Our first complex Linux board done completely in KiCAD is near the finish.
As you can see from the picture above all the complex high speed signals routing is already done.
What left is GPIO, audio etc low speed signals which are easy to complete. CAD files are updated to GitHub
olimex 
Jan 08, 2016 @ 14:15:57
How was the routing experience with KiCad for the high speed lines? Did you find the differential matching useful or was it mostly done manually?
Jan 08, 2016 @ 14:18:52
not bad at all, but during the development we made looooong list with suggestions how to improve KiCAD 🙂 which I will spoke about at FOSDEM https://fosdem.org/2016/schedule/event/kicad_oshw/
Jan 08, 2016 @ 15:00:03
Brilliant, looking forward hearing your experience in the talk!
I’m using KiCad exclusively for board design too (just getting to re-learn a bunch of things for the new release), though only for not-very-demanding low speed cases, so far.
Cheers for this!
Jan 12, 2016 @ 00:14:12
Cool. Have you filed ’em bug reports?
Jan 19, 2016 @ 11:50:03
As someone who is not going to FOSDEM, I would be really interested to hear about your experience with KiCAD, will you be sharing those insights elsewhere?
Jan 21, 2016 @ 15:42:39
@paul sykes
As far as I know, FOSDEM records all talks, so check the videos after the event!
Jan 08, 2016 @ 14:30:51
So the whole board is done by hand? No autorouting?
Jan 08, 2016 @ 14:34:33
we do not use auto routing on boards with high speed signals
Jan 08, 2016 @ 14:43:09
How many layers is it?
Jan 08, 2016 @ 14:44:52
six
Jan 08, 2016 @ 14:51:24
Is the performance gain enough to justify the cost of six layer board and two RAM chips vs a 32b design with a single RAM?
Jan 08, 2016 @ 16:56:44
LIME is 6 layers, LIME2 is 8 layers, and those are low-cost boards 😛
About the 64-bit thing, mostly buzzword at this time for normal users, but the 64-bit ARM ISA should have significant changes. Maybe the ARM64 will be much more useful at current time on the server side.
Jan 08, 2016 @ 17:05:55
Main reason to go 64B is to get a larger address space. But that larger address space comes at a price, all of your apps and data gets a lot larger because you are carrying around 64b addresses.
A64 can only address 3GB of RAM which fits into the 32b address space. So there is no benefit of getting more RAM. There is another minor benefit from 64b registers, but that will be more than offset by the baggage of carrying around 64b addresses. Another benefit is 64b bandwidth to the RAM chips.
So… it is not clear to me if at 3GB memory whether a 64b chip is better than a 32b one.
At 4GB or more you have to have 64b chips. Servers want all of this RAM to implement virtualization.
Jan 08, 2016 @ 17:11:48
BGA escape in 4 layers is possible, but will need more space and we wanted to make compact design, board now is 90×60 mm and will be base for our laptop design
you didn’t look at A64 specs 🙂 it has 32 bit memory bus although being 64 bit SoC
Jan 08, 2016 @ 17:27:05
Yes, I assumed a 64b chip would have a 64b bus. Without that 64b bus this chip may end up being slower than it’s 32b counterparts due to the baggage of dragging around 32b addresses.
But, 32b bus means I should be able to make a board with a single 32b DDR chip.
Jan 08, 2016 @ 17:28:46
do you mean these phone flash+ram chips which mortals can’t buy yet?
Jan 08, 2016 @ 21:27:45
I guess 32b DDR doesn’t exist. I had stumbled onto this, but it is not mainstream.
http://www.microsemi.com/document-portal/doc_view/134074-mif2092-2gb-x32-ddr3-sdram
So SOC + 2 x DDR + flash is the simplest solution for A64.
Jan 10, 2016 @ 05:47:12
We did a test using the Freescale imx6 dual lite Soc and one or two dram chips (32 bit vs 64 bit dram I/F). All other things being equal, we measured about a 5% difference in android performance across various things like canned benchmarks, boot times, and opengl frame rates.
Jan 08, 2016 @ 19:27:16
Any chance you could use a individual configurable regulator for sd/mmc I/O supply (may not be possible, since there’s no separate VCC pin for PF pins), and another for eMMC I/O (VCC-PC) and VQMMC?
Being able to control the signaling voltage is crucial to getting more performance from MMC.
Thanks
Jan 11, 2016 @ 12:58:50
There is any header for external power/reset button? It’s a common problem for most of us when using big enclosures / embedded solutions.
Jan 12, 2016 @ 01:04:27
…because in case of embedded devices there is often nobody around, so nobody can press any buttons, dammit. Device supposed to come alive at power available and do what it should, as long as power present. Reseting locked up system? Use watchdog, luke. It would reset hanged system automatically.
Jan 12, 2016 @ 01:51:26
Well in our particular case we are using portable enclosures with batteries and only few required external ports & buttons. We need a power button because these devices are used like for a specific purpose, does not need to be powered all the day like a personal tablet/smartphone.
These computers are used under hazard environment, so its mandatory to have the right buttons instead of a molded plastic fitted into a hole that pushes the micro-switch from the board.
Jan 13, 2016 @ 07:25:39
>> Carlos
On second thought I’ve got idea poweron & resets signals can actually look reasonably somewhere on extension headers. But keep in mind: system reboot is power hungry process, and it takes a lot of power, dissipated power can be worth of idling like a hour or maybe more on low frequency. Allwinner supports really low freqs like 60 and IIRC even 30MHz, under reduced core voltage. In this mode system power consumption is quite low.
Jan 11, 2016 @ 20:59:10
I hope, F-Antenna dimensions isn’t random and property simulated in some RF-software
Jan 13, 2016 @ 10:36:10
Not possibly to use ethernet AND lcd at the same time? This is just silly…
Jan 13, 2016 @ 10:38:45
makes perfect sense from tablet point of view, you either need LCD tablet and use WiFi, either desktop with HDMI TV and wired Ethernet
Jan 19, 2016 @ 21:16:54
Well, what I’m looking for is something like a “tablet” connected through ethernet (with power supply throught 802.3af/at)…
Jan 13, 2016 @ 14:43:50
You can always add a USB to Ethernet chip. They cost under $1. Or use external USB to Ethernet adapter.
Jan 19, 2016 @ 21:14:12
USB to Ethernet is slow.