**** BEGIN LOGGING AT Mon Apr 09 03:00:04 2018 Apr 09 03:28:18 Sunday! Apr 09 06:02:07 Monday! Apr 09 09:36:22 zmatt, could you please have a look at this: in order to safely shutdown all power rails via pmic in case of an abrupt power loss and to prevent damage of the am335x, it would be sufficient to supply max current (~600mA) for 12 ms (wich is the shutdown time for all rails on pmic Apr 09 09:41:01 if 5v supply goes down below 3,3V with no battery attached, will undervoltage lockout occur? Apr 09 11:34:46 microdevel2: the pmic unconditionally switches to battery power at the start of that 12ms shutdown sequence, effectively running on just caps, so no power is being drawn from the supply anymore at that point Apr 09 11:35:39 microdevel2: you can find some scope plots of undervoltage shutdown at https://elinux.org/BeagleBone_Power_Management (search for "undervoltage") Apr 09 11:36:59 zmatt so in case of a power cut on AC, it makes no sense to add a capacitor to ac supply line to ensure proper sequential shutdown? Apr 09 11:37:35 it does because it gives the pmic time to detect a shutdown is needed in the first place Apr 09 11:37:52 otherwise you get the scenario of the last set of scope images on that page Apr 09 11:37:56 yes thats what i was aiming for Apr 09 11:38:07 but how to dimension the cap? Apr 09 11:38:17 no idea Apr 09 11:38:48 i guess it will be 18ms instead of 12ms, there's also a deglitch time for Vuvlo of 6ms Apr 09 11:39:55 so the cap should provide enough power for 600mA, 18ms @ approx. 3,4V Apr 09 11:40:23 have no idea how to calculate this :D Apr 09 11:40:26 that means the supply voltage needs to go down by not too much during those 6ms Apr 09 11:40:50 the remaining 12ms are irrelevant to the cap since the power consumption is way less then and moreover not drawn from the supply Apr 09 11:42:29 you mean the power consumption is lower than max. system power consumption because the first rails have already been shut down? Apr 09 11:43:16 the very first thing the pmic does (along with switching to battery power) is deasserting PGOOD, which asserts power-on-reset to the processor Apr 09 11:44:06 ahh, i missed that. ok so the required power will be the power the soc draws after reset Apr 09 11:44:50 and components other than the SoC, especially the HDMI framer if you use it (since it is oblivious to reset) Apr 09 11:45:52 yes, everything that draws power from the pmic that point Apr 09 11:46:21 Hello, just checking in if someone knows how to test the wifi chip on the blue ? Apr 09 11:49:26 ok zmatt but you never put a cap on supply yet? Apr 09 11:51:25 microdevel2: and how to calculate it: say if you don't want a cap to drop by more than 0.2 V using 6 ms while providing 600 mA, it needs to be (600 mA * 6 ms) / (0.2 V) = 18 mF Apr 09 11:51:44 s/using/during/ Apr 09 11:53:21 eh, our original plan was to use a li-ion to carry the system to clean shutdown, so the power supplies never got carefully analyzed, even though the battery was abandoned later. so basically, our current strategy is "hope it'll be okay" Apr 09 11:53:26 :P Apr 09 11:53:51 fortunately we don't expect to be turned on and off that frequently Apr 09 11:53:58 and to cover the following 12ms, the internal caps will be good enough? Apr 09 11:54:26 yeah, as you know, li-ion and high temp on a motorbike are bad :D Apr 09 11:55:39 they seem to be enough to at least make shutdown look not too horrible Apr 09 11:56:28 something like this may not look pretty, but I don't think it's harmful in practice -> https://elinux.org/File:Bbb-c-3v3u-rampdown-dc.png Apr 09 11:57:29 i would be happy if we can achieve this Apr 09 11:57:31 if in doubt, do your own scope measurements and add extra capacitance to vsys if you feel it needs it Apr 09 11:58:17 to vsys or to AC ? Apr 09 11:58:56 vsys for what happens after the pmic starts sequencing powerdown Apr 09 12:00:37 you can also power the system through vbat instead of AC to have it be able to continue to receive supply during this time, but it adds other complications Apr 09 12:01:47 hi how to i enable all gpio pins Apr 09 12:02:13 so the cap on AC would only be there to bring the PMIC safely to undervoltage lockout, then it disconnects AC and (hopefully) does a safe poweroff sequencing by internal caps? Apr 09 12:03:23 i did uncomment dissable Emmc statement in uEnu.txt Apr 09 12:03:36 than after i reboot Apr 09 12:03:51 i need to enable P8_30 Apr 09 12:04:03 i cant make it LOW or HIGH Apr 09 12:04:05 prakash: since you're booting from SD card, be sure to erase eMMC first (sudo blkdiscard /dev/mmcblk1) to ensure you're not accidently using an old u-boot still on eMMC Apr 09 12:04:13 its showing always LOW Apr 09 12:04:30 otherwise disable_uboot_overlay_emmc may have no effect Apr 09 12:04:41 oho kk Apr 09 12:05:00 (if eMMC still contains an older u-boot that doesn't recognize that variable) Apr 09 12:05:25 previously i din't do sudo blkdiscard /dev/mmcblk1 Apr 09 12:05:50 