Hello,
almost every GUI application is intended to interact with a real system - so it needs to display some real data from a certain machine or it needs to control some activities of the underlying system. However this is sometimes not the simplest part.
Let me refer to the articles Integrating with the device and Device Class and Device Driver, both are part of our online documentation. They explain all basics about native code and the integration of external software APIs or hardware drivers. Knowing this, you should be able to exchange data (e.g. time) with your target device (e.g. STM32).
The other aspect is how to exchange data with the Time Picker component. Use for this purpose the component's properties Hour, Minute and Second. After receiving a time information from your device you can assign values to these properties. The another way (when the user interacts with the Time Picker) the component will send signals to a slot method connected to its property OnChange. Within the slot method you can implement code to read the component's properties Hour, Minute and Second and then to update the setting in your target (e.g. STM32).
Best regards,
Paul Banach
