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Programming Upgrades Hardware Technology

Raspberry Pi Compute Module Release 51

First time accepted submitter ControlsGeek (156589) writes "The Raspberry Pi Foundation has developed a new product. It is basically a Raspberry Pi model A processor, memory, and flash memory on a DDR2-style SODIMM connector. Also available will be a development board that breaks out all the internal connections. The board design will be open sourced so you can develop your own devices using the BCM2835 processor. No network, but support for 2 HDMI displays and 2 cameras, so 3D TV is a possibility.
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Raspberry Pi Compute Module Release

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  • by Radium_ ( 150865 ) on Monday April 07, 2014 @01:40PM (#46685709)

    As discussed on the Raspberry forum, there is some integrated memory, but no USB or Ethernet are present.
    Liz from the RPI foundation writes that "there’s much more IO, so you can add your own . The idea here is that it’s the barest minimum, so folks working on industrial applications can add the ports and extra connectivity they need."

    • by Anonymous Coward
      Sounds like a good fit for ATM machines.
    • The idea here is that itâ(TM)s the barest minimum, so folks working on industrial applications can add the ports and extra connectivity they need.

      I thought the purpose of the Raspberry Pi foundation was for education, not to produce embedded hardware for industrial control developers. Yes, the latter was a side effect of the former, but this new board is hardly an educational tool anymore.

      • Re: (Score:1, Interesting)

        by Anonymous Coward

        Why not both? I could see students using this to control a robot. Use only the requires pins and connect it directly without the IO board and its a much better solution than then original RPi. Less power since you won't need USB/ethernet if you're just tapping the GPIO pins.

        Seems like there's lot of potential.

      • TFA:

        The Raspberry Pi Foundation is a charity, and as with everything we make here, all profits are pushed straight back into educating kids in computing.

        ...so it's a little less direct, but no great loss.

  • Well, I love this, but can we PLEASE get more RAM or at least the ability to add some more in somehow? The Pi is limited to 512Meg and so is this new format.

    • by psergiu ( 67614 ) on Monday April 07, 2014 @03:02PM (#46686585)

      The BMC chip can access 1GB of RAM, but unfortunatelly 512MB is the largest size currently produced in that form-factor (Chip-on-Chip BGA DDR1).
      And the Raspberry Pi Foundations does not buy RAM chips in enough volume to justify to any vendor a custom made memory chip at that price.
      So we're stuck with 512MB ... unless this new SODIMM form-factor is so succesful that they have enough volume to get that custom 1GB chip made for them at the same price as the current 512MB one.

      • Ummm.. So provide a chip and mount one on the board? Surely BMC has a part in mind for this. Or are you saying NOBODY makes a way to connect the BMC part to 1 GB of RAM?
        • Currently, the RAM is actually on top of the CPU/GPU in a Package-on-package arrangement. It's the way that the SoC is designed and provided by Broadcom. The only way to provide 1GB of RAM seems to be to redesign the whole board and separate the RAM from the CPU (trading off speed for capacity).
        • by Agripa ( 139780 )

          Ummm.. So provide a chip and mount one on the board? Surely BMC has a part in mind for this. Or are you saying NOBODY makes a way to connect the BMC part to 1 GB of RAM?

          As far as I can tell from the sparse documentation available, the BCM2835 lacks an external memory bus so a different processor with a different package and/or pinout would be necessary. This makes sense for a chip intended for embedded controller applications.

          I have no idea if Broadcom makes a suitable alternative. Their web site reads li

  • by nbritton ( 823086 ) on Monday April 07, 2014 @01:48PM (#46685793)

    How much compute power do these guys have, would it be worthwhile to produce a backplane to run several of them in parallel? What about for redundancy in mission critical applications?

    • by bobbied ( 2522392 ) on Monday April 07, 2014 @01:55PM (#46685879)

      How much compute power do these guys have, would it be worthwhile to produce a backplane to run several of them in parallel? What about for redundancy in mission critical applications?

      They have an IO board that can run ONE of these, but you don't just toss multiple processors on the same bus to get redundancy. The CPU and inter-processor communication setup is going to be an issue you'd have to work out, not to mention the OS support for redundancy or Mufti-Processor operation. Neither the hardware or software problems are always straight forward...

      Good luck and let me know when you get it working. I'd love to have one or two.

      • One of the previous times that Raspberry Pis came up in conversation around here I heard of a guy who set up a Hadoop cluster running on a number of Pis.
        It's possible, and educational, but the throughput is simply not significant to justify.

        Sure, they're cheap. But putting a bunch next to each other won't give you all the processing power you've ever dreamed of.

        • Hadoop on a Pi? LOL Yea, that was destine to be a performance nightmare.

          If you can go to DIRECT inter-processor communications and bypass all the load sucking USB 2.0 Ethernet connection business, not to mention having to go though the SAME USB connection for your storage, Hadoop might actually be able to do something for you on a pile of Pis. As it is, all that USB interrupt servicing is going to be a real bottleneck. Not that I'd suggest Hadoop on the Pi to start with....

    • by ArhcAngel ( 247594 ) on Monday April 07, 2014 @02:07PM (#46686021)
      You meant to say "Imagine a Beowulf cluster of these" didn't you?
      • by LWATCDR ( 28044 )

        Funny that you should say that. I am pretty sure that meme started off when the uCSimm story was posted on slashdot a long time ago.

