From richard.wilbur at gmail.com Mon Oct 2 05:50:59 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Sun, 1 Oct 2017 22:50:59 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: For recommended wiggle dimensions consult Toradex, p. 22, figure 23, (reproduced below for convenience of discussion): Here s = spacing between traces of a differential pair = 5mil (for our layout) w = width of traces in differential pair = 5mil (for our layout) Hence, Toradex suggests deviating away no more than 10mil and staying at that distance no more than 15mil. I would suggest spending less distance away, say 7.5mil before turning back so that we get more length at a 45 degree angle with the other trace which is where we make up path length. -------------- next part -------------- A non-text attachment was scrubbed... Name: serpentine-ideal.jpg Type: image/jpeg Size: 9161 bytes Desc: not available URL: From richard.wilbur at gmail.com Mon Oct 2 06:30:06 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Sun, 1 Oct 2017 23:30:06 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: Regarding the taper, I am sure we don't want to reduce the spacing over a long enough distance to reduce the impedance below the HDMI tolerance: differential = 100 +/-15% Ohm = [85,115] Ohm, single-ended = 55 +/15% Ohm = [42.5,57.5] Ohm. What does PADS report for the impedance of our HDMI differential traces on the current or a recent layout? (We opened up the clearance to 15mil around the differential pairs in order to try to keep the impedance up.) If the impedance is too low, we may need to forgo the taper altogether and just live with the small discontinuities caused by a few vias and component lands that are significantly closer. From richard.wilbur at gmail.com Mon Oct 2 05:01:55 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Sun, 1 Oct 2017 22:01:55 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: Be careful in the wiggles if you make a high-frequency trace turn parallel to itself that those parallel sections are at least separated by a distance of 4*trace width=20mil. Otherwise the parallel sections look like antennae to the high-frequency signals which simply radiate straight across and bypass the intended delay path. In other words if the edge of the copper of a trace faces a different part of the same trace, the electric field will overlap significantly if they aren't far enough apart and the signal will jump the gap. I painted the likely problematic edges with red and circled in green the wiggle you created with a geometry that completely avoids the problem. -------------- next part -------------- A non-text attachment was scrubbed... Name: eoma68-a20-hdmi-275-new-keepout-wiggles.jpg Type: image/jpeg Size: 52126 bytes Desc: not available URL: From lkcl at lkcl.net Mon Oct 2 09:45:02 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Mon, 2 Oct 2017 09:45:02 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 On Mon, Oct 2, 2017 at 5:01 AM, Richard Wilbur wrote: > Be careful in the wiggles if you make a high-frequency trace turn > parallel to itself that those parallel sections are at least separated > by a distance of 4*trace width=20mil. yyehhh it's a bitch doing these by hand. > I painted the likely problematic edges with red and circled in green > the wiggle you created with a geometry that completely avoids the > problem. yehyeh thank you for that, makes it really clear. the thing is there's really not a lot of space, in which we need to get rid of about... i think it's something like almost 0.8mm length discrepancy: difference between two BGA pads *and* the right-angle turn. the toradex-recommended wiggle method is fine for compensating for a single 45 degree turn (found that out a few weeks back, now) but for the amount of length discrepancy here it would be something like... maybe... eight or nine toradex-style wiggles. i'll see how it looks. l. From lkcl at lkcl.net Mon Oct 2 17:00:53 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Mon, 2 Oct 2017 17:00:53 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: ok so... blegh. as i suspected, using the toradex recommended wiggle layout results in the extension of the use of wiggles for well over 150 possible 200 mils. 0.2 inches! that's over 5mm! the use of only a 45 degree bend basically results only in 2 * (2-sqrt(2)) * 7 or so being added to the length. when you use a U-shaped wiggle that becomes 2 * (2-sqrt(2) * 7 _and_ 2 * (sqrt(2) * 7 _and_ whatever length is on the uprights of the U. getting fed up of doing these by hand. i'll use the accordion feature. it makes them curved but at least it will be a regular / fixed distance... i wonder if i can switch off the curves... yes you can! ok i'll give that a shot. l. -------------- next part -------------- A non-text attachment was scrubbed... Name: Untitled1.jpg Type: image/jpeg Size: 48547 bytes Desc: not available URL: From richard.wilbur at gmail.com Mon Oct 2 22:15:00 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Mon, 2 Oct 2017 15:15:00 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: The alternative is to use the "U"-shaped with spacing of at least 20mil between facing copper of the same trace. I agree you are better off when trying to add length to use the 45° corners rather than the arcs since arcs are known for turning a corner with minimal distance. From lkcl at lkcl.net Mon Oct 2 22:33:22 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Mon, 2 Oct 2017 22:33:22 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 On Mon, Oct 2, 2017 at 10:15 PM, Richard Wilbur wrote: > The alternative is to use the "U"-shaped with spacing of at least 20mil between facing copper of the same trace. yyeah that's 4x track width... it's gonna be really really tight to get 20 mil in. will see. > I agree you are better off when trying to add length to use the 45° corners rather than the arcs since arcs are known for turning a corner with minimal distance. ... they are? :) From saitdude at hotmail.com Mon Oct 2 23:51:11 2017 From: saitdude at hotmail.com (Joseph Lira) Date: Mon, 2 Oct 2017 22:51:11 +0000 Subject: [Arm-netbook] EFI/UEFI bios question Message-ID: Hello I know this is an arm project, but honestly I didn't know where else to ask this question without getting lynch, well hopefully I wont get lynch here neither So I'm in the market for a new laptop and I recently rediscovered the finding for legbacore when if come to malware attacks on UEFI, http://www.legbacore.com/Research_files/HowManyMillionBIOSesWouldYouLikeToInfect_Whitepaper_v1.pdf http://www.legbacore.com/Research.html and how until today there seems to be no real solution to the problem as no manufacture continues to support hardware through bios/firmware updates after usually 1 year of purchasing a product, well Apple seems to be the only one. And no I don't consider as a solution running old x200 with coreboot or libreboot as this approach is not really practical for the day-day user. Let face is who doesn't know someone like this https://duckduckgo.com/?q=cloudy+with+a+chance+of+meatballs+dad+computer&t=ffsb&ia=videos&iax=1&iai=2bTBVdumayw Just one thing, please don't give me the libre speech about Intel ME, I get it, I just don't want the replies to become a holy fight as to why I'm evil or x person is evil, I want to understand better the situation and possibly get some suggestions So my questions are 1. Is my pre 2014 non uefi hardware more susceptible to vulnerabilities than lets say a laptop that was bough last year that is no longer getting bios updates? 2. Should I be concerned about running old hardware? If not is there anything I can do to better protect my hardware and for the wise guy unplugging the computer from the internet is not a solution LOL 3. If I run uefi with secure boot enabled with my own keys em I more protected against having my system compromised?Remember this is not about Intel ME 4. Em I better off buying a macbook vs pc? lets face it, both are companies that are for profit and both have there own evils 5. Should I consider buying a librem laptop? Though I do think $1300 plus is to much. Seems to me that they are closer to have coreboot and disabling ME on there laptops than anyone else 6. Is there hope for the new AMD ryzen cpu at delivering what is required to port it to coreboot? Should I wait for it? 7. A little of topic but is PureOS from purism any good at doing what it promises? Or are there other distro better? thank you in advance to anyone who replies, links and articles are welcome From eaterjolly at gmail.com Tue Oct 3 01:22:58 2017 From: eaterjolly at gmail.com (Jean Flamelle) Date: Mon, 2 Oct 2017 20:22:58 -0400 Subject: [Arm-netbook] EFI/UEFI bios question In-Reply-To: References: Message-ID: Despite the negative press and the huge skepticism over their posh brand and shell-shocking optimism in area people have been cynical for a long while, they claim they've completely disabled Intel ME as well as completed their coreboot port. Both of these have been relatively recent developments, but I think it's not unreasonable to say there is a correlation between these successes and the endorsements they are getting from gnome and kde with their new phone project. And, I'm sure these people would have checked. That in mind, EOMA is still designed around portability, hardware openness, and reparability (with importance expressed in reverse order). x86 got torn apart to shreds at the last Blackhat as far as I can tell. Libre linux on RISC is definitely going to be the first 100% safe harbor for secure computing. It would be very nice if the folks at Purism added a EOMA card slot at some point in the coming future to their computers. I doubt these Purism laptops