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1082 discussions

Re: [Arm-netbook] A question about VREFTTL
by Internet 27 Dec '16

27 Dec '16

Great! That really helps me. By the way: In the pinouts table on elinux.org <http://elinux.org/Embedded_Open_Modular_Architecture/EOMA68/Hardware> (http://elinux.org/Embedded_Open_Modular_Architecture/EOMA68/Hardware) there are duplicate signals on pins 27 and 28, I am pretty sure that pin 27 was meant to be SSRX- instead of SSTX-. On 27.12.2016 05:23, Luke Kenneth Casson Leighton wrote: > --- > crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 > > > On Mon, Dec 26, 2016 at 6:00 PM, Internet <internet(a)devpi.de> wrote: >> Hey, I am planning a custom project utilizing the EOMA68 standard > cool! > >> and I was wondering about VREFTTL. > ya. > >> What I have read so far (elinux.org) is that VREFTTL refers to the >> maximum voltage that can be applied to the GPIOs. My questions are >> though: Is VREFTTL always 3.3V > *NO* it's not. > >> or can it be lower? > between 1.8 and 3.3v, at the moment. anything lower will need to be > negotiated in a FUTURE standard (and the "default" range of 1.8v to > 3.3v will be respected, for older Housings. that means SoCs will need > to have variable voltage power domains, but that's actually becoming > quite common. > > >> What should I do, if >> some ICs require a certain supply voltage > please do NOT make the mistake of using VREFTTL as a *SUPPLY* > voltage. most (complex-function) ICs have a VDD (digital supply > voltage) and a VCCIO. the VCCIO is what you connect to the VREFTTL. > take a look at the SN75LVDS83b or the TFP401a for examples. > >> and VREFTTL does not meet the >> requirements? > find another IC that meets the variable-voltage 1.8 to 3.3v CMOS > reference voltage or do level conversion. > >> Would it be necessary do level shifting in advance (to be >> compatible with other voltages)? > yyep. there's a number of ways to do it, dozens of ICs and circuits: > the TXS0104 is great because it supports both open drain and > push-push, you can use a MOSFET, or in some cases a straight diode > will do (in a really counter-intuitive way, but it works). take a > look on the rk3288 schematic PDF, look for the HDMI page, you'll find > a suitable converter circuit using a MOSFET (and protection diode). > > http://hands.com/~lkcl/eoma/rockchip_rk3288/ > > l. > > > >> How much current can I draw out of the >> computing card? > up to around 300mA. do *not* go beyond that. > > _______________________________________________ > arm-netbook mailing list arm-netbook(a)lists.phcomp.co.uk > http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook > Send large attachments to arm-netbook(a)files.phcomp.co.uk

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A question about VREFTTL
by Internet 27 Dec '16

27 Dec '16

Hey, I am planning a custom project utilizing the EOMA68 standard and I was wondering about VREFTTL. What I have read so far (elinux.org) is that VREFTTL refers to the maximum voltage that can be applied to the GPIOs. My questions are though: Is VREFTTL always 3.3V or can it be lower? What should I do, if some ICs require a certain supply voltage and VREFTTL does not meet the requirements? Would it be necessary do level shifting in advance (to be compatible with other voltages)? How much current can I draw out of the computing card? Thank you, Julius Lehmann

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EOMA68 and display upsampling
by Tor, the Marqueteur 23 Dec '16

23 Dec '16

I was reading through the recent archives, and the question of displays and upsampling caught my eye. On list it was noted that upsampling is an expensive operation (and it certainly is), but I'm not sure it has to be. As I recall, most LCDs when driven with a lower resolution than native, will simply repeat interspersed rows/columns as needed to fill the display. It looks dreadful, but it works. Alternatively, is there any reason a display for type I couldn't be set to recognize a type II 1366x768 and display it in the centre of the display to avoid artifacts? Or should such a display have a button to switch modes so that it can display full screen with anything? Tor -- Tor Chantara http://www.fineartmarquetry.com/ GPG Key: 2BE1 426E 34EA D253 D583 9DE4 B866 0375 134B 48FB *Be wary of unsigned emails* Stop spying: http://www.resetthenet.org/

