**** BEGIN LOGGING AT Sun Jun 11 03:00:03 2017 Jun 11 17:31:34 hi Jun 11 17:38:52 yo Jun 11 18:11:36 hello, i am working with the am335x starter kit and running in to some trouble. am i in the right place? Jun 11 18:12:43 probably not since the SK is not a beagle product but a TI product, i.e. the appropriate forum would probably be e2e.ti.com, but of course you can always just try by asking a question Jun 11 18:13:55 plenty of knowledgable people here, though it can sometimes take a while for one to happen to be awake and peek at IRC, so sticking around after asking a question is highly recommended Jun 11 18:13:59 is there a more specific channel for the ti product? sorry i got mixed up Jun 11 18:14:11 probably not on IRC Jun 11 18:14:32 hm. some of the questions i have are pretty general and might apply actually, if it is acceptable for me to ask here Jun 11 18:26:51 basically i'm trying to cat over ssh, yet there is no output Jun 11 18:27:15 (on the board itself, works fine if i just ssh in) Jun 11 18:27:53 what did you try specifically? Jun 11 18:33:37 ok, since you're clearly in no hurry, I'm first going to do some shopping :P Jun 11 18:33:55 bbl Jun 11 20:01:35 zmatt: hey something came up. i flush output from script to fifo, nc that to server -> fifo, cat over ssh Jun 11 20:02:40 can you just show the actual command that's not working for you? Jun 11 20:02:52 because your description is a bit vague Jun 11 20:19:20 zmatt: yes hold on Jun 11 20:19:52 ssh -p $SSH_PORT $YOU@$IP cat /tmp/cdda_$HOST Jun 11 20:20:02 where cdda_$HOST is a fifo Jun 11 20:20:58 echo "whatever" works fine though Jun 11 20:23:46 hmm, that is a bit odd indeed... maybe cat uses different buffering depending on whether stdout is a tty or not? Jun 11 20:23:54 try passing the -t option to ssh Jun 11 20:26:36 Hey guys! Quick question regarding the BeagleBone Blue GPIO connectors. My electronics knowledge is next to zero so forgive me if this is a trivial question. I'd like to attach a rangefinder (specifically the HC-SRO4 v2) to the board via GPIO. However, the BeagleBone Blue doesn't seem to have typical headers like the other boards. What kind of connector can I use to accomplish this? Jun 11 20:28:56 people do use beaglebones with this type of ultrasonic sensor Jun 11 20:29:03 just use jumper wires to connect it Jun 11 20:29:24 a better question is which pins are best suited for something like this Jun 11 20:29:53 Is GPIO not a suitable pin? Jun 11 20:30:07 depends on what kind of accuracy you were hoping for Jun 11 20:30:42 having the pulse be measured in hardware instead of in software might make a significant difference in precision Jun 11 20:30:46 Nothing crazy. I'm building a rover and would like to detect if it is approaching a wall Jun 11 20:31:21 there are subsystems in the AM335x which can perform measurements with 10ns accuracy Jun 11 20:32:10 https://github.com/luigif/hcsr04 Jun 11 20:32:39 PRU... yeah that could work too, I was thinking more of pwmss Jun 11 20:33:19 wait, it uses PRU yet doesn't use actual PRU GPIOs ? Jun 11 20:33:25 that's a waste... Jun 11 20:33:36 nfc, it was among the first google results Jun 11 20:33:53 tbr: How can I connect that thing to the blue since it does not have headers? Is there some kind of adapter I can use? Jun 11 20:34:04 uhhh, and if that module indeed has 5V output then a series resistor is *not* going to be sufficient to protect the beaglebone from damage Jun 11 20:34:42 although if I google the part number you mentioned it seems that it can also work on 3.3v ? Jun 11 20:35:27 on Sparkfun it says 5v Jun 11 20:36:02 is there another recommended range finder for the BeagleBone Blue? Jun 11 20:36:19 some other page google found said 3-5.5V Jun 11 20:36:33 with slightly less range when powered at 3.3V than when powered at 5V Jun 11 20:36:33 personally, I'm quite fond of the infra-red distance sensors by sharp Jun 11 20:36:47 also easier to interface as the output is an analogue voltage Jun 11 20:38:00 https://www.sparkfun.com/products/242 Jun 11 20:38:01 this guy? Jun 11 20:38:44 yes, there are 3 different versions of this sensor, with different range Jun 11 20:39:34 okay. Given that it is a 3-pin JST connector how do I attach that to the 6-pin JST on the Blue? Jun 11 20:40:28 carefully Jun 11 20:40:52 it can apparently produce output up to 3.3v, so you'll need a few components to interface it safely to an analog input of the beaglebone Jun 11 20:41:07 (which have an abs max of 1.8V) Jun 11 20:42:08 so I'm not sure I'd agree that these are easier to use... but that depends on personal preferences w.r.t. hardware vs software :) Jun 11 20:42:36 do you have any recommended readings I can look at to learn more about what I'm trying to do? Jun 11 20:43:01 I have a bucket full of level shifters to throw at such things ;) Jun 