Q. Structure of Input - Output Interface?

Due to complexity and number of external devices that I/O interface control, there is not any standard structure of I/O interface. Let's give a general structure to an I/O interfaces:

• There is a requirement of I/O logic that must interpret and execute dialogue between processor and I/O interface. Thus there need to be control lines between I/O interface and processors.
• Data line associating I/O interface to system bus should exist. These lines serve purpose of data transfer.
• Data registers may behave as buffer between I/O interface and processor.
• The I/O interface comprises logic specific to interface with every device that it controls.

Figure: The General Structure of an I/O

Figure above is a typical figure of an I/O interface that additionally to all registers as defined above has status/control registers that are used to pass on status information or control information.