Difference between Memory Mapped IO and IO Mapped IO with reference to 8085 Microprocessor

The microprocessor is unable to act independently; therefore, it must be connected to memory, additional peripherals, or IO devices. Interfacing is the term for this connecting.

There are two methods to interact with the I/O devices in 8085:

1. Memory-Mapped I/O Interfacing

In this type of interface, a memory address is assigned that may be utilized in the same way that a typical memory location is used. I/O ports are given 16-bit addresses within the memory as part of memory mapping for I/O devices. Since each bus is shared in this case, storage and I/O device utilize the very same set of instructions. I/O device utilize the same network address of memory devices, therefore they are treated as memory. As a result, the memory's capacity to be accessed is reduced. In this case, the CPU sees the I/O ports as memory locations that may be read from and written to.  As a result, anytime an address is created on the address bus, a control signal for memory reading is also generated. The memory write operation follows a similar pattern.

2. I/O Mapped I/O Interfacing

The reason it is also known as Isolated I/O mapping is that the address space of the memory and I/O are separated in this case. I/O and memory utilize different read and writes commands as a result. This method uses independent read and write control lines for I/O device but a shared bus for memory and I/O devices. Here, the process is set up so that, if the information needed to accomplish the action is obtained from the I/O devices. Then I/O read and I/O writes control lines, together with the address, are added. Will become active to enable data transmission between the CPU and I/O. The isolated mapping solely makes use of the IN and OUT commands to transmit files between the CPU and I/O devices.

Difference between Memory-Mapped I/O Interfacing and I/O Mapped I/O Interfacing

Features	Memory Mapped IO	IO Mapped IO
Address Size	They get 16-bit address values provided to them.	They get 8-bit address values supplied to them.
Instructions Used	LDA, STA, and other directives are used.	IN and OUT are the commands utilized.
Cycles	Memory Read and Memory Write cycles are used during operation.	In the case of IO Mapped IO, cycles engaged during operation are IO read and IO writes.
Registers Communicating	Any register can connect with the IO device when using memory-mapped IO.	When using IO Mapped IO, only Accumulator can interface with IO devices.
IO/M` signal	In the case of Memory Mapped IO, during writing or read cycles (IO/M' = 0).	When using IO Mapped IO, (IO/M' = 1) during writing or read cycles.
Control Signal	Since we have a single memory area when using Memory Mapped IO, there is no need for a separate control signal.	In the case of IO Mapped IO, special control signals are employed.
Arithmetic and Logical operations	Arithmetic and logical operations are carried out directly on the data.	Functions including such math and logic cannot be performed directly on the data.

Conclusion

As a result of this discussion, we can get the conclusion that memory-mapped I/O decodes more difficultly than I/O-mapped I/O and the latter has a greater number of address lines, which is the cause for the same.