You definitely need a supply that can generate enough current to have a 
decent ramp-up of 5V or the PMIC gets angry.  But, there's also the issue 
of u-boot stopping if it sees a "phantom character" from the UART.  So, if 
you need high reliability start-up you should rebuild u-boot for "keyed 
entry" as well.

-Ron


On Tuesday, November 10, 2015 at 1:29:40 PM UTC-6, Fohnbit wrote:
>
> I forgot: 
>
> I power up the power supply ... So not only connected the BBB on the 
> Running power supply. 
>
> Trank you 
>
> Am Dienstag, 10. November 2015 18:58:40 UTC+1 schrieb Wulf Man: 
> > rise time spec 
> > 
> >       1000ms setup 50ms rise time 
> > 
> >       maybe gerald can give his thumbs up on that spec 
> > 
> >       
> > 
> >       seems fast enough  can you put a scope on it to be sure ? 
> > 
> >       maybe the power supply is out of spec some of the time 
> > 
> >       
> > 
> >       i have been using a cheap 5 dollar chinese supply for 2 years with 
> >       no issues 
> > 
> >       
> > 
> >       On 11/10/2015 10:30 AM, Fohnbit wrote: 
> > 
> >     
> >     
> >       
> > Hello, 
> > 
> >         
> > 
> >         I use this: 
> > 
> >         http://www.meanwell.com/webapp/product/search.aspx?prod=dr-15 
> > 
> >         
> > 
> >         DR-15-5 
> > 
> >         
> > 
> >         Am Montag, 9. November 2015 16:23:14 UTC+1 schrieb Wulf Man: 
> >         
> >           
> > 
> >             
> > As posted here a few times. 
> > 
> >               If your power supply does not have a fast enough rise time 
> >               getting up to voltage 
> > 
> >               your BBB will not boot reliable. 
> > 
> >               You have not said what specs your power supply is or where 
> >               you got it from. 
> > 
> >               
> > 
> >               
> > 
> >               
> > 
> >               On 11/9/2015 8:02 AM, Fohnbit wrote: 
> > 
> >             
> >             
> >               
> > Hello! 
> > 
> >                 
> > 
> >                 Sometimes my BBB Rev C dont boot, when I connect the 5V. 
> > 
> >                 The Power LED is on but the 4 USR LED are off. 
> > 
> >                 
> > 
> >                 This happen not really often ... So I have no debug 
> >                 information. 
> > 
> >                 
> > 
> >                 But maybe someone has the same problem and know where 
> >                 the problem is? 
> > 
> >                 
> > 
> >                 Thank you! 
> > 
> >               
> >               -- 
> > 
> >               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/d/optout. 
>
> > 
> >             
> >             
> > 
> >           
> >         
> >       
> >       -- 
> > 
> >       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/d/optout. 
>
>

-- 
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/d/optout.

Reply via email to