Power supply options

In BBB we have two options to provide supply USB PORT & POWER JACK.
I observed that P9-5 is connected (short) with POWER JACK.
If it is true; then I can provide power supply to BBB using P9-5 and GND pins.
Is it possible? Is it risky?

As stated in the SRM, yes it is possible to use those pins. That is what there are there for.



You probably measured this short? If so I would advise against such practice, because resistance measurements might exceed (or reverse) the maximum allowed voltage on many pins.

Both P9-5 and P9-6 are connected to P1-1, this is the central pin of the power plug You can power the BBB from these pins with the same type of power supply you would use for P1. What you should not do, is use power on both P1 and P9 at the same time, like you can do with usb and P1 (or usb and P9). This would put the power supplies in parallel, with unpredictable results, ranging from nothing to fireworks.

P9-7 and P9-8 are connected to the 5 volt output of the PMIC and should not be used to power the board. These pins are intended to power capes.

Please read the schematics, They are provided for exactly this reason.
To answer the last question is - it risky? Only if you don’t know what you are doing. P-1 is idiot-proof (or mostly) Using P9 requires extra care. There are many posts like "I accidentally connected x to y, end now my board is dead. " Don’t let it happen to you.