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adafruit / uf2-samdx1

MSC bootloader (based on UF2) for SAMD21
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change default USB power down to 100mA #189

Closed jepler closed 2 years ago

jepler commented 2 years ago

Since a device in bootloader mode shouldn't be powering any external peripherals, a 100mA default power level is more sensible than 500mA and may give better compatibility e.g., in USB OTG settings

dhalbert commented 2 years ago

Was there a use case pointed out by a discord user? There might be some peripheral attached that is powered at all times, but I agree it doesn't inherently need 500mA

dhalbert commented 2 years ago

@hathach Do you have a comment here based on various scenarios? Never mind, I see an internal Slack discussion about this.

makermelissa commented 2 years ago

It was pointed out by me. When connected to an iOS device, if it advertised over 100ma, the iOS device shuts down the port.

dhalbert commented 2 years ago

OK, never mind, I see the discussion in slack.

hathach commented 2 years ago

from my exp, despite our declared current, iOS will still keep an eye on the actual drawing current and will disable usb port when we violate/exceed its limit. I guess we are safe since bootlaoder doesn't do much.

makermelissa commented 2 years ago

I was able to run a strip of 30 neopixels off an iPad without any problems, so I agree we're safe. :)