The BB uses the TPS65217 power management IC. Per the data sheet, it will not turn on if the applied power has a ramp of greater than 50 mSec.
On Thursday, August 1, 2013 at 5:07:13 PM UTC-4, [email protected] wrote: > > Yes, I checked the Wiki. The 2A wall wart from Adafruit was purchased > because the Wiki pointed at it and said it was a power supply that worked. > > So I have three perfectly working boards and one not-working board, and > I'm using a power supply recommended by the Wiki. If that recommendation > was in error and there's another one which will work better I'm all ears. > > On the other hand, is it not possible that the problem might not always be > the power supply but in fact might sometimes be the board? > > Dennis Ferguson > > On Thursday, August 1, 2013 8:37:36 AM UTC-4, Gerald wrote: >> >> Did you check the Wiki? We have power supplies listed there >> under accessories. Just because a distributor recommends it, does not make >> it so. >> >> http://circuitco.com/support/BeagleBoneBlack >> >> >> Again, it is not an amperage question. >> >> Gerald >> >> >> On Wed, Jul 31, 2013 at 11:23 PM, <[email protected]> wrote: >> >>> Which power supply is the right one? >>> >>> I have four boards and three different power supplies. Three of the >>> boards always boot, on any of those supplies, when the AC is turned on or >>> when the power connector is plugged in. The fourth board never does with >>> any of the power supplies. >>> >>> The fourth board will boot 100% of the time if the reset button is >>> pushed after it has failed to boot on power up. When I connected the >>> serial cable to see if I could find out what it was doing when it didn't >>> boot I also discovered it would boot 100% of the time when powered up with >>> the serial cable connected. When the serial cable is disconnected it stops >>> booting. >>> >>> I run NetBSD from an SD card currently, the original Linux is still on >>> the internal flash. It doesn't boot on power up with the SD card plugged >>> in and it doesn't boot with it taken out. The other three boards always do. >>> >>> The three supplies I've got are a 2A wall wart from either Newark or >>> Adafruit which was recommended for the BBB, a 5A supply with 4 USB outputs >>> and an old HP bench supply. It behaves the same with all of them. >>> >>> I need the cards to recover from power failures on their own so it's a >>> concern. It certainly seems that not all BBB cards are created equal. If >>> there's a particular power supply that fixes all problems, however, I'd be >>> interested in knowing which. >>> >>> Dennis Ferguson >>> >>> On Wednesday, July 31, 2013 11:15:23 PM UTC-4, Gerald wrote: >>> > The PORz, PMIC_PGOOD, is programmable via a register setting in the >>> TPS65217C. >>> > >>> > >>> > Get the right power supply, and the issue should not exist. >>> > >>> > >>> > Gerald >>> > >>> > >>> > >>> > >>> > On Wed, Jul 31, 2013 at 10:09 PM, evilwulfie <[email protected]> >>> wrote: >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > for an embedded device that does not >>> > have the reset button visable >>> > >>> > this poses an issue, is there something that can be done in >>> > hardware to hold the reset low longer ? >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > On 7/31/2013 7:56 PM, Gerald Coley wrote: >>> > >>> > >>> > >>> > >>> > >>> > >>> > This is what I mentioned earlier. This was one of >>> > the reasons I added the power button. Using that to turn on and >>> > off helps this issue. The SW handles it OK, but it takes a >>> > little too long to shut down. >>> > >>> > >>> > >>> > >>> > >>> > >>> > Gerald >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > On Wed, Jul 31, 2013 at 9:40 PM, David >>> > Lambert <[email protected]> >>> > wrote: >>> > >>> > I have >>> > found that both BBB and BBB seem to be rather sensitive to >>> > the rise time of the DC power supply. I did some tests with >>> > a controlled rate power circuit and found that if the rise >>> > time was greater than around 500uS, then certain of our >>> > boards would not start. My solution was to hold reset until >>> > the power was stable, then release it. Now we get 100% >>> > success. I thought the PMIC chip was designed to be >>> tolerant >>> > to slowly rising power, but I have not had time to >>> > investigate further. >>> > >>> > >>> > >>> > HTH, >>> > >>> > >>> > >>> > Dave. >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > On 13-07-31 04:48 PM, [email protected] wrote: >>> > >>> > >>> > Hi guys, >>> > >>> > >>> > >>> > we have a problem with our Beagle Bone Black (A5C). >>> We >>> > are using Ubuntu Raring 13.04 armhf v3.8.13-bone21 >>> > (2013-06-14) on the eMMC (no SD Card). The Beagle >>> Bone >>> > is placed in a case and we have connected it to a DC >>> > power supply. Sometimes (I would say every 5 to 10 >>> > times), when we are plugging in our power supply, the >>> > BeagleBone powers on (Power LED is on), but nothing >>> > more happens (none of the other four LEDs is on). If >>> > we are now removing the power supply and putting it >>> in >>> > again, the BBB starts normally. I guess the power >>> > supply is strong enough: 5A@5V. >>> > >>> > >>> > >>> > Thanks for your help in advance. >>> > >>> > >>> > >>> > Regards, >>> > >>> > duckhunter >>> > >>> > -- >>> > >>> > For more options, visit >>> http://beagleboard.org/discuss >>> > >>> > --- >>> > >>> > You received this message because you are subscribed >>> > to the Google Groups "BeagleBoard" group. >>> > >>> > To unsubscribe from this group and stop receiving >>> > emails from it, send an email to >>> [email protected]. >>> > >>> > For more options, visit >>> https://groups.google.com/groups/opt_out. >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > -- >>> > >>> > For more options, visit http://beagleboard.org/discuss >>> > >>> > --- You received this message because you are >>> subscribed >>> > to the Google Groups "BeagleBoard" group. >>> > >>> > To unsubscribe from this group and stop receiving >>> emails >>> > from it, send an email to >>> [email protected]. >>> > >>> > For more options, visit >>> https://groups.google.com/groups/opt_out. >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > -- >>> > >>> > For more options, visit http://beagleboard.org/discuss >>> > >>> > --- >>> > >>> > You received this message because you are subscribed to the >>> Google >>> > Groups "BeagleBoard" group. >>> > >>> > To unsubscribe from this group and stop receiving emails from it, >>> > send an email to [email protected]. >>> > >>> > For more options, visit https://groups.google.com/groups/opt_out >>> . >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > -- >>> > >>> > For more options, visit http://beagleboard.org/discuss >>> > >>> > --- >>> > >>> > You received this message because you are subscribed to the Google >>> Groups "BeagleBoard" group. >>> > >>> > To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> > >>> > For more options, visit https://groups.google.com/groups/opt_out. >>> >>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "BeagleBoard" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> For more options, visit https://groups.google.com/groups/opt_out. >>> >>> >>> >> -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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