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Deep sleep

Deep sleep is what makes a battery-powered Inkplate sketch practical. E-paper holds its image without any power, so Inkplate 6MOTION can draw almost nothing while asleep and still keep a sketch running for months on a battery.

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If all peripherals are in sleep mode, deep sleep current will be around 20-30µA

Simple deep sleep​

The function below is a compound of all function calls required to put Inkplate 6MOTION in deep sleep mode:

void deepSleep()
{
    // Disable all peripherals including WiFi, microSD card, SDRAM, sensors etc
    inkplate.peripheralState(INKPLATE_PERIPHERAL_ALL, false);
    // Disable USB voltage detection on USB OTG (This causes high current consumption in sleep!)
    HAL_PWREx_DisableUSBVoltageDetector();
    // Use different voltage scale for internal voltage regulator (lower current consumption in sleep mode)
    HAL_PWREx_ControlStopModeVoltageScaling(PWR_REGULATOR_SVOS_SCALE5);
    // Put every domain into standby mode
    HAL_PWREx_EnterSTANDBYMode(PWR_D3_DOMAIN);
    HAL_PWREx_EnterSTANDBYMode(PWR_D2_DOMAIN);
    HAL_PWREx_EnterSTANDBYMode(PWR_D1_DOMAIN);
    // Code does not continue past this point!
}
⚠️
Code will not continue after the final call to HAL_PWREx_EnterSTANDBYMode!
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For more information on turning off peripherals via peripheralState, see this page

In a sketch built around deep sleep, it's common practice to put all your code in setup() and then put Inkplate to sleep at the end.

Wake on button press​

To wake on button press of the WAKE button, use the STM32 function HAL_PWR_EnableWakeUpPin after resetting the wakeup flags:

// Check if the wake up from sleep did reset the board. If so, clear the flags
if (__HAL_PWR_GET_FLAG(PWR_FLAG_SB) != RESET)
{
    // Clear Standby flag
    __HAL_PWR_CLEAR_FLAG(PWR_FLAG_SB);
    // Wake-up button on Inkplate 6MOTION is PC13 = WAKEUP PIN 4.
    HAL_PWR_DisableWakeUpPin(PWR_WAKEUP_PIN4);
}
// Enable wake up button. By setting PC13 to low (button press), Inkplate will wake up
HAL_PWR_EnableWakeUpPin(PWR_WAKEUP_PIN4_LOW);

Wake on timer​

The most common usage of deep sleep is to periodically wake Inkplate to refresh the display with new data, this is documented in the RTC section of the documentation:

RTC deep sleep wakeup

How to use the built-in RTC to set a timer wake up from deep sleep

Full examples​

Inkplate 6MOTION deep sleep example

This example demonstrates a sketch structured around deep sleep, it's an overview of all the deep sleep possibilities on Inkplate 6MOTION, with waking on timer or pushbutton