Correct Answer - Option 4 : Arithmetic and logic operations can be directly performed with I/O data
I/O Mapped I/O Interfacing:
A kind of interfacing in which we assign an 8-bit address value to the input/output devices which can be accessed using IN and OUT instruction is called I/O Mapped I/O Interfacing.
Memory-mapped I/O-
It uses the same address space to address both memory and I/O devices.
The memory and registers of the I/O devices are mapped to (associated with) address values.
So when an address is accessed by the CPU, it may refer to a portion of physical RAM, or it can instead refer to memory of the I/O device.
Differences between Memory Mapped I/O and I/O Mapped I/O-
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Memory Mapped I/O
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I/O Mapped I/O
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1. It is a 16 Bit address.
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8 Bit address.
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2. We use \(\overline {{\rm{MEMR}}} /{\rm{\;}}\overline {{\rm{MEMW}}}\) as control signal for input and output
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\(\overline {{\rm{IOR}}} /{\rm{\;}}\overline {{\rm{IOW}}}\) control signal.
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3. Memory Related LDA, STA, MOV M instruction used.
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IN and OUT for port address
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4. 64K Memory shared between I/O device and Memory.
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256 input and 256 output devices can be connected.
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5. Arithmetic and logical operation can be performed directly with I/O data.
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No facility available.
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