would be any bit disappointing. On 10/2/17, Joseph Lira wrote: > Hello > > > I know this is an arm project, but honestly I didn't know where else to ask > this question without getting lynch, well hopefully I wont get lynch here > neither > > > So I'm in the market for a new laptop and I recently rediscovered the > finding for legbacore when if come to malware attacks > > on UEFI, > http://www.legbacore.com/Research_files/HowManyMillionBIOSesWouldYouLikeToInfect_Whitepaper_v1.pdf > > http://www.legbacore.com/Research.html > > and how until today there seems to be no real solution to the problem as no > manufacture continues to support hardware through bios/firmware updates > after usually 1 year of purchasing a product, well Apple seems to be the > only one. And no I don't consider as a solution running old x200 with > coreboot or libreboot as this approach is not really practical for the > day-day user. Let face is who doesn't know someone like this > > https://duckduckgo.com/?q=cloudy+with+a+chance+of+meatballs+dad+computer&t=ffsb&ia=videos&iax=1&iai=2bTBVdumayw > > > Just one thing, please don't give me the libre speech about Intel ME, I get > it, I just don't want the replies to become a holy fight as to why I'm evil > or x person is evil, I want to understand better the situation and possibly > get some suggestions > > > So my questions are > > 1. Is my pre 2014 non uefi hardware more susceptible to vulnerabilities > than lets say a laptop that was bough last year that is no longer getting > bios updates? > 2. Should I be concerned about running old hardware? If not is there > anything I can do to better protect my hardware and for the wise guy > unplugging the computer from the internet is not a solution LOL > 3. If I run uefi with secure boot enabled with my own keys em I more > protected against having my system compromised?Remember this is not about > Intel ME > 4. Em I better off buying a macbook vs pc? lets face it, both are > companies that are for profit and both have there own evils > 5. Should I consider buying a librem laptop? Though I do think $1300 plus > is to much. Seems to me that they are closer to have coreboot and disabling > ME on there laptops than anyone else > 6. Is there hope for the new AMD ryzen cpu at delivering what is required > to port it to coreboot? Should I wait for it? > 7. A little of topic but is PureOS from purism any good at doing what it > promises? Or are there other distro better? > > > thank you in advance to anyone who replies, links and articles are welcome > _______________________________________________ > arm-netbook mailing list arm-netbook at lists.phcomp.co.uk > http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook > Send large attachments to arm-netbook at files.phcomp.co.uk From lkcl at lkcl.net Tue Oct 3 02:56:07 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Tue, 3 Oct 2017 02:56:07 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: On Mon, Oct 2, 2017 at 10:33 PM, Luke Kenneth Casson Leighton wrote: > On Mon, Oct 2, 2017 at 10:15 PM, Richard Wilbur > wrote: >> The alternative is to use the "U"-shaped with spacing of at least 20mil between facing copper of the same trace. > > yyeah that's 4x track width... it's gonna be really really tight to > get 20 mil in. will see. it was. best i could do (attached) - accordion wasn't having any of it, had to do them by hand. the defaults in PADS for the gap separation btw were set to 2x. 4x seems an _awful_ lot, to my eye: i don't believe i've ever seen wiggles with such large separation. are you sure the app note didn't mean "4x separation centre-to-centre of the traces"? or, was the app note specifically applying to really *really* high frequency traces (above say... 2 or even 3 ghz)? l. -------------- next part -------------- A non-text attachment was scrubbed... Name: Untitled1.jpg Type: image/jpeg Size: 78825 bytes Desc: not available URL: From richard.wilbur at gmail.com Tue Oct 3 20:48:56 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Tue, 3 Oct 2017 13:48:56 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: On Oct 2, 2017, at 19:56, Luke Kenneth Casson Leighton wrote: > > On Mon, Oct 2, 2017 at 10:33 PM, Luke Kenneth Casson Leighton > wrote: > >> On Mon, Oct 2, 2017 at 10:15 PM, Richard Wilbur >> wrote: >>> The alternative is to use the "U"-shaped with spacing of at least 20mil between facing copper of the same trace. >> >> yyeah that's 4x track width... it's gonna be really really tight to >> get 20 mil in. will see. > > it was. best i could do (attached) - accordion wasn't having any of > it, had to do them by hand. > > the defaults in PADS for the gap separation btw were set to 2x. 4x > seems an _awful_ lot, to my eye: i don't believe i've ever seen > wiggles with such large separation. are you sure the app note didn't > mean "4x separation centre-to-centre of the traces"? or, was the app > note specifically applying to really *really* high frequency traces > (above say... 2 or even 3 ghz)? Toradex, p. 17, section 6.2 as illustrated in figure 13. It matters more the greater the length of facing copper. So if you can only get 15mil separation but split it into two or more wiggles, that would be better than having one wiggle at 15mil separation (between facing copper of the same trace). From laserhawk64 at gmail.com Thu Oct 5 01:26:54 2017 From: laserhawk64 at gmail.com (Christopher Havel) Date: Wed, 4 Oct 2017 20:26:54 -0400 Subject: [Arm-netbook] Well, /this/ looks relevant... Message-ID: This just turned up on Hackaday. Looks like the folks over at SiFive have been very, very busy... https://hackaday.com/2017/10/04/sifive-announces-risc-v-soc/ Might want to grab a bag of popcorn, guys, I think this is one to watch. From calmstorm at posteo.de Thu Oct 5 01:47:57 2017 From: calmstorm at posteo.de (zap) Date: Wed, 4 Oct 2017 20:47:57 -0400 Subject: [Arm-netbook] Well, /this/ looks relevant... In-Reply-To: References: Message-ID: <3837c025-8930-7507-8d45-26d13e292a98@posteo.de> > This just turned up on Hackaday. Looks like the folks over at SiFive have > been very, very busy... > > https://hackaday.com/2017/10/04/sifive-announces-risc-v-soc/ > > Might want to grab a bag of popcorn, guys, I think this is one to watch. You may want to read the first two comments on that page... before you decide this is worth it. at least that's my thought anyways. > _______________________________________________ > arm-netbook mailing list arm-netbook at lists.phcomp.co.uk > http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook > Send large attachments to arm-netbook at files.phcomp.co.uk From laserhawk64 at gmail.com Thu Oct 5 02:00:24 2017 From: laserhawk64 at gmail.com (Christopher Havel) Date: Wed, 4 Oct 2017 21:00:24 -0400 Subject: [Arm-netbook] Well, /this/ looks relevant... In-Reply-To: <3837c025-8930-7507-8d45-26d13e292a98@posteo.de> References: <3837c025-8930-7507-8d45-26d13e292a98@posteo.de> Message-ID: Hackaday commenters are usually a bit curmudgeonly. I wouldn't pay the peanut gallery there too much attention. From calmstorm at posteo.de Thu Oct 5 02:42:30 2017 From: calmstorm at posteo.de (zap) Date: Wed, 4 Oct 2017 21:42:30 -0400 Subject: [Arm-netbook] Well, /this/ looks relevant... In-Reply-To: References: <3837c025-8930-7507-8d45-26d13e292a98@posteo.de> Message-ID: On 10/04/2017 09:00 PM, Christopher Havel wrote: > Hackaday commenters are usually a bit curmudgeonly. I wouldn't pay the > peanut gallery there too much attention. Dunno, we'll see I suppose, if it is completely free software then it is worth it, but if not, if there is some dumb licensing, then avoid it. that's about all I can say... > _______________________________________________ > arm-netbook mailing list arm-netbook at lists.phcomp.co.uk > http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook > Send large attachments to arm-netbook at files.phcomp.co.uk From lkcl at lkcl.net Thu Oct 5 05:26:07 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Thu, 5 Oct 2017 05:26:07 +0100 Subject: [Arm-netbook] Well, /this/ looks relevant... In-Reply-To: References: <3837c025-8930-7507-8d45-26d13e292a98@posteo.de> Message-ID: On Thu, Oct 5, 2017 at 2:42 AM, zap wrote: > > > On 10/04/2017 09:00 PM, Christopher Havel wrote: >> Hackaday commenters are usually a bit curmudgeonly. I wouldn't pay the >> peanut gallery there too much attention. > Dunno, we'll see I suppose, if it is completely free software then it is > worth it, but if not, if there is some dumb licensing, then avoid it. > that's about all I can say... there's no reason - at all - why they would put or require any proprietary firmware on it. there's no VPU, no GPU, nothing special at all. the nice thing is it looks like it'll be actual first silicon 64-bit so people can at last start doing native compiles. that's particularly important for debian: cross-compiled or qemu-compiled packages are *not* accepted (arch they don't mind). for an EOMA68 module the need for an FPGA is... disappointing. i suspect this chip will be somewhere around the 650 to 700 pins mark if they have only 2 32-bit lanes but if they've done 4 32-bit lanes it'll be a bit of a monster, close to 900 or a thousand pins (each 32-bit DDR3/DDR4 lane requires about 150 pins including power). we just have to see. l. From calmstorm at posteo.de Thu Oct 5 19:38:22 2017 From: calmstorm at posteo.de (zap) Date: Thu, 5 Oct 2017 14:38:22 -0400 Subject: [Arm-netbook] Well, /this/ looks relevant... In-Reply-To: References: <3837c025-8930-7507-8d45-26d13e292a98@posteo.de> Message-ID: > there's no reason - at all - why they would put or require any > proprietary firmware on it. there's no VPU, no GPU, nothing special > at all. the nice thing is it looks like it'll