The GATE Grind

GATE 2020 BM – Question 21

Analog and Digital Electronics · Microprocessors and Interfacing · 1 mark · Multiple choice

In a microprocessor system with memory-mapped I/O, which statement is true?

  1. Only devices with internal memory can be interfaced
  2. Devices are accessed using IN and OUT instructions
  3. Each I/O device can be addressed as a memory location
  4. Arithmetic and logic operations cannot be performed directly on I/O data

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Correct answer: (C) Each I/O device can be addressed as a memory location

Explanation

Memory-mapped I/O places device registers in the ordinary memory address space. Hence memory-addressing instructions access those registers, C. Dedicated IN/OUT instructions describe isolated I/O, and internal device memory is not required for address decoding.