The $1 Linux-capable ARM processor in TQFP... - Page 1
Forum section: electronics / general

author: technix
author_rank: Super Contributor
timestamp: September 12, 2018, 05:55:45 pm
content: I have been evaluating multiple ARM-based processors, and one caught my eye again for a different reason: price. There are only a few ARM processors in TQFP package that is capable of running Linux, and one of which costs only $1 each: Allwinner A13. That is a 1GHz ARM Cortex-A8 processor with built-in Mali GPU, resistive touch panel support, and a maximum supported memory of 512MB DDR3.I repeat, it is a $1 chip capable of running Linux.It is pretty ironic when its memory chip costs $4 or more. Usually the processor is more expensive than the processor, but in this case things are the other way around somehow.

author: rsjsouza
author_rank: Super Contributor
timestamp: September 12, 2018, 06:04:07 pm
content: Despite the price is quite astonishing, to be honest I am not terribly impressed. Maybe they provide complete support for their customers, but to me the most expensive part of these projects is having a workable linux distro with decent support for a device's peripherals. Last time I tried to evaluate an AllWinner part, I found out they were quite closed and typically had one (maybe two) working linux distro. The terrible datasheet did not help wonders either.

author: technix
author_rank: Super Contributor
timestamp: September 12, 2018, 06:23:20 pm
content: Quote from: rsjsouza on September 12, 2018, 06:04:07 pmAFAIK that is an older chip that has more community support and mainline drivers available. Allwinner is a difficult company to work with as a SME or hobbyists (as do most Chinese chip manufacturers, although UniIC and Pango seemed like quite an exception but they all have the same parent company that has a strong academic background) but they do have cheap enough chips to warrant some effort.I have investigated other manufacturers:* Hisilicon and Mediatek flat out refused to sell me anything, and they don't have publicly available documentation on anything they made.* Allwinner don't provide docs either, but someone else have uploaded the docs so work can be done from those docs and independent resources.* Microchip's processors are all fairly weak, be it SAM9, SAM A5 or PIC32MZ DA.* NXP does have good chips with public documents, but they are all expensive.

author: rsjsouza
author_rank: Super Contributor
timestamp: September 12, 2018, 06:47:32 pm
content: Thanks for the other references; the unit price is usually moot when talking about hobby/academia/low production volume, therefore the strongest factor of AllWinner ends up being lost.Since you are going to the more established manufacturers (and higher $$$), the most capable and open architecture I see in the 1GHz class is the BeagleBone ecosystem. You can buy a single part and the documentation, distros and SDK are quite up-to-date. It also has heaps of add-on HW.

author: jmelson
author_rank: Super Contributor
timestamp: September 12, 2018, 07:01:44 pm
content: Quote from: technix on September 12, 2018, 05:55:45 pmVery interesting, but how much available I/O does it have? I've been using the Beagle Bone, and love the features of that board. I have to buy the board, as the processor is a BGA, and I'm not set up to deal with that. Does somebody make a generic board for this? I'd want to have at least 16, say, GPIOs plus network interface.Jon

author: stmdude
author_rank: Frequent Contributor
timestamp: September 12, 2018, 07:05:13 pm
content: The AllWinner A13 is basically an AllWinner A10, but with a bunch of integrated peripherals removed, such as HDMI, SATA, I2S, etc.The only use I see for it is if you have an product that works with the reduced number of peripherals, _and_ can live in the integrated 64MB of RAM. The chip being TQFP is kind of moot if you need to put a BGA-96 DDR chip next to it.It's certainly doable to do a product with the AW chips. The datasheets are out there, and the mainline kernel (through the sunxi linux efforts) supports a lot of functionality in the chips.For the more "established" (read: western) manufacturers, I've evaluated TIs Sitara (aka, beaglebone, aka, Octavo), but didn't like their codebase. Quite old and hacky. Also, only single-core, and no upgrade route.I've settled for the NXP iMX6ULL chips (fairly cheap) for more price sensitive designs, and iMX6Dual/Quad for more powerful designs that require 3D acceleration. It allows me to be a bit more scalable than I would have been with TI, and allows me to re-use my know-how and software base.

author: stmdude
author_rank: Frequent Contributor
timestamp: September 12, 2018, 07:09:57 pm
content: Quote from: jmelson on September 12, 2018, 07:01:44 pmYou should probably look at the pocketbeagle first. If that doesn't fit you, have a look at the Octavo Systems SiPs. It's basically a beaglebone in a chip. IIRC, they require 3.3V+5V, a crystal, and a few passives to give you a booting linux system. All the highspeed black magic is done within the chip itself.It's BGA though, but with a massive 1mm pitch, so it's no issue with using $2 chinese PCBs with it. However, I'd really recommend getting a reflow oven to solder it. The chip is so large that a hot-air gun doesn't seem to be able to reflow all the balls at once (I've tried).

