Circuit and method for interfacing with vehicle computer
First Claim
1. An interface circuit for automatically providing bi-directional communication with at least one on-board vehicle computer under a plurality of different communication protocols, comprising:
- bi-directional communication means for enabling communication under a first communication protocol;
full duplex communication means for enabling communication under a second communication protocol, said full duplex communication means having a receive bus and a complimentary transmit bus;
edge-detect means for distinguishing between identification data and communication data, said edge-detect means having an input;
comparator means having a first input for receiving a voltage reference, a second input for receiving a data input and an output coupled to said input of said edge-detect means, said comparator means and edge-detect means changing a mode of communication between said first communication protocol and said second communication protocol; and
feedback means coupled to the bi-directional communication means for enabling reception of incoming messages while filtering a local echo of a transmitted message.
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Accused Products
Abstract
An interface circuit for providing signals necessary to monitor one or more on-board vehicle computers through a serial communication link between an off-board controller and the on-board vehicle computer. The interface circuit is provided on the vehicle in order to provide the command signals to the off-board controller which will enable a standard monitoring device to read key information from the on-board vehicle computer. Additionally, the interface circuit also provides support of a second mode of operation that conforms to a proprietary communications protocol. The interface circuit automatically recognizes and adapts to the proper communication protocol for the tool sensed. The interface circuit complies with both a proprietary communication protocol and with an ISO 1941 format which satisfies an OBDII/CARB specification which all automobiles sold in the United States must comply with by the 1996 model year.
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Citations
14 Claims
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1. An interface circuit for automatically providing bi-directional communication with at least one on-board vehicle computer under a plurality of different communication protocols, comprising:
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bi-directional communication means for enabling communication under a first communication protocol; full duplex communication means for enabling communication under a second communication protocol, said full duplex communication means having a receive bus and a complimentary transmit bus; edge-detect means for distinguishing between identification data and communication data, said edge-detect means having an input; comparator means having a first input for receiving a voltage reference, a second input for receiving a data input and an output coupled to said input of said edge-detect means, said comparator means and edge-detect means changing a mode of communication between said first communication protocol and said second communication protocol; and feedback means coupled to the bi-directional communication means for enabling reception of incoming messages while filtering a local echo of a transmitted message. - View Dependent Claims (2, 3, 4, 5)
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6. A method of communicating information between an onboard vehicle computer and a proprietary monitoring and programming device using a first protocol and for communicating information between said on-board vehicle computer and a second monitoring device using a second protocol, comprising the steps of:
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providing a first communication protocol using a bi-directional communication bus; providing a second communication protocol using said bi-directional communication bus for an omni-directional receive bus and a second bus for a complimentary omni-directional transmit bus; distinguishing between an identification message and a communication data packet and providing an output which is indicative of the distinguished message or data; switching automatically between said first communication protocol and said second communication protocol as a result of said output; and enabling reception of incoming messages while filtering a local echo of a transmitted message. - View Dependent Claims (7)
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8. An interface circuit for providing bi-directional communication with at least one on-board vehicle computer under a plurality of different communication protocols, said interface circuit comprising:
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bi-directional communication means for providing communication under a first communication protocol; full duplex communication means for providing communication under a second communication protocol, said full duplex communication means including an omni-directional receive bus and a complementary omni-directional transmit bus; means for detecting connection of a diagnostic tool to the interface circuit and selecting one of the communication protocols for said. diagnostic tool; and feedback means coupled to the bi-directional communication means for enabling reception of incoming messages while filtering a local echo of a transmitted message. - View Dependent Claims (9, 10, 11, 12)
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13. An interface circuit for providing bi-directional communication with at least one on-board vehicle computer under a plurality of different communication protocols, said interface circuit comprising:
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bi-directional communication means for providing communication under a first communication protocol; full duplex communication means for providing communication under a second communication protