Interesting "Competitors" for the Raspberry Pi

The parallela sounds and looks cool but we are talking about a major project that includes sillicon rebake and that probably is 6-12months away from mass production.

Meanwhile while there are other developments that are not exactly comparable to the R-Pi, they are slowly but steady making progress, like the OLinuXino boards from Olimex. I'm testing both the micro and maxi using the Freescale iMX233 application processor SoC (fully documented by the way,) waiting for the A13 one and they also have under development one using the A10. The iMX233 Maxi uses also the LAN9512 and I didn't find any issues with it yet (and BTW the connectors are properly aligned and it has a nice swtiching power supply, the board is slightly bigger than the R-pi, no HDMI/VGA tough.)

I also recently got a TI AM335x Starter Kit, you will start to see more stuff based on the AM335x and TI will get more agressive to dettach the OMAP from some applications and put it on boards similar to the R-Pi.

Still the R-pi continues to be a good idea, unfortunatelly with an associated plan badly executed and with more focus on hype and promotion than really make it a strong and solid "product" with the participation of a community that is eager and able to contribute.

No schematics, no Gerbers, major concern is "cloning" .... I'd not clone something that is not working properly ...

-J

At least it looks like Olimex is taking the problems from people using their boards seriously.

Their Forum is an example of what a forum should be like.

The supply dip when you connect an usb device is a known fact. It might be hard to notice it on a scope, unless you have a good memory scope and are able to trigger it properly. The issue happens more frequently on the newer boards with the usb polyfuses removed. If you look at the Pi schematics, there aren't much buffer capacitors on the 5V supply rail. (just 1 small capacitor). I guess we get what we payed for.

It looks like a lot of the Pi usb issues are caused by timing.

As linux isn't a real time OS, and as stated before that the cpu can become heavy loaded, I doubt they will ever be able to fully fix the issue.

Besides the usb, there are other dissapointing things. One mentionned already is the fact that X11 isn't hardware accelerated.

Another one is the poor quality of the analog audio output. A third one is the fact that you need to properly shutdown the system to avoid sd card corruption. This makes it difficult to use the Pi as an embedded solution. A fourth one is the critical power requirement of the board.

Some of those can be resolved, but all solutions make your cheap solution (not so cheap) anymore.

I know it's a little off topic, but these points are worth checking when seeking for "Competitors" and might rectify a higher price.

George: We can hope that "the market" fixes it! Maybe a smart manufacturer will come up with a hardware / software package (a bit of a long shot, but at least potential manufacturers now have a blueprint of how not to bring a low cost board to market!). We can also try to apply continual gentle pressure to the Foundation to provide proper fixes (rather than handing them workarounds that just buy them time) and let people out in the wider world know what's really going on. It's not much, but it's all I've got just now! *

I don't think that the BCM2835 is a terrible chip per se (notwithstanding the ongoing USB fun) - if the GPU were better utilised then it would free up some CPU time. It is a shame that it's older architecture, but an ounce of tight software integration is worth a pound of overclocking, as my mum might have said.

* Edit: If at some point in the future it appears that the Foundation have pulled up the drawbridge on development in a particular direction then it will doubtless spur the community into an independent fix. That's great IMO - I'm not suggesting that people abandon Pi development work, or to stop writing applications for it, or to stop providing help for other users. I just feel that providing basic functionality  is the responsibility of the Foundation. They are best equipped to do it and it's what they are there for. Let them show what level of support they can provide.

There, I didn't want anyone thinking that I was being even more grumpy than usual.:)

Assume the goal is really education.

To get a computer class up and running, you will indeed need a lot more than just a bunch of cheap Pi computers.

The biggest cost seems to be the screens.

I would expect a low budget computer class setup to use second hand screens, but those don't have a hdmi or dvi connection.

So the problem is they just learn how to use word and how to create websites...

The closed nature of the Pi isn't very helpfull either to learn what is going on under the hood.

The non hardware accelerated x makes it feel sluggish.

In my opinion, if price is what matters, a good classroom setup could be some thin clients or old pc's used as thin client, connected to a decent computer used as terminal server.

