Can you explain the difference between polling and interrupt in embedded systems and provide an example of when you would use each method?

Polling: Polling is a technique in embedded systems where the microcontroller continuously checks the status of a peripheral device to see if it needs attention or has data ready. This method involves actively querying the device, which may result in wastage of CPU cycles when the device is not ready.

Interrupt: Interrupt is a mechanism in embedded systems where the peripheral device itself notifies the microcontroller that it requires attention. The microcontroller temporarily pauses its current execution, handles the interrupt, and then resumes its previous task. This method is more efficient than polling as it allows the microcontroller to focus on other tasks until the interrupt occurs.

Example:

• Polling: You would use polling when dealing with a simple input device that needs to be checked at regular intervals, such as a button press sensor or a temperature sensor. The microcontroller would continuously poll the device to check for any new data or events.
• Interrupt: Interrupts are commonly used for time-sensitive tasks or events that require immediate attention, such as data reception in a communication module or a real-time control system. When new data arrives, the interrupt signal is triggered, and the microcontroller can respond promptly without wasting time on continuous polling.