**** BEGIN LOGGING AT Fri Jun 09 03:00:04 2017 Jun 09 03:15:53 Need help with beaglebone black converting HDMI to VGA video Jun 09 03:33:04 zmatt: yes Jun 09 03:37:19 aaronm04: uhh, and you're sure you're measuring the right pin? Jun 09 03:38:16 it's the P9 header (the one next to the 5V port) Jun 09 03:38:26 and the 7th pin on the center side of that header Jun 09 03:38:32 counting from the 5V port Jun 09 03:38:57 that's P9.14 ? Jun 09 03:39:11 should be P9.12 Jun 09 03:39:38 the first pin of that column is 2 Jun 09 03:39:41 oh good grief Jun 09 03:39:45 looks like I miscounted Jun 09 03:39:48 :) Jun 09 03:40:21 thanks for your help Jun 09 03:40:25 it would be nice to have stickers to put on the sides of those headers Jun 09 03:40:38 cool program, although hard to understand what all the columns mean Jun 09 03:40:50 yeah I ought to make a readme or something Jun 09 03:41:05 that would help a lot! Jun 09 03:45:01 so I learned something surprising about electronics just now: measuring the voltage between a pulled high pin and my breadboard's ground shows close to 0V, but measuring the pin to the BBB's ground shows 3.3V Jun 09 03:45:41 I assumed it would be 3.3V for both, because they're both grounded using the neutral wire of the building power, right? Jun 09 03:47:23 how did you connect the breadboard to the BBB ? Jun 09 03:47:54 I didn't. It's separately powered Jun 09 03:48:00 there's your problem Jun 09 03:48:21 that's... strange but ok Jun 09 03:49:50 a "wall-wart" adapter just creates 5V (or whatever) potential between its two output wires, but that set of wires is essentially floating relative to everything else Jun 09 03:50:57 why would my multimeter say 0V if they're floating, rather than some random voltage? Jun 09 03:51:32 your multimeter is a resistor via which you connected the 3.3V of the BBB to the ground of your breadboard Jun 09 03:51:48 thereby fixing their relative levels Jun 09 03:52:55 it probably *is* being subject to some junk, but it might filter that out if it's selected to measure DC voltage Jun 09 03:52:58 try AC voltage Jun 09 03:54:28 it says 3.6V AC Jun 09 03:54:39 voila, there's your "random voltage" :) Jun 09 03:54:53 or more like not random but 50 or 60 Hz Jun 09 03:55:16 since that's the most probably junk you'll be picking up Jun 09 03:55:21 *probably Jun 09 03:55:27 argh Jun 09 03:55:29 *probable Jun 09 03:55:45 still don't understand fully, but this is damn interesting :) Jun 09 03:57:31 basically your breadboard and the BBB are sort of "floating" relative to each other, but they'll be pulled at least slightly to the AC voltage either due to some capacitance between the high and low voltage sides in the power supplies, or because you've effectively created an antenna to pick up the 50/60 Hz that's everywhere around you Jun 09 03:58:18 the multimeter has a fairly high resistance when measuring voltage, so it doesn't connect the breadboard's ground to the BBB's ground very well Jun 09 03:58:24 BBB's 3.3V I mean Jun 09 03:59:14 hmm, I see Jun 09 03:59:14 so although it manages to keep one centered around the other (hence 0V DC), they're still bouncing up and down relative to each other Jun 09 03:59:59 so, first thing to do when interconnecting independently powered electronics... make a good solid ground connection Jun 09 04:00:18 would connecting BBB ground to breadboard ground hurt anything? Jun 09 04:01:14 no, since the two are floating relative to each other. you get to make 1 solid connection to fix the potentials on one relative to the other Jun 09 04:03:36 cool, thanks for explaining that Jun 09 04:03:41 do be careful with grounded power supplies... https://www.youtube.com/watch?v=xaELqAo4kkQ Jun 09 04:05:21 (oscilloscopes are a typical example of something that's commonly connected to other electronics, yet unfortunately typically grounded rather floating) Jun 09 04:06:14 why btw are you powering the breadboard separately rather than using the BBB's ground and 3.3V to begin with? Jun 09 04:07:54 no good reason Jun 09 04:07:55 when connecting independently powered electronics to the BBB you need to be really careful since powering up the external electronics before the BBB is powered could fry it Jun 09 04:08:29 the I/Os are _not_ 3.3V-tolerant