In times of windows nt4, M$ already had a version for an arm desktop platform. They are creating a version of windows 8 for arm as well.

So, it looks like arm will find it's way into desktop computing.

The reason we find it in so many consumer products is due to it's low power specification that makes it the best choice for battery operated equipment.

The fact you need to properly shutdown the Pi to avoid sd card corruption is indeed something you have with all os.

My point is that nothing is provided in case of the Pi to do this properly, specially not when you intend to use your Pi as an embedded board. The competitors and most commercial products using linux have an on board flash chip used to store the os "read only".

Some of the Olimex boards have a connector for a battery that can gracefully shutdown the system in case of a power failure.

And don't we all connect our servers to an UPS so that they can proper shutdown in case of a power failure?

Besides that, the Pi seems to corrupt it's sd card more frequently than a desktop linux corrupts it's harddisk.

Some say it's due to the nature of sd cards making them a bad choiche for such applications.

All I can say is that it is an existing issue you should consider when you start using the Pi.

Jamodio:  We are not worthy!!!  /me bows in admiration.

John, perhaps the answer is to go non-commercial.  A modular open hardware board could be layed out to enthusiast-level specifications, avoiding the problems of soldering BGA packages by accepting a SoC on a header instead of the BGA device directly.  Separately, we could commission a tiny BGA SoC on a corresponding breakout header to be manufactured for us after a suitable SoC is chosen by community consensus.

It's certainly doable if the open hardware community wanted to do it.  The cost of the unpopulated boards would be minimal, far undercutting Raspberry Pi.  Admittedly it's not a fair comparison, but unpopulated boards are not a disincentive to most electronics enthusiasts, and I'm sure that companies would spring up selling kits of parts as well as fully assembled boards for profit.

PS.  We could even ask competing SoC manufacturers to develop their own SoC-on-a-breakout-header for us.  Very little effort and cost for them, and potentially good PR since it constitutes a form of marketing targetted at engineers and enthusiasts, just like normal prototyping boards but even cheaper.

Morgaine.

The competitors and most commercial products using linux have an on board flash chip used to store the os "read only".

Well you can also treat the sdcard as "read only" and use something like jffs2 instead of ext4, but it does take somewhat more effort to build a useable system with a read-only root filesystem. The obvious problem here is that the current OS images for the Pi want to think it's a 'normal' desktop PC, fill it with essentially irrelevant crap that doesn't need to be running etc.  Frankly I'm surprised it works as well as it does given the choices you make for spinning rust can be so very wrong for sdcard.

@Morgaine Well I'm in a unique position to do start such a project, on the funding, design, and manufacturing. I've waited for years now to find a good solution in the market and I had hoped that the RPi would hit most of the requirements but it just didn't happen. I don't think it's reasonable to find a solution that isn't BGA, besides, how many people really are doing any soldering on parts with pin counts more than ~50, and why would they need to?

Personally I like the OMAP line of parts but all the boards are higher cost than what I want and the BeagleBone doesn't do 1080P and if I was to do anything it doesn't make sense not to support 1080P. Is TI/distribution pricing their boards like standard retail markets so the real cost is sub $50? The last time I spoke with TI the OMAP was still only sold to major OEMs but with recent announcements that might not be the case.

 

Regarding the long-running discussion on Broadcom's closed tech - I don't buy into this at all. Any serious customer will (in return for signing a few non- disclosures) have access to extended technical specs and will hopefully have the brains to do something useful with it.

I tend to agree, and I'm pragmatic enough to realise that the closed nature isn't necessarily a problem. Taken to it's logical conclusion the 'everything must be open' argument means you need the SMT placement machine to be completely OSS along with the CAD programs, design tools, semiconductor manufacturing plant, and eventually the ideas in the designers head. It may be an interesting goal,  but likely an unrealistic one for as long as there's money involved.

Keep in mind though that with the volumes the RPF are building it's unlikely that Broadcom would even have entertained talking to them if the ideas hadn't originated with Broadcom employees.  That sort of problem alone means it'd be hard for you or me as individuals to do what the RPF did using a Broadcom device.