microdevel2: well the annoying bit is that the cap on AC will mostly be to keep it from going down too much during the uvlo detection window Apr 09 12:06:18 microdevel2: if you'd be able to trigger reset sooner on powerloss, the cap could be much smaller Apr 09 12:06:46 microdevel2: also beware that the input power must not slew up too slowly during power-up Apr 09 12:06:55 kk what you said that i will do tq . Apr 09 12:07:34 microdevel2: specifically, ramp up must take place within 50 ms Apr 09 12:07:50 but, I gotto run Apr 09 12:08:05 yeah, got it. hmm i could use a microprocessor that monitors input power of the bike (12V), if it drops significantly, pull reset Apr 09 12:08:06 afk Apr 09 12:19:40 hi zmatt what you said same way i did but it's not working enable P8-30 pin Apr 09 12:19:50 sudo blkdiscard /dev/mmcblk1 Apr 09 12:20:36 @zmatt hi what you said same way i did but it's not working enable P8-30 pin Apr 09 12:20:43 sudo blkdiscard /dev/mmcblk1 Apr 09 12:23:06 hello any one can you help me how to enabled all gpio pins Apr 09 12:26:21 @zmatt excuse me sir Apr 09 12:32:34 hi anyone can help to me how to enabled all gpio pins Apr 09 12:41:58 hello anyone can replay to me please Apr 09 12:56:54 naga_: don't spam a question when you don't immediately get a reply, have some patience Apr 09 12:58:15 naga_: and "not working" is too vague for anyone to be able to help you. what is not working? did the blkdiscard command not work? did the gpios not appear in sysfs after subsequently disabling eMMC? do they appear but are you still having a problem of some sort? Apr 09 13:09:10 @zmatt thank you your valuable information to solve to gpio enabling.now it's working Apr 09 13:40:01 Can you share any serial debug pin out serial comminication example Apr 09 13:40:26 sitara: for what? Apr 09 13:40:54 I try to learning Apr 09 13:41:46 okey ı will join Apr 09 17:48:37 What IDE I can use for BeagleBoneBlack? Apr 09 17:49:21 whatever IDE you like Apr 09 18:28:25 Hey, Im trying to write to a Adafruit 16x2 LCD screen from my BeagleBone Green and I want to do it in C++ but I cant find anything online Apr 09 18:36:38 JoCuse: what sort of display is that? i2c ? Apr 09 18:37:12 the HD44780 one? Apr 09 18:38:27 https://www.adafruit.com/product/181 Apr 09 18:38:28 this one Apr 09 18:40:18 I'm finding tons of code in a variety of languages if I google for HD44780 Apr 09 18:40:19 JoCuse: How have you wired it to the beagle? Apr 09 18:43:08 Its wired up yes Apr 09 18:44:04 generally speaking, "yes" is not the expected answer to a question that begins with "How" Apr 10 00:28:10 meh, there's a kernel and userspace lib for those Apr 10 01:17:48 Hey! Apr 10 01:17:52 and Hello! Apr 10 01:18:23 Guess what? That is correct...I got some type of MOTOR DRIVER in! Apr 10 01:19:27 Big baller over here w/ up to 24v at 1A to kick in some super MOTORS. Oh and interfacing w/ the BBB, no doubt. Gangster enough for you? Apr 10 01:19:39 hahaahah. Apr 10 01:20:17 ... Apr 10 01:20:19 sorry. Apr 10 01:38:42 Are there any people in here interested in motors and 24v Motor Drivers? Apr 10 01:39:48 If not...okay. But, if so, look here: https://www.dimensionengineering.com/. I would be able to interface w/ the BBB and variations easily over serial and/or R/C. Apr 10 01:42:34 ... Apr 10 01:59:20 what kind of motor? Apr 10 02:02:04 Electric...electric motor. Apr 10 02:02:22 I have only geared motors for now. Apr 10 02:02:35 3PH? DC? Universal? Stepper? etc Apr 10 02:02:40 Oh. Apr 10 02:02:41 DC Apr 10 02:02:51 oh brushed? Apr 10 02:02:55 Yep. Apr 10 02:03:03 blah... those are no fun Apr 10 02:03:08 Why? Apr 10 02:03:17 Too easy? Apr 10 02:03:26 a few MOSFETs is all you need Apr 10 02:03:33 Oh. Apr 10 02:03:36 they aren't that controllable either Apr 10 02:04:06 forward/backward and the speed varies based on load Apr 10 02:04:19 about the only good about them is they are cheap Apr 10 02:04:26 Yea. Cheap! Apr 10 02:04:39 What do you mess w/? What type of motors? Apr 10 02:05:06 whatever the job calls for. steppers are useable in 3axis machines Apr 10 02:05:20 3PH is good for spindles or RC vehicle propulsion Apr 10 02:05:43 I have to learn more about steppers. 3phase motors are good for R/C? Apr 10 02:05:48 I was unaware of that. Apr 10 02:14:00 the RC guys call them brushless motors Apr 10 02:23:24 Oh. Apr 10 02:23:26 See. Apr 10 02:23:34 Now...I understand. Apr 10 02:24:34 To tell you the truth, I never purchased 3 phase motors b/c of the complications. But, I did recently for a drone project. Apr 10 02:26:46 more wires = more stuff in general Apr 10 02:27:24 I would have to spend 25% more time on 3PH/brushless compared to DC. Apr 10 02:27:44 That is per motor...Yikes! Apr 10 02:28:48 ds2: I have not soldered in a while. The drone frame I got, that is GOING to work w/ the BBBlue, came w/ a "chip" board w/ connector. Apr 10 02:29:02 I am going to have to solder again. Apr 10 02:29:06 <<<< lazy **** ENDING LOGGING AT Tue Apr 10 03:00:02 2018