An interrupt alerts a CPU or microcontroller that an immediate event requires attention, such as a timer expiring or a peripheral receiving data. The processor saves its current state, runs an interrupt service routine (ISR) to handle the event, and then resumes its previous workload. This avoids the inefficiency of constantly polling pins for changes.
The button press isn't registering because the debounce circuit is triggering the interrupt too many times.
Keep interrupt service routines as short as possible. Doing heavy lifting inside an ISR will stall the rest of the system.
Related terms
Microcontroller
A compact integrated circuit designed to govern a specific operation in an embedded system.
Central processing unit
The primary silicon processor responsible for fetching, decoding, and executing instructions in a computer system.
Debounce
To filter out the rapid, unintended multiple electrical contacts made when a mechanical switch closes.