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AssigneeHoneywell International Inc.
InventorSteven C. Nichols
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A communication system has a number of nodes connected to a serial data bus. Nodes communicate with each other by transmitting dominant and recessive bits during bit intervals as taught by the CAN (controller area network) arbitration protocol. According to the CAN arbitration protocol, any dominant bit transmitted during a bit interval causes the bit value received to be a dominant bit regardless of the number of recessive bits being sent. The system is arranged so that two or more nodes each respond to a report query message sent by one of the nodes, with a report message sent simultaneously by each of the nodes. The headers (leading bits) of each of the report messages sent by nodes responding to a report query message are the same, allowing arbitration on a trailing node data field. This results in the message having the numerically largest (or smallest) node data field value to survive arbitration. Thus a number of nodes can be polled with a report query message and will respond by simultaneously sending each node's numerical data value with the largest or smallest of these data values received by the system's nodes.
In a system of at least first and second nodes for sending data on a shared serial data path, each using dominant and recessive signals to encode bit values, each said node having a send register recording the bits of a message to be sent, and a message-sending module responsive to a send signal, sending on the data path during successive bit intervals the signal values specified by bit values in sequential bit positions of the send register, where a dominant signal level sent on the data path by any node during a bit interval creates a dominant signal level on the data path during that bit interval irrespective of the number of recessive signal levels sent by other nodes, wherein each node while sending senses the signal level on the data path during each bit interval, and if the sensed signal level differs from that sent by that node, halts further sending of signal levels by that node, wherein each of at least first and second nodes generates a data signal associated with that node and encoding a node data value, said system including a report query module providing a report query message signal to each of the first and second nodes, said report query message signal encoding a query data field having a value specifying a report message header value;
A method for operating a system of at least first and second nodes for sending data on a shared serial data path, each using dominant and recessive signals to encode bit values, each said node having a send register recording the bits of a message to be sent, and a message-sending module responsive to a send signal, sending on the data path during successive bit intervals the signal values specified by bit values in sequential bit positions of the send register, where a dominant signal level sent on the data path by any node during a bit interval creates a dominant signal level on the data path during that bit interval irrespective of the number of recessive signal levels sent by other nodes, wherein each node while sending senses the signal level on the data path during each bit interval, and if the sensed signal level differs from that sent by that node, halts further sending of signal levels by that node, wherein each of at least first and second nodes generates a data signal associated with that node and encoding a node data value, said system including a report query module providing a report query message signal to each of the first and second nodes, said report query message signal encoding a query data field having a value specifying a report message header value;
Dependencies are inferred from the claim text.