arm-netbook July 2020

arm-netbook@lists.phcomp.co.uk

11 participants
10 discussions

Schematic and PCB layout CAD files
by Arun Isaac 01 Feb '22

01 Feb '22

Hi, Are the schematic and PCB layout CAD files for the EOMA68 computer card and the various housings available for download? I'm wondering if I can fabricate some of the housings on my own using a CNC mill. Hence, my interest in them. Sorry I had to ask. I searched very hard through the crowdsupply page and the rhombus-tech site, but couldn't find them. Thanks, Arun.

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Current status
by George Sokolsky 28 Nov '20

28 Nov '20

Hi, sorry to interrupt - does that look like we're not getting our EOMAs this year again, if ever? How people are moving forward with their computing needs? What's the 'next best thing' to invest here? George

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EOMA68-A20, MD 1.7 severe Power Problems
by Pablo Rath 26 Jul '20

26 Jul '20

I am very sorry to inform everyone on this list that I had a severe power problem with my Micro Desktop 1.7. I applied power to the DC Jack and the area right to the jack burned out. (see attached picture). One thing that I noticed today was that UART worked when the card was powered up whilst attached to USB OTG alone (DC Jack on MD not connected)! But according to the wiki this should not work at all because of the Y6280 current control IC set at 1A acting as a diode in this case. When I applied power only to the MD I noticed that UART output was complete garbage (random characters). I don't know if only sometimes or everytime. When on DC power, board in FEL-mode with no card and pressing '2', then connecting USB OTG and booting U-Boot sunxi over FEL everything worked flawlessly. As I said I am very sorry that I screwed up. Luke, do you have any ideas what went wrong? Do you think this +also destroyed the computer card? If the error is on my side (embarassing but still the better +case) I will have to swallow the bitter pill that I screwed up badly. I am still going to cover the costs of computer card and MD so there will not be a financial loss to the project. I am very disappointed as I have made could progress. Had sunxi U-Boot, sunxi 3.4.104 kernel running and booting Debian Stretch rootfs... On the other hand if this is a general problem better we know it now and can take the necessary steps. Pablo

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2.7.5 latest pre-production boards tested and working
by Luke Kenneth Casson Leighton 26 Jul '20

26 Jul '20

yes, a few months ago, mike sent me 2 new prototypes, using "single-panel" PCB from a high-quality manufacturer. i tested them just now (yes, long story, very busy with Libre-SOC) and they work fine. boot off of the usual micro-sd card i've been using. l. --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68

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Resending: EOMA68-A20, MD 1.7 severe Power Problems
by Pablo Rath 26 Jul '20

26 Jul '20

Resending without attachement: I am very sorry to inform everyone on this list that I had a severe power problem with my Micro Desktop 1.7. I applied power to the DC Jack and the area right to the jack burned out. (see attached picture). One thing that I noticed today was that UART worked when the card was powered up whilst attached to USB OTG alone (DC Jack on MD not connected)! But according to the wiki this should not work at all because of the Y6280 current control IC set at 1A acting as a diode in this case. When I applied power only to the MD I noticed that UART output was complete garbage (random characters). I don't know if only sometimes or everytime. When on DC power, board in FEL-mode with no card and pressing '2', then connecting USB OTG and booting U-Boot sunxi over FEL everything worked flawlessly. As I said I am very sorry that I screwed up. Luke, do you have any ideas what went wrong? Do you think this +also destroyed the computer card? If the error is on my side (embarassing but still the better +case) I will have to swallow the bitter pill that I screwed up badly. I am still going to cover the costs of computer card and MD so there will not be a financial loss to the project. I am very disappointed as I have made could progress. Had sunxi U-Boot, sunxi 3.4.104 kernel running and booting Debian Stretch rootfs... On the other hand if this is a general problem better we know it now and can take the necessary steps. Pablo ----- End forwarded message -----

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DDR3 RAM Design Rules and Techniques
by Paul Boddie 25 Jul '20

25 Jul '20

Hello, One thing that just came up in another forum is the matter of routing PCB tracks for DDR3 RAM, and this is probably a topic that was encountered by both the Pyra... https://pyra-handheld.com/boards/threads/analyzing-4gb-ram.81687/ https://pyra-handheld.com/boards/threads/is-there-really-a-light-at-the-end… ...and the EOMA68 initiatives. Is there any pertinent documentation describing this exercise in the EOMA68 board design process? Searching for DDR3 on the Rhombus Tech site [*] indicates that some boards were done with guidance (at some level) from the vendors: http://rhombus-tech.net/ingenic/jz4775/news/11jul2014_routing_completed/ http://rhombus-tech.net/allwinner/a31/news/ Previous discussions of KiCad and Olimex boards, which presumably involved DDR3 routing, can be found via this message: http://lists.phcomp.co.uk/pipermail/arm-netbook/2019-May/016062.html I ask about this in the context of someone who just made design files available for a board using the Ingenic JZ4780 that they had been working on. Those files are here: https://gitlab.com/igagis/cranberrypi Paul [*] http://rhombus-tech.net/cgi-bin/rhombus/ikiwiki.cgi?P=DDR3