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Laptop Housing Questions
by Jonathan Frederickson 21 Dec '16

21 Dec '16

Hey, I have a few questions about the laptop housing. - How does one connect it to power? Can it be powered over USB or does it require a specific AC adapter? I have a portable solar array with a battery pack that can charge portable devices over USB, and I'm trying to work out whether or not I'll be able to power the laptop from it. - What's the average power draw of the laptop housing with an EOMA68-A20 card? If my rough calculations are correct, I think it should be around 6.25-8.3 W? (Looking into CPU power specs has given me quite a bit of respect for Intel's engineers; it's amazing that modern laptops are able to do so much with so little power.)

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Warning about tablets/netbooks with detachable keyboards
by dumblob 19 Dec '16

19 Dec '16

Hi Luke, just a tiny note about your mentions of a "tablet/netbook" in https://www.crowdsupply.com/eoma68/micro-desktop/updates/latest-from-shenzh… . In case you're planning to have the keyboard detachable (even worse if this detachable piece should have some connectors like USB), think of it twice as per experience of many users of different such tablets/netbooks (youtube is full of such reviews), the detachable connection is very fragile (because the detachable design requires a shallow or rather just "touching" connection in contrast to "sliding" deeper connectors like USB). Therefore there will be a need for advanced SW means (from Linux kernel through all daemons up to GUI) to cope with interrupted keyboard input, interrupted USB communication, etc.). I'm though not aware of any such comprehensive solutions, so this will most likely become very painful and will stay so forever if introduced. Keep going, -- Jan

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offlineimap syncing off of gmail...
by Luke Kenneth Casson Leighton 16 Dec '16

16 Dec '16

after trying for 90 minutes to connect to accounts.google.com last night, with over twenty refreshes, finally obtaining just the HTML of a page then having to spend ANOTHER hour just to get the matching CSS... only to run into HTTP proxy problems and having to clear the cache and DO IT ALL OVER AGAIN.... ... i'm absolutely sick and tired of the fucking fucked internet here, how it's interfering with my ability to communicate, get source code and much more. so, i'm converting to offline imap, setting up the "prayer webmail" client, a cyrus imap server, and syncing everything to my laptop now i have the spare space on the 500GB SSD. the only thing is... well... look at the numbers: Folder INBOX [acc: lkcl]: Copy message UID 143 (98/155030) Remote:INBOX -> Local Folder INBOX.bak.sent [remote name [Gmail]/Sent Mail] [acc: lkcl]: Copy message UID 307 (116/55244) Remote:[Gmail]/Sent Mail -> Local Folder INBOX.bak.flagged [remote name [Gmail]/Starred] [acc: lkcl]: Copy message UID 508 (161/3185) Remote:[Gmail]/Starred -> Local Folder INBOX.bak.important [remote name [Gmail]/Important] [acc: lkcl]: Copy message UID 296 (114/51381) Remote:[Gmail]/Important -> Local that's nearly 10 GIGABYTES of mail over a ten year period (i created the gmail account in 2006 when i was running out of space on my laptop to hold all the email i had in mutt Maildirs). 55 *thousand* messages in the "sent mail" folder. a hundred and fifty five thousand in the inbox. after hacking offlineimap so that it would only use HTTPS proxy for connecting to accounts.google.com but would connect direct to imap.gmail.com (using a fixed IP address because the china government MODIFIES the DNS entries to point to the wrong locations...).... ... i was able to initiate the download / sync process. connectivity is so fucking slow it's about one message every... two to five seconds. at this rate it's going to take TWO HUNDRED hours to sync the entire mailbox. that's ten DAYS for god's sake. we may actually have to go stay in a hotel in hong kong (where they have a 100 mbytes / sec internet connection) just so i can sync all the email. dang. l.

