[Arm-netbook] asus eeepc 7inch, modifying it to accept a pc card

[Pičugins Arsenijs]

> This post is about modifying an asus eeepc 7inch notebook into accepting
> a pc card. You are invite to contribute.

Following up on the "RK3399" email:

> 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.

I'm going to get an EEEoma Wiki up in the following week and start documenting everything there; if you end up losing posting privileges, feel free to email me directly.

> I do not follow lkcl's opposition on this.

He's trying to make sure that the resulting design is safe and 1) won't ruin reputation of EOMA68 2) will be a good reference design for other designers that want to make EOMA68-compatible things, so that their designs won't ruin the EOMA68 reputation.

> It is a weller sp 40l 40w.

It seems to have a wide tip, so I'm wondering if it's suitable for soldering things like a 0.8-pitch connector... We'll see. At worst, you can get a working soldering iron for $5 from China, and a set of good tips for $5 more.

> 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.

Those could be useful for testing, I think.

> I still have the asus eeepc's mainboard.

That's great =) So we likely can harvest a couple of chips from it if necessary.

> The pocketchip's keyboard is an i2c keyboard. Is the asus
> eeepc's keyboard also an i2c keyboard?

The pocketchip's keyboard, just like the EEE PC keyboard, is not I2C by itself - it's a key matrix, and there's usually a controller that connects to this key matrix. In PocketCHIP's case, it talks I2C - in case of EEE PC, that controller is a part of Embedded Controller on the EEE PC mainboard (which controls a whole load of  functions), so we're making our own controller by taking a microcontroller, putting it on a board with a 28-pin connector and writing a firmware for it.

> Instead of
> modifying the asus eeepc's keyboard into an usb
> keyboard, what about i2c connecting the keyboard to 
> the pc card? 

Either that, or use PS2 - since we likely will have a PS2-USB chip anyway (for the touchpad). The benefit of using PS/2 is that we won't need to write our own kernel driver - however, we will need to find a way to reliably source PS2-UAB converter chips, or converter boards.

> To my knowledge you can use the 
> beaglebone black revision c to test i2c devices.

You can also use the Pi Zero for the same task, if I understand you correctly (just FYI).

> 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.

Hmm. That's tricky - I was planning to suggest the "cutting" approach, but I don't know of a good way to cut into the cabinet so that it's easy and mistake-proof. Thankfully, I have 2 spare cases to experiment with, and I have some ideas =)

> 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'll measure it and see if it's suitable - that is, if we can even insert the card. I can't yet imagine how it would work, but I will think about it. (the space inside the EEE case is quite limited, so there's only so many ways to keep the card in).

> 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 haven't yet found PCMCIA breakouts (or EOMA68 breakouts, for that matter), so it's not a commodity item, and I'm guessing that places that have them will have it at high prices, just because it's not that popular. Lkcl has breakouts listed on Crowdsupply, but I imagine there's some time until they will be manufactured and available. Until that, we can either work on other tasks - and, later on, we can design our own breakouts if it proves necessary.

Cheers!
Arsenijs