be actual first silicon > 64-bit so people can at last start doing native compiles. that's > particularly important for debian: cross-compiled or qemu-compiled Well, if you are certain then... I guess it is important. > packages are *not* accepted (arch they don't mind). I am curious why arch is different then debian... From themuso at themuso.com Thu Oct 5 22:51:07 2017 From: themuso at themuso.com (Luke Yelavich) Date: Fri, 6 Oct 2017 08:51:07 +1100 Subject: [Arm-netbook] Well, /this/ looks relevant... In-Reply-To: References: <3837c025-8930-7507-8d45-26d13e292a98@posteo.de> Message-ID: <20171005215107.GA22285@buffalo.yelavich.home> On Fri, Oct 06, 2017 at 05:38:22AM AEDT, zap wrote: > > packages are *not* accepted (arch they don't mind). > I am curious why arch is different then debian... If my understanding is correct from what I've seen, Arch don't even have an automated build system. Package maintainers are trusted to build and upload packages themselves. Arch even do weird stuff like build their 32-bit x86 multilib packages with their 64-bit toolchain. Luke -- Please check out my Patreon campaign and spread the word. https://patreon.com/lukefoss From lkcl at lkcl.net Fri Oct 6 01:32:02 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Fri, 6 Oct 2017 01:32:02 +0100 Subject: [Arm-netbook] Well, /this/ looks relevant... In-Reply-To: References: <3837c025-8930-7507-8d45-26d13e292a98@posteo.de> Message-ID: On Thu, Oct 5, 2017 at 7:38 PM, zap wrote: >> there's no reason - at all - why they would put or require any >> proprietary firmware on it. there's no VPU, no GPU, nothing special >> at all. the nice thing is it looks like it'll be actual first silicon >> 64-bit so people can at last start doing native compiles. that's >> particularly important for debian: cross-compiled or qemu-compiled > Well, if you are certain then... I guess it is important. >> packages are *not* accepted (arch they don't mind). > I am curious why arch is different then debian... smaller team, less well-established, rolling releases. debian's strict rules, established and tested over 20+ years now, means it can be trusted for critical infrastructure. l. From lkcl at lkcl.net Fri Oct 6 19:19:08 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Fri, 6 Oct 2017 19:19:08 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: On Tue, Oct 3, 2017 at 8:48 PM, Richard Wilbur wrote: >> the defaults in PADS for the gap separation btw were set to 2x. 4x >> seems an _awful_ lot, to my eye: i don't believe i've ever seen >> wiggles with such large separation. are you sure the app note didn't >> mean "4x separation centre-to-centre of the traces"? or, was the app >> note specifically applying to really *really* high frequency traces >> (above say... 2 or even 3 ghz)? > > Toradex, p. 17, section 6.2 as illustrated in figure 13. > > It matters more the greater the length of facing copper. So if you can only get 15mil separation but split it into two or more wiggles, that would be better than having one wiggle at 15mil separation (between facing copper of the same trace). ok understood. sorry took a while to reply. ok so i think what i'll do is, turn HX1T into two wiggles (still with 20mil separation), there's space to do that, but otherwise leave everything else alone. nearly there - i still have to reply to the message a few days ago about the keepout area. l. From richard.wilbur at gmail.com Fri Oct 6 22:33:01 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Fri, 6 Oct 2017 15:33:01 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: <81CA8BA1-9E3D-44B2-9DC9-69FB0E2F9979@gmail.com> You probably already mentioned it but what is the spacing between the copper of the A20 pads/lands? From richard.wilbur at gmail.com Fri Oct 6 22:45:37 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Fri, 6 Oct 2017 15:45:37 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> Message-ID: <72396096-4F21-4668-877C-112A19194EB0@gmail.com> On Oct 6, 2017, at 12:19, Luke Kenneth Casson Leighton wrote: > sorry took a while to reply. No worries. I took a careful look at my E-mail messages to make sure I hadn't missed something from you. (I was concerned that maybe the ball was actually in my court without me being aware of the fact.) > ok so i think what i'll do is, turn HX1T into two wiggles (still with > 20mil separation), there's space to do that, but otherwise leave > everything else alone. Sounds good. > nearly there - i still have to reply to the message a few days ago > about the keepout area. I'll try to elaborate further when I get home and in striking distance of a more powerful paint program. Richard From lkcl at lkcl.net Sat Oct 7 02:20:48 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Sat, 7 Oct 2017 02:20:48 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: <72396096-4F21-4668-877C-112A19194EB0@gmail.com> References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> Message-ID: On Fri, Oct 6, 2017 at 10:45 PM, Richard Wilbur wrote: >> nearly there - i still have to reply to the message a few days ago >> about the keepout area. > > I'll try to elaborate further when I get home and in striking distance of a more powerful paint program. mythbusters. definitely mythbusters. you want C-4, a 1 ton deathstar (jamie's creation), and a "house at the alameda county bomb range". https://www.discovery.com/tv-shows/mythbusters/videos/explosive-painting-aftershow ... back to our reguarly-scheduled programme... http://rhombus-tech.net/allwinner_a10/news/eoma68-a20-275-hdmi-new-wiggles-layer6.jpg so a different program (PADS Router) this time, sorry i had one of the tracks highlighted when i ran import -window root... i moved TX2's wiggle to the right a bit, that gave me some space to get 2 20-ish mil wiggles on TX1 instead of one reaally large one. not enough space to do the same thing for TX0 or TX2. reason for showing you the router view is, keepouts are clearly hatched (it's a bit of a pain to work with to be honest, don't know how to switch it off..) but the extent of the keepout area is much clearer. anything outside of that will be 5mil clearance, i used that fact at the right end to just... let flood-fill go round all the VIAs, tracks and ESD components @ 5mil. two grey dots (one overlapping one of the hdmi tracks) which don't have white in them are component-centres and can be ignored. l. From adam at vany.ca Wed Oct 11 05:03:28 2017 From: adam at vany.ca (Adam Van Ymeren) Date: Wed, 11 Oct 2017 00:03:28 -0400 Subject: [Arm-netbook] Cost of pre-production prototypes? Message-ID: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> Hey Luke, Your latest crowd supply update mentions wanting people to buy the pre-production prototypes and ideally help contribute to the software. How much are you planning to sell them for? I'd be interested in one, and I'd love to help contribute to the software side of this project as it's much more within my skill set than high frequency HDMI routing. Cheers, -Adam From lkcl at lkcl.net Wed Oct 11 05:27:04 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Wed, 11 Oct 2017 05:27:04 +0100 Subject: [Arm-netbook] Cost of pre-production prototypes? In-Reply-To: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> References: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> Message-ID: On Wed, Oct 11, 2017 at 5:03 AM, Adam Van Ymeren wrote: > Hey Luke, > > Your latest crowd supply update mentions wanting people to buy the > pre-production prototypes and ideally help contribute to the software. yehyeh that would be awesome. and a huge help to everyone. > How much are you planning to sell them for? well they cost around $USD 200 each (possibly more) to make - 10 of them were made @ around $USD 2,000. however i have a very simple rule: i can only accept what people are *grateful* and willing to pay. so, basically: offers accepted immediately without hesitation, and with gratitude. i have... five left i think. also you'll likely need a micro-desktop (i have some 1.6 boards available) they were something like...$50 to put together. also please bear in mind, i'm in taiwan, i can't read the street signs: i travel by recognition of bus stop numbers and landmarks. i mention this because it would be really *really* helpful if you could arrange collection (DHL is ok, Fedex is better as they deliver first and invoice for customs duty afterwards: DHL will *hold* packages until you've paid). the alternative is Track-and-Trace EMS Post, which i've done to NZ and that was absolutely fine. it's also cheaper, but bear in mind it ends up in your country's *local* (registered / signed-for) postal service. if you're happy with that then i know exactly where the post office is, done 2 packages already (one to HK as well), arrived absolutely fine. just bear in mind it'll be a leeetle bit slower. btw likewise this goes for the various other people who've asked for a dev-board, i know there's 2 people in Austria / Germany... no wait three: phil as well, you're based in germany now. > I'd be interested in one, and I'd love to help contribute to the software side of this project _great_. > as it's much more within my skill set than high frequency HDMI routing. ha, funny :) man that's a long ride... l. From Marqueteur at FineArtMarquetry.com Wed Oct 11 08:27:14 2017 From: Marqueteur at FineArtMarquetry.com (Tor, the Marqueteur) Date: Tue, 10 Oct 2017 21:27:14 -1000 Subject: [Arm-netbook] Cost of pre-production prototypes? In-Reply-To: References: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> Message-ID: <63ef87b8-9cf9-fb07-61bf-03aa451a13f7@FineArtMarquetry.com> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I'm interested, and I should be able to cover the costs. That said, I don't have sofware dev skills, so except perhaps for a micro-desktop board (depends on final design of the micro-desktop), there's not much advantage to the project in my having one. Therefore, since it's more a toy and chance to (hopefully, if the project succeeds) hold an interesting piece of computer history, if there are people with the dev skills, I'll willingly cede any position I have. Tor - -- Tor Chantara http://www.fineartmarquetry.com/ 808-828-1107 GPG Key: 2BE1 426E 34EA D253 D583 9DE4 B866 0375 134B 48FB *Be wary of unsigned emails* Stop spying: http://www.resetthenet.org/ -----BEGIN PGP SIGNATURE----- iF0EARECAB0WIQQr4UJuNOrSU9WDneS4ZgN1E0tI+wUCWd3HzgAKCRC4ZgN1E0tI +6SkAJ9pTegO2vAOwg/cMgDpAjbsjCDokACfYZs/IxTaoQz3jLA7IanyFgpQTPU= =O9HX -----END PGP SIGNATURE----- From lkcl at lkcl.net Wed Oct 11 09:07:45 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Wed, 11 Oct 2017 09:07:45 +0100 Subject: [Arm-netbook] Cost of pre-production prototypes? In-Reply-To: <63ef87b8-9cf9-fb07-61bf-03aa451a13f7@FineArtMarquetry.com> References: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> <63ef87b8-9cf9-fb07-61bf-03aa451a13f7@FineArtMarquetry.com> Message-ID: --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 On Wed, Oct 11, 2017 at 8:27 AM, Tor, the Marqueteur wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > I'm interested, and I should be able to cover the costs. That said, I > don't have sofware dev skills, so except perhaps for a micro-desktop > board (depends on final design of the micro-desktop), there's not much > advantage to the project in my having one. Therefore, since it's more > a toy and chance to (hopefully, if the project succeeds) hold an > interesting piece of computer history, if there are people with the dev > skills, I'll willingly cede any position I have. thx tor. btw i still need to send you a micro-desktop and some of the laser-cut casework i have here, so you can design and test the wooden corners. l. From richard.wilbur at gmail.com Wed Oct 11 17:58:54 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Wed, 11 Oct 2017 10:58:54 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> Message-ID: Your change to TX1 definitely looks like an improvement. In order to make a determination on the best course of action regarding the keepout at the connector end and whether to recommend some type of taper I still have a burning question: What does PADS currently give as the impedance of the HDMI differential lines? Does it give an impedance for a particular trace? (That would likely be the single-ended impedance.) Does it offer a differential impedance value for a pair of traces? If PADS offers us some impedance values, then we can compare those with the specification to determine whether we are within the specified tolerances and, if so, whether we have enough room to spend more impedance on a taper. If we are outside the specified impedance tolerance, then we need to take measures to get back within tolerance. If we are barely inside the tolerance, we can probably only make some slight adjustments to try to move the impedance closer to nominal and/or minimize reflections. If we are well within the specified tolerance, we can consider some taper of clearances and keepouts to minimize reflections. From richard.wilbur at gmail.com Wed Oct 11 18:18:03 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Wed, 11 Oct 2017 11:18:03 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> Message-ID: Afterthought: If PADS does give impedance values, please include the values for each of the HDMI differential traces and a URL to images of the top and bottom layers of that layout. That way I'll be able to make recommendations and markup the picture to hopefully make everything clear. Thanks, Richard From Marqueteur at FineArtMarquetry.com Wed Oct 11 22:40:34 2017 From: Marqueteur at FineArtMarquetry.com (Tor, the Marqueteur) Date: Wed, 11 Oct 2017 11:40:34 -1000 Subject: [Arm-netbook] Cost of pre-production prototypes? In-Reply-To: References: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> <63ef87b8-9cf9-fb07-61bf-03aa451a13f7@FineArtMarquetry.com> Message-ID: <60d1bbec-0075-5a73-4869-3fb5b7875864@FineArtMarquetry.com> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 10/10/2017 10:07 PM, Luke Kenneth Casson Leighton wrote: > > On Wed, Oct 11, 2017 at 8:27 AM, Tor, the Marqueteur > wrote: >> >> I'm interested, and I should be able to cover the costs. ... > thx tor. btw i still need to send you a micro-desktop and some of > the laser-cut casework i have here, so you can design and test the > wooden corners. > Sooner or later, yes. I haven't worried too much because of the work to get the card itself working. > l. > - -- Tor Chantara http://www.fineartmarquetry.com/ 808-828-1107 GPG Key: 2BE1 426E 34EA D253 D583 9DE4 B866 0375 134B 48FB *Be wary of unsigned emails* Stop spying: http://www.resetthenet.org/ -----BEGIN PGP SIGNATURE----- iF0EARECAB0WIQQr4UJuNOrSU9WDneS4ZgN1E0tI+wUCWd6PygAKCRC4ZgN1E0tI +8FNAKCS0G+BaEPvXgZTd50MpkhgFLe89QCfZZi9qZAW99QD+l4DZzWO6YBlfnI= =/Q90 -----END PGP SIGNATURE----- From lkcl at lkcl.net Wed Oct 11 23:24:49 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Wed, 11 Oct 2017 23:24:49 +0100 Subject: [Arm-netbook] Cost of pre-production prototypes? In-Reply-To: <60d1bbec-0075-5a73-4869-3fb5b7875864@FineArtMarquetry.com> References: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> <63ef87b8-9cf9-fb07-61bf-03aa451a13f7@FineArtMarquetry.com> <60d1bbec-0075-5a73-4869-3fb5b7875864@FineArtMarquetry.com> Message-ID: On Wed, Oct 11, 2017 at 10:40 PM, Tor, the Marqueteur wrote: >> thx tor. btw i still need to send you a micro-desktop and some of >> the laser-cut casework i have here, so you can design and test the >> wooden corners. >> > Sooner or later, yes. I haven't worried too much because of the work > to get the card itself working. well the microdesktop has to go out at the same time, and that's been ready for months. it's a little limiting to use the card on its own (no access to UART boot messages for example) and pushing USB-UART wires into the 68-pin connector... i mean... i've _done_ it... l. From Marqueteur at FineArtMarquetry.com Thu Oct 12 00:34:02 2017 From: Marqueteur at FineArtMarquetry.com (Tor, the Marqueteur) Date: Wed, 11 Oct 2017 13:34:02 -1000 Subject: [Arm-netbook] Cost of pre-production prototypes? In-Reply-To: References: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> <63ef87b8-9cf9-fb07-61bf-03aa451a13f7@FineArtMarquetry.com> <60d1bbec-0075-5a73-4869-3fb5b7875864@FineArtMarquetry.com> Message-ID: <99743e56-8fc2-b418-b52a-25655b01b98a@FineArtMarquetry.com> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 10/11/2017 12:24 PM, Luke Kenneth Casson Leighton wrote: > On Wed, Oct 11, 2017 at 10:40 PM, Tor, the Marqueteur > wrote: > >>> thx tor. btw i still need to send you a micro-desktop and some >>> of the laser-cut casework i have here, so you can design and >>> test the wooden corners. >>> >> Sooner or later, yes. I haven't worried too much because of the >> work to get the card itself working. > > well the microdesktop has to go out at the same time, and that's > been ready for months. it's a little limiting to use the card on > its own (no access to UART boot messages for example) and pushing > USB-UART wires into the 68-pin connector... i mean... i've _done_ > it... True enough. I'll send you my address. On my end postal is reliable, so there's no reason not to use the cheap option there. Tor > > l. - -- Tor Chantara http://www.fineartmarquetry.com/ 808-828-1107 GPG Key: 2BE1 426E 34EA D253 D583 9DE4 B866 0375 134B 48FB *Be wary of unsigned emails* Stop spying: http://www.resetthenet.org/ -----BEGIN PGP SIGNATURE----- iF0EARECAB0WIQQr4UJuNOrSU9WDneS4ZgN1E0tI+wUCWd6qZQAKCRC4ZgN1E0tI +8spAKCVK/moINbJkO1jtnT9QjkVlq+FXgCdEWbnor8a9K8DIMsRJDRsB+JQjBM= =/Adv -----END PGP SIGNATURE----- From lkcl at lkcl.net Thu Oct 12 00:57:39 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Thu, 12 Oct 2017 00:57:39 +0100 Subject: [Arm-netbook] Cost of pre-production prototypes? In-Reply-To: <99743e56-8fc2-b418-b52a-25655b01b98a@FineArtMarquetry.com> References: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> <63ef87b8-9cf9-fb07-61bf-03aa451a13f7@FineArtMarquetry.com> <60d1bbec-0075-5a73-4869-3fb5b7875864@FineArtMarquetry.com> <99743e56-8fc2-b418-b52a-25655b01b98a@FineArtMarquetry.com> Message-ID: On Thu, Oct 12, 2017 at 12:34 AM, Tor, the Marqueteur wrote: >> well the microdesktop has to go out at the same time, and that's >> been ready for months. it's a little limiting to use the card on >> its own (no access to UART boot messages for example) and pushing >> USB-UART wires into the 68-pin connector... i mean... i've _done_ >> it... > > True enough. I'll send you my address. On my end postal is reliable, > so there's no reason not to use the cheap option there. great. need tel no as well (goes on the form...) From lkcl at lkcl.net Thu Oct 12 01:04:21 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Thu, 12 Oct 2017 01:04:21 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> Message-ID: --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 On Wed, Oct 11, 2017 at 5:58 PM, Richard Wilbur wrote: > Your change to TX1 definitely looks like an improvement. > > In order to make a determination on the best course of action > regarding the keepout at the connector end and whether to recommend > some type of taper I still have a burning question: > > What does PADS currently give as the impedance of the HDMI > differential lines? each line is 90 ohms. > Does it give an impedance for a particular trace? yes. 90 ohms. or... 89. > (That would likely be the single-ended impedance.) Does it offer a > differential impedance value for a pair of traces? no. from what i gather you're expected to read up on diff-pair rules. l. From lkcl at lkcl.net Thu Oct 12 01:08:11 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Thu, 12 Oct 2017 01:08:11 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> Message-ID: --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 On Wed, Oct 11, 2017 at 6:18 PM, Richard Wilbur wrote: > Afterthought: If PADS does give impedance values, please include the > values for each of the HDMI differential traces and a URL to images of > the top and bottom layers of that layout. they're all 89 ohms, single-line. > That way I'll be able to make recommendations and markup the picture > to hopefully make everything clear. appreciated... there's no differences: they're all 89 ohms. i'm assuming that's calculated from track width and board / layer widths. capacitance is slightly different: the shorter traces (TX2) are 3.06pF, the longer ones (CK) are 3.55pF - i would imagine that the extra length results in a directly-proportionally larger capacitance? l. From silverskullpsu at gmail.com Thu Oct 12 01:41:53 2017 From: silverskullpsu at gmail.com (Jonathan Frederickson) Date: Wed, 11 Oct 2017 20:41:53 -0400 Subject: [Arm-netbook] Cost of pre-production prototypes? In-Reply-To: References: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> <63ef87b8-9cf9-fb07-61bf-03aa451a13f7@FineArtMarquetry.com> Message-ID: I'm interested as well, though I likewise don't have the low-level software experience that would likely be required. I'm a Linux sysadmin, so Linux I can do, but ARM kernel/boot stuff is a bit out of my depth thus far. That said, I do have access to a laser cutter and a (small) 3D printer, so I can play around with case designs for the micro-desktop. Is it simple enough to put them in PCMCIA cases so I could use it day-to-day assuming it works well? (Or do they already have PCMCIA cases from the factory at this point?) If so, I'm definitely in, unless someone with more dev skills wants one. From lkcl at lkcl.net Thu Oct 12 02:08:25 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Thu, 12 Oct 2017 02:08:25 +0100 Subject: [Arm-netbook] Cost of pre-production prototypes? In-Reply-To: References: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> <63ef87b8-9cf9-fb07-61bf-03aa451a13f7@FineArtMarquetry.com> Message-ID: On Thu, Oct 12, 2017 at 1:41 AM, Jonathan Frederickson wrote: > I'm interested as well, though I likewise don't have the low-level > software experience that would likely be required. if it's ok with you the priority will be on people with linux kernel / u-boot (etc.) experience > I'm a Linux > sysadmin, so Linux I can do, but ARM kernel/boot stuff is a bit out of > my depth thus far. well, "sysadmin" to me says "clearly capable of trusting and following written instructions to the letter" which surprisingly, from my brother's experience as a teacher, is a rare skill: he found that many of the kids just totally locked up and froze, and were literally incapable of following step-by-step written instructions, even when verbally prompted as to what to do. > That said, I do have access to a laser cutter and a > (small) 3D printer, so I can play around with case designs for the > micro-desktop. great! that would definitely be worthwhile getting you one of these prototypes. > Is it simple enough to put them in PCMCIA cases so I could use it > day-to-day assuming it works well? (Or do they already have PCMCIA > cases from the factory at this point?) If so, I'm definitely in, > unless someone with more dev skills wants one. they don't... but i have some casework sets. the primary thing to make absolutely sure when putting them on is: (a) get the plastic part on the right way up (as it tells the PCMCIA socket which pin is which) and (b) make absolutely sure that there's yellow insulating stickers on the inside, and that they're not damaged in any way. also bear in mind they're hell to take off again...but that you really shouldn't need to. l. From lkcl at lkcl.net Thu Oct 12 02:31:46 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Thu, 12 Oct 2017 02:31:46 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> Message-ID: https://ez.analog.com/docs/DOC-11303 Each TMDS signal shall have single ended impedance of 50 Ω ± 10%. Each TMDS pair shall have differential impedance of 100 Ω ± 5%. whoops.... :) 89 ohm... 50 ohm. 89 ohm... 50 ohm. oops... :) From silverskullpsu at gmail.com Thu Oct 12 03:10:32 2017 From: silverskullpsu at gmail.com (Jonathan Frederickson) Date: Wed, 11 Oct 2017 22:10:32 -0400 Subject: [Arm-netbook] Cost of pre-production prototypes? In-Reply-To: References: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> <63ef87b8-9cf9-fb07-61bf-03aa451a13f7@FineArtMarquetry.com> Message-ID: > if it's ok with you the priority will be on people with linux kernel > / u-boot (etc.) experience Understandable, that seems to be what you need the most at this point. > well, "sysadmin" to me says "clearly capable of trusting and > following written instructions to the letter" which surprisingly, from > my brother's experience as a teacher, is a rare skill: he found that > many of the kids just totally locked up and froze, and were literally > incapable of following step-by-step written instructions, even when > verbally prompted as to what to do. Previous to my current position I worked in Linux customer support, so... I'm unfortunately quite familiar with that behavior. :) Sometimes it's a result of making hidden assumptions in the instructions though, when you have enough experience with something you'll make mental leaps that someone without exposure to the material might not. > they don't... but i have some casework sets. the primary thing to > make absolutely sure when putting them on is: (a) get the plastic part > on the right way up (as it tells the PCMCIA socket which pin is which) > and (b) make absolutely sure that there's yellow insulating stickers > on the inside, and that they're not damaged in any way. also bear in > mind they're hell to take off again...but that you really shouldn't > need to. Sounds good to me - if you can find more people with kernel/u-boot experience they can jump ahead of me, but let me know if the prototypes aren't all accounted for and I'm in for one. From lkcl at lkcl.net Thu Oct 12 03:47:37 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Thu, 12 Oct 2017 03:47:37 +0100 Subject: [Arm-netbook] Cost of pre-production prototypes? In-Reply-To: References: <409D00A1-FD54-4AA8-8222-0669E8DE5622@vany.ca> <63ef87b8-9cf9-fb07-61bf-03aa451a13f7@FineArtMarquetry.com> Message-ID: On Thu, Oct 12, 2017 at 3:10 AM, Jonathan Frederickson wrote: >> if it's ok with you the priority will be on people with linux kernel >> / u-boot (etc.) experience > > Understandable, that seems to be what you need the most at this point. that and some extra cash. i'm currently doing contract work which helps. could do with more of that, too. >> well, "sysadmin" to me says "clearly capable of trusting and >> following written instructions to the letter" which surprisingly, from >> my brother's experience as a teacher, is a rare skill: he found that >> many of the kids just totally locked up and froze, and were literally >> incapable of following step-by-step written instructions, even when >> verbally prompted as to what to do. > > Previous to my current position I worked in Linux customer support, > so... I'm unfortunately quite familiar with that behavior. :) :) > Sometimes it's a result of making hidden assumptions in the > instructions though, when you have enough experience with something > you'll make mental leaps that someone without exposure to the material > might not. yehyeh. >> they don't... but i have some casework sets. the primary thing to > Sounds good to me - if you can find more people with kernel/u-boot > experience they can jump ahead of me, but let me know if the > prototypes aren't all accounted for and I'm in for one. *thumbs-up* From richard.wilbur at gmail.com Thu Oct 12 19:15:30 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Thu, 12 Oct 2017 12:15:30 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> Message-ID: On Oct 11, 2017, at 18:04, Luke Kenneth Casson Leighton wrote: > On Wed, Oct 11, 2017 at 5:58 PM, Richard Wilbur > wrote: >> >> What does PADS currently give as the impedance of the HDMI >> differential lines? > > each line is 90 ohms. > >> Does it give an impedance for a particular trace? > > yes. 90 ohms. or... 89. > >> (That would likely be the single-ended impedance.) Those are surprisingly high for single-ended impedance on that board stack and geometry. I would have expected something less than or equal to about 60 Ohm. 89 or 90 Ohm sounds more like what I might expect for our differential impedance (less than twice the single-ended impedance). >> Does it offer a >> differential impedance value for a pair of traces? > > no. from what i gather you're expected to read up on diff-pair rules. What version of PADS Layout are you using? Mentor responded to a question about version 9.2 saying it calculates a general impedance value taking into account: "PADS uses Diff Pair gap value and the two nearest planes (Cam or Split/Mixed) to calculate trace impedance; if the trace goes between two planes (Stripline), or just one trace to the nearest plane (Micro Stripline) in other case. Cut outs are ignored for both cases."