A $1, Linux-Capable, Hand-Solderable Processor

Over on the EEVblog, someone noticed an interesting chip that’s been apparently flying under our radar for a while. This is an ARM processor capable of running Linux. It’s hand-solderable in a TQFP package, has a built-in Mali GPU, support for a touch panel, and has support for 512MB of DDR3. If you do it right, this will get you into the territory of a BeagleBone or a Raspberry Pi Zero, on a board that’s whatever form factor you can imagine. Here’s the best part: you can get this part for $1 USD in large-ish quantities. A cursory glance at the usual online retailers tells me you can get this part in quantity one for under $3. This is interesting, to say the least.

The chip in question, the Allwinner A13, is a 1GHz ARM Cortex-A8 processor. While it’s not much, it is a chip that can run Linux in a hand-solderable package. There is no HDMI support, you’ll need to add some more chips (that are probably in a BGA package), but, hey, it’s only a dollar.

If you’d like to prototype with this chip, the best options right now are a few boards from Olimex, and a System on Module from the same company. That SoM is an interesting bit of kit, allowing anyone to connect a power supply, load an SD card, and get this chip doing something.

Currently, there aren’t really any good solutions for a cheap Linux system you can build at home, with hand-solderable chips. Yes, you could put Linux on an ATMega, but that’s the worst PC ever. A better option is the Octavo OSD335x SoC, better known as ‘the BeagleBone on a Chip’. This is a BGA chip, but the layout isn’t too bad, and it can be assembled using a $12 toaster oven. The problem with this chip is the price; at quantity 1000, it’s a $25 chip. At quantity one, it’s a $40 chip. NXP’s i.MX6 chips have great software support, but they’re $30 chips, and you’ll need some DDR to make it do something useful, and that doesn’t even touch the fiddlyness of a 600-ball package

While the Allwinner A13 beats all the other options on price and solderability, it should be noted that like all of these random Linux-capable SoCs, the software is a mess. There is a reason those ‘Raspberry Pi killers’ haven’t yet killed the Raspberry Pi, and it’s because the Allwinner chips don’t have documentation and let’s repeat that for emphasis: the software is a mess.

Still, if you’re looking for a cheap chip you can solder at home, this one seems to be the only game in town. We’re really looking forward to seeing what you make with it!

84 thoughts on “A $1, Linux-Capable, Hand-Solderable Processor

  1. A very similar chip is the Allwinner V3S. 1.2Ghz Cortex A7. For about $3.25. The bonus is that the V3S has 64MB of integrated DRAM inside the package. 128-pin eLQFP. There is a newer Allwinner S3 with same CPU and 128MB DRAM, but it is in a BGA package.

    1. And the V3S is all over the electronic postcard, digital picture-frame, and other consumer devices. Comes on a board with some RAM and some flash, and maybe if you’re lucky a USB port or two!

          1. The GPL fud on Allwinner is overblown. Allwinner buys IP from other vendors for use in their chips. Some of those vendors refuse to open source their drivers. The biggest offender of this is the NAND flash controlled used in their chips. But this is easy to avoid, simply use eMMC chips. A similar situation occurs with the GPU, it is not Allwinner sitting on the Mali source code, it is ARM Inc. Their VPU support is closed source, but it is a user space library so the GPL does not apply. The A13 is supported in Debian and mainline Linux.

            The ‘backdoor’ was some debug code that did not get turned off when it should have been. That event occurred about five years ago. It wasn’t much of a backdoor since Allwinner also supplied the source code for it which is why everyone knew it was there. A simple checkbox in Kconfig turned it off.

            What Allwinner is guilty of is not participating in mainlining their own code. Personally I think the company is foolish for not participating. They are a billion dollar company and could easily participate if they chose to. Instead the sunxi community does the work for them.

      1. You can buy BGA cell phone chips like that but the cheapest I have seen them is in the $45 range for the chip+DRAM combo. Cellphone combos are the only versions I have seen with a GPU included.

        I am currently working with the Allwinner V5.
        http://www.lindeni.org/lindenis-v5.html
        It is rumored that AW is going to release an integrated DRAM version of it, but that hasn’t happened yet.
        V5 does not have a GPU but it has an AI coprocessor. BGA chip.

        Elecrow is a cheap place to have PCBs made and to get your BGAs soldered on.
        https://www.elecrow.com/
        Website is screwy so just get a human quote. You can get 5-10 boards made, have the BGAs soldered on, and get them shipped for under $200.

        1. BTW, Elecrow can acquire common parts from the Shenzhen market for you if they are doing the assembly. There is no need to buy an Allwinner CPU or DDR RAM, have it sent overseas and then send it back to them. Just let them buy it for you, much cheaper than shipping chips back and forth. Of course if you use some hard to locate part you will have to ship them some.

