[Arm-netbook] Future case idea: subnotebook/PDA with QWERTY keyboard

[Joseph Honold]

On 09/02/2016 09:33 AM, Joseph Honold wrote:
> I've been looking at various LCD options and all of the RGB ones that are 3.5"-4" have low resolution (320x240, 480x320, and expensive 640x480). This lead me to look at MIPI DSI displays which are cheaper with higher resolution but more complicated requiring a conversion IC. I see mention of the SSD2828 RGB to MIPI chip in the mailing list which seems low cost and it is already used in a couple A20 devices. Has anyone had experience with this chip? It seems u-boot enables it but I'm not sure how linux interacts with it.
> 
> http://arm-netbook.phcomp.co.narkive.com/tTYfuse7/rgb-to-mipi
> http://linux-sunxi.org/SSD2828

I poked #linux-sunxi on irc and found out u-boot (mainline) sets up the SSD2828 device and passes it over to linux (mainline) SimpleFB driver. The MSI Primo 8.1 tablet uses the SSD2828 and has an example configuration 

https://github.com/linux-sunxi/u-boot-sunxi/blob/mirror/next/configs/MSI_Primo81_defconfig

I currently have a Marsboard A20 and was able to get u-boot/linux mainline running on it the other day. My plan is to create a ssd2828 breakout board that I can do some testing with the Marsboard in preparation for designing an EOMA68 housing. The LH350WS1-SD01 3.5" 640x960 LCD is used in the iPhone 4 and I have several (with cracked glass, but working display :) that I will use for testing. This LCD seems like a good option as it appears to be available from some distributors and ebay/alibaba. Popularity of the iPhone 4 (even while being older) should hopefully mean parts will be available for some time. Cracked touchscreens/glass with working LCD is common so used/refurbished parts are an option. I'm looking at the CAT4237 from onsemi for the backlight circuit with this LCD (6 series white LEDs). 

The eoma68-A20 card is shipping with linux 3.4 and is (of course) possible to upgrade to u-boot/linux mainline. How would a special configuration like this be handled by the standard where your housing requires a special bootloader/kernel? Is it just a matter of having a boot device on the housing (sd card, usb, etc)? Does the eeprom fit in this process somehow?

>> On 09/04/2016 03:11 PM, Paul Boddie wrote:
>>>
>>> That's asking for trouble! One thing I wouldn't mind knowing is how
>>> decent space bars are done using domes. Do they really involve multiple
>>> domes, or are there elongated ones that do this job?
>>
>> What trouble?
>
>I just meant that everybody has their own favourite layout. 

Agreed :) I'm not tied to the layout I posted, it was just an example idea and was partly based off the Zipit layout which I'm quite familiar/comfortable with now. Keyboard layout is probably going to be one of the difficult things and that's why I hope more people here can post examples that they do approve-of/prefer/make-up.