Event-driven scheduling can be an extremely convenient technique for developers whose systems are driven by events that are happening on the system. For example, the system may need to respond to a user button press, an incoming data packet, or a limit switch being reached by an actuator.

In event-driven systems, there may be no need to have a periodic background timer; instead, the system can just respond to the event using interrupts. Event-driven scheduling may have our common infinite while loop, but that loop will do nothing or put the system into a low-power state until an event occurs. Developers who are using event-driven systems can follow the interrupt best practices that we discussed earlier and should also read the MicroPython documentation on ISR rules, which can be found at https://docs.micropython.org/en/latest/reference/isr_rules.html. It's important to note that when you do use interrupts, MicroPython automatically clears the interrupt flag for the developer so that using interrupts is simplified.