        1. For some value of “working”, but when you have multiple supplies and reasonably high speeds you really want to be looking at a 4-layer stackup (or higher).

          iTead will do you a batch of 10 4-layer PCBs for $100 these days, which is steep for a hobbyist, but not unattainable for a once-a-year type project

          1. There are cheaper options now. JLCPCB has become my go-to fab for anything over a couple square inches (where OSH Park still does well). They’ll do qty. 10 of 100mmx100mm 4-layer for $32 plus about $20 shipping, and you’ll have them in a week or so. Keep the design under 50×50 and the $32 drops to $15. And they’ll ship the boards along with a parts order from LCSC, which is stupidly cheap for basic components if you’re willing to navigate the clunky site and frequently poor or nonexistent English (but not an authorized distributor for much of anything, so maybe don’t source the parts for your pacemakers from there).

    1. There aren’t since the pinout of DDR is standardized, but it is easy enough to route it out on a 4-layer PCB. 2-layer can work topologically but is a risk signal integrity wise. Anyway, the A13 uses SDRAM.

    1. I just finished a project with a iMX6ULL and I don’t recommend it. The efuse boot configuration is insanely over complex, there don’t reliably boot anything other than a NAND, the U-Boot can’t initialize some premium SD card, PWM Linux driver is buggy, etc.. I have done more projects on Allwinner H3 or H2+ without all that crap, especially since the mainline Linux kernel support is usable: http://linux-sunxi.org/Linux_mainlining_effort

        1. A cheap way to play with distributed computing is to sign up for a free AWS account. Don’t go nuts and you can stay inside the free limits. Even if you exceed the free limits it is not too expensive. It is a good place to learn, but not a good place to mine bitcoins 24/7.

    1. I gather that the noteworthiness is not that it’s a linux capable single chip package, but rather that it’s a linux capable single chip package that can be soldered with a hand and a soldering iron.

    1. If you just want to use the chip you can boot a mainline kernel, don’t worry. The proprietary trade secret IP is mostly for the camera ISP and video encoder. The A13 doesn’t even have that.

    2. It’s also Allwinner that released pretty much the entire software chain for the A13 as open source, meaning that – thanks to a lot of community work to push support upstream – you can use official Debian releases and mainline Linux kernels on this chip.

      The big advantage the Raspberry Pi has is not the quality of the software but a PR one: even on this Hackaday article, about something you can’t do with the Pi because the chips are neither home-solderable nor available to buy, which is also prohibited by the Pi’s bootloader license, and which it also lacks the documentation and tools for, the Pi is still presented as the better option.

      1. The Pi also has the advantage there’s tons of documentation on how to program for it, and tons of people know how to program for it, which in turn means there’s lots of help available when you get stuck. It’s easily available, often good enough, and doesn’t require any crazy toolsets or additional hardware beyond power and an SD card. All that together means it gets to be the default option, despite some obvious faults.

        Same with Arduino. The AVR platform is getting left behind by the cheap ARM chips coming out, but we stick with it because we all know what to do with an ATmega328 board.

        I’m hoping RISC-V will eventually make a board that’s cheap enough to compete, and can start building a community as deep as the RPi.

        1. The PI is a great learning tool for software and limited projects. But if you are building your own PCBs you will discover that Broadcom won’t sell you the CPU used on the Raspberry Pi so you won’t be able to make your own boards. That policy is what creates the opening for all of these other chips.

  2. I think I hae a tablet with similar CPU, AmLogic AML-8726-MX dual-core A9 processor running at 1.5GHz. It works, but OS is broken and I can’t fix it (It’s an older Android with some file system issues that prevents it from installing any software and storing any configuration changes)…

  3. The software is a mess? Maybe if you rely on the ancient, vendor-supplied, hacked-together kernel.
    But look over on linux-sunxi.org and you’ll see the A13 has been well supported by the mainline kernel for quite a while.

    Seriously, why can’t a site dedicated to hacking do a quick Google search and find the community support for these chips?

  4. Do any of these cheap ARM chips support more RAM? Say 8GB? I want to try and make a pluggable RAMdisk in usb memory stick format. But your options for using (lots of) DRAM are limited. FPGAs? Would likely need USB 3 to really do the concept justice, but 2 should be good enough as a proof of concept.

      1. as far as my limited knowledge I know a few Snapdragon chips can handle the 8GB RAM as some high-end phones have that amount of RAM.
        However it’ll likely be a costly board and hardly any support: The literal opposite of the RasPi at the moment.

        Though it would be good if a manufacturer could cheaply make such boards with a DDR3 or 4 RAM card socket.
        Or…. a separate bank-select on this chip (I assume it has cache?) to act as a rudimentary PAE (Expect issues though)…. Technically a DIY PAE could map up TB’s of RAM :)

      2. None of the thin client ARM chips (i.e. tablet/phone/netbook) support more than 2G usefully AFAIK. The 64 bit server chips do but they’re not cheap because there are by the nature of networks fewer servers than clients and even fewer of those servers are ARM based :-/

  5. Do any of these cheap ARM chips support more RAM? Say 8GB? I want to try and make a pluggable RAMdisk in usb memory stick format. But your options for using (lots of) DRAM are limited. FPGAs? Would likely need USB 3 to really do the concept justice, but 2 should be good enough as a proof of concept.