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 12, 2018, 08:51:58 pm
content: Quote from: stmdude on September 12, 2018, 07:09:57 pmA hotplate (/skillet) may be another option

author: technix
author_rank: Super Contributor
timestamp: September 13, 2018, 03:34:41 am
content: Quote from: jmelson on September 12, 2018, 07:01:44 pmIt has about 40 or so GPIO multiplexed with various other functionalities after you has a basic booting board, you get 21 if you don't use the display output.Quote from: stmdude on September 12, 2018, 07:05:13 pmThe DDR SDRAM chip is the only BGA required, and if you are okay with wasting 3/4 of the capacity you can go with a SODIMM memory module and use only 1/4 of its byte lanes. And that chip maxes out at 512MB not 64.Quote from: stmdude on September 12, 2018, 07:05:13 pmTI suffers from the same problem as Microchip: weak processors.

author: stmdude
author_rank: Frequent Contributor
timestamp: September 13, 2018, 06:57:36 am
content: Quote from: technix on September 13, 2018, 03:34:41 amYes, it maxes out with 512MB, but it has 64MB _built in_, so you can get away without the BGA DDR if you can live with 64MB.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: September 13, 2018, 07:06:09 am
content: Quote from: stmdude on September 12, 2018, 07:05:13 pmI think you have conflated A13 with V3 and V3s. The V3 has the internal 64MB ram, small for linux but huge for a roll your own RTOS, which I considered once apon a time.A13 has 48Kstatic ram, external 16 bit sdram bus, (as well as the typical ARM 32k i-cache, 32k d-cache, and 256k L2 cache)I agree with the sentiment that the need for external memory and all of the other draw backs you get with AllWinner quenches the interest.

author: rasteri
author_rank: Contributor
timestamp: September 13, 2018, 10:23:19 am
content: Olimex sells an A13-based board with 256/512MB DDR3, €13.50 in 100-off quantity...https://www.olimex.com/Products/SOM/A13/A13-SOM-256/Assuming software support isn't completely terrible, this is a VERY good alternative to the Raspberry Pi compute module in a project I have coming up.

author: technix
author_rank: Super Contributor
timestamp: September 13, 2018, 04:19:57 pm
content: Quote from: rasteri on September 13, 2018, 10:23:19 amI am actually rolling my own A13 module with 512MB SDRAM. I am actually trying to build this board with exclusively made in China chips: Allwinner V3s SoC, XPower AXP209 PMIC, UniIC DDR3 SDRAM, etc. (It is just within this year that a Chinese chip fab, UniIC, backed by Tsinghua University, finally managed to make DDR3 SDRAM chips. They are now trying DDR4.)

author: SiliconWizard
author_rank: Super Contributor
timestamp: September 18, 2018, 06:53:25 pm
content: Quote from: rsjsouza on September 12, 2018, 06:04:07 pmI agree with that point. Which makes those chips attractive ONLY if you target very high volumes.Software is actually also where all those SBCs (some of which are very cheap) fall short. There are dozens of such small boards which look great spec-wise but turn out unusable in a lot of cases due to the lack of proper software support.

author: technix
author_rank: Super Contributor
timestamp: September 18, 2018, 08:00:20 pm
content: Quote from: SiliconWizard on September 18, 2018, 06:53:25 pmI has a fairly nice ARM Cortex-A53 board collecting dust, simply because of the poor software support. One point: while the board comes with an unpopulated eMMC and SPI Flash footprints, there is no support of using those in the accompanying software at all, let alone boot from them, although the underlying chipset is capable of doing so. I have hacked my board with both 16MB SPI Flash and 16GB eMMC, none of them work at all, and the chip maker flat out refuses to respond to my documentation and open source code requests (that means I was asking for GPL-licensed software Linux kernel and u-boot.)

author: rsjsouza
author_rank: Super Contributor
timestamp: September 18, 2018, 08:50:05 pm
content: Quote from: technix on September 18, 2018, 08:00:20 pmThat was my observation as well; sometimes the basic distro works well with whatever is put on the board but not with what the device itself is capable. To add to your list, I have seen inoperative or terribly non-optimized QSPI, USB OTG, SATA, etc.

author: hermit
author_rank: Frequent Contributor
timestamp: September 19, 2018, 01:25:56 am
content: https://hardware.slashdot.org/story/18/09/18/183237/a-1-linux-capable-hand-solderable-processor#comments

author: LapTop006
author_rank: Unknown
timestamp: September 19, 2018, 02:28:30 am
content: I've been working with the packaged upOctavo SiPused in the PocketBeagle, it's as hand-solderable as a BGA ever gets, but is rather easier to use from the built-in components.Rathermore expensive though.

author: technix
author_rank: Super Contributor
timestamp: September 19, 2018, 03:00:45 am
content: Quote from: hermit on September 19, 2018, 01:25:56 amWhy is this deemed Slashdot- and Hackaday-worthy?Quote from: LapTop006 on September 19, 2018, 02:28:30 amThat is the reason why I never considered Octavo: can't quite afford it.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: September 19, 2018, 06:19:09 am
content: Quote from: technix on September 19, 2018, 03:00:45 amEvery site needs some clickbait, it keeps the lights on.It was worth reading for the reply from Olimex though.

author: technix
author_rank: Super Contributor
timestamp: September 19, 2018, 09:22:53 am
content: Quote from: donotdespisethesnake on September 19, 2018, 06:19:09 amSad to see they even failed some research on the chip though. A13 is R8, which is used in the $9 CHIP board. My version of A13 base module isn’t too dissimilar from CHIP either (although I do have 512MB DDR3 and 32GB eMMC, a step up from the 4GB/8GB NAND.)

author: MT
author_rank: Super Contributor
timestamp: September 19, 2018, 12:05:43 pm
content: It always puzzled me why all those 0.99cent Linux SOC manufacturers so closed and secret of the SOC since lifetime is so short and they basically do the same thing, namely run Linux on a small plattform?! I hardly imagine there is so much IPin there thats making them so much more "profiled" then next in line SOC manufacturer.

author: rsjsouza
author_rank: Super Contributor
timestamp: September 19, 2018, 03:22:55 pm
content: Quote from: technix on September 19, 2018, 09:22:53 amI loved Olimex' response as well, and their only mistake was to say they were part of refurbished tablets. Otherwise, a lot of what was said is quite relevant and can be used as warning to the ill-advised.If Allwinner is selling these devices at $1 unit price directly or from one of their distributors, then I can say Olimex' post is BS. Otherwise, it is spot on.