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Huzzah32 usb-to-serial power off
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Huzzah32 usb-to-serial power off

by Ottoask on Tue Aug 13, 2019 1:40 pm

I’ve seen other threads on the Huzzah32 and battery use. I’ve wired EN to GND to turn off the regulator, and wired a 3v li-ion to 3V, which seems to work fine.

Is there a way to prevent this from powering the usb-serial chip as well? That seems wasteful when I’m not connecting to the usb port at all.

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Re: Huzzah32 usb-to-serial power off

by adafruit_support_carter on Wed Aug 14, 2019 1:01 pm

The 3V pin is the output of the regulator. If you are directly applying power there, then you are bypassing the voltage regulator and disabling/enabling it has essentially no effect on anything downstream. The 3V rail (vreg output) is directly connected to other items on the board.
https://learn.adafruit.com/adafruit-huz ... -print-7-2

Why are you not using the BAT pin?

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Re: Huzzah32 usb-to-serial power off

by Ottoask on Sun Aug 18, 2019 2:08 am

adafruit_support_carter wrote:The 3V pin is the output of the regulator. If you are directly applying power there, then you are bypassing the voltage regulator and disabling/enabling it has essentially no effect on anything downstream. The 3V rail (vreg output) is directly connected to other items on the board.


Won't the usb-serial chip feed off of this 3V too, though? That's what I'm looking to disable, to minimize power use.

adafruit_support_carter wrote:Why are you not using the BAT pin?


I did try using the BAT pin, but the board would not start. I'm feeding it ~3V from a li-ion battery, and the only way I could seem to get it up was through feeding directly into the 3V rail. I'm still seeing the battery drain awfully quickly, though.

Is there a current writeup or guide to how to minimize power use to the Huzzah32?

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Re: Huzzah32 usb-to-serial power off

by adafruit_support_carter on Mon Aug 19, 2019 12:05 pm

There's no way to selectively power the CP2104 and the ESP32. They are both powered by the 3V rail. And sorry, we don't have a guide on this. In addition to hardware considerations, there would also be some software aspects. Like possibly putting the ESP32 into sleep mode, waking up from it, etc.

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