Push-pull serial bus coupled to a plurality of devices each having collision detection circuit and arbitration circuit

A high speed serial bus including an SDA line, an SDB line and a ground reference line, for transferring data comprised of a plurality of bits between a plurality of data processing devices ("agents") coupled to said bus, comprising:

• message control means coupled between each of said agents and said serial bus for transferring data in the form of digital signals representing said plurality of bits between a transmitting and a receiving agent along said serial bus, said message control means including:
• transmitter means coupled to said serial bus for transmitting data provided by an agent, said data in the form of said digital signals being driven on said SDA and SDB lines 180.degree. out of phase with respect to one another such that the combination of said digital signals on each of said SDA and SDB lines relative to said ground reference line represents said bits comprising said data;
• bus state detector means coupled to said serial bus for detecting collisions of data transmitted by at least two agents over said bus, said collision being detected in the event said SDA and SDB lines are at a first logical state relative to said ground reference line, said bus state detector sensing an idle bus on which no data has been transmitted when said SDA and SDB lines are at a second logical state inverse to said first logical state relative to said ground reference line;
• receiving means coupled to said bus state detector means for receiving said digital signals representing said data and reconstructing said data into the form transmitted by said transmitting agent;
• message serial control logic including arbitration means for providing an orderly allocation of access to said serial bus for said transmitting agents, such that said arbitration means initiates an arbitration cycle wherein each agent coupled to said serial bus;
• generates a JAM signal driving both of said serial bus lines SDA and SDB to the same logic state for a predetermined time;
• maintains said serial bus idle for a predetermined time such that any residual electrical signals on said bus lines are damped;
• and
• maintains said serial bus in a "WAIT" state to insure that a valid JAM signal has occurred and then maintains said bus in an idle state for an additional "CLEAR" period to permit the resynchronization of all agents;
• whereby data is serially transferred between agents coupled to said bus.