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.
Cheers! Arsenijs
On Fri, Feb 9, 2018 at 11:38 AM, Pičugins Arsenijs crimier@yandex.ru wrote:
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.
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.
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
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....
On Saturday, February 10, 2018, Pičugins Arsenijs crimier@yandex.ru wrote:
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
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.
axp209 functionality is whats needed.
full triple power negotiation and protection.
axp209 does otg vbus detect, dc in and battery.
it is extremely complex.
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
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?
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.
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.
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.
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.
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.
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!
Arsenijs
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Christopher Havel -
Luke Kenneth Casson Leighton -
Pičugins Arsenijs