Programmable input/output circuit

Abstract

Abstract In a programmable input/output circuit which is used in a programmable integrated circuit, for interfacing between an external circuit and an internal logic circuit, both disposed exterioly and interiorly of said integrated circuit, an input/output terminal(40) connected to a bus of the internal logic circuitg and a tri-state input buffer (44, 48) are provided, and hereby assured that an external input signal is transmitted to either of the input/output terminal and an ordinary input terminal(42) by switching the status of the tri-state input buffer. In a programmable logic device, which incorporates said input/output circuit, a tri-state buffer(106) is provided between an input/output circuit block(80) and a wiring element(102), and hereby a driving capability of the wiring element used as a bus line is increased.

Inventors

• 👤 Keiichi Kawana

Bibliographic Details