http://rhombus-tech.net/community_ideas/laptop_15in/news/
it's by no means perfect, but i have at least data on-screen. i suspect EM interference is causing the corruption, so another revision of PCB1 will need the LVDS IC layout to be reworked. this is however huge progress. the only 2 parts of PCB1 that need to be checked and debugged are the MicroSD card slot and the 1W speaker/headphone amplifier circuits. the CM108AH USB Audio IC has already been confirmed as operational on the USB bus, as has the GL850G and the 3 USB ports.
l.
On Tuesday 1. December 2015 17.05.31 Luke Kenneth Casson Leighton wrote:
http://rhombus-tech.net/community_ideas/laptop_15in/news/
it's by no means perfect, but i have at least data on-screen. i suspect EM interference is causing the corruption, so another revision of PCB1 will need the LVDS IC layout to be reworked. this is however huge progress. the only 2 parts of PCB1 that need to be checked and debugged are the MicroSD card slot and the 1W speaker/headphone amplifier circuits. the CM108AH USB Audio IC has already been confirmed as operational on the USB bus, as has the GL850G and the 3 USB ports.
Nice work on getting this far, despite the "gothic" font. ;-)
Now if only the established players would see sense and support this effort instead of dumping excess stock SoCs into newsagents on the covers of magazines and causing scuffles in the aisles. :-/ OK, well, maybe not that established player, but at least the likes of Adafruit and Sparkfun...
Paul
On Tue, Dec 1, 2015 at 5:25 PM, Paul Boddie paul@boddie.org.uk wrote:
On Tuesday 1. December 2015 17.05.31 Luke Kenneth Casson Leighton wrote:
http://rhombus-tech.net/community_ideas/laptop_15in/news/
it's by no means perfect, but i have at least data on-screen. i suspect EM interference is causing the corruption, so another revision of PCB1 will need the LVDS IC layout to be reworked. this is however huge progress. the only 2 parts of PCB1 that need to be checked and debugged are the MicroSD card slot and the 1W speaker/headphone amplifier circuits. the CM108AH USB Audio IC has already been confirmed as operational on the USB bus, as has the GL850G and the 3 USB ports.
Nice work on getting this far, despite the "gothic" font. ;-)
it gets really weird when doing echo "hello" > /dev/tty1 - the on-screen display is rather... garbled. i'll try a 3rd CPU Card later, and/or perhaps set up dual-output (via HDMI) to check that it's not the framebuffer that's corrupted.
Now if only the established players would see sense and support this effort instead of dumping excess stock SoCs into newsagents on the covers of magazines and causing scuffles in the aisles. :-/
yehhh you saw the report a few days ago by Make magazine, which showed that the cost of that $5 board is considerably higher:
"Solving this lack of connectivity makes the cost of owning a Pi Zero increase greatly. It’s not just that you need a USB Wi-Fi dongle, you’d need a powered USB hub to have a Wi-Fi dongle, keyboard, and mouse (it only has one USB slot for peripherals; the other is for power)."
http://makezine.com/2015/11/28/chip-vs-pi-zero/
further down, it shows that the only thing you need to operate the C.H.I.P is a $1 USB cable, to provide power. the alternative board - which is "only" $5 - requires a whopping *$19* of additional components in order to make it actually useful.
l.
On Tue, Dec 1, 2015 at 4:05 PM, Luke Kenneth Casson Leighton lkcl@lkcl.net wrote:
... the only 2 parts of PCB1 that need to be checked and debugged are the MicroSD card slot
confirmed working. the GPIO pin of the T-FLASH slot had not been soldered, despite having 260 Centigrade temperatures applied from an IR heat lamp placed 2cm above it for around 4 minutes. soldering iron took care of that, and the micro-sd card slot on PCB1 is operational.
that means that the laptop can boot directly from external micro-sd, now, when using an A20 CPU Card. reason: space is so tight on the 6-layer 43x78mm EOMA68-A20 PCB that it was impossible to route SDC0 over to the *opposite* side of the PCB whilst at the same time crossing SDC3 in the reverse direction, as the A20 and the DDR3 RAM take up the centre of the board, leaving very little space for routing. there are only 3 signal layers (TOP, BOTTOM, layer3).
just the TDA2822 amplifier circuits and the microphone to verify as operational, and to track down why the LCD is wobbly, and PCB1 is done.
l.
Great to see further progress. Keep it up!
At the Dutch T-Dose conference had a couple of visitors at the FSFE-booth mentioning how great it would be if finally a totally free laptop would become available. Have referred them to this project because this seems the only sensible approach to reach this ultimate end goal, and because it shows just how difficult it is to achieve this goal in a voluntary effort. Getting a fully free laptop is certainly easier set then done.
Furthermore I couldn't help but notice that one of the most restricted laptops in the world is being used to create the most free laptop in the world.