[*] Reference: [*] https://communities.mentor.com/thread/5743 From richard.wilbur at gmail.com Thu Oct 12 19:30:37 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Thu, 12 Oct 2017 12:30:37 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> Message-ID: <7B3E3253-2C88-4A7A-96C7-CE2E6EAB6F99@gmail.com> On Oct 11, 2017, at 18:08, Luke Kenneth Casson Leighton wrote: > On Wed, Oct 11, 2017 at 6:18 PM, Richard Wilbur > wrote: >> Afterthought: If PADS does give impedance values, please include the >> values for each of the HDMI differential traces and a URL to images of >> the top and bottom layers of that layout. > > they're all 89 ohms, single-line. > > >> That way I'll be able to make recommendations and markup the picture >> to hopefully make everything clear. > > appreciated... there's no differences: they're all 89 ohms. i'm > assuming that's calculated from track width and board / layer widths. > > capacitance is slightly different: the shorter traces (TX2) are > 3.06pF, the longer ones (CK) are 3.55pF - i would imagine that the > extra length results in a directly-proportionally larger capacitance? I think you are probably correct here. I think the capacitance has to do with length of trace near other copper (same layer or not) and separation distance between the trace in question and the other copper. Also the area of the trace and other copper which are facing each other. Which layout are these measurements coming from? Is it pictured at a publicly available URL? From richard.wilbur at gmail.com Thu Oct 12 21:16:45 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Thu, 12 Oct 2017 14:16:45 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> Message-ID: <9CEB80E3-5172-41E2-BECC-FE5551E070FE@gmail.com> On Oct 11, 2017, at 19:31, Luke Kenneth Casson Leighton wrote: > > https://ez.analog.com/docs/DOC-11303 > > Each TMDS signal shall have single ended impedance of 50 Ω ± 10%. > Each TMDS pair shall have differential impedance of 100 Ω ± 5%. > > whoops.... :) 89 ohm... 50 ohm. 89 ohm... 50 ohm. oops... :) Well, if the reported impedance is the single-ended impedance of those lines we have considerable margin to burn and should aggressively pursue the taper structure and bring in the keepouts at each end. For the geometry that fit our constraints, we calculated a single-ended impedance of ~72 Ohm and differential impedance of ~111 Ohm (which corresponds to a tolerance of 11%). From lkcl at lkcl.net Fri Oct 13 01:52:56 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Fri, 13 Oct 2017 01:52:56 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: <7B3E3253-2C88-4A7A-96C7-CE2E6EAB6F99@gmail.com> References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> <7B3E3253-2C88-4A7A-96C7-CE2E6EAB6F99@gmail.com> Message-ID: --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 On Thu, Oct 12, 2017 at 7:30 PM, Richard Wilbur wrote: > On Oct 11, 2017, at 18:08, Luke Kenneth Casson Leighton wrote: >> On Wed, Oct 11, 2017 at 6:18 PM, Richard Wilbur >> wrote: >>> Afterthought: If PADS does give impedance values, please include the >>> values for each of the HDMI differential traces and a URL to images of >>> the top and bottom layers of that layout. >> >> they're all 89 ohms, single-line. >> >> >>> That way I'll be able to make recommendations and markup the picture >>> to hopefully make everything clear. >> >> appreciated... there's no differences: they're all 89 ohms. i'm >> assuming that's calculated from track width and board / layer widths. >> >> capacitance is slightly different: the shorter traces (TX2) are >> 3.06pF, the longer ones (CK) are 3.55pF - i would imagine that the >> extra length results in a directly-proportionally larger capacitance? > > I think you are probably correct here. I think the capacitance has to do with length of trace near other copper (same layer or not) and separation distance between the trace in question and the other copper. Also the area of the trace and other copper which are facing each other. i honestly don't know if PADS is that sophisticated. the Lynx SI add-on (which is... tens of thousands of dollars) certainly will be. > Which layout are these measurements coming from? Is it pictured at a publicly available URL? no change in a week. i'll always update the news page and send a message here indicating that i've done that. latest will always be here http://rhombus-tech.net/allwinner_a10/news/ - i will always add the latest image onto the end of the latest news. so at this time, right now, that will be http://rhombus-tech.net/allwinner_a10/news/eoma68-a20-275-hdmi-new-wiggles-layer6.jpg l. From lkcl at lkcl.net Fri Oct 13 01:56:12 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Fri, 13 Oct 2017 01:56:12 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: <9CEB80E3-5172-41E2-BECC-FE5551E070FE@gmail.com> References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> <9CEB80E3-5172-41E2-BECC-FE5551E070FE@gmail.com> Message-ID: On Thu, Oct 12, 2017 at 9:16 PM, Richard Wilbur wrote: >> whoops.... :) 89 ohm... 50 ohm. 89 ohm... 50 ohm. oops... :) > > Well, if the reported impedance is the single-ended impedance > of those lines we have considerable margin to burn and should > aggressively pursue the taper structure and bring in the keepouts at each end. i sort-of understand that. am i right in thinking: at the ends we have to treat them as single-ended, and achieve a sngle-ended impedance of 50 ohms, but 100 ohms for the diff-pairs. > For the geometry that fit our constraints, we calculated a single-ended impedance of ~72 Ohm and differential impedance of ~111 Ohm (which corresponds to a tolerance of 11%). ok so 72's not really very close to 50 ohms... interested to learn how that can be achieved. l. From maillist_arm-netbook at aross.me Tue Oct 17 02:43:12 2017 From: maillist_arm-netbook at aross.me (Alexander Ross) Date: Tue, 17 Oct 2017 02:43:12 +0100 Subject: [Arm-netbook] Hack GPD Pocket Into EOMA68 Computer? Message-ID: <264422e4-3a31-794f-4913-40328ab07456@aross.me> Looking at the tear down: https://www.reddit.com/r/GPDPocket/comments/6j1jfo/gpd_pocket_full_teardown_and_photos/ I can’t help myself from wondering how hard would it be to mod it into a eoma68 handheld computer? not many port holes to line upto. lcd ? lvds? i guess the inner base is mostly flat. to make a mod easier i was thinking one could use the lipo cell space for pcb instead and have a replacement back panel or 3d printed case width extender which the base lid goes on top of? kinda like this case extension for the openmoko phones [1]. To make extra room for new typical lipo or standard 18650 cells battery and some extra goodies :). Like usb ports for more storage, gps, mob modem, usb audio DAC choice or just a really big usb hub for Do What Ya Want? Maybe 3dprinted case extension or replacement back panel even would help with getting better wifi reception? put the anteriors in the plastic edging? [1] https://image.slidesharecdn.com/jmbouffardopenmokast-1233718845598943-2/95/openmokast-the-open-broadcasting-software-stack-for-mobile-devices-26-728.jpg?cb=1235050506 https://image.slidesharecdn.com/jmbouffardopenmokast-1233718845598943-2/95/openmokast-the-open-broadcasting-software-stack-for-mobile-devices-27-728.jpg?cb=1235050506 https://image.slidesharecdn.com/jmbouffardopenmokast-1233718845598943-2/95/openmokast-the-open-broadcasting-software-stack-for-mobile-devices-28-728.jpg?cb=1235050506 pics are from the end of this presentation slides: https://www.slideshare.net/jmbouffard/openmokast-the-open-broadcasting-software-stack-for-mobile-devices From lkcl at lkcl.net Tue Oct 17 03:58:59 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Tue, 17 Oct 2017 03:58:59 +0100 Subject: [Arm-netbook] Hack GPD Pocket Into EOMA68 Computer? In-Reply-To: <264422e4-3a31-794f-4913-40328ab07456@aross.me> References: <264422e4-3a31-794f-4913-40328ab07456@aross.me> Message-ID: --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 On Tue, Oct 17, 2017 at 2:43 AM, Alexander Ross wrote: > Looking at the tear down: > https://www.reddit.com/r/GPDPocket/comments/6j1jfo/gpd_pocket_full_teardown_and_photos/ dang that's nice. but... woo, four 32-bit-wide LPDDR3 RAM ICs, that close together? that's one hell of an impressive PCB design > I can’t help myself from wondering how hard would it be to mod it into a > eoma68 handheld computer? pretty hard. it's a really small space. remember i had a hard enough time designing something that would fit into a *seven* inch tablet space. if you allowed the EOMA68 Card to stick out the side it would likely be doable. weird, but doable. l. From penyuanhsing at gmail.com Thu Oct 19 15:33:35 2017 From: penyuanhsing at gmail.com (Pen-Yuan Hsing) Date: Thu, 19 Oct 2017 15:33:35 +0100 Subject: [Arm-netbook] MNT Reform DIY portable computer Message-ID: <92209798-34d7-5f05-3cb6-137c593512e7@gmail.com> Hi all, Just FYI, I just stumbled upon the MNT Reform project: http://mntmn.com/reform/ Is there anything here that's of use to the project? What do folks think of it? Constructive criticisms? From lkcl at lkcl.net Thu Oct 19 16:19:57 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Thu, 19 Oct 2017 16:19:57 +0100 Subject: [Arm-netbook] MNT Reform DIY portable computer In-Reply-To: <92209798-34d7-5f05-3cb6-137c593512e7@gmail.com> References: <92209798-34d7-5f05-3cb6-137c593512e7@gmail.com> Message-ID: --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 On Thu, Oct 19, 2017 at 3:33 PM, Pen-Yuan Hsing wrote: > Hi all, > > Just FYI, I just stumbled upon the MNT Reform project: > > http://mntmn.com/reform/ > > Is there anything here that's of use to the project? What do folks think of > it? Constructive criticisms? not half bad! i love that they bypassed all the hassle you normally get with keyboard suppliers and simply... made their own. l. From mike.valk at gmail.com Fri Oct 20 13:23:15 2017 From: mike.valk at gmail.com (mike.valk at gmail.com) Date: Fri, 20 Oct 2017 14:23:15 +0200 Subject: [Arm-netbook] "NonDesktop" Proposed