Reducing power consumption

Official Hardware Classic Zero
7

Well I disabled just about every peripheral with no major change in current draw... I tried with both a Sparkfun SAMD21 Dev board and an Adafruit Feather M0. Both boards drew 15mA before and after while I'd expect current draw to be less than 5mA per page 955 of the SAMD21 datasheet.

Here's my code...

void setup() {
  
  SERCOM0->USART.CTRLA.bit.ENABLE=0;
  SERCOM1->USART.CTRLA.bit.ENABLE=0;
  SERCOM2->USART.CTRLA.bit.ENABLE=0;
  SERCOM3->USART.CTRLA.bit.ENABLE=0;
  SERCOM4->USART.CTRLA.bit.ENABLE=0;
  SERCOM5->USART.CTRLA.bit.ENABLE=0;
  
  I2S->CTRLA.bit.ENABLE=0;
  
  ADC->CTRLA.bit.ENABLE=0;
  
  DAC->CTRLA.bit.ENABLE=0;
  
  AC->CTRLA.bit.ENABLE=0;
  
  TCC0->CTRLA.bit.ENABLE=0;
  TCC1->CTRLA.bit.ENABLE=0;
  TCC2->CTRLA.bit.ENABLE=0;
  
  RTC->MODE0.CTRL.bit.ENABLE=0;
  RTC->MODE1.CTRL.bit.ENABLE=0;
  RTC->MODE2.CTRL.bit.ENABLE=0;
  
  USB->HOST.CTRLA.bit.ENABLE=0;
  USB->DEVICE.CTRLA.bit.ENABLE=0;
  
  
}

void loop() {

while(1){}
  
}