      • by stor ( 146442 )

        You don't need to simply imagine it:

        http://hackaday.com/2013/05/21... [hackaday.com]

        Complete with blinkenflashen!

      • by E241R ( 3613421 )

        You meant to say "Imagine a Beowulf cluster of these" didn't you?

        Beowolf - I've heard of that. I think that the poem, Beowolf, has an old vernacular. The computing concept, however - with the term, "cluster," appended - there is a Wikipedia page.[1] As far as clustering with RPi, there's the proof of concept work at the U. Southampton[2].

        Personally, I would inquire "MPICH or OpenMPI?" There is some proof of concept work towards the latter on RPi[3]. I'm not sure if it would be of a lot of use outside of C programs, but maybe.

        Of course, there would be the question, "W

    • The top speed of Videocore IV programmable units is supposed to be 24 GFLOPS, but of course that's with all the execution units running FMACs all the time or something like that. Anything actually useful will be limited by memory bandwidth. The ARM core is dual-issue, so expect something like...what, 1000-1200 MIPS at 700 MHz in real world? I'm not sure what the FPU is capable of, but the SoC is really, really old.
      • by psergiu ( 67614 )

        It depends.

        How about a 1U rack-mounted box, with redundant PSUs, hosting around a hundred of Pi SODIMMs, with a USB-Ethernet chip for each slot, every X (7..24) ethernet lines connected to a switch chip with a gigabit uplink on the back of the enclosure.

        Current RPi USB-Ethernet is slow because of the USB-HUB-and-Ethernet chip used. You won't have a USB hub in this configuration, and you can use a better USB-ETH chip.

        Also you don't need a single, huge, expensive PCB. You can have multiple small PCBs side by

        • For pretty much every single problem set that exists, you would be better off with a typical 1U Xeon server with a good chunk of memory. For redundancy, you add a second 1U Xeon server.
    • No, it would not be worthwhile, unless you were using them mostly for their GPUs. The RPi CPU is not super-slow, but it's not really competitive. And you'd need to come up with all the glue logic.

  • How does this help the children? That's what RPi is all about, right?

    • The Raspberry Pi Foundation is a charity, and as with everything we make here, all profits are pushed straight back into educating kids in computing.

    • How does this help the children?

      1. By generating money to support educational programs.
      2. By getting more people involved in improving the RP ecosystem.

    • How does this help the children? That's what RPi is all about, right?

      It won't! And I'll tell you something, it's not just them... other charities like NSPCC and Save the Children, they run these 'shops' where they sell stuff that isn't for children either! Ridiculous!

  • Must... go.... get... more... christmas.... lights... NOW!!! :)
  • Mostly pointless (Score:4, Informative)

    by wiredlogic ( 135348 ) on Monday April 07, 2014 @02:33PM (#46686293)

    The Compute Module is primarily designed for those who are going to create their own PCB. However, we are also launching something called the Compute Module IO Board to help designers get started.

    Anyone going through the process of developing a board can get a simpler and less constrained solution by slapping down the three ICs directly and not have to deal with the cost and headaches of integrating a separate module.

    • Re:Mostly pointless (Score:5, Informative)

      by Lemming Mark ( 849014 ) on Monday April 07, 2014 @03:07PM (#46686619) Homepage

      I do remember a talk where Eben Upton said that the routing was relatively complex under the main chip. Pinning it out onto an edge connector presumably gives you the luxury of building a much simpler board to plug it into - design-wise and possibly cost-wise since you might get away with fewer layers.

      Seems like small-to-mid volume manufacturers might find it handy, even though high volume manufacturers would presumably just plonk the chips directly on.

      Not that I'm an electronic engineer, so obviously take this with a pinch of salt.

      • That's about right. If you're making a small (and by small I mean 50k unit) run it's likely to be worth buying a system on module rather than paying someone to do the fiddly HDI PCB design, finding someone who can assemble PoP reliably and buying your application processor, RAM and Flash out of distribution at high margin.

        • Re: (Score:2, Insightful)

          by Anonymous Coward

          1. SoC design work mostly done for you - you'll still need to add your own peripherals on your own board.
          2. Fully working Linux with accelerated graphics/video comes as standard
          3. It's the only way to buy the Bcm2835 in small quantities.
          4. Prototype on the very cheap Raspberry Pi.

          It's $30 in batches of 100. I'd say that's a bargain for this sort of thing and should save lower quantity embedded firms a load of money in dev time.

      • by labnet ( 457441 )

        You are one the money. Our company has done exactly this. An imx.287 with ram, rom, eth. Laid out on sodimm module. I did the layout and it took me 8 layers and plated in hole vias to do it. The hardest part of these designs is the impedance and length matching between cpu and dram.
        The advantage of this design is being able to fit it too a 2 layer board, and upgrade cpu without having to change the baseboard.

    • Have you ever tried to fanout a high density Ball Grid Array part on a two layer circuit board? There are certain form factor chips which are cost prohibitive without some kind of adapting device. This is exactly such a device which comes pre-assembled in a way that allows you to expand on it with nothing more than a soldering iron, something you can't do if you work with BGA parts normally especially if you have to stack multiple BGA parts such as the memory module.

      It allows someone to tinker with the co

  • No, there is only one HDMI.
    There are two DSI and two CSI-2 ports routed, but DSI is not supported at all, and only one CSI-2 has any support (in closed source blob you cant modify).

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