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Meadow Application Sleep

Meadow can be put into a power-saving sleep state. In this state, your code stops executing and reduces the power draw to only what is required to recover from being in a sleep state. After resuming from a sleep state, your code will resume executing where it left off.

To put the Meadow into sleep mode, call Sleep on the current platform OS object and providing either a TimeSpan or a DateTime. If you provide a TimeSpan, Meadow will sleep for that duration.

// Put Meadow to sleep for 5 seconds.
Device.PlatformOS.Sleep(TimeSpan.FromSeconds(5));

If you provide a DateTime, Meadow will sleep until that time.

In order for this to work properly, you must set the current date via the Device.PlatformOS.SetClock method.

Device.PlatformOS.SetClock(new DateTime(2022, 10, 19, 21, 58, 27));
...
// Put Meadow to sleep until this time tomorrow.
Device.PlatformOS.Sleep(DateTime.Now.AddDays(1));

Additionally, you can respond to the sleep state changes in application lifecycle events, specifically BeforeSleep and AfterWake. BeforeSleep is called right before your application goes into sleep mode. And AfterWake is called right after Meadow resumes from sleep but before your code resumes.

These are exposed as events on the Device.PlatformOS object and can have event handlers added to them like any standard .NET event.

Device.PlatformOS.BeforeSleep += () => {...};

Device.PlatformOS.AfterWake += (sender, wakeSource) => {...};

Wake up on Interrupt​

If Meadow is put into sleep mode, you can have it wake up when listening to an interupt port. Just use the same Sleep method and pass an interrupt-capable pin:

Device.PlatformOS.Sleep(Device.Pins.D05, InterruptMode.EdgeRising, ResistorMode.InternalPullDown);

When the event is triggered, Meadow will wake up and AfterAwake event gets fired.

Interrupt and maximum F7 sleep duration​

On F7 devices, Meadow will sleep for a maximum of 28 days. If your device sleeps that long, it will wake when the timer elapses. You can detect for this in the AfterAwake event, and checking if wakeSource is Timer instead of Interrupt.