Bi-directional data transfer circuit that is directionally responsive to the impedance condition of an associated input/output port of a microcomputer

摘要

A bi-directional interface circuit which functions as an output driver to drive a corresponding communication data bus in response to the output of an associated microcomputer and as an input buffer to communicate data from the associated data bus to the microcomputer, wherein such input and output data to and from the microcomputer is communicated to a single port on the microcomputer. The bi-directional interface circuit is controlled by sensing the impedance condition existing on the input/output port of the microcomputer and correspondingly switches to either its output driver mode or input buffer mode.