bela mini usb host power only on usb supply

RafaeleAndrade

RafaeleAndrade the power coming from the battery pack is 5.2 V and the diode puts downs 0.3v into v usb pin 1.05 , as you mentioned

RafaeleAndrade

I made this schematic

alt text

giuliomoro

You should only send power to one of P1.01 or P1.05. Because of mysterious reboots reported when using P1.01, you should probably use P1.05 (via the diode) instead (which also powers USB devices).

RafaeleAndrade

giuliomoro thanks! I’ve just tried what you mentioned and I don’t get successful results still. The power light blinks shortly and stops. Maybe is the type of batteries that I am using?

giuliomoro

Is the wiring correct? I cannot tell whether you are using the correct pin for ground (P1.16).
Can you measure the voltage between ground and P1.05 when you try to give it power? What do you read?

Also, try plugging the USB back in with the battery disconnected to verify the board is still in good shape.

RafaeleAndrade

giuliomoro Yes, the bela ( thanks God XD ) is still working with usb.

I connected to p1.05 as you can see in this pic
alt text

giuliomoro

giuliomoro Can you measure the voltage between ground and P1.05 when you try to give it power? What do you read?

giuliomoro

But you still have one wire to P1.01?

RafaeleAndrade

giuliomoro yes, this picture was the previous trial but I was using the same position of the pin 1.05 when you asked me to try without the pin 1.01

RafaeleAndrade

giuliomoro I get 4.8V from the diode signal ( without the diode is 5.2v

giuliomoro

Do you get 4.8V while powering up the board? I am wondering if they cannot provide the inrush current needed by the board, causing a turn-on voltage dip which results in the power management IC to shut off everything. I cannot find a proper datasheet for the batteries, but I would expect them to work OK for this based on this little information. Could you try using the BAT.VIN pin (P2.14) instead? And/or try with P1.05 but with the LiPo stack and 5V SparkFun regulator you showed in the diagram above

RafaeleAndrade

giuliomoro nice ! I will try tomorrow with a separate pocket beagle ( without the bela). I am but traumatized from my previous experiments burning 2 minibela when playing with the power source. I will come back here for some updates tomorrow afternoon!

RafaeleAndrade

giuliomoro Tomorrow I will try with the sparkfun regulator

giuliomoro

Also try leaving the battery connected (to either of the input points mentioned above) and then briefly connecting SYS PWR BTN (P2.12) to GND to trigger a power up.

In order to switch on Bela it is necessary to connect P2 Pin 12 (labelled PB) to GND and then to disconnect it, like a switch.

halldorophone

Hi Guilo et al. Looking for good documentation to set up Bela Mini Multichannel Expander simultaniously powered from external source and micro USB.

Have been using a toggle switch to choose between a dedicated power supply and Micro USB (when connected to laptop for data connection) but we have had some issues which makes me want to have setup which requires no extra steps when having a data connection.

It would be a bonus to be able to power a USB connected device on the USB-A but this is secondary if not easy or ideal.

Any post with diagram and practical tips?

Many thanks,
Halldór / IIL

giuliomoro

The 5V input voltage that powers the board is taken from P1.01 or P2.14 or usb , in this order, whichever is the first one active. So you don't need a switch.

The only caveat is that powering of USB devices plugged into the USB-A port is only available when powering from USB. If you need to power those when powering the board from one of the other sources you'll need extra components.

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