[Arm-netbook] RK3399

[Pičugins Arsenijs]

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
Loading Image....
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.

Cheers!
Arsenijs

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[Luke Kenneth Casson Leighton]

Post by Pičugins Arsenijs
I've been looking at battery power solutions. EEE PCs use 2S LiIon batteries, meaning that usual PMIC like AXP209 don't fit.

there are dual-cell solutions out there, google bunnie huang laptop
power board.

Post by Pičugins Arsenijs
Thankfully, we don't need to do as much as AXP209 does (and the computer card has an AXP209 in it anyway).

yes but it's placed into "5V DC input only mode" i.e. VBUS is shorted
to DCIN (read the datassheet on this). cards must be treated as
OTG-POWER-CAPABLE. this is IMPORTANT. you need to respect the fact
that EOMA68's 5V power is DUAL DIRECTION JUST LIKE OTG POWER.

so you cannot just shove 5V in to the EOMA68 card you ABSOLUTELY MUST
have a one-way current-limiter at the ABSOLUTE MINIMUM (SY6280 does
this job very well). this will terminate all and any possibility of
doing OTG powering from incoming OTG Chargers but it is safer than
fucking up and killing the card *and* the Housing *and* the battery
*and* the DC mains power supply *and* the OTG Charger due to a current
fight between conflicting incoming power supplies.

bottom line: please do NOT design this circuit without public
consultation and without my FINAL approval. remember, i am
responsible for ensuring that the standard is safe for people to use.
if you do not agree to this then you may NOT claim it is interoperable
with EOMA68, you may not make ANY mention of EOMA68 anywhere at all.
not even to say "it is quotes like quotes EOMA68...."

apologies but i really need to be strict about this as it is down to
user safety. get it wrong and you could end up killing someone due to
a lithium battery fire.

l.

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[Pičugins Arsenijs]

 there are dual-cell solutions out there, google bunnie huang laptop
power board.

I've found AXP259, will give it a shot - but will also look into Novena power circuit, thank you!

 Thankfully, we don't need to do as much as AXP209 does (and the computer card has an AXP209 in it anyway).

 yes but it's placed into "5V DC input only mode" i.e. VBUS is shorted
to DCIN (read the datassheet on this). cards must be treated as
OTG-POWER-CAPABLE. this is IMPORTANT. you need to respect the fact
that EOMA68's 5V power is DUAL DIRECTION JUST LIKE OTG POWER.

That is very important - thank you for noting this. It should be straightforward to solve, thankfully. I've read the AXP209 datasheet before, and this is pretty much what I expected from looking at the card.

 so you cannot just shove 5V in to the EOMA68 card you ABSOLUTELY MUST
have a one-way current-limiter at the ABSOLUTE MINIMUM (SY6280 does
this job very well). this will terminate all and any possibility of
doing OTG powering from incoming OTG Chargers but it is safer than
fucking up and killing the card *and* the Housing *and* the battery
*and* the DC mains power supply *and* the OTG Charger due to a current
fight between conflicting incoming power supplies.

Makes sense. If my understanding is correct, this won't terminate the possibility of OTG charger powering the board. Say, you plug the card into the laptop (powered from battery), then plug a USB charger into the card. Given that the protection is, AFAIU, supposed to be right after the card's 5V pins on the PCMCIA socket, the end result would be: 1) protection IC being triggered 2) card being powered from the USB charger 3) all the remaining laptop internals being powered from the laptop battery. There's also one more question:

If a laptop is plugged in an AC source, plugging a USB charger will result into two power supply grounds being connected together - is there a possibility of anything destructive happening? Say, one charger is grounded and the other isn't, or they both are grounded, is there a possibility of current flowing?

 bottom line: please do NOT design this circuit without public
consultation and without my FINAL approval. remember, i am
responsible for ensuring that the standard is safe for people to use.
if you do not agree to this then you may NOT claim it is interoperable
with EOMA68, you may not make ANY mention of EOMA68 anywhere at all.
not even to say "it is quotes like quotes EOMA68...."

No worries! Will send you the schematic for a review - of course, to this mailing list, too (and I have other people to consult locally). You might want to make a set of requirements for EOMA68-compatible products that make them eligible for the "EOMA68" mention - I imagine that, if you don't set as much requirements as possible beforehand (especially when they're as important as this), it will be problematic for you to track down everybody who might create an EOMA68-capable housing and review their design practices. I also imagine that reviewing a schematic after a schematic will get tiring quickly.

Additionally, I suggest adding appropriate reverse current limiting to EOMA68 breakouts (available as Crowdsupply perks). If that's a feature that each and every breakout is very likely to need, you might as well make it easier for people to comply with the EOMA68 requirements (especially since all the people that ordered these breakouts are likely to do something out-of-line with them).

 apologies but i really need to be strict about this as it is down to
user safety. get it wrong and you could end up killing someone due to
a lithium battery fire.

This is perfectly understandable - if my product ended up causing an injury for somebody through no fault of my own, it wouldn't be pretty.

Cheers!
Arsenijs

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[Christopher Havel]

Ground is 0v. It's hard for me to explain, but it works both as sort of a
reference for whatever you use as +V supply (VCC) and as a return path...
if you have two power supplies, unless there are optocouplers involved, you
/want/ their grounds connected, as a general rule. That, however, does not
guarantee further trouble. Needing two supplies to power one device
typically results in one supply or the other trying to take on most of the
load, overloading, and blowing up -- leaving the second one to do the same
since it can't handle the full power of the circuitry....
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[Luke Kenneth Casson Leighton]

Post by Pičugins Arsenijs

Post by Luke Kenneth Casson Leighton
there are dual-cell solutions out there, google bunnie huang laptop
power board.

I've found AXP259, will give it a shot - but will also look into Novena
power circuit, thank you!

havent investigated it, basicalky if it does triple way powe managemt youre
good. batt otg dc

Post by Pičugins Arsenijs

Post by Luke Kenneth Casson Leighton

Post by Pičugins Arsenijs
Thankfully, we don't need to do as much as AXP209 does (and the

computer card has an AXP209 in it anyway).

Post by Luke Kenneth Casson Leighton
yes but it's placed into "5V DC input only mode" i.e. VBUS is shorted
to DCIN (read the datassheet on this). cards must be treated as
OTG-POWER-CAPABLE. this is IMPORTANT. you need to respect the fact
that EOMA68's 5V power is DUAL DIRECTION JUST LIKE OTG POWER.

That is very important - thank you for noting this. It should be
straightforward to solve, thankfully. I've read the AXP209 datasheet
before, and this is pretty much what I expected from looking at the card.

axp209 functionality is whats needed.

full triple power negotiation and protection.

axp209 does otg vbus detect, dc in and battery.

it is extremely complex.

Post by Pičugins Arsenijs

Post by Luke Kenneth Casson Leighton
so you cannot just shove 5V in to the EOMA68 card you ABSOLUTELY MUST
have a one-way current-limiter at the ABSOLUTE MINIMUM (SY6280 does
this job very well). this will terminate all and any possibility of
doing OTG powering from incoming OTG Chargers but it is safer than
fucking up and killing the card *and* the Housing *and* the battery
*and* the DC mains power supply *and* the OTG Charger due to a current
fight between conflicting incoming power supplies.

Makes sense. If my understanding is correct, this won't terminate the
possibility of OTG charger powering the board. Say, you plug the card into
the laptop (powered from battery), then plug a USB charger into the card.
Given that the protection is, AFAIU, supposed to be right after the card's
5V pins on the PCMCIA socket, the end result would be: 1) protection IC
being triggered 2) card being powered from the USB charger 3) all the
remaining laptop internals being powered from the laptop battery.

i will need to re-read this more later on a larger screen, i dont havevtine
to read it fully right now to check

it would help if you made a drawing or schematic.

or drew out the power tree of an axp209

Post by Pičugins Arsenijs
If a laptop is plugged in an AC source, plugging a USB charger will result
into two power supply grounds being connected together - is there a
possibility of anything destructive happening?

absolutely!

if two power supplies are comnected together without diodes or mosfets the
difference in their voltage results in a short circuit load across the path
between them. this is incredibly dangerous as if the pcb track does not
burn out the two sources definitely will.

Post by Pičugins Arsenijs
Say, one charger is grounded and the other isn't, or they both are
grounded, is there a possibility of current flowing?

grounded? you mean no circuit? then of course not.

you need to be clearer, draw a diagram.

Post by Pičugins Arsenijs

Post by Luke Kenneth Casson Leighton
bottom line: please do NOT design this circuit without public
consultation and without my FINAL approval. remember, i am
responsible for ensuring that the standard is safe for people to use.
if you do not agree to this then you may NOT claim it is interoperable
with EOMA68, you may not make ANY mention of EOMA68 anywhere at all.
not even to say "it is quotes like quotes EOMA68...."

No worries! Will send you the schematic for a review - of course, to this
mailing list, too (and I have other people to consult locally). You might
want to make a set of requirements for EOMA68-compatible products that make
them eligible for the "EOMA68" mention - I imagine that, if you don't set
as much requirements as possible beforehand (especially when they're as
important as this), it will be problematic for you to track down everybody
who might create an EOMA68-capable housing and review their design
practices. I also imagine that reviewing a schematic after a schematic will
get tiring quickly.

this has been done, as much as i could stand at the time, so there are
sections on the standard describing exactly what i have just Said.

libre people i.e. entire design, i will not charge and will go out of my
way to help.

anything proprietary, i have to charge for it as the impact has to be
carefully assessed.

Post by Pičugins Arsenijs
Additionally, I suggest adding appropriate reverse current limiting to
EOMA68 breakouts (available as Crowdsupply perks). If that's a feature that
each and every breakout is very likely to need,

too complex. akso there are two different approaches. thus itself is too
xomokex. akao there ate different current rewuiremenys different
voktages. all far too complex.

Post by Pičugins Arsenijs
you might as well make it easier for people to comply with the EOMA68
requirements (especially since all the people that ordered these breakouts
are likely to do something out-of-line with them).

if there was one battery standard one power requirement yes. too much
right now.

microdesktop is already a reference design. laptop is second. etc etc.

Post by Pičugins Arsenijs

Post by Luke Kenneth Casson Leighton
apologies but i really need to be strict about this as it is down to
user safety. get it wrong and you could end up killing someone due to
a lithium battery fire.

This is perfectly understandable - if my product ended up causing an
injury for somebody through no fault of my own, it wouldn't be pretty

and the reputation of eoma68 would be destroyed in the process.

all rhe work of the past 6 years... all gone, because someone arrogantly
thought they knew better and didnt have to listen. so i will be really
really strict about this

just the way it has to be

Cheers!

Post by Pičugins Arsenijs
Arsenijs
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[r***@Safe-mail.net]

-------- Original Message --------
From: Pičugins Arsenijs<***@yandex.ru>
Apparently from: arm-netbook-***@lists.phcomp.co.uk
To: "arm-***@lists.phcomp.co.uk" <arm-***@lists.phcomp.co.uk>
Subject: Re: [Arm-netbook] RK3399
Date: Fri, 09 Feb 2018 13:38:40 +0200

For your information, I am in a censorship dispute with lkcl. I do
not know what he will come up with. Maybe some or all of my
posts will be stopped.

Post by Pičugins Arsenijs
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).

When the pc card is being shipped there will be no cabinet
or a 15inch notebook available in terms of cabinets with
a display.
I agree the more different cabinet sizes present, even if
modified computer cabinets, the better. I do not
follow lkcl's opposition on this.

Post by Pičugins Arsenijs
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).

Yes.

Post by Pičugins Arsenijs
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?

It is a weller sp 40l 40w.
In case I did not mention it before. I have a raspberry pi 0 and
a beaglebone black revision c if that could be useful.

Post by Pičugins Arsenijs
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 will get the ribbonconnector. I still have the asus eeepc's mainboard.

The pocketchip's keyboard is an i2c keyboard. Is the asus
eeepc's keyboard also an i2c keyboard?
Lkcl has said, the pc card supports i2c. Instead of
modifying the asus eeepc's keyboard into an usb
keyboard, what about i2c connecting the keyboard to
the pc card? To my knowledge you can use the
beaglebone black revision c to test i2c devices.
I found a video on youtube on the matter.

I have this forestalled remark. I would prefer not to cut
in the asus eeepc's cabinet. If I do it wrongly, I do not have
another cabinet.
Instead at the bottom of the asus eeepc there is a removable
plate. There is a balk which likely can be removed. I would
prefer to insert the pc card by that plate.

I have not been able to find something like the pcmcia/eoma
68 breakout board. Should we not find a shop to buy
one?

I will start a new post named 'asus eeepc 7inch, modifying
it to accept a pc card' for further postings.

Post by Pičugins Arsenijs
bottom line: please do NOT design this circuit without public
consultation and without my FINAL approval.

Thank you for your warning. And participation.

Post by Pičugins Arsenijs
http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook

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