How to wake on USB connection

Firmware
#1

Hi there!
I am using a Boron that sleeps for a long period in ULTRA_LOW_POWER mode (STOP mode would also be OK), then periodically wakes up to take sensor readings.
The Boron is currently powered via the 5V VUSB pin. 3.3V Li+ powering would also be OK for this application.
I’m wondering how to set it up so that the device automatically wakes up whenever a USB cable is inserted?
I have thought of using Li+ to power the Boron and connecting VUSB to the wakeup pin (D8?). However, I’m unsure if this would cause backfeeding to my power supply on Li+.

I’ve read a few offhand posts where people have mentioned this as a possibility. Just wondering if there’s anyone who has actually done it? Or, is there a better approach I should know about?

Thanks in advance! Really enjoying the board so far!

#2

When connecting VUSB to a GPIO make sure you reduce the 5V down to no more than 3.3V as none of the GPIO pins on Gen3 devices are 5V tolerant.

You also cannot power a Boron via the 3v3 pin and Li+ requires 3.6…4.2V to run safely.

1 Like
#3

@Jeremiah, Below are results from my Solar Testing that might be useful to your Application.

Device OS 2.0.0.rc-1 , Boron LTE …
Hibernate Sleep will wake the Boron LTE when the Solar Panel Cycles.

That would be similar to [you] inserting a USB cable, but you also have the VUSB pin powered, so I’m not sure. Hibernate might be worth a try.
Here’s the post.

1 Like