RTC wakeup

Other than just measuring time while Inkplate is running, it's possible to use the built-in RTC to wake Inkplate up from deep sleep at a certain time.

ℹ️

For more info on deep sleep on Inkplate 6 MOTION, see this page.

⚠️

If you want to keep RTC data between sleeps and power-offs, place a CR2032 battery in the battery holder.

Wake from deep sleep at a certain time

To wake the Inkplate from deep sleep at a predefined time, use the RTC's built-in alarm functionality. This allows the device to enter deep sleep mode and automatically wake up at a set time, reducing power consumption.

To configure the RTC alarm for deep sleep wake-up, initialize the RTC and set an alarm using enableAlarm. Then, enable the alarm interrupt to allow waking from deep sleep.

// Initialize RTC library and set it to 24-hour format
inkplate.rtc.begin(RTC_HOURFORMAT_24);

// Clear any previous alarm flags
inkplate.rtc.checkForAlarm(true);

// Set the RTC time and date if not already set
if (!inkplate.rtc.isRTCSet())
{
    inkplate.rtc.setTime(hours, minutes, seconds, subSeconds);
    inkplate.rtc.setDate(day, month, year, weekday);

    // Enable alarm on RTC Alarm A
    inkplate.rtc.enableAlarm(alarmDay, alarmHour, alarmMinute, alarmSeconds, RTC_ALARM_A, alarmMask);

    // Enable interrupt on alarm event (also used for wake-up)
    inkplate.rtc.enableAlarmInterrupt(NULL);
}

inkplate.rtc.enableAlarm()

Sets an RTC alarm that can wake the Inkplate from deep sleep at a specific time.

Returns: Returns true if the alarm was successfully enabled, false otherwise.

Function parameters:

Type	Name	Description
`uint8_t`	`day`	Day of the month for the RTC alarm.
`uint8_t`	`hour`	Hour of the alarm time (24-hour format).
`uint8_t`	`minute`	Minute of the alarm time.
`uint8_t`	`second`	Second of the alarm time.
`uint32_t`	`alarmType`	Select the alarm type, RTC_ALARM_A or RTC_ALARM_B. Note: Alarm B has limited functionality.
`uint32_t`	`alarmMask`	Bitmask defining which fields must match for the alarm to trigger. Options include RTC_ALARMMASK_DATEWEEKDAY (daily), RTC_ALARMMASK_HOURS (hourly), RTC_ALARMMASK_MINUTES (every minute), RTC_ALARMMASK_SECONDS (every second), and RTC_ALARMMASK_ALL (always triggers).
`uint8_t`	`pmAm`	PM/AM indicator, used only if 12-hour mode is enabled. Options: RTC_HOURFORMAT12_AM, RTC_HOURFORMAT12_PM.
`uint32_t`	`dayLightSaving`	Daylight saving time adjustment. Options: RTC_DAYLIGHTSAVING_SUB1H (subtract 1 hour), RTC_DAYLIGHTSAVING_ADD1H (add 1 hour), RTC_DAYLIGHTSAVING_NONE (no adjustment).

For more info on alarmMask check the RTC alarm page.

inkplate.rtc.enableAlarmInterrupt()

Enables an interrupt for the RTC alarm event. This allows Inkplate to wake up from deep sleep when the alarm triggers.

Returns: Returns true if the interrupt was successfully enabled, false otherwise.

Function parameters:

Type	Name	Description
`void(*)()`	`callback`	Pointer to a function that executes when the alarm triggers. Use NULL if no callback function is required.

Full example

For a complete example that demonstrates how to use RTC alarms to wake Inkplate from deep sleep, see the link below:

Inkplate_6_Motion_RTC_Alarm_Interrupt.ino

Full example demonstrating how to configure RTC wake-up from deep sleep.

Wake from deep sleep at a certain time​

inkplate.rtc.enableAlarm()

inkplate.rtc.enableAlarmInterrupt()

Full example​

Inkplate_6_Motion_RTC_Alarm_Interrupt.ino

Wake from deep sleep at a certain time

Full example