BBB Power supply over pin Header

GoogleGroups
1

Hello!

Can I use two pins for power supply?
I want to made a cape for own powersupply.

If yes, which pins are + and -
And which voltage?

Thank you!

2

Found this in manual:

VDD_5V is the main power supply from the DC input jack. This voltage is not present
when the board is powered via USB. The amount of current supplied by this rail is
dependent upon the amount of current available. Based on the board design, this rail is
limited to 1A per pin from the main board.
The SYS_5V rail is the main rail for the regulators on the main board. When powered
from a DC supply or USB, this rail will be 5V. The available current from this rail
depends on the current available from the USB and DC external supplies.

and:

DO NOT APPLY VOLTAGE TO ANY I/O PIN WHEN POWER IS
NOT SUPPLIED TO THE BOARD. IT WILL DAMAGE THE
PROCESSOR AND VOID THE WARRANTY.
NO PINS ARE TO BE DRIVEN UNTIL AFTER THE SYS_RESET
LINE GOES HIGH.

I´m not sure what it means.
Have I use 5V on VDD or SYS?
And when I try to use an input, I must boot the BBB before the Input Pin is going high? This is unpossible. Because when the Input is high and the BBB lost Power it damaged?

Thanks for helping a newbie!

3

Thank you for reading the manual. I ma not sure how to make the statement any simpler.

Check the schematic. VDD is an input. VDD_SYS is an output. .

Use VDD to power the BBB in place of the power jack. Use VDD_SYS to power the complements on your board if needed. But do not connect any signals to the expansion header that are 5V. Do not connect any signals that are 3.3V before the 3.3V rail from the BBB is active.

Gerald

Gerald

4

Hello Gerald!

Its my english level. Not the manual :slight_smile:

Ok:
VDD: input
SYS: output

Now its also for me clear.

5

Great! Let me know if you have any other questions.

Gerald

6

Hi, I’m seeking some clarification myself. I’m looking at the pinout under “expansion headers”: https://seeeddoc.github.io/Beaglebone_green_wireless/.

I’m looking to produce a cape as well (any resources, tutorials, or walkthroughs on producing a cape for a beagleboard are 100% welcome).

What I want to clarify:

  • DGND - this is the digital ground which I should connect to any digital devices (whether 5V or 3.3V)
  • GNDA_ADC - this is the analog ground which I should supply to any devices that return an analog signal for me to read on the ADC
  • VDD_3V3 - use this to power 3.3v electronics
  • VDD_5V - use this to bower the beagleboard (i.e. through a barrel jack, if you are going to put one on the cape/shield), NOT to power 5V electronics because this could risk signals hitting the beagleboard before it is ready?
  • SYS_5V - use this to power 5V electronics
  • VDD_ADC - use this to power 5V electronics which return an analog signal?
    Is my summary about right? Or do I need to go back and read the manual in better depth?

Thanks for your help,
Troy