Hi Rico,

Any reason that you can't use a cape to solve the problem?  The PowerCape 
<http://elinux.org/AndiceLabs:PowerCape> will prevent brown-outs and 
transients from bringing the BB down.  Your application/script can monitor 
DC power good and battery voltage/current and then do a clean shutdown if 
necessary.  The cape can also restart the system when DC power returns.  
It's my cape so feel free to ping me with any questions about it...

-Ron

On Thursday, August 7, 2014 9:16:07 AM UTC-5, Rico wrote:
>
> Hello Gerald,
>
> What way would that be to fix it? I thoght the problem is the PMIC itself 
> and not the BBB design.
>
> On Thursday, 7 August 2014 15:19:15 UTC+2, Gerald wrote:
>>
>> Well, I didn't design the board for that application. There is a way to 
>> take care of that if you are willing to fix it. It is not something that I 
>> will put in the design just for your application.
>>
>> Gerald
>>
>>
>>
>> On Thu, Aug 7, 2014 at 7:07 AM, Rico <[email protected]> wrote:
>>
>>> @ John:
>>> Thanks for your answer. I measured with a multimeter directly at the 
>>> BBB. The BBB normally even starts with only 4.5V so its definitely 
>>> something wrong with the PMIC. 
>>>
>>> @Gerald:
>>> Thank you. The problem is, we are using the BBB in an industrial product 
>>> that has to run 24/7. Replugging the device is therefore no option. 
>>> Powering the BBB with at least 5.1V seems to resolve the problem but I 
>>> wondered if there is a reason for that.
>>>
>>>
>>>
>>> On Thursday, 7 August 2014 02:13:51 UTC+2, Gerald wrote:
>>>
>>>> Unplug it and plug it back in. It was designed to work that way. 
>>>> Temporary power loss can confuse the PMIC and put it in an bad state.
>>>>
>>>> Gerald
>>>>
>>>>
>>>> On Wed, Aug 6, 2014 at 6:42 PM, William Hermans <[email protected]> 
>>>> wrote:
>>>>
>>>>>  John, this happens to me too, but powering via USB. Once in w blue 
>>>>> moon, there seems to be some sort of race condition, or something where 
>>>>> the 
>>>>> BBB is not getting enough power.
>>>>>
>>>>> So in order to thwart this I've stopped using shutdown now -r, and 
>>>>> instead use shutdown now -h. Then manually remove / reapply the USB cable.
>>>>>
>>>>>
>>>>> On Wed, Aug 6, 2014 at 3:44 PM, John Syn <[email protected]> wrote:
>>>>>
>>>>>>
>>>>>>  From: Rico <[email protected]>
>>>>>> Reply-To: "[email protected]" <[email protected]>
>>>>>>
>>>>>> Date: Wednesday, August 6, 2014 at 3:34 PM
>>>>>> To: "[email protected]" <[email protected]>
>>>>>>
>>>>>> Subject: [beagleboard] Re: Beaglebone sometimes doesn't start after 
>>>>>> a power loss
>>>>>>
>>>>>> Sorry to push... Gerald, maybe you have an idea?
>>>>>>
>>>>>>
>>>>>> On Sunday, 3 August 2014 15:28:45 UTC+2, Rico wrote:
>>>>>>>
>>>>>>> Hello,
>>>>>>>
>>>>>>> I've noticed that the beaglebone black sometimes does not startup 
>>>>>>> after a short power loss, even when pressing the power button, it does 
>>>>>>> not 
>>>>>>> start.
>>>>>>>
>>>>>>> To reproduce with a regulated power supply (tested with BBB rev B 
>>>>>>> and C):
>>>>>>>
>>>>>>> 1) Output of power supply 5V
>>>>>>> 2) connect power supply to BBB
>>>>>>> 3) BBB starts up normally
>>>>>>> 4) down-regulate the output slowly
>>>>>>> 5) at 3.5 V, the beaglebone turns off
>>>>>>> 6) go back to 5V
>>>>>>> 7) press the power button, the beaglebone won't startup
>>>>>>> 8) go above 5.1V and press the power button => now the beaglebone 
>>>>>>> starts
>>>>>>>
>>>>>> Are you measuring the voltage at the BBB terminals or are you reading 
>>>>>> the voltage from your power supply? Do you use thin wires to connect 
>>>>>> from 
>>>>>> your power supply to the BBB? My thinking is there is a voltage drop 
>>>>>> across 
>>>>>> the wires of 100mV or more. 
>>>>>>
>>>>>> Regards,
>>>>>> John
>>>>>>
>>>>>>
>>>>>>> I've read the datasheet of the PMIC (TPS65217C) but I cannot find 
>>>>>>> out why the BBB starts at 5.1V but not at 5V, has anyone an idea?
>>>>>>>
>>>>>>> Many thanks,
>>>>>>> Rico
>>>>>>>
>>>>>>> -- 
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>>>>>
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