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Levels of restarting on a device

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Important

This is the Azure Sphere (Legacy) documentation. Azure Sphere (Legacy) is retiring on 27 September 2027, and users must migrate to Azure Sphere (Integrated) by this time. Use the Version selector located above the TOC to view the Azure Sphere (Integrated) documentation.

There are two levels of restarting that can occur on an Azure Sphere device:

  • Device reboot: The MCU restarts and consequently resets peripherals, reconnects to the network layer, and restarts the applications and the Azure Sphere operating system (OS).
  • Application restart: The application restarts, but peripherals, connection to the network layer, and the operating system remain in their current state.

The following circumstances cause a device to reboot:

  • An update of the Azure Sphere OS is installed.
  • An application update changes the peripheral configuration and the peripheral configuration is locked.
  • The device is unplugged from the USB port and plugged in again.
  • The Reset button on the device is pressed.
  • The azsphere device restart CLI command is run.
  • The PowerManagement_ForceSystemReboot function is called from a high-level application.

The following circumstances cause a high-level application or a real-time capable application to restart:

  • An update of the application is installed.
  • The application exits unexpectedly.
  • An OS event or hardware event has occurred.
  • The azsphere device app stop and azsphere device app start CLI commands are run.

Tasks that a high-level application should perform when starting or exiting are described in Initialization and termination. For details about when a high-level application or a real-time capable application should exit, see Lifecycle of an application.

For information about when a device checks for updates, see When do updates occur. Details about locking the peripheral configuration are described in Peripheral configuration locking.