Your chosen software may not even have an ARM port. Obviously this is no barrier for the dedicated geek with access to source code, but it's a faff.

That's the one part that puzzles me. Given we are talking Linux and therefore largely open source stuff, most things will just work and you can train almost anyone to type './configure ; make ; make install' you hardly need to understand what it does or how it works.

But simplistically, if we assume it's still about education then where's the downside to some learning about what the commands mean and do ?

If we assume that the Pi is a consumer toy, then I agree it's different, but in that case it should be an 'iPi' with a fancy touch screen etc..

but as ARM is so splintered I really don't see the situation changing any time soon for consumers who want an ARM P.C. for general duties and want it to work out of the box without having to constantly *** around in terminal.

 

Maybe one day it will be as easy as x86 and I'll wonder what all the fuss was about.

It will change, and probably sooner than you think. Mostly driven by something called Windows 8 which will drive crap like ACPI into the Arm arena and force some degree of standardisation.

x86 isn't really all that easy, possibly actually much worse. The difference being that it's better understood. To quote something you said earlier "if something is clearly broken and fixes are not forthcoming then don't keep it on life support - just toss it out and make room for something better" but that's exactly the opposite of what x86 has done - it's still carrying most if not all of the mistakes of the past 30 odd years all in the name of compatibility and standardisation.

Take for example my shiny new i7 laptop that still has this:

00:1f.0 ISA bridge: Intel Corporation QM67 Express Chipset Family

'ISA' being a throwback to the very early days of the PC - the physical slot has gone, but the logical part of the architecture remains.

how many people really are doing any soldering on parts with pin counts more than ~50, and why would they need to?

Well I certainly do.  It's becoming less of a problem these days as lots of stuff is moving to being connected serially meaning that pin counts are coming down.

You're right though, until something can challenge the Pi in terms of cost with a roughly equivalent set of features it's kind of pointless. The $25/$35 is some sort of magic number that boards costing many times more really can't compete with, people aren't looking beyong the headline price - it doesn't matter if the more expensive one is somehow 'better'.

Separately, we could commission a tiny BGA SoC on a corresponding breakout header to be manufactured for us after a suitable SoC is chosen by community consensus.

Not exactly the same, but that's effectively what that Rhombus-tech EOMA thing is trying to do, and as far as I can tell we'll all be old and grey by the time it goes on sale.

It probably needs another RPF-alike group to actually go produce some and show the ODM's that there's volume/demand similar to the Pi behind it before it'll take off.  There's plenty of other candidate boards - beaglebone for one - that don't seem able to gain the momentum.

There are even places doing exactly what you describe - producing a module with all the bga stuff on it. One I found recently http://bluetechnix.at/rainbow2006/site/i_mx_family/__core_modules/i-mx31-/387/i-mx31-.aspx but go check out the prices and you see why they don't gain the momentum to challenge the Pi either.

My comment about the sodlering of parts was aimed more at the comments made earlier about "needing/wanting" a board that didn't have a BGA. I just don't see that as a requirement even for a hobbist board. Are any of the Arduino users even replacing the processor on those boards? Morgaine's comments about utilizing an add on module for the main CPU is what I'm seeing more and more of with a 200-pin SO-DIMM being rather common. The problem with what I've seen though is that those aren't cheap. Even the Variscite AM335x SO-DIMM board is priced at $39 which seems nice but then you need a baseboard and all the connectors which brings you right back the BeagleBone cost.

My comment about the sodlering of parts was aimed more at the comments made earlier about "needing/wanting" a board that didn't have a BGA. I just don't see that as a requirement even for a hobbist board. Are any of the Arduino users even replacing the processor on those boards? Morgaine's comments about utilizing an add on module for the main CPU is what I'm seeing more and more of with a 200-pin SO-DIMM being rather common. The problem with what I've seen though is that those aren't cheap. Even the Variscite AM335x SO-DIMM board is priced at $39 which seems nice but then you need a baseboard and all the connectors which brings you right back the BeagleBone cost.

