Apparatus for performing bit sensitive parallel bus peer addressing

Abstract

Methods and apparatus used in systems for communicating data (e.g., voice, video and alphanumeric data), including but not limited to telecommunications systems, computer systems, to efficiently utilize bandwidth by performing bit sensitive peer addressing. Apparatus (and related methods) for performing bit sensitive peer addressing include a parallel bus of data bits, a clock bit, a bid/busy bit, and an ack bit. The invention further includes a plurality of port devices coupled to the bus. Each port device includes bus interface circuitry, port control circuitry, and line interface circuitry. The clock signal is used to synchronize messages on the bus and to divide the time domain into timeslots (one timeslot being the reciprocal of the clock frequency). According to the invention, no frame reference is used and traffic on the bus is controlled using a protocol. Each port has an address which is one of the data bits of the bus. Ports bid for access to the bus by asserting their data line and the bid/busy line whenever the bid/busy line is not asserted by another. After seizing the bus, a source port keeps the bid/busy line asserted until it is done transmitting. When two or more ports bid for bus access at the same time, access is given to the port with the highest priority. According to a preferred embodiment of the invention priority is associated with the bit number.