if the BBB's own 3.3V supply isn't up yet Jun 09 04:08:29 thanks for the tip. I'm going to just power it with the BBB then! Jun 09 04:11:03 so the BBB really needs to be on for a little while before connecting anything, and turned not turned off before disconnecting Jun 09 04:11:45 afaik it already required quite a bit of magic from TI to get the I/Os working at 3.3V (instead of 1.8V). AFAIK the abs max voltage allowed across the crazy thin gate oxide of the tiny tiny transistors of the 45nm process used for the am335x is 2.0V :-) Jun 09 04:12:13 well if the external electronics is powered from the BBB's 3.3V supply there's no problem leaving it connected Jun 09 04:12:26 ...magic which they couldn't pull off for the analog inputs, I guess Jun 09 04:12:30 nope Jun 09 04:14:23 I know it involves trickery with series transistors and intermediate bias voltages to prevent 2V getting across any single transistor Jun 09 04:15:43 the I/O supply inputs of the AM335x are appropriately named "VDDHV" -- High Voltage :) Jun 09 04:16:02 huh cool Jun 09 04:16:34 well I got my transistor-switched LED to be controlled by software on the BBB Jun 09 04:16:50 yay Jun 09 04:19:11 fyi it *is* of course possible to interconnect the BBB and independently powered electronics in various ways, but it requires careful analysis whether some particular circuit is safe or not. unless you have a real need for it, it's easier to stick to a single shared supply Jun 09 04:21:27 I see Jun 09 04:23:53 I guess it has to be possible, seeing as Ethernet cables do that :) Jun 09 04:23:55 if you do have a need for it later on, a simple rule to avoid trouble is: ensure that whatever is connected to BBB pins is either grounded or floating while the BBB's 3.3V supply is down (or, even safer, while the reset-signal is low) Jun 09 04:24:34 or old-school phone lines (> 40 years ago) Jun 09 04:24:54 zmatt: there are buffers designed exactly for that purpose Jun 09 04:24:54 ethernet is actually isolated, there are small transformers inside or nearby the ethernet connector Jun 09 04:25:02 ds2: indeed Jun 09 04:25:05 huh Jun 09 04:25:41 so the data crosses the transformer? Jun 09 04:26:25 more specifically - ethernet is galvanically isolated Jun 09 04:26:53 yes, differential changes are effectively AC hence pass through the transistor Jun 09 04:27:00 but a DC potential does not Jun 09 04:27:07 you mean transformer, zmatt? Jun 09 04:27:15 eh, yes Jun 09 04:27:36 hands didn't type what brain wanted :P Jun 09 04:27:49 autonomous hands Jun 09 04:28:10 aaronm04: http://mycollins.net/ethernettransformer.jpg Jun 09 04:28:26 (this is for 100BASE-TX ) Jun 09 04:30:39 (the part of the schematic left of the transformers can vary a bit depending on the ethernet phy used) Jun 09 04:41:59 nice Jun 09 04:42:02 have a good night Jun 09 06:47:35 Hi, I'm trying to use a ViewSonic 2220 touchscreen with a BeagleBone Black rev C. using Debian Jessie, I tried on Raspberry Pi and it worked just pluging, but in BeagleBone I'm having troubles. beaglebone debian dmesg: http://paste.debian.net/970621/ raspberry pi raspbian dmesg: http://paste.debian.net/970637/ On Beaglebone it detects the touchscreen because it starts xinput-calibrator, but it doesnt detect my finger click Jun 09 06:55:12 Hiii Jun 09 07:10:51 i want to know the life of beaglebone black industrial if i am using it 24*7 hours Jun 09 08:28:58 "24 kilokibihertz" is kinda a funny unit Jun 09 11:25:02 Hello can some tell me where to find a CAD 3D Model for the X15 Board? Jun 09 11:25:14 Step or Parasolid would be fine **** BEGIN LOGGING AT Fri Jun 09 23:33:10 2017 Jun 10 01:31:01 Hi. I'm running Ubuntu 16.04 on my BeagleBone Black, and I've just upgraded from linux-image-4.4.0-armv7-x3 to linux-image-4.4.68-ti-r107. Jun 10 01:31:29 Now I no longer have a /dev/gps0 driver file; any ideas how I can track down why? Jun 10 01:32:17 bone_capemgr still shows up in dmesg output, and it recogises my gps cape in slot 0 Jun 10 01:33:39 http://pastebin.ubuntu.com/24819745/ Jun 10 02:39:39 Solved my issue; looks like the tty changed from ttyO4 to ttyS4 Jun 10 02:39:45 changed it back, and all good Jun 10 02:40:02 s/changed it back/changed references to point to ttyS4/ **** ENDING LOGGING AT Sat Jun 10 03:00:01 2017