George, it's no different to hobbiest suppliers often providing a semi-populated board containing only the SMT components for the design already placed, in order to support those enthusiasts who like to construct but for whom soldering SMT is difficult.  There are many such people, even today with the wide presence of SMT.

Likewise, soldering BGA would be problematic for the majority of hardware enthusiasts, so providing the BGA part on a plugin module would play a similar role.  The rest of the board would be constructable by the majority of enthusiasts using their more common building skills, which does not include handling BGA.

Morgaine Dinova wrote:

 

George, it's no different to hobbiest suppliers often providing a semi-populated board containing only the SMT components for the design already placed, in order to support those enthusiasts who like to construct but for whom soldering SMT is difficult.  There are many such people, even today with the wide presence of SMT.

 

Likewise, soldering BGA would be problematic for the majority of hardware enthusiasts, so providing the BGA part on a plugin module would play a similar role.  The rest of the board would be constructable by the majority of enthusiasts using their more common building skills, which does not include handling BGA.

I don't mind SMT, as long as lead pitch isn't below 1 mm.  I really like the EOMA-68 form factor, which uses a PCMCIA 68-pin connector.  Then you design and build a base board with your custom thingummies, and plug in the EOMA module to provide computing.  Next year, you plug in the next generation module with twice the computing, keeping your base board.

I like SODIMM connectors except for the fine pitch, because they have reliable high-pressure contacts.  I might be convinced to use an SODIMM-144 connector (0.8 mm pitch), but fuggeddabout an SODIMM-200 with 0.6 mm pitch.

John Beetem wrote:

 

I like SODIMM connectors except for the fine pitch, because they have reliable high-pressure contacts.  I might be convinced to use an SODIMM-144 connector (0.8 mm pitch), but fuggeddabout an SODIMM-200 with 0.6 mm pitch.

There are already a few companies using the SO-DIMM-200 and it's mainly used because you almost need all of those pins to get all of the signals out off of the processor. They aren't that bad to solder because most of them have mounting feet which lock there posistion down on the board and then you only need to add solder. But if "we" went this route, wouldn't you want to provide a low cost baseboard that brings all the signals out anyways? If you're trying to reach economy of scale, what percentage of people are really going to care that they might not be able to solder their own connector? Did millions of people not buy the RPi because they couldn't solder the parts themselves? Or for that matter, how many people are even building their own Arduino boards even though you could? If you price a board at ~$50 I don't think too many people are going to go, oh, that's too much, I could solder those parts down and save $5. Look at what TI has done with their launchpad boards, how can you beat a $5 development board? Let people buy the base and fiddle with their own stuff.

George Ioakimedes wrote:

 

John Beetem wrote:

 

I like SODIMM connectors except for the fine pitch, because they have reliable high-pressure contacts.  I might be convinced to use an SODIMM-144 connector (0.8 mm pitch), but fuggeddabout an SODIMM-200 with 0.6 mm pitch.

 

There are already a few companies using the SO-DIMM-200 and it's mainly used because you almost need all of those pins to get all of the signals out off of the processor. They aren't that bad to solder because most of them have mounting feet which lock there posistion down on the board and then you only need to add solder. But if "we" went this route, wouldn't you want to provide a low cost baseboard that brings all the signals out anyways? If you're trying to reach economy of scale, what percentage of people are really going to care that they might not be able to solder their own connector? Did millions of people not buy the RPi because they couldn't solder the parts themselves? Or for that matter, how many people are even building their own Arduino boards even though you could? If you price a board at ~$50 I don't think too many people are going to go, oh, that's too much, I could solder those parts down and save $5. Look at what TI has done with their launchpad boards, how can you beat a $5 development board? Let people buy the base and fiddle with their own stuff.

I'm not interested in soldering to save money.  That concept went away a few years before Heathkit went out of business.  The reason I'm interested in 1mm+ pitch is so I can create custom baseboards with specialized interfaces and assemble them myself, and then plug in a module that has all the fine pitch and BGA components, such as Variscite SODIMM-200 or Gumstix.  However, both of those require fine-pitch connectors.  Now, it may be that in addition to low-cost PCBs you can find places that will also solder down a few fine-pitch components as well.  Unless such exist, I either need 1mm+ pins or I'll just buy a BeagleBone or Cubieboard or ST Discovery or whatever and make the case tall enough to fit it.

