1.These are two complementary methods of performing input/output between the CPU and peripheral devices in a computer.
2.Memory-mapped I/O (not to be confused with memory-mapped file I/O) uses the same address bus to address both memory and I/O devices – the memory and registers of the I/O devices are mapped to (associated with) address values.
3.So when an address is accessed by the CPU, it may refer to a portion of physical RAM, but it can also refer to memory of the I/O device.
4.Thus, the CPU instructions used to access the memory can also be used for accessing devices.
5.Each I/O device monitors the CPU's address bus and responds to any CPU access of an address assigned to that device, connecting the data bus to the desired device's hardware register.
2.Memory-mapped I/O (not to be confused with memory-mapped file I/O) uses the same address bus to address both memory and I/O devices – the memory and registers of the I/O devices are mapped to (associated with) address values.
3.So when an address is accessed by the CPU, it may refer to a portion of physical RAM, but it can also refer to memory of the I/O device.
4.Thus, the CPU instructions used to access the memory can also be used for accessing devices.
5.Each I/O device monitors the CPU's address bus and responds to any CPU access of an address assigned to that device, connecting the data bus to the desired device's hardware register.
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