Memory Mapped I/O

- 16-bit device address
- Data transfer between any general-purpose register and I/O port.
- The memory map (64K) is shared between I/O device and system memory.
- More hardware is required to decode 16-bit address
- Arithmetic or logic operation can be directly performed with I/O data


Peripheral MappedI/O

- 8-bit device address
- Data is transfer only between accumulator and I.O port
- The I/O map is independent of the memory map; 256 input device and 256. output device can be connected
- Less hardware is required to decode 8-bit address
- Arithmetic or logical operation cannot be directly performed with I/O data