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Rhombus Tech A10 EOMA-68 CPU Card Schematics Completed
lkcl writes "Rhombus Tech's first CPU Card is nearing completion and availability: the schematics have been completed by Wits-Tech. Although it appears strange to be using a 1ghz Cortex A8 for the first CPU Card, the mass-volume price of the A10 was lower than other offerings. Not only does the A10 classify as 'good enough' (in combination with 1GB of RAM), Allwinner Tech is one of the very rare China-based SoC companies willing to collaborate with Software (Libre) developers without an enforced (GPL-violating) NDA in place. Overall, it's the very first step in the right direction for collaboration between Software (Libre) developers and mass-volume PRC Factories. There will be more (faster, better) EOMA-68 CPU Cards: this one is just the first."
Too many links... no intro telling me what this is.
For those who want to know... it is a PCMCIA (PC-card) sized integrated computer designed to compete with the Raspberry Pi... supposedly cheaper and faster. Raspberry Pi does have one major advantage though: it is in production and shipping whereas this is still in the schematics stages. So... nothing to see here...
The schematic is often the easiest part of the design. An EMC compliant PCB is usually harder; passing FCC/CE/* EMI compliance is harder; setting up for mass production is not for beginners either. Those guys just made the first step on a long road. And that's exactly why it's so hard to build hardware these days; the progress is so fast that by the time you are ready to manufacture the key parts are obsolete and out of production. Even if the parts are still available your design may be already obsolete because newer, better parts became available. It's either "design it under 3 months" or "do something else with your life."
you know what? i'm really glad you raised this point. it's *exactly* why we sub-divided the CPU Card from the actual device. independent development and product life-cycles for the CPU and the device! so yes, sure, the CPU becomes obsolete, but that's ok: you can just buy the latest CPU card... *without* having to throw away the entire product. so you've highlighted the very core of the strategy, here. it's not just about upgradeability, it's about being eco-conscious as well as providing redundancy without disrupting the user.
think about it: yes, sure, we're having a hard time getting the first CPU Card out, but you know what? it's just the first. it took 3 months to source just 5 connectors at reasonable prices (mostly because they are unusual: mid-mount HDMI, mid-mount audio, sub-1.8mm Micro-SD, mid-mount USB-OTG and the increasingly-obscure PCMCIA). but guess what? having found those suppliers, we won't have to do that again for subsequent CPU Cards, and we will have pre-established relationships by the time the 2nd CPU Card comes out.
also, with the 2nd and subsequent CPU Cards, we expect to actually have some profits made so that we can pay good people to work promptly and according to *our* timescales. one of the issues that we have is that we've got this far with *zero* investment. absolutely none. think about that for a moment. no money has changed hands; we are beholden to no-one, yet there are software engineers ready to get the OS onto the CPU Card, but not only that, the CPU Card Schematics have been made.
how is that even possible? we did deals, based on the strength of committment and the desire of our PRC State-Sponsored client to make use of the EOMA-68 solution and concept that we came up with. it's *perfect* for them.
so CE compliance will be covered by our client: they are big enough to be able to self-certify. FCC is more problematic: we're simply not going to even bother unless we receive an order from a USA/Canadian company of minimum 50k units, and the cost of the FCC Certification will be included in the quote. as the USA market is below 1/10th the size of the PRC market, we don't see this as being a problem.
but yes - the key here is that this first CPU Card is a heavy learning curve. we're on the lookout for faster and better CPU Cards, and we fully anticipate - especially with the Linaro-sign-ups such as TI, Samsung and Freescale creating fully open Schematics for the Origen, Pandaboard, IMX53QSB and the upcoming iMX6 - being able to very rapidly adapt those Open Schematics into EOMA-68 CPU Cards. what we would *really* like is for someone else to step forward and do that work, and we'd do a deal with them to introduce their product to our clients. that would be great. we much prefer to do these kinds of "cost-plus" deals. it's fairer to everyone who is involved.
It's a schematic (actually, the picture shows a board layout)
shit. you're right. it is! no wonder the other guy said we'd be 6 months from release :) no, it's definitely a board layout. first samples will be available for testing by next week. definitely not 6 months from now.
It's not clear why you'd want an Allwinner A10 in a PCMCIA form factor. The Allwinner A10 has a sizable set of peripherals on-chip. Ethernet, HDMI, etc. Usually, boards for this part have a whole row of connectors. Bringing out the pins on a PCMCIA connector means you need another board to fan out the peripherals.
ah. right. this is covered here: http://elinux.org/Embedded_Open_Modular_Architecture
we wanted something that is user-installable and user-upgradeable. if we had wanted factory-installable (only) then we would a) not really have bothered at all, given the proliferation of offerings from direct-insight.co.uk and variscite.com and many many others b) we would have created something like the q-seven standard and, again, really to be honest, would not have bothered with that, either, because why create a competing standard?
no, you're missing a couple of points. one is that the A10 EOMA-68 CPU Card can operate stand-alone, powered by USB-OTG, booting from USB-OTG, NAND or Micro-SD as you choose, and having both HDMI out and Stereo Audio. that's not bad, right there.
the other point is that we picked interfaces that happen to be "common buses", that happen to all have backwards-compatible speed negotiation. 24-pin RGB/TTL you can drop down even to as low as 15 pin by ignoring the higher-res bits; you can reduce the clock-rate to run a 320x240 LCD or you can ramp it up to run 2048x2048 @ 30fps in full colour. USB2 goes all the way from 11mbit/sec to 480mbit/sec. SATA-II has down-level negotiation all the way to 150mbit/sec. I2C goes from something like 75khz up to 4mbit/sec or thereabouts. Gigabit Ethernet goes through 10 to 100 to 1000.
so there is a hell of a lot of thought gone into the selection of those interfaces, in order to keep the pin-count down. it was just pure luck that when you added 16 GPIOs and some power and ground that the pin-count came to *exactly* 68. jammy or what. and if you look at that interface set, it's *extremely* flexible and powerful. but i believe i know what you're saying: why didn't you make *all* the pins available? because if you've looked at the cost of user-hot-swappable 100-pin connectors, they're insanely expensive: $12 is not uncommon.
so instead, we're recommending the use of a low-cost STM32F on the other side (I/O Board side). we've tracked down the OpenEC2 project (originally the firmware for the OLPC XO-1) and intend to port it to RTEMS-lite, then extend it to provide Audio Drivers in the form of A/D and D/A converters, amongst other things. ST Micro actually recommend their 75mhz+ CPUs for use as Audio ICs. but it can pretty much cover everything. this practice is standard in x86 PCs (using an Embedded Controller) but is quite rare in the ARM world: normally you'd use the ARM CPU itself to do this job! but, because of the EOMA-68 "break", we can't do that. swings and roundabouts: it'll come out in the wash :)