What is an interrupt and why is it important in embedded systems?

An interrupt is a signal that causes the processor to suspend current execution and jump to a special routine (ISR - Interrupt Service Routine) to handle an event. Types: Hardware interrupts from external pins or peripherals (timer, UART, ADC). Software interrupts from program instructions. Exceptions from processor errors (divide by zero, invalid instruction). Importance in embedded systems: Enables responsive real-time behavior without polling. Reduces power consumption (CPU can sleep until event). Handles asynchronous events efficiently. Critical for time-sensitive operations. ISR guidelines: Keep short, no blocking operations, use volatile for shared variables, be aware of interrupt priorities and nesting.