discover how to accomplish their requirements using the Propeller (or even advise them when another solution may be more appropriate).
  • AleAle Posts: 2,363
    edited 2011-05-18 08:08
    The most unique feature I find is the DIP40 package. So much power in an easy-to-use package. Just one power supply, a crystal and a PC... nothing fancy.

    Leon: We know the XMOS is great but it comes in a package that is not protoboard-friendly, needs 2 power supplies, power sequencing, and so on. Yes, it is great, quite flexible but once it is up and running... The propeller is somewhat less powerful but the easier setup and DIP40 win for us (and I designed a board with that hard (for me) to solder package...) :(
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-05-18 08:14
    One unique feature of the prop is that Leon will nearly always provide these forums a comparison to the X chip. I know of no other processor that has this feature.
  • ericballericball Posts: 774
    edited 2011-05-18 08:15
    Leon wrote: »
    You should have checked your facts before making unjustifiable claims! I actually like and use both devices, as well as many others. It all depends on the application.

    Not have the opportunity to play around with the XMOS, I can't judge it's merits & limitations versus the Propeller. But perhaps you can provide some insight into reasons you have used the Propeller (versus the XMOS or other hardware).
  • LeonLeon Posts: 7,620
    edited 2011-05-18 08:19
    We were using it for a complex data logger application for refrigerated containers, for which it was an ideal platform and enabled us to offer a one-chip solution at a price that couldn't be achieved with any other solution. The on-chip VGA was especially useful, as we could provide a display in the vehicle cab. We were using most of the cogs, and had a very neat, small, PCB design. Unfortunately, the customer decided to pull out of the project, and my client lost a lot of money. I got paid, anyway. :)
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-05-18 08:20
    ericball wrote: »
    I think Leon has shown that some, maybe all, of the features which might be considered "unique" to the Propeller exists, or are achievable, by other hardware.

    In that case, would the only aspect of the propeller that can be considered "unique" be the "PARALLAX P8X32-A" printed on it? I don't think this is the orignal poster's intent; rather what sets it a part from "traditional" controller like AVR and PIC's. I was hoping this thread would address that subject, but that's just me.
  • Dave HeinDave Hein Posts: 6,347
    edited 2011-05-18 08:22
    Heater. wrote: »
    That was naughty:)
    By asking Leon a leading question I may have appeared to switch to the dark side. However, I think Leon is good at keeping us honest. So other processors can implement drivers and co-processors in parallel hardware and simulated parallel hardware. I think the Prop is unique in how it does it because it can provide deterministic timing. I also think the software approach make it easier for novices to work with the Prop. I believe the other processors that Leon has mentioned have a steeper learning curve.
  • LeonLeon Posts: 7,620
    edited 2011-05-18 08:27
    They might be a bit harder to use by hobbyists, but they are capable of much more advanced applications.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2011-05-18 08:30
    It's one thing to pick a single Propeller feature and find another chip that includes it. For every such feature there probably is (or was) a processor somewhere that had it. But so what? It's a far different proposition to consider the collection of these rare-but-maybe-not-unique Propeller features taken as a whole and to try finding another processor that combines them in such a symbiotic fashion. The whole, in this case, is greater than the sum of its parts. By deconstructing the Prop feature-by-feature, in the manner of blind men examining an elephant, we risk losing sight of that fact.

    -Phil
  • ericballericball Posts: 774
    edited 2011-05-18 08:36
    Leon wrote: »
    We were using it for a complex data logger application for refrigerated containers, for which it was an ideal platform and enabled us to offer a one-chip solution at a price that couldn't be achieved with any other solution. The on-chip VGA was especially useful, as we could provide a display in the vehicle cab. We were using most of the cogs.

    Thanks for the response, and I think you've proven my point. You used the Propeller because it met your requirements:
    1. One chip solution (well, I expect you had a few other components :-) )
    2. Low price point (I assume for both the Prop and the solution as a whole)
    3. VGA output capabilities
    4. Complex data logging (presumably significant I/O and other processing)

    Could other hardware have met those requirements? Perhaps, perhaps not.
  • LeonLeon Posts: 7,620
    edited 2011-05-18 08:40
    Not at that price, or on such a small board! That was why the Propeller was chosen. I've never seen another application that was as well suited to it, than that one!

    OTOH, I've been involved with a medical instrument design for which we used an LPC2148 ARM7 device. The Propeller would have been quite unsuitable for that, as we needed lots of analogue and digital inputs - far more than are available on the Propeller. There would have been too much code, as well, which had to be written in C.
  • potatoheadpotatohead Posts: 10,261
    edited 2011-05-18 08:47
    Seconded on Leon keeping us honest. I've no worries on the thread progress so far.
  • davidsaundersdavidsaunders Posts: 1,559
    edited 2011-05-18 09:17
    Firstly let me apologise to Loen; I meant nothing against other MCUs, I was just attempting to keep this thread on track.