For RandR: Useful For VR & Apple Touch Bar Like Devices Message-ID: https://www.phoronix.com/scan.php?page=news_item&px=NonDesktop-RandR Handy extension for the LCD touchpad. From lkcl at lkcl.net Sun Oct 22 07:00:22 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Sun, 22 Oct 2017 07:00:22 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> <9CEB80E3-5172-41E2-BECC-FE5551E070FE@gmail.com> Message-ID: hiya richard, so how you getting on? --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 On Fri, Oct 13, 2017 at 1:56 AM, Luke Kenneth Casson Leighton wrote: > On Thu, Oct 12, 2017 at 9:16 PM, Richard Wilbur > wrote: > >>> whoops.... :) 89 ohm... 50 ohm. 89 ohm... 50 ohm. oops... :) >> >> Well, if the reported impedance is the single-ended impedance >> of those lines we have considerable margin to burn and should >> aggressively pursue the taper structure and bring in the keepouts at each end. > > i sort-of understand that. am i right in thinking: at the ends we > have to treat them as single-ended, and achieve a sngle-ended > impedance of 50 ohms, but 100 ohms for the diff-pairs. > >> For the geometry that fit our constraints, we calculated a single-ended impedance of ~72 Ohm and differential impedance of ~111 Ohm (which corresponds to a tolerance of 11%). > > ok so 72's not really very close to 50 ohms... interested to learn > how that can be achieved. > > l. From ronwirring at Safe-mail.net Sat Oct 21 21:06:03 2017 From: ronwirring at Safe-mail.net (ronwirring at Safe-mail.net) Date: Sat, 21 Oct 2017 16:06:03 -0400 Subject: [Arm-netbook] MNT Reform DIY portable computer Message-ID: -------- Original Message -------- From: Pen-Yuan Hsing Apparently from: arm-netbook-bounces at lists.phcomp.co.uk To: Eco-Conscious Computing Subject: [Arm-netbook] MNT Reform DIY portable computer Date: Thu, 19 Oct 2017 15:33:35 +0100 > http://mntmn.com/reform/ Can the i mx8 work on entirely libre software? Libre software gpu? > > _______________________________________________ > arm-netbook mailing list arm-netbook at lists.phcomp.co.uk > http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook > Send large attachments to arm-netbook at files.phcomp.co.uk From richard.wilbur at gmail.com Sun Oct 22 19:33:26 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Sun, 22 Oct 2017 12:33:26 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> <9CEB80E3-5172-41E2-BECC-FE5551E070FE@gmail.com> Message-ID: <6DA57CDA-F7CC-42BF-B69C-0245D61F3E07@gmail.com> I'll try to get some computer time today and markup a picture with some ideas for the taper and geometry towards the connector end and send it to the list. By the way, the Analog Devices employee's recommendations can't be exactly normative with my understanding of transmission line impedances--differential impedance < 2 * single-ended impedance. (In other words you'll want single-ended > 50Ω if you hope to get differential = 100Ω.) I'd consider them design guidelines or goals in order to try and keep the process from going in the ditch. From lkcl at lkcl.net Sun Oct 22 20:12:06 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Sun, 22 Oct 2017 20:12:06 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: <6DA57CDA-F7CC-42BF-B69C-0245D61F3E07@gmail.com> References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> <9CEB80E3-5172-41E2-BECC-FE5551E070FE@gmail.com> <6DA57CDA-F7CC-42BF-B69C-0245D61F3E07@gmail.com> Message-ID: --- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 On Sun, Oct 22, 2017 at 7:33 PM, Richard Wilbur wrote: > I'll try to get some computer time today and markup a picture > with some ideas for the taper and geometry towards the connector end > and send it to the list. thx richard. > By the way, the Analog Devices employee's recommendations can't be exactly > normative with my understanding of transmission line impedances-- > differential impedance < 2 * single-ended impedance. > (In other words you'll want single-ended > 50Ω if you hope to get differential = 100Ω.) that makes a kind of sense > I'd consider them design guidelines or goals in order to try and > keep the process from going in the ditch. well... in theory it might be possible to change the layer stack slightly (move layer 5 a bit further away from layer 1), or go to 4mil track widths (but preferably *without* moving any of the traces!) the layer stack height alteration is an easy one to do. track width changes... yyeah... 4 mil would be the thinnest tracks on the entire board, i'm reluctant to do it but we can do it if necessary. l. From lkcl at lkcl.net Wed Oct 25 09:05:13 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Wed, 25 Oct 2017 09:05:13 +0100 Subject: [Arm-netbook] preview of latest update Message-ID: https://www.crowdsupply.com/eoma68/micro-desktop/updates/shenzhen-maker-faire-10-12-november-2017 From richard.wilbur at gmail.com Thu Oct 26 17:36:49 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Thu, 26 Oct 2017 10:36:49 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> <9CEB80E3-5172-41E2-BECC-FE5551E070FE@gmail.com> <6DA57CDA-F7CC-42BF-B69C-0245D61F3E07@gmail.com> Message-ID: My wife was sick last week so I spent more quality time with my daughters taking them to appointments, working with them on their studies, et cetera. I'm working on the geometry of the taper for this afternoon, but first a few questions to clarify some points. On Sun, Oct 22, 2017 at 1:12 PM, Luke Kenneth Casson Leighton wrote: > On Sun, Oct 22, 2017 at 7:33 PM, Richard Wilbur > wrote: >> By the way, the Analog Devices employee's recommendations can't be exactly >> normative with my understanding of transmission line impedances-- >> differential impedance < 2 * single-ended impedance. >> (In other words you'll want single-ended > 50Ω if you hope to get differential = 100Ω.) > > that makes a kind of sense > >> I'd consider them design guidelines or goals in order to try and >> keep the process from going in the ditch. > > well... in theory it might be possible to change the layer stack > slightly (move layer 5 a bit further away from layer 1), or go to 4mil > track widths (but preferably *without* moving any of the traces!) > > the layer stack height alteration is an easy one to do. > > track width changes... yyeah... 4 mil would be the thinnest tracks on > the entire board, i'm reluctant to do it but we can do it if > necessary. I think we can get away without much of the special considerations we are spending on this and it will probably work just fine at HDMI v1.4 but moving up to higher clock speeds with the later versions will likely require more care. That said, 1. do you have a picture of the HDMI layout you referred to which is known to have worked? I'm working under the assumption that we can leave the board fabrication parameters alone (stack thickness, smallest trace, smallest gap) and still make a working HDMI transmitter. 2. Does Mentor Graphics give any documentation to explain the provenance of the impedance numbers it reports from PADS layout? I am somewhat surprised to hear that our impedance is higher than we calculated with the TI equations--especially since we have several incursions within the guidelines they suggested. I expected to be on the low side, not the high side, of what we designed for. Thus my initial reaction that the 89Ω value sounded more like the differential impedance which had sagged a bit (from ~110Ω) under the pressure of close copper. I expected to design for a little higher impedance with the knowledge that we would likely lose some to unavoidable spacing issues. So if the impedance number from PADS is to be useful we really need to know what it is measuring. If it is single-ended, we are high and take measures to reduce it such as bringing ground fill closer to traces. If it is differential, then we are about 10% below nominal and we should make sure any change to the layout doesn't further lower the impedance. If it is neither, we will have to come to some understanding of what it is in order for it to be useful as design feedback. 3. How far do the differential pairs travel in the northeast direction after turning up from the bottom of the board? (Dimension 'A' in the diagram below.) 4. How far do the TX0 traces travel after turning northeast from the bottom of the board before they have to turn due north to avoid those ground vias? (Dimension 'B' in the diagram below.) -------------- next part -------------- A non-text attachment was scrubbed... Name: eoma68-a20-275-hdmi-new-wiggles-layer6-markup.png Type: image/png Size: 282401 bytes Desc: not available URL: From lkcl at lkcl.net Thu Oct 26 19:51:22 2017 From: lkcl at lkcl.net (Luke Kenneth Casson Leighton) Date: Thu, 26 Oct 2017 19:51:22 +0100 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> <9CEB80E3-5172-41E2-BECC-FE5551E070FE@gmail.com> <6DA57CDA-F7CC-42BF-B69C-0245D61F3E07@gmail.com> Message-ID: On Thu, Oct 26, 2017 at 5:36 PM, Richard Wilbur wrote: > My wife was sick last week so I spent more quality time with my > daughters taking them to appointments, working with them on their > studies, et cetera. not a problem richard. as you may have (or probably more sensibly didn't) see, i'm taking the opportunity to focus on shenzhen maker faire and the two 3d printers, plus sensor boards, plus low-cost STM32F-based arduino-due board, plus RD3D (a major upgrade to RAMPS) and so on. > I'm working on the geometry of the taper for this afternoon, but first > a few questions to clarify some points. cool. >> track width changes... yyeah... 