CO321 Embedded Systems Interrupts

What is the main disadvantage of programmed I/O?

• Processor waits continuously
• Requires complex hardware
• Slower than DMA
• Uses too much memory

In programmed I/O, how often must a 64kbps UART port be checked?

• Every 171.9 μs
• Every 1 ms
• Only when data arrives
• Every 100 μs

What triggers an interrupt-driven I/O?

• Clock cycle
• Software loop
• Memory overflow
• Hardware signal

What is an ISR?

• Internal System Resource
• Input Status Register
• Instruction Set Reference
• Interrupt Service Routine

Which component saves the PC during an interrupt?

• BIOS
• Cache
• ALU
• Stack

What is the purpose of an interrupt vector?

• Increase CPU speed
• Handle errors
• Manage memory
• Jump to ISR

In 8051, where are interrupt vectors located?

• High memory addresses
• Low memory addresses
• ROM
• External storage

What does NMI stand for?

• Network Management Interface
• New Memory Instruction
• Non-Maskable Interrupt
• No More Interrupts

Which is a hardware interrupt?

• Illegal opcode
• Timer overflow
• Divide by zero
• Array out of bounds

Which instruction disables interrupts?

• NOP
• EI
• DI
• HLT