11 20:43:47 based on some googling, the HC-SRO4 v2 is indeed 3.3V tolerant (unlike v1 of that module which is 5V-only), so you should be able to just wire it up and from there it's a Simple Matter of Programming™ Jun 11 20:44:32 (which is only actually 'simple' if one is already quite familiar with the AM335x's capabilities) Jun 11 20:45:23 What do you think would be the simplest avenue to take? This is my first hardware project so I'd like to keep it straight forward as possible (I build apps, this is a new realm for me lol) Jun 11 20:45:33 I agree with tbr that something that produces an analog output is simpler from a software point of view, but it requires more complicated electronics to interface something unless it happens to have an output in the right voltage range Jun 11 20:46:34 don't think too much about connectors or "adapters"... there are no standards here, so don't expect a cable that happens to perfectly connect the two unless you make that cable yourself :) Jun 11 20:47:51 Okay. So is it perfectly acceptable to have 4 wires going into a 6-pin connector? Jun 11 20:48:04 what's on that 6-pin connector? Jun 11 20:48:54 I read that the onboard GPIO on the BB is 6-pin Jun 11 20:49:10 there seem to be various connectors actually Jun 11 20:49:19 (browsing the schematic right now...) Jun 11 20:49:57 3-pin, 4-pin, 6-pin Jun 11 20:50:52 http://www.mouser.com/pdfdocs/BeagleBone_Blue_ShortSpec11-3.pdf Jun 11 20:51:13 Mouser says GPIO is available via 6-pin JST-SH connectors Jun 11 20:51:27 among others yes Jun 11 20:51:28 can I plug the HC-SR04 into another connector? Jun 11 20:52:15 I guess a better question is does the HC-SR04 need to be ran over GPIO? Jun 11 20:52:57 no, but that may be easiest way to start playing with it. note that nearly all pins can be configured as GPIO Jun 11 20:54:40 Okay Jun 11 20:54:56 thank you Jun 11 20:55:01 if you want to get an impression of what functionality is available on the many processor pins, you can refer to this spreadsheet I made: Jun 11 20:55:23 (... if my computer is kind enough to stop swapping...) Jun 11 20:55:53 (... damnit chrome...) Jun 11 20:56:20 there we go... https://goo.gl/Jkcg0w Jun 11 20:57:26 the P9 and P8 tabs are especially useful for users of the BeagleBone Black and its various close relatives.... nothing in there is specific to the Blue, although it shares the same processor so it's mostly a matter of figuring out which pins went where Jun 11 20:58:08 awesome, thank you. i'll give it a look and try to interpret what I'm looking at lol Jun 11 20:59:05 if I'd personally want to interface that HC-SR04 v2, I would probably use a eHRPWM output and eCAP input (abbreviated "pwm" and "cap" in my spreadsheet) since those can be synchronized together Jun 11 21:00:09 so then pwm would generate the start pulse, and at the same time the counter of the input capture would start running, and then the echo pulse would get nicely timestamped Jun 11 21:01:23 the software for that would mostly involve figuring out the right settings of those peripherals, after which you can just read the latest distance measurement from a register Jun 11 21:01:39 zmatt: oo! that is a good idea Jun 11 21:01:42 i will get back to you Jun 11 21:02:08 okay. since you said the BB can receive a max of 1.8v do I somehow have to minimize the voltage coming from the HC-SR04? Jun 11 21:02:21 1.8v maximum only applies to the analog inputs Jun 11 21:02:29 the digital I/O is all 3.3V Jun 11 21:02:29 oh okay Jun 11 21:02:32 gotcha Jun 11 21:02:50 and like I said, apparently v2 of the HC-SR04 supports 3.3V Jun 11 21:03:45 if you want to know more about the pwm and capture modules, see chapter 15 of the AM335x TRM Jun 11 21:05:09 just downloaded it Jun 11 21:05:47 the TRM can be a bit intimidating at first ;) Jun 11 21:06:46 this is all intimidating lol. Like I said, I build apps professionally so for my senior project I figured I'd dive into something I know nothing about. So here I am lol Jun 11 21:07:01 welcome! :D Jun 11 21:07:15 thanks :) Jun 11 21:07:37 ultimately, knowing nothing about this is the state in which we all began Jun 11 21:09:04 absolutely. gotta start somewhere. I find the low level stuff incredibly fascinating. its much more interesting than building CRUD apps Jun 11 21:10:12 low level ftw Jun 11 21:10:21 I also made this once -> https://github.com/mvduin/bbb-asm-demo/releases/tag/v1 Jun 11 21:11:07 just as silly example :) someone on TI's e2e forum specifically wanted an example written in assembly for some reason Jun 11 21:12:12 wow! how long did that take? Jun 11 21:13:07 not long, I'm pretty familiar with the processor and this is a really really tiny program Jun 11 21:19:33 it's 452 bytes of code apparently Jun 11 21:19:45 :) Jun 11 21:19:48 brb **** ENDING LOGGING AT Mon Jun 12 03:00:01 2017