Low Power Sketch

This sketch will put the board and components off or into sleep.

Libraries

There are no additional libraries required.

Code

// Test sleep current
#include <SPI.h>

void DFlashUltraDeepSleep()
{
  // SPI initialization
  SPI.begin();

  // Initialize the CS pin for the data flash
  pinMode(SS_DFLASH, OUTPUT);
  digitalWrite(SS_DFLASH, HIGH);

  transmit(0x00); // In case already in sleep, wake
  transmit(0x79); // Now enter sleep
  //transmit(0x00); // Wake again, for testing

  // SPI end
  SPI.end();

  // Resets the pins used
  resetSPIPins();
}

void transmit(uint8_t val)
{
  SPISettings settings;
  SPI.beginTransaction(settings);
  digitalWrite(SS_DFLASH, LOW);

  SPI.transfer(val);

  digitalWrite(SS_DFLASH, HIGH);
  SPI.endTransaction();

  delayMicroseconds(1000);
}

void resetSPIPins()
{
  resetPin(MISO);
  resetPin(MOSI);
  resetPin(SCK);
  resetPin(SS_DFLASH);
}

void resetPin(uint8_t pin)
{
  PORT->Group[g_APinDescription[pin].ulPort].PINCFG[g_APinDescription[pin].ulPin].reg=(uint8_t)(0);
  PORT->Group[g_APinDescription[pin].ulPort].DIRCLR.reg = (uint32_t)(1<<g_APinDescription[pin].ulPin);
  PORT->Group[g_APinDescription[pin].ulPort].OUTCLR.reg = (uint32_t) (1<<g_APinDescription[pin].ulPin);
}

void setup()
{
  // LED On
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, HIGH);

  // Start delay of 5s to allow for new upload after reset
  // Do not remove as there is no wake up trigger
  delay(5000);

  // LED Off
  digitalWrite(LED_BUILTIN, LOW);

  // Set sleep mode
  SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;

  DFlashUltraDeepSleep();

  //Disable USB
  SerialUSB.flush();
  SerialUSB.end();
  USBDevice.detach();
  USB->DEVICE.CTRLA.reg &= ~USB_CTRLA_ENABLE; // Disable USB

  //Enter sleep mode
  __WFI();

  //...Sleep forever

  //Enable USB
  USB->DEVICE.CTRLA.reg |= USB_CTRLA_ENABLE;
}

void loop()
{
}

Note

The board will immediately go into sleep mode after 5 seconds, to reprogram you must double press the reset button, the LED will fade.

Sleep current

The power consumption in sleep will be ~15uA.
Measured with :

• Arduino IDE 1.8.13
• SODAQ Board files version 1.8.9
• Autonomo rev5