Semicustom made integrated circuit equipped with controller for input/output buffers

DETAILED DESCRIPTION It is therefore an important object of the present invention to provide a semicustom made integrated circuit which can prevent a manufacturer from wiring error between an incomplete logic gate array and buffer circuits.
To accomplish these objects, the present invention proposes to select complete signal paths between a logic gate array and associated buffer circuit depending upon the function of a logic gate array.
In accordance with the present invention, there is provided a semicustom made integrated circuit fabricated on a single semiconductor chip, comprising: a) at least one first function block a wiring arrangement of which has been completed so as to fix the function thereof before accepting an order of a customer; b) at least one second function block a wiring arrangement of which is completed so as to fix the function thereof after the acceptance of the order of the customer, the at least one second function block producing instruction signals indicative of what kind of buffer circuit is necessary for the function thereof; and c) at least one buffer circuit means associated with the at least one second function block, and selectively serving as one of an input buffer, an output buffer, a bidirectional buffer and a three-state buffer depending upon the instruction signals.