John Beetem wrote:

 

I really like the EOMA-68 form factor, which uses a PCMCIA 68-pin connector.  Then you design and build a base board with your custom thingummies, and plug in the EOMA module to provide computing.  Next year, you plug in the next generation module with twice the computing, keeping your base board.

Me too.  What's more, it's very appealing for making clusters, since such a large number of vertically-oriented EOMA-68 modules can be placed side by aside in a horizontal rack.

This is the age of multicore, allegedly.  We should not be building general purpose computers of any ilk with single CPUs anymore, it will count against our karma at the pearly gates.

Morgaine Dinova wrote:

 

Me too.  What's more, it's very appealing for making clusters, since such a large number of vertically-oriented EOMA-68 modules can be placed side by aside in a horizontal rack.

 

This is the age of multicore, allegedly.  We should not be building general purpose computers of any ilk with single CPUs anymore, it will count against our karma at the pearly gates.

Yes, a EOMA-68 cluster sounds great!  It would look something like the inside of the HAL-9000 in 2001: A Space Odyssey

The lesson of multicore: if RasPi had a multicore SoC, one core could handle USB properly and one could run X server full time, eliminating two serious performance issues.

I totally agree with a multicore processor but I fail to see how you think 68 pins is near enough. If we're considering the embedded space then you can't ignore direct connection to an LCD which means 24 pins just for RGB, then there's Ethernet, USB, SPI, PWM, and on and on. You guys were complaining about wanting an easy method to solder devices but it's specialized equipment to weld those PCMCIA clam shells together.

George Ioakimedes wrote:

 

I totally agree with a multicore processor but I fail to see how you think 68 pins is near enough. If we're considering the embedded space then you can't ignore direct connection to an LCD which means 24 pins just for RGB, then there's Ethernet, USB, SPI, PWM, and on and on. You guys were complaining about wanting an easy method to solder devices but it's specialized equipment to weld those PCMCIA clam shells together.

The pincount on a processor module within a multiprocessing cluster isn't really related to all those things you mention, for a variety of interrelated reasons:

• Memory should be local to each processor module because global memory doesn't scale beyond very small processor numbers.
• I/O isn't done on processor modules because all processors need to access it symmetrically without bothering other processors.
• Realtime I/O should be handled by dedicated microcontrollers, not by a  *nix kernel which is very bad at it.
• Microcontrollers provide large numbers of GPIOs and are dirt cheap, so microcontroller-based I/O modules should do all the I/O.
• Communication between processor modules and I/O modules is best done as high-speed serial messaging.
• Serial message communication doesn't need a lot of pins and is topologically very flexible.  Remember the transputer.

I suspect we have completely different designs in mind and hence we are talking about different things.

Morgaine.

I really like the EOMA-68 form factor, which uses a PCMCIA 68-pin connector.

As someone who used to have to solder pcmcia connectors on some early Thinkpads - 386 vintage, I know I never want to have to do it again.  Besides, if you look in a modern laptop that still has pcmcia the pitch has reduced down to the sub 1mm problem you entioned in another post.

It's certainly one thing I don't like - fine pitch connectors. From the experimenters perspective you either need easily available, cheap, and can be hand soldered without requiring solder paste hot air and/or liquid flux.  While those requirements won't put some of us off, they significantly reduce the accessibility for most people.

Or else you need a cheaply available adapter board to go from the fine pitch connector to something more useable - and a bigger case

selsinork wrote:

 

Or else you need a cheaply available adapter board to go from the fine pitch connector to something more useable - and a bigger case

Well I have no shortage of DIN41612 connectors.

More seriously, what are the major options in high pinout connectors these days without dropping below 0.1" pitch?  While DIN41612 is still available and viable, I assume that there are more modern alternatives, not to mention cheaper as well.  "Industrial strength" is probably not needed here.