Abstract: An interface controller is designed to separately define the first control information to be supplied to the first latch means for controlling an operation of an interface-controlled device connected to the same controller and the second control information to be supplied to the second latch means for controlling an interface operation with the interface-controlled device, in a form of a pair of the first and second information. When there is an addition or a change in a command defined for the interface-controlled device, as for a command transmission to the interface-controlled device and as for an interface control operation of the interface controller itself, both the control information can be independently amended to cope with the addition or the change.