First things first – this might seem to be a very trivial thing. Powering is simply plugging in that AC-to-DC converter into that barrel, right? Well, that is partly correct. But, how else can you power up your Beagle? And what operation modes are available and what power considerations do we have to keep in mind while operating in a particular mode? In this post, I try to throw light upon this topic and try to integrate information from different sources on the internet.

There are two ways in which you can power-up your Beagle – the USB OTG port and using a AC-to-DC supply (barrel connector). I was surprised when I found out that it is not possible to power up the Beagle using the USB host ports. For an explanation (rather vague), you can visit the ‘USB-related’ section of this page.

Powering up using the USB OTG port

If you plan to power up your BeagleBoard-xM using the USB OTG port, there are two things you have to keep in mind:

1) Please use an externally powered USB hub
2) You can use the USB OTG port in as a client only – not as a master.

But, in case, you don’t have an externally-powered hub and only want to use a pen-drive (or something similar – for a short while), you can use a Y-cable. It is a cable that can connect to the Beagle’s OTG port and the other two ends draw power from your laptop/PC. But, please keep in mind – don’t load all your USB ports in this condition because the manual clearly says that each USB port will draw 500 mA of current.

Please do not try using any of the USB hosts when powering up using the OTG port using a normal cable – the power delivered by the OTG to the on-board USB-hub is simply not enough. Check this out! And if you are still doubtful, check out the info in the ‘Powering the BeagleBoard-xM’ floating box on this page.

Powering up using the 2.1 mm barrel

This is the best way to power up your Beagle. The reason for this is that it does not require any current-limiting from your side. But, one thing you have to consider is that the power supply you use should be of a good quality. The excursions should not take the supply to >5.2 V else, you may end up damaging the board. The BB-xM does have a safety LED which glows (RED in color) whenever the power supply is improper (exceedingly low or high) and cuts off all supply to the circuitry. But, at the end of the day, it is a circuit!

The absolute maximum rating of the power supply should be 5V/3A with 2A being perfect for most of your applications.

Powering up using the barrel allows you to use our OTG port in the host mode which opens up more possibilities for you.

You don’t need an externally-powered USB hub when using a DC supply. I have worked with a keyboard, a mouse, a Logitech C905 webcam and an HP v165w pen-drive plugged in and there was absolutely no problem faced. (My power supply’s rating is 5v/3A max.)

One more thing – suppose you are using the OTG port to power up your Beagle and suddenly turn on the DC power supply using the barrel, the ‘hand-over’ of the powering-up business will be seamless because the circuitry is such that the power-path from  the OTG to the various parts of the board is automatically removed.

Have you experienced a problem in powering up your Beagle? Do you have any suggestions or changes that I can add to this post? Anything that you want to tell me? If yes, please comment away! 🙂

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