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MIPI DSI instead of RGB/TTL - the only way out of the blind alley
by dumblob 16 Dec '16

16 Dec '16

Hi Luke, sorry for the few months delay - I was stuck with moving, family, job applications, etc. I would like to bring up again the painful topic of a long-sustainable graphical interface in the EOMA68 specification ( http://rhombus-tech.net/whitepapers/ecocomputing_07sep2015/ ) as the RGB/TTL solution is so utterly bad choice. RGB/TTL is way too slow and highly limited (alone, but even more in EOMA specifications): a) maximum resolution 1366x768 (even though the current EOMA should be capable of 1440x900) b) maximum pixel clock about 148.5 MHz (~ max 71.6 fps at the mainstream 1920x1080 with visual artifacts and high EMI disqualifying EOMA for mobile devices with radios) c) maximum color depth 18 bits (3x6) d) eats a lot of pins (18) already in this lowest quality set up e) requires HW changes (i.e. disallows sustainable plug & play) in case EOMA should mitigate the limitations above (parallel interfaces require addition of many pins) - this is anyway impossible, because all pins are already in use f) easy (not requiring a chip) conversion to VGA output; conversion chips to all (!) other interfaces (which are modern, serial, and ubiquitous) is needed (and is more expensive than a serial->RGB/TTL because of very low purchaser interest) g) easy implementation in FPGA (few hundreds of LUTs) Yet EOMA does not even allow adding any better display interface, because there are not enough "free" pins for any modern serial interface (MIPI DSI, eDP, HDMI, ...). This effectively totally (!) disallows manufacturers of EOMA cards to add an SoC <-> MIPI/eDP/HDMI circuity on an EOMA card to provide at least mainstream (!) resolution output with 24 bit colors for internal displays (not talking about 2017, when it will supposedly be 4K at 30 fps with 24 bit colors). In other words, this only one fact degrades the whole EOMA to the category of yet another toy (as every other libre general-purpose user computer HW failed up until now). By the way I had to publicly confess this during my talk at the conference OpenAlt 2016 (https://openalt.cz/2016 , there is a full recording). After reading through all the important emails from Arm-netbook beginning in 2010 (yeah, 571509 lines of text), many of your posts on different web servers, and watching nearly all your videos, I did some research on display interfaces. Few quick facts based on my findings follow (yes, I focus on lower mainstream and mainstream "fat" embedded and mobile segment, not on total low-end, because there we have zillion of existing PCBs all offering basically the same HW interfaces - some of them even libre). >From panelook.com (size >= 7.0", px density >= 160 PPI): * LVDS: 382 panels in MP YEAR 2016 (2015: 53) => ratio (the higher the better) 53/382 = 0.138 * MIPI DSI: 239 panels in MP YEAR 2016 (2015: 50) => ratio 50/239 = 0.209 * eDP: 233 panels in MP YEAR 2016 (2015: 66) => ratio 66/233 = 0.283 * RGB/TTL: 15 panels in MP YEAR 2016 (2015: 2) ratio 2/15 = 0.133 (the ratio shows how much is the certain interface on rise) Video interfaces from data sheets of few tens of more performant (i.e. having more computing power) mobile SoCs (no AMDs, no Intels) in 2015 & 2016: * LVDS: nearly nowhere * MIPI DSI: everywhere (!) * eDP: nearly nowhere (in contrast to big chips like Intel i5/i6/i7, where eDP is largely prevalent) * RGB/TTL: nearly everywhere (but especially on smaller SoCs) We can see a strong trend of LVDS disappearing (though having still the major position in 2015 & 2016), MIPI DSI and eDP on fast rise and RGB/TTL on a total decline reaching it's physical limits. Add the fact, that MIPI DSI is present on basically every mobile SoC since cca 2014 (in contrast to 2012 when EOMA was looking for "the ultimate video interface" and when RGB/TTL was really the only portable option) and moreover is easily and cheaply convertible to eDP or to LVDS, we have a clear winner. By the way, even Intel also recommends an external MIPI DSI to LVDS and MIPI DSI to eDP bridges for his SoCs. Based on all that I'm confident, that in the upcoming 10 years, the SoC market will use MIPI DSI everywhere as the main standard and eDP for the few biggest chips. MIPI DSI also doesn't have the issues as LVDS, when the