[Arm-netbook] RK3399

Pičugins Arsenijs crimier at yandex.ru
Fri Feb 9 11:38:40 GMT 2018

> If the pc card gets shipped, then I got one.

Great, I got one, too - so we can start the design, keeping a computer card in mind =) Rounded up all my EEE PCs and EEE PC accessories, turns out I have a box full of EEE PCs - got three 701s (one working) and one working 900 (basically, 701 with a bigger screen & slightly extended motherboard).

> I want to frame this enterprise a bit more.
> It must be a hobby thing. You are not obliged
> to anything and you can skip any time you
> want. I will not hold it against you.

It's a hobby thing for me, too - it's just that I'm really interested in making it work, partly because I don't see why it wouldn't, partly because I'd like to build something new and interesting with EOMA68! There's even a chance I'll get so caught up with my other projects so as to never finish this one - while it's an unlikely outcome, it's still possible. I assume you expect the same treatment from my side - which is perfectly fine to me.

> One
> reason why I will not put large money
> into it. That way it is not a big deal if
> we do not succeed.

About large amounts of money - this project being expensive is unlikely, mostly because I don't *have* any large amounts of money to put into such a thing, so it will indeed have to be low-budget.

> We should do without time frames.
> Shipping the pc card appears to lay
> months ahead.

Yep, thankfully, the laptop will likely take a while anyway. What I'd personally be interested in is making it all work before the start of next EOMA crowdfunding, or maybe during it (so that the crowdfunding gets some more publicity and is taken even more seriously).

>>  would you be interested in a videocall
>>  of some sorts?
> On forums I prefer to stay anonymous.
> If things turn ugly I can walk away.
> If required can we get by using an
> irc or another messenger?

I'm mostly interested in desktop sharing from my side, so that I can show how to draw a simple board. No other requirements from your side, webcam definitely not needed (though having a voice channel would be great). If you're interested, I can stream my desktop to something like Twitch, so that you can view it (and whoever else wants to).

>>  drawing the PCB, I can show you
>>  the basics of KiCad
> For preparation, maybe you could
> state some links I should have a
> look on?

I have no idea, I learned KiCad when I started drawing stuff. I think that something like "KiCad: Getting To Blinky" ( https://contextualelectronics.com/courses/getting-to-blinky/ ) could help with basics, a lot - it's a well-known KiCad tutorial.

> I should mention I have a solder
> iron and a multimeter.

Great! Once we'll have first boards (say, keyboard matrix), we might require some more tools - but nothing expensive or complicated. Do you have a photo of your soldering iron somewhere (maybe a similar photo on the internet) - just to make sure it's the right one for the job?

> About my comments on the devices
> I wanted to express that I prefer less
> complicated solutions. I was not
> telling you what solution to
> select.

Oh, that's OK, and totally makes sense - I'm just starting to round up components, see what's suitable for us, and what isn't =)

> The asus eee pc 4g's keyboard is
> model v072462ak1 revision
> 1.0 gr. The ribbon has 28
> wires and the ribbon is 28mm
> wide.
> On ebay I have found this ribbon
> connector
> https://i.ebayimg.com/images/g/gkgAAOSwZB9Z-YIL/s-l1600.jpg.
> Should I get one?

I've measured connectors on my boards, and it looks like the right one. Worst case - I can desolder a connector from my boards and mail it to you. Notes: from these 28 pins, one is GND (for some reason) and one is NC (not connected), and two pairs of pins are in parallel. So, we'll need a microcontroller with 24 free GPIOs, or a cheap I2C IO expander added. Seeing how the keyboard is a 16x8 matrix, a GPIO expander could fit very well (alternatively, we could copy whatever solution is used in some kind of popular DIY keyboards, provided we can find one that suits the row/column count).

I've been looking at battery power solutions. EEE PCs use 2S LiIon batteries, meaning that usual PMIC like AXP209 don't fit. Thankfully, we don't need to do as much as AXP209 does (and the computer card has an AXP209 in it anyway). For a start, we need to charge the battery, have some kind of signal when charger is present, optionally, step down the voltage to 5V. I've found AXP259, which does all three and should fit. I'll ask for a sample - I don't expect it any soon though, it's Chinese New Year, after all. I wonder if they'll even send a sample - I guess I'll purchase a couple of these in parallel, just in case.


More information about the arm-netbook mailing list