    Now I think that we would be hard pressed to find any single feature that is 100% unique to the Prop (other than perhaps its counters). Now taken together it seems that we have something to use for Jazzeds stated purpose:
    1) A multi core highly deterministic architecture with out interrupts.
    2) An instruction set that is very well thought and designed (arguably making Prop Assembly as simple as C).
    3) Very versatile counters, and separate counters per COG, with a separate PLL per COG.
    4) The ability to easily access any Pins from any COG at any time in a very simple manner.
    5) Relatively low cost. Both the Prop, and the application of peripherals are relatively inexpensive, especially as you can implement a huge number of peripherals in software with a minimum of passive components.

    Am I missing anything?
  • jazzedjazzed Posts: 11,803
    edited 2011-05-18 09:24
    ...
    Now I think that we would be hard pressed to find any single feature that is 100% unique to the Prop (other than perhaps its counters). Now taken together it seems that we have something to use for Jazzeds stated purpose:
    1) A multi core highly deterministic architecture with out interrupts.
    2) An instruction set that is very well thought and designed (arguably making Prop Assembly as simple as C).
    3) Very versatile counters, and separate counters per COG, with a separate PLL per COG.
    4) The ability to easily access any Pins from any COG at any time in a very simple manner.
    5) Relatively low cost. Both the Prop, and the application of peripherals are relatively inexpensive, especially as you can implement a huge number of peripherals in software with a minimum of passive components.

    Am I missing anything?

    Nice. I've updated the top post and may add a variation of this as a summary.
  • LeonLeon Posts: 7,620
    edited 2011-05-18 09:24
    Video hardware on each cog?
  • BatangBatang Posts: 234
    edited 2011-05-18 09:33
    I think it's most unique feature is to elicit near religious fervour from it's devotees in response to the mention of X chips:)
  • LeonLeon Posts: 7,620
    edited 2011-05-18 09:37
    There does seem to be a remarkable number of fanboys on this forum. :) The only other one I know of which has members who are equally devoted to one manufacturer is the AVR Freaks forum, and even they have started to admit that the ARM is better than their beloved AVR in many ways. They still jump up and down at any suggestion that a PIC might be better than an AVR in a given application, though.
  • AleAle Posts: 2,363
    edited 2011-05-18 09:57
    The package, the package. The OBEX, the forum :)
  • davidsaundersdavidsaunders Posts: 1,559
    edited 2011-05-18 10:16
    Yes, for a thirty two bit Chip the DIP40 is a definite plus. While you can always find something "better" in some way, the Prop is one of the best rounded MCUs I have yet dealt with. And the Prop II will take this to a whole new level. I just hope that we do not end up with quite as many debates of Propeller II vs. ????, as we have with the Propeller I (I guess a couple very occasional debates are needed to keep us in check).
  • Invent-O-DocInvent-O-Doc Posts: 768
    edited 2011-05-18 10:55
    I'll second the lack of interrupts. That is a valuable feature!

    The prop doesn't have to be the best chip in the world. The best MCU argument sounds to me like a group of kids comparing themselves in the locker room. If you look around enough, eventually you will see someone bigger and stronger. The comparative effort produces no benefit and is kind of creepy!

    The propeller represents a unique approach to MCUs that allows for suprising ease and capability for some applications. Isn't that wonderful.
  • Sal AmmoniacSal Ammoniac Posts: 213
    edited 2011-05-18 12:25
    I'll second the lack of interrupts. That is a valuable feature!

    But not unique. In a sense, you can say that most MCUs have this feature--if you don't want to use interrupts, just turn them off.

    In my experience, fear of interrupts is inversely proportional to the experience of the programmer.
  • schillschill Posts: 741
    edited 2011-05-18 13:07
    In my experience, fear of interrupts is inversely proportional to the experience of the programmer.

    On the other hand, maybe only people with a lot of experience using interupts can understand how nice it is to not need them.
  • schillschill Posts: 741
    edited 2011-05-18 13:10
    Leon wrote: »
    There does seem to be a remarkable number of fanboys on this forum. :) The only other one I know of which has members who are equally devoted to one manufacturer is the AVR Freaks forum, and even they have started to admit that the ARM is better than their beloved AVR in many ways. They still jump up and down at any suggestion that a PIC might be better than an AVR in a given application, though.

    It's funny, but I don't think the number of fanboys on this forum is really all that large - not if you mean people who put down all other options. There are many fans here, but only a few who really like to claim the prop (or stamp for that matter) is better than everything else.

    AVRfreaks, on the other hand, can really get kind of scary. It's been a while since I frequented the forum but I always found the amount of noise and antagonism to be pretty high. It was also not particularly beginner friendly. Maybe it's changed since I stopped paying much attention to it.
  • Sal AmmoniacSal Ammoniac Posts: 213
    edited 2011-05-18 13:14
    schill wrote: »
    On the other hand, maybe only people with a lot of experience improperly using interupts can understand how nice it is to not need them.

    There, fixed that for ya. ;-)
  • davidsaundersdavidsaunders Posts: 1,559
    edited 2011-05-18 13:17
    Invent-O-Doc:
    I will definitely second that comparing MCUs is more a futile effort than productive.
    Unless of course you are comparing features related to a current project to determine which MCU is the best fit (we must try on our shoes before we leave the store).
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