Powering BeagleBone Black from Expansion Header

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1

Hi all,

I’ve been reading the reference manual of Beaglebone black, and in page 42, it says “The 5VDC rail is connected to the expansion header. It is possible to power the board via the expansion headers from an add-on card.” Can anyone point out which expansion header the manual is referring to and where is it? And is there any difference than supplying power from the barrel jack (eg. max current allowable)?

Thanks a lot.

Regards,
Yeo

2

It is called P9.
The pins are 5 and 6.
It is in the System Reference Manual.
Table 12

Gerald

3

Thanks for the quick reply.

My board is revision A5A. Should I be concerned with the SRM Rev A5.3 or I should be looking at A5.6 which is referring to Production A5C? Because Table 12 is not the same between the two SRM.

4

Thanks for the quick reply.

My board is revision A5A. Should I be concerned with the SRM Rev A5.3 or I should be looking at A5.6 which is referring to Production A5C? Because Table 12 is not the same between the two SRM.

5

I see no reason not to use the latest manual. It takes just as much energy to use an old one as is does to use the most current one.

Just look up P9 and you will find the right table. The latest SRM covers all versions of the board.

Gerald

6

You can check out this link with all the expansion header pins.
http://circuitco.com/support/index.php?title=Cape_Expansion_Headers

7

Hello

I am trying to powering up the BBB through the header p9… but when using connecting the 5V to pins 5 and 6 it is still not turning on automatically. I still need to press its power button. So how to make it turn on by just connecting the power?

Best Regards

8

Sounds like you are doing something wrong. Those pins connect to the power jack, so it should power the board. What else can you tell me about your setup?

Gerald

9

Hi Gerald… many thanks for your support… I revised the the cape design again and I found my mistake… I was connecting power to pin 7 and 8 as well… it seams like those pins should stay without any volts applied before the device start and supply them with 5V itself.

Thanks…

10

Glad you figured it out!

Gerald

11

Gerald

I'm a little confused on this point. As I understand it, you can supply 5 V regulated to P9, pins 5 & 6, correct? Do I use P9 pins 7 & 8 to supply 5V to an external breadboard? What happens if you supply 5V to pins 5 or 6 if you power the BBB with 5V from the barrel connector or the USB port.

Carl

12

Try reading the System Reference Manual and looking at the schematics. You will see that one conects to the DC input and the other connects to the DC output of the power management IC,

http://www.elinux.org/Beagleboard:BeagleBoneBlack

Gerald

13

Hello. I’ve found this thread to be quite helpful so far, thank you all.
I have a question regarding where one would connect the “minus” side of my regulated voltage. I have AC → 24 → regulated 5v. I know I would connect positive to P9_5,6, but would I connect the negative of my 5v regulated supply to P9_1,2 (BBB gnd)?

14

Yes. The negative side of the 5 Volt regulated supply goes to BBB system ground, which includes P9-1 and P9-2.
— Graham