Patent ID: 7143215

Claim:
A data bus system arranged to convey a message between a message originating device and a message receiving device at a bus speed negotiated between them, comprising: a data bus for conveying messages between devices connected to said bus, a message originating device connected to said data bus and arranged to place a first bus speed negotiation pulse onto said bus which toggles from a first logic state to a second logic state, thereby toggling said bus from said first logic state to said second logic state, prior to toggling to a third logic state and thereby ending said first pulse, and a message receiving device connected to said data bus and arranged to place a second bus speed negotiation pulse onto said bus in response to said first pulse, said data bus system arranged such that the elapsed time between the start of said first pulse and the end of said first or second pulse, whichever occurs last, establishes a negotiated bus speed at which a message is to be conveyed between said originating device and said receiving device, wherein a message conveyed on said bus following said second pulse is comprised of data bits and said data bus system is arranged such that each of said data bits occupies a “bit time” which is equal to said elapsed time multiplied by an integer N.