METHOD AND APPARATUS FOR DETECTING AND ISOLATING CONTROLLER AREA NETWORK PERMANENT DOMINANT STATES
First Claim
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1. A controller area network node comprises:
- a controller area network protocol engine having a transmit output assuming dominant and recessive states;
a controller area network transceiver having a transmit input for receiving the transmit output;
a clock;
a shift register connected to be clocked by the clock and further connected to the transmit output for storing uninterrupted sequences of states of the transmit output; and
a logic array coupled to the shift register for comparing the states stored thereon for a specific pattern among the stored uninterrupted sequences of states indicative of a node fault.
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Abstract
Detection of a permanent dominant state on a Controller Area Network node, occurring nearly simultaneously with development of the state, is used to the node from the network. Detection is independent of the application environment.
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Citations
12 Claims
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1. A controller area network node comprises:
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a controller area network protocol engine having a transmit output assuming dominant and recessive states; a controller area network transceiver having a transmit input for receiving the transmit output; a clock; a shift register connected to be clocked by the clock and further connected to the transmit output for storing uninterrupted sequences of states of the transmit output; and a logic array coupled to the shift register for comparing the states stored thereon for a specific pattern among the stored uninterrupted sequences of states indicative of a node fault. - View Dependent Claims (2, 3, 4)
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5. A controller area network comprising:
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a bus; a plurality of nodes each including a protocol engine and a transceiver, the protocol engines being coupled to the transceivers to supply data for transmission over the bus and the transceivers being connected to the bus; at least a first node potentially subject to faults leading to a permanent dominant state on the bus; and the first node including an interruptible connector between the protocol engine and the transceiver of the first node, the interruptible connector being responsive to a monitor and judging circuit connected to the output of the protocol engine for controlling connection of the protocol engine to the transceiver. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A method of isolating at least one of a plurality of nodes connected for communication over controller area network, the method comprising the steps of:
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providing each node with a protocol engine and a transceiver, the protocol engines being coupled to the transceivers to supply data for transmission over the bus by the transceivers; providing an interruptible connection between the protocol engine and the transceiver of each node subject to interruption due to faults; monitoring the output of the protocol engine for disallowed outputs; and responsive to occurrence of a disallowed output interrupting the interruptible connection between the protocol engine associated with the disallowed output and its respective transceiver. - View Dependent Claims (12)
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Specification