Patent ID: 6111888
Filing Date: 2000-08-29
Classification: H04J,H04L

Abstract:
A method for reducing the number of messages needed to transfer data in a deterministic manner between a plurality of nodes communicatively connected by a bus using the Controller Area Network (""CAN"") serial communications protocol, said method including the steps of:1) broadcasting a synchronization message having a high priority over said bus to said plurality of nodes wherein said synchronization message includes a synchronization signal that indicates a common time division for transmitting messages that includes sufficient time for transmitting a plurality of high priority messages and at least one low priority message;2) performing arbitration between said plurality of nodes to transmit a one of said plurality of high priority messages from one of said plurality of nodes;3) transmitting said one of said plurality of high priority messages from said one of said plurality of nodes responsive to one of said plurality of nodes winning said arbitration;4) repeating steps 2 and 3 responsive to at least one of said high priority messages remains to be transmitted;5) determining whether said common time division has time remaining responsive to none of said plurality of high priority messages remain to be transmitted;6) performing arbitration between said plurality of nodes to transmit said at least one low priority messages responsive to said common time division having time remaining;7) transmitting one of said at least one low priority messages from one of said plurality of nodes that wins said arbitration;8) determining whether low priority messages remain to be transmitted; and9) Repeating steps 5-8 responsive to low priority messages remaining to be transmitted and time remaining in said common time division.