Regards, Nico (NL)
On di, 2015-12-01 at 16:05 +0000, Luke Kenneth Casson Leighton wrote:
http://rhombus-tech.net/community_ideas/laptop_15in/news/
it's by no means perfect, but i have at least data on-screen. i suspect EM interference is causing the corruption, so another revision of PCB1 will need the LVDS IC layout to be reworked. this is however huge progress. the only 2 parts of PCB1 that need to be checked and debugged are the MicroSD card slot and the 1W speaker/headphone amplifier circuits. the CM108AH USB Audio IC has already been confirmed as operational on the USB bus, as has the GL850G and the 3 USB ports.
l.
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On Tue, Dec 1, 2015 at 9:31 PM, Nico Rikken nico@nicorikken.eu wrote:
Great to see further progress. Keep it up!
:)
At the Dutch T-Dose conference had a couple of visitors at the FSFE-booth mentioning how great it would be if finally a totally free laptop would become available. Have referred them to this project because this seems the only sensible approach to reach this ultimate end goal, and because it shows just how difficult it is to achieve this goal in a voluntary effort.
in a word... yes. i had to make some... interesting design decisions shall we say - going for example with a custom 3D-printed case instead of attempting to work with china-based factories [who will not respond to enquiries for anything less than 10k orders, because they know the cost of injection-mold casts]. and that took 6 *MONTHS* to complete the [15] parts needed, which is just a staggering amount of time - waay more than i was expecting.
keeping it simple - going with USB2 not USB3. cutting out all hard drives and using USB or MicroSD storage. finding a low-power 15.6in screen (sub 5 watt). keeping the power consumption to under 15 watts so that a single-cell battery charger IC could be used instead of needing multiple cells (which wouldn't fit into the casework design anyway)...
a whole boat-load of details all of which basically steer things in ways that you might not have considered at the outset...
Getting a fully free laptop is certainly easier set then done.
yeah. there's quite a few efforts popped up in the past year, including http://www.powerpc-notebook.org. they're going to run into the same challenges, and i hope that they have the good sense to read the reports of the experiences i've encountered along the way, just like i read the experiences of the openpandora, the kosagi laptop and other projects and learned from those.
Furthermore I couldn't help but notice that one of the most restricted laptops in the world is being used to create the most free laptop in the world.
*sigh* i knowww... it's rather unfortunate that the higher perceived quality of the proprietary software means you end up with a highly profit-rich company that can afford to purchase the best components and make the highest quality hardware products. first thing i did though was blow away the OS, install rEFInd, and boot up debian. i'm not interested - at all - in the proprietary OS, i want a hardware product with an exceptionally high resolution screen, light weight, good build quality, and high specs all round for the money.... and now that i've got one, i won't replace it for 5-8 years.
at the time i _did_ try to buy an IBM laptop... their web site failed, at the time, however, preventing and prohibiting me from giving them any money!
later on i'll be able to tackle creating high-end hardware - not entirely sure about how to go about that, yet. have to see what SoCs are available in 5-8 years time, as well as what display output standards become commonplace.
i can say that i am most certainly *NOT* going to be buying a smartphone. ever. i bought *nine* HTC hand-helds back around 2002 to 2005, i was one of the early reverse-engineers working on removing wince from HTC phones and replacing it with openembedded-built GPE/Familiar based on Angstrom Linux. so i've made the decision: i'm not going to own another smartphone - ever - unless i've made it myself.
laptop/workstation however.... yyeah, i have to have something otherwise i can't get anything done at all!
l.
On Tue, 2015-12-01 at 16:05 +0000, Luke Kenneth Casson Leighton wrote:
http://rhombus-tech.net/community_ideas/laptop_15in/news/
it's by no means perfect, but i have at least data on-screen. i suspect EM interference is causing the corruption
Looks to me like a timing signals error from the CPU with the LCD driver chip trying to do its best to keep sync.
Need to check with a scope against the specs of the LCD and what the CPU is generating.
On Wed, Dec 2, 2015 at 2:49 PM, joem joem@martindale-electric.co.uk wrote:
On Tue, 2015-12-01 at 16:05 +0000, Luke Kenneth Casson Leighton wrote:
http://rhombus-tech.net/community_ideas/laptop_15in/news/
it's by no means perfect, but i have at least data on-screen. i suspect EM interference is causing the corruption
Looks to me like a timing signals error from the CPU with the LCD driver chip trying to do its best to keep sync.
it's as if the HSYNC - no matter what parameters are used - is entirely missing. so the LCD takes the very first bits of each line and uses that as "sync".
Need to check with a scope against the specs of the LCD and what the CPU is generating.
yehh my scope's only a max of 75mhz (maplin's digital scope)
and i can't ramp things down in order to check, because the 3.4 kernel sunxi lcd code changes the clk_div parameter when the dclk rate is set lower, such that entirely different code is activated.
tricky...
l.
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