Patent ID: 7742496
Filing Date: 2010-06-22
Classification: G06F

Abstract:
1. A method comprising: coupling a plurality of nodes via a serial data bus that uses dominant and recessive signals to represent message bits, wherein the nodes use bitwise arbitration so that simultaneous transmission on the bus of the dominant signal by at least one of the nodes and the recessive signal by the other nodes results in the dominant signal being detectable on the bus, wherein the nodes are configured to cancel transmission of a selected message if bitwise arbitration is lost while sending the selected message and subsequently retransmit the selected message when the bus is available; associating the plurality of nodes with a common report message group identifier; sending a report query message via the bus, wherein the report query message is associated with the report message group identifier; receiving the report query message at first and second nodes of the plurality of nodes, wherein the first and second nodes provide respective first and second messages in response to the report query message, the first and second messages each having higher-order bits representing identical report message headers and lower-order bits representing data generated by the respective first and second nodes; simultaneously transmitting the first and second messages from the respective first and second nodes to the bus; canceling retransmission of the first message from the first node in response to determining that a) the report query message is associated with the report message group identifier, and b) the first node has lost bitwise arbitration to the second node while sending the lower-order bits of the first message.