    1. I too was interested in using and ARM SBC with lots of RAM. My research lead me to conclude that most cheap ARM SoC can’t physically handle more than 1 GB. A very small number can handle 2 GB and only a really tiny number can handle more than that. There is a very good reason why most ARM SBCs (like the RPi) aren’t available with more than 1 GB.

      1. You’re not looking hard enough. There are a lot of ARM boards with 4GB of RAM. Look for rk3328 or rk3288 based SBCs.

        ROCK64 costs $44.95 https://www.pine64.org/?page_id=7147

        Cost is clearly not the issue. $10 more gets you 4x as much RAM and USB 3.0. The RPi is crippled by the Video Core 4, which cannot access more than 1GB of RAM. It’s a purely technological limitation.

        1. “ROCK64 costs $44.95″…
          No it doesn’t. It’s $79.99 + shipping. A quick look at the forum shows there are many issues with this board so it’s still quite new and not what I would consider stable.

  6. Would be great to see an article on making a small board with one of these or similar and getting it to a point where it can do a hello world example.Something to bridge the gap between a bare metal arduino script and a full linux kernel running and doing something useful.

    1. I would also like to figure out how to do this. I’m guessing it would be atleast two steps. Use a progammer to load firmware like you do on a bare metal chip, then load linux from an SD card. But I’m not sure what that firmware would be. Probably some kind of bios that’s already available somewhere.

      All the hardware connections needed would be another issue. But I think I could mostly figure that out from the datasheet. Hopefully whatever bios it used would make it apparent what pins the SD card needs.

  7. What about recycling RAM from defunct old laptop DDR? these are readily available and can be overclocked to hell and back if you are really creative with clocking etc.
    Also the newer chips are something like 64MB so thats more than enough for basic uses. Incidentally I looked into using one of these today on my £10 el cheap helis as “brains” because they use a fraction of the power needed by a Zero.
    No need for anything but the basics here, even altimeter can be ultrasonic based for indoor use.

    1. I assume the A13 can only “talk” to a single RAM module IC.
      And all DDR3 ram IC’s are BGA in my experience.
      So you’d need to carefully desolder them, verify they’re still working somehow, reball them and THEN use them on your pcb.

  8. The thing about this chip not having HDMI….
    I’ve seen a few tablet PCs (People chuck out) with this chip and HDMI.
    They do it by use of a support chip if I remember correctly.
    I’m guessing they use an asic with 2x frame-buffers and an i2c for virtual display settings?
    i.e. makes the HDMI and internal one appear as one display….
    This I’ve tested and found the HDMI to drive the output at the same resolution as the (usually smashed screen when I find them) integrated screen.

    However this is still one hella capable chip.

    1. A bit off topic…. but:
      Sorry… I meant to send via this IP address….
      I still can’t get my boss or the guy incharge of IT to understand the password for everything being the same as the name of the company is insecure.
      I’d guess they found out the IP of the building and logged in with the obvious password.
      They then very likely used the no-password telnet on a cheap networked camera DVR with some software for their mayhem.
      I know it was the DVR because all vulnerable DVRs got wiped a week before we got a break-in and all our lorry fuel stolen.
      However this entry point has been closed by changing the password to a safe one and shutting down the camera DVR (wouldn’t reboot…. It leaves the DSP and GPU running… strangely)
      So… treat this IP as still hostile for now please….

  9. Othernet (nee Outernet) Dreamcatcher board is based on the A13 as well.

    A13 is supported in mainline uboot and mainline linux kernel for a while – its essentially the best supported chinese SoC, linux-wise.

  10. “Over on the EEVblog, someone noticed an interesting chip that’s been apparently flying under our radar for a while. ” LOL This new chip is 6 years old https://olimex.wordpress.com/2012/04/24/cortex-a8-in-tqfp-sure-allwinner-a13/ … the C.H.I.P the $29 computer which was sold for $9 plus $20 shipping back in 2016 was also made with A13. The price of original A13 chip when you buy from Allwinner directly is close to $3 as this is obsolete chip made on 40nm technology and cost of manufacture in obviously now small volumes is high. Sure you can find it on Taobao, Aliexpress etc for prices from $1 up to $3-4, the secret is that these are not new, but pulled from old tablets. Lot of companies in China recycle old electronics, and pull chips which they later sell at different prices (some close to the original Allwinner sale price and depend on how unexperienced the buyer is). These chips are always sold in bulk, with no original packing neither with lot, datacode etc marking on the package which to allow tracebility with Allwinner. Buying $1 A13 guarantee that these are not new and may or may not work depend on how this chips was abused during the use and during the re-cycling.

    1. I have done some good deals on that, in a previous job I often needed to quickly test a PCB that required an expensive FPGA. I bought a few recycled ones for a fraction of the price. All but one worked (but that could just as well have been my fault due to manual soldering)

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