Method and system utilizing a negotiation phase to transfer commands and data in separate modes over a host/peripheral interface

摘要

A command information transfer method and system capable of transferring command information by discriminating it from data information, and capable of using protocols of IEEE P1284, when a nibble or byte mode is incorporated which is stipulated by IEEE P1284 as bi- directional parallel I/F. A new communication mode simulating the extensibility link is set by an extensibility request value undefined by IEEE P1284 and command information is transferred at the second and following bytes of such multiple-byte negotiation. An nFault signal is used for both a notice of error and for a reverse direction information transfer request.