Data processing apparatus having a bidirectional interface with receiving buffers, three-state buffers, and enable terminals for automatically switching the direction of data transmission and reception

摘要

A data processing apparatus having a bidirectional interface which usually remains in a receiving mode during operation ready to receive data signals from an external device over a receiving data bus. When the apparatus is to transmit a data signal to the external device, the data signal placed on a transmitting data bus automatically causes the bidirectional interface to enter transmitting mode in preparation for the transmission.