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Current not intel Laptop/UMPC/Handheld Options
by Alexander Ross 25 Jul '20

25 Jul '20

Been wondering if theres any new products from the last say 2years? As i’ve not kept up with whats new else where. I know pyra is progressing and dare i say, nearly ready. For a laptop/umpc the more ram the better but a netbook size keyboard thats easy for large adult hands to type on. when i was a teenager i think keyboards like GPD pocket 1 where not so hard to type on but the pocket came at a time when i was at the end of teenage years and had grow more/fully and now i find it it bit awkward to type on, unlike my 10inch asus netboot. Any fav chrome books to librate? new handheld computers?, including intel cpus out of curiosity. like pyra, smaller or a bit bigger. or heck large laptops but not intel or amd? I do know of power cpu laptop projects. https://pyra-handheld.com/boards/forums/pyra-news.250/

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openpower virtual coffee
by Luke Kenneth Casson Leighton 23 Jul '20

23 Jul '20

https://openpowerfoundation.org/openpower-virtual-coffee-calls/ in 2 hours. conference call dial-in numbers at the above web page (which do not involve running non-free proprietary software to attend) these are an open informal chat, not recorded, no "agenda". topics have been thoroughly eclectic and enjoyable. l. --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68

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2.7.4 preproduction sample, 1.7 MD, Questions
by Pablo Rath 22 Jul '20

22 Jul '20

I have recieved an EOMA68-A20 2.7.4 preproduction computer card and the 1.7 micro desktop (MD) last week. Just for clarification these boards are nothing new and have been discussed on this mailing list. If some of you already have their preproduction boards ready, I would appreciate any help, hints and suggestions to help me getting started. Altough I have some experience with handling arm-boards I am now afraid to do something **stupid** and break/fry the boards. After some digging in the list-archives I found this thread ([1]) where Richard and Luke discuss how to connect the bare computer card with the bare micro desktop. I have many questions: 1. Connecting computer card and micro desktop: I am aware of the photos attached to [2]. Does the mentioned video exist? Richard, did you send photos to Luke? (If yes, can I have them?) Luke, do you want me to send you photos too before apllying power? 2. PSU for micro desktop: According to the mentioned thread ([1]): "5.5mm jack with a 2.1mm centre hole, middle is +ve (aka "pin positive")", "Anywhere between 7 and 21v is fine, minimum 1A, 1 5A is better" So I searched for a DC PSU in my household and read Wikipedia where it is mentioned that OD 5.5 mm / ID 2.1 mm is common on guitar effect pedals but my multi guitar effect pedal PSU did not fit (ID too small). Finally I found a matching DC PSU from a low volatage guitar amp. It says O / P: DC 15V, 2A and a symbol (positive polarity): L. P. S. - -(.- + So I think this should be good to go. Can anyone please confirm. Thank you. Should we document this somewhere on rhombus-tech.net? 3. Soldering iron ready: I have my soldering iron ready. Richard, did you solder UART pins to the micro desktop ([3])? 4. SD-card ready / U-Boot Tried to compile u-boot-sunxi [4] and make exits with "System not configured". So Luke, what did you use as config or has something changed over the years? I also tried mainline U-Boot but could not find "EOMA68-A20-foo_defconfig" and "sun7i-eoma68-a20-foo.dts". What kind of defconfig and *.dts was used for the mainline U-Boot demos? My search of the mailing list archives and rhombus-tech was not futile. I could only dig up an old thread from 2014 where wookey was "assigned" to work on a minimal dts/dtb. 5. Git, notes and documentation Finally I am wondering where to put my notes. A subpage on rhombus-tech seems like a good idea good to me and indicates a work in progress in contrast to the various wikis out there. Where do you want me to push my work in progress git branches if I manage to hack something useful together? Pablo References: [1] http://lists.phcomp.co.uk/pipermail/arm-netbook/2019-July/016149.html [2] http://lists.phcomp.co.uk/pipermail/arm-netbook/2019-July/016154.html [3] http://lists.phcomp.co.uk/pipermail/arm-netbook/attachments/20190722/914a32… [4] http://rhombus-tech.net/allwinner/a20/boot/

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EOMA68 Computing Devices Update: Command Not Found
by Pičugins Arsenijs 07 Jul '20

07 Jul '20

https://www.crowdsupply.com/eoma68/micro-desktop/updates/command-not-found Note on the 'lsusb' thing: I personally like the 'dmesg -Hw &' command, it stays in the background and prints the dmesg info in realtime - in particular, letting you see detailed data about newly-connected devices.

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arm-netbook July 2020