I/O interfaces and controllers (1)

• I/O interfaces are circuits inserted between a group of I/O ports and the corresponding device controller

• The I/O interface translates the I/O port values into commands and data for the device. It also detects changes in the device state and updates the I/O port that plays the role of status register

• They can be connected through an IRQ line to a Programmable Interrupt Controller (see later)