4 mil would be the thinnest tracks on >> the entire board, i'm reluctant to do it but we can do it if >> necessary. > > I think we can get away without much of the special considerations we > are spending on this and it will probably work just fine at HDMI v1.4 > but moving up to higher clock speeds with the later versions will > likely require more care. later versions are *never* going to go to HDMI 2.0 speeds... because there will never be a version of the A20 which can do HDMI 2.0 speeds. basically for an upgrade to HDMI 2.0 that means using a totally new SoC, that means completely starting from scratch with a completely and entirely new PCB layout. > That said, > 1. do you have a picture of the HDMI layout you referred to which is > known to have worked? ha. very funny joke. as in, it's so bad that you'll laugh hysterically at how completely they failed to follow the HDMI design rules. in fact, i am sure that they actually knew them... just so as to be able to *deliberately fail* to obey EVERY SINGLE ONE OF THEM, because it is statistically significant that they actually failed to follow all of them, 100%. it's spread out on 3 layers: CLK goes onto layer 6, TX0-2 on layer 3, there's not even the slightest effort to provide GND separation, HSCL and so on are routed within 5 mil of the diff-pairs, there's absolutely no respecting diff-pair via spacing whatsoever, intra and inter pair vias are separated by 5mil, absolutely no GND vias nearby of any kind, and the pairs don't even length-match, not inter or intra. at all. the ESD protection was all on layer 6, meaning that there were totally unnecessary via jumps from layer 3 to layer 6 and then to layer 1 just to get to the ESD and then back to the connector, all within about... 1.5mm of each other. basically the tracks were treated as if they were ORDINARY tracks, jammed in tightly together because of space restriction down that edge of the board. there's absolutely no chance it would pass EMI... but incredibly it did actually get 1080p30 out the connector without any kind of visual artefacts or failures to display. stunning, really. i'm actually too embarrassed to send you any kind of pictures as it will only put you into shock. oh - when i say "no ground vias" i mean ABSOLUTELY NO ground vias whatsoever (either side), even though the HDMI tracks travel within 25 mil of the board edge for the entire distance. the rule has appeared to be: take everything we've done here.... and do the total opposite. > I'm working under the assumption that we can leave the board > fabrication parameters alone (stack thickness, smallest trace, > smallest gap) and still make a working HDMI transmitter. if the above is anything to go by, it should be pretty clear that you can get away with a hell of a lot more than expected. HDMI 2.0 absolutely no chance, but 1.4? seems to be... pretty tolerant. amazingly. > 2. Does Mentor Graphics give any documentation to explain the > provenance of the impedance numbers it reports from PADS layout? not that i've ever looked for it, but i can make some guesses. it's a lot LOT simpler than you're expecting. there's absolutely no consideration taken of neighbouring GND on the same layer *whatsoever*, for example. > I am somewhat surprised to hear that our impedance is higher than we > calculated with the TI equations--especially since we have several > incursions within the guidelines they suggested. the numbers have absolutely nothing to do whatsoever with neighbouring tracks. as in: the fact that neighbouring tracks exist - or not - or the fact that there may - or may not - exist any copper pour within any distance of any kind, to any part of any track, is COMPLETELY AND UTTERLY IGNORED. the only factors taken into consideration appear to be board thickness, track length, and distance to any plane SPECIFICALLY marked as "GND". i tested this out by changing the thickness of the substrate between Layer 1 (TOP) and Layer 2 (GND) and then compensating for that change by matching it in LAYER 3 (GND) and Layer 4 (POWER). the result was: the reported impedance of the HDMI tracks changed. so we *can* actually adjust the impedance by altering the stack: i know a fab house that has an extremely good engineer who knows how to do that just from the gerbers alone, but i don't have access to him any more. > I expected to be on > the low side, not the high side, of what we designed for. you may be believing that i have access to "Hyperlinx" which is the Signal Integrity / Simulation package. that CAN - as best i know - do the kinds of impedance analysis that you're expecting / believing that is reported. i do NOT have access to that package. the impedance value reported by PADS DOES NOT in ANY WAY take into account the nearby copper. not even when you actually run the flood-fill. it's simply too complicated to do (requires Signal-level electronics Simulation) and that's just not part of the PADS program: it's part of Hyperlynx. > Thus my > initial reaction that the 89Ω value sounded more like the differential > impedance which had sagged a bit (from ~110Ω) under the pressure of > close copper. nope. not at all. under no circumstances is PADS (on its own) capable of taking into account the closeness of any copper (pour or tracks). in the reported impedance value it COMPLETELY ignores ALL copper and ALL nearby tracks, taking into account ONLY those three parameters: length, width, and distance to any GND plane(s). > So if the impedance number from PADS is to be useful we really need to > know what it is measuring. If it is single-ended, we are high and > take measures to reduce it such as bringing ground fill closer to > traces. it's single-ended, and has absolutely nothing whatsoever to do with any copper on the same layer, whatsoever. > 3. How far do the differential pairs travel in the northeast > direction after turning up from the bottom of the board? (Dimension > 'A' in the diagram below.) 5.6mm > 4. How far do the TX0 traces travel after turning northeast from the > bottom of the board before they have to turn due north to avoid those > ground vias? (Dimension 'B' in the diagram below.) 1.3mm. btw.. *sigh* one very important bit of info: the layer stack parameters i double-checked, i wasn't confident that they were for a 1.2mm board, and it's good that i checked. https://www.quick-teck.co.uk/TechArticleDoc/4138811771353606590.pdf the pre-preg distance is supposed to be 0.2mm not 0.254 to create a standard 1.2mm 6-layer stack. i had 0.254 which is for a 1.6mm. whoops. so the actual impedance reported - now that i've modified the design rules for the stack to match 1.2mm total height, are 81 ohms. sorry! l. From richard.wilbur at gmail.com Fri Oct 27 05:31:06 2017 From: richard.wilbur at gmail.com (Richard Wilbur) Date: Thu, 26 Oct 2017 22:31:06 -0600 Subject: [Arm-netbook] HDMI High-Frequency Layout: Recommendations In-Reply-To: References: <04496B4C-7BB6-4619-804C-C0296761F558@gmail.com> <0620D014-55E0-41C1-9CBF-B671898D7187@gmail.com> <110EC969-7221-42CE-9B54-F6D658E8BC90@gmail.com> <61C5A163-9A5C-4BD4-8DE6-65A418082907@gmail.com> <8A03534C-A3F6-4689-98FA-C4DD6CF465E2@gmail.com> <4E311CA5-D091-4E6B-8CD7-82F8DC7ECBD1@gmail.com> <544AD58E-3E36-411F-B75D-F49D08AD677B@gmail.com> <72396096-4F21-4668-877C-112A19194EB0@gmail.com> <9CEB80E3-5172-41E2-BECC-FE5551E070FE@gmail.com> <6DA57CDA-F7CC-42BF-B69C-0245D61F3E07@gmail.com> Message-ID: Thank you for the very informative reply! I'm going to bed now. I look forward to sending my technical reply tomorrow. From cel at celehner.com Sat Oct 28 02:12:36 2017 From: cel at celehner.com (Charles Lehner) Date: Fri, 27 Oct 2017 15:12:36 -1000 Subject: [Arm-netbook] DIY laptop part 3: Where can I get an EDP connector? In-Reply-To: <20170801145910.6f6e5520@ulgy_thing> References: <20170801145910.6f6e5520@ulgy_thing> Message-ID: <20171027150634.7a869a3c.cel@celehner.com> Hi all, On Fri, 22 Sep 2017 00:19:06 -0400 doark at mail.com wrote: > I now own a > cable labelled as 30-pin EDP to 30-pin EDP but actually 30-pin EDP to > 30-pin something else right angle connector. > > Anyone know a good store? I'm also looking for an eDP cable, to replace the one in my pi-top that broke. I read that an LVDS cable can be used, but I haven't got one yet. Regards, Charles From isacdaavid at isacdaavid.info Sun Oct 29 18:55:30 2017 From: isacdaavid at isacdaavid.info (Isaac David) Date: Sun, 29 Oct 2017 12:55:30 -0600 Subject: [Arm-netbook] MNT Reform DIY portable computer In-Reply-To: References: Message-ID: <1509303330.1184.0@plebeian.isacdaavid.info> > Can the i mx8 work on entirely libre software? > Libre software gpu? That was the case with the i.MX6. Proprietary firmware had to be loaded for the VPU to work,[1] but the GPU line was successfully reverse-engineered[2] and integrated into Mesa. No bootloader blobs either, definitely one of the best platforms for libre software. That said, the i.MX8 is using a newer Vivante GPU, which apparently hasn't been worked on yet.[3] [1]: https://www.fsf.org/campaigns/priority-projects/hardware-firmware-drivers [2]: https://github.com/etnaviv/etna_viv [3]: https://www.cnx-software.com/2017/08/25/purism-librem-5-open-source-linux-smartphone-focuses-on-privacy-crowdfunding/ -- Isaac David GPG: 38D33EF29A7691134357648733466E12EC7BA943 From isacdaavid at isacdaavid.info Sun Oct 29 19:06:08 2017 From: isacdaavid at isacdaavid.info (Isaac David) Date: Sun, 29 Oct 2017 13:06:08 -0600 Subject: [Arm-netbook] MNT Reform DIY portable computer In-Reply-To: <1509303330.1184.0@plebeian.isacdaavid.info> References: <1509303330.1184.0@plebeian.isacdaavid.info> Message-ID: <1509303968.1184.1@plebeian.isacdaavid.info> Isaac David wrote : > That said, the i.MX8 is using a newer Vivante GPU, which apparently > hasn't been worked on yet. correction: work is ongoing and promising: https://www.youtube.com/user/wladiwump/video -- Isaac David GPG: 38D33EF29A7691134357648733466E12EC7BA943