The Background DFU library exposes a common API for the following tasks:
Currently, the only allowed operation is an application update.
The Background DFU library implements the IoT TFTP transport (Trivial File Transfer Protocol (TFTP)) for DFU image transfer.
For information on creating the firmware packages, see Creating DFU images.
Application initialization of the Background DFU requires a call to the initialization function of the selected transport. See API reference of the selected transport for more details.
An application triggers firmware update procedure by calling the trigger function of the selected background DFU transport. See API reference of the selected transport for more details. The DFU procedure is performed in the background during normal operation of an application. An application does not have to handle any events from the Background DFU module, or execute any call to the library in order to perform a successful firmware update.
After the new firmware is written to flash memory, a validation procedure is called automatically.
The last operation of the Background DFU library is to apply the correct settings for the bootloader and perform a software reset. After the reset, the bootloader context will swap firmware according to the given settings. This operation is performed automatically if validation of the stored image succeeded.