specification did not cover the chosen width and properties of implementation and thus prevented bundling universal conversion chips. MIPI DSI offers: a) highest state-of-the-art resolutions (not limited to, but supporting 4096x2160) b) highest state-of-the-art refresh rates (not limited to, but supporting 120 fps at 1920x1200; i.e. pixel clock about 276.4 MHz) without visual artifacts and while remaining low-power c) 24 bit color depth (3x8) d) eats just 4 pins for minimal configuration with one lane (in practise 4 lanes are most common, so 10 pins will be needed) e) requires none (increasing frequency) or very minimal (adding two pins as a new data lane) HW changes (MIPI DSI is a serial interface) f) VGA output (hell it should die out already!) requires a conversion chip (which is not so expensive, so it shouldn't influence the Micro Desktop PC PCB nor notebook PCB price; actually I would not provide VGA at all on these consumer devices, but rather (e)DP or HDMI, because consumers do not want VGA any more and external eDP -> VGA converters are about 5$ with free shipping world-wide for those who need it or want to be really eco-friendly and use the few surviving VGA devices at the expense of higher electrical consumption) g) easy implementation in FPGA (there are fully functional existing implementations having just about 2000 LUTs) But how to cope with this when there is already an EOMA card in manufacturing? Let me boldly demonstrate "thinking outside the box" (kicked off by email from Luke from Sat, 13 Jul 2013 17:22:41 +0100 and supported by the "take advantage of the MIPI / eDP" statement of Luke from Thu, 10 Apr 2014 10:48:46 +0100). Can we provide both interfaces (RGB/TTL + MIPI DSI) on the same pins while having a HW way to choose from these? Yes we can! EOMA already counts on several types of PC Cards (originally called PCMCIA). At minimum two - thinner (Type I - 3.3 mm) and thicker (Type II - 5 mm). Let's declare the thicker cards to be high-end and offer only MIPI DSI while thinner cards low-end with just RGB/TTL. Problem solved! The "high-end" specification shall then also be extended allowing higher thermal dissipation (5W is too low - maybe 15W would be OK as it's still easy to cool passively) etc. to accommodate "high-end" (actually mainstream, but in this context it's high-end) requirements. Speaking about thermal dissipation, I'm not sure that in case of the high-end card type, this limit should be a fixed one. I would probably prefer the 15W value as a strong recommendation instead of a firm requirement. While always (disregarding whether it's smaller than 15W or not) requiring to readably and fully visibly to the end user quote (at best on the outermost coating) the maximum dissipation of the whole particular card under heavy load. Why? Because there will be a manufacturer offering a special super hyper mega powerful card implementing a "turbo" mechanical switch automatically overclocking the by default heavily underclocked 8-core beast. This could then be finally called useful and sustainable for 10 years. Recap of solved issues: * No more copyleft-like/religious constraints ("we require you to only use libre and eco-friendly stuff, not the new fast non-libre SoCs with non-refurbished eco-unfriendly displays"), but rather a permissive approach. * No more issues with non-tiny display panels. * No issues with users putting a wrong card to the slot. * No more issues with dissipation. * No more issues with libre world being old, slow, ugly looking, etc. (as I'm often told, because it unfortunately currently holds). * No more issues with decision makers, who will finally get the freedom of choice from several cards (keep in mind what the marketing/portfolio research says - a set of more similar but still diversified products/services sell significantly better than one product/service disregarding whether it's high-quality or not). * Useful for the upcoming hybrid phone ( http://rhombus-tech.net/community_ideas/hybrid_phone/ ) - lower number of pins, lower consumption. Enjoy the new life in China with your family and good luck with discovery how the world's real HW production and market works, -- Jan

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test 2 please ignore
by lkcl＠lkcl.net 16 Dec '16

16 Dec '16

2nd test sending indirect message to list, please ignore l.

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EOMA68 Type III thickness
by Benson Mitchell 14 Dec '16

14 Dec '16

While checking my data for that last email, I noticed the PCMCIA standard for Type III cards is 10.5mm thick, while the EOMA68 standard is 8mm. Luke, is this deliberate? It seems like thinner limits user-facing connectors, and makes fan-cooled card designs a bit harder. OTOH, it does permit devices to be 2.5mm thinner -- I'm not a big fan of thinner-is-better, but it undeniably sells. Benson Mitchell

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new development laptop needed, looking at dell xps 13 9350
by Luke Kenneth Casson Leighton 12 Dec '16

12 Dec '16

around 3 years ago i bought an apple macbook pro 13in because it was well-built, high spec'd and high-priced (translation: plenty of profit so that no corners need to be cut in manufacturing, which in turn means less chance of component failure). that was the theory, anyway. one design flaw, though: the PCIe SSD could be "spiked" by the lack of earthing of the power supply, resulting in resets of the SATA bus about twice per second. setting "min_power" on the SATA bus stopped this flood of entries in /var/log/syslog... but the setting was OVER-RIDDEN at the slightest opportunity. also, i had no idea that i would need more than 8GB of RAM (and the macbook pro is NOT UPGRADABLE - the RAM is soldered down). i've also just had my backup SSD (a 4 year old kingston 512mb SSD which is hardly used) totally fail after a non-intensive *READ*. not write: READ. with the macbook pro's internal SSD being difficult to get at, i'm feeling a leetle paranoid: this machine is a CRITICAL resource, now a single point of failure. my partner's machine only has 4GB of RAM and a 1600x1080 LCD. lovely machine but it would in no way cope with what i'm doing. also... i've literally worn holes in two of the keys (ctrl and S)... basically it's time to get a new laptop, and i need something that has particularly special high-end specifications in certain areas: * 2560x1600 or greater resolution LCD (CAD development) * 13in size (has to fit in my backpack) * below 1.5kg weight (carryable) * 16GB of RAM (i'm maxing out the 8GB) * 512GB SSD (i've maxed out the 256GB drive) * cooperative manufacturer that hasn't caved in to microsoft cartelling business practices actual processor and processor speed isn't actually relevant. battery life: also not really relevant. doesn't *particularly* need a dedicated GPU: intel shared graphics turns out to work well enough for the 3D CAD work that i do (even when the framerate is seconds per frame in openscad). i run mostly from mains, and processors are so insanely fast these days that speed is not really an issue. now, the machine i came up with is the Dell XPS 13, 9350: https://wiki.debian.org/InstallingDebianOn/Dell/Dell_XPS_13_9350 i looked at the lenovo yoga 900: zowee, lenovo are unethical. they've locked the BIOS so that you can't switch the NVMe SSD out of RAID mode (so you can't even install windows from a windows CD), they've refused refunds to people who claim mis-selling, they're ACTIVELY working to release new BIOS updates that prevent and prohibit people from installing linux, and they're scrambling to constantly censor reports and complaints on their forum. i also looked at the asus zenbook: fantastic machine.... except the 13in variant peaks at 12GB of RAM. sony... have stopped doing laptops! that's the end of an era: i'm amazed... now, before i go spending $USD 1500 of crowd-funding money (which is easily justifiable as it's absolutely essential that i have a working machine and a half-decent backup) i'd like to double-check with people if they know of anything better than the XPS 9350, both in terms of specification as well as support for the linux community from the manufacturer. dell appear to be cooperating, releasing BIOS updates that *actively* help linux users (as opposed to lenovo who do the complete opposite and then try to hide the fact, generally being incredibly evasive and unethical). thoughts and suggestions appreciated for evaluation. the 9350's at the top of the list right now. l.

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