SAMD51 Voltage Regulator Default

[jacky4566]

In pursuit of maximum power savings I noticed that Adafruit is not using the onboard SAMD51 Buck regulator despite the inclusion of an inductor onboard. Is there any reason for this?
On my own custom board I brought the idle from 10.4mA to 6.1mA just with one line.
SUPC->VREG.bit.SEL = 1;

The core code seems to use the LDO regulator by default:

ArduinoCore-samd/cores/arduino/startup.c

Line 247 in cec0a6b

SUPC->VREG.bit.SEL = 0;

[ladyada]

you can totally use it if you like, but it makes the ADC noisy so we haven't used it much.

[ladyada]

added a note here on using it. https://learn.adafruit.com/adafruit-metro-m4-express-featuring-atsamd51/adapting-sketches-to-m0#enabling-the-buck-converter-on-some-m4-boards-7-27

[jacky4566]

Whoah! @ladyada had her coffee this morning! Makes sense about the ADC.
Thanks that'll probably do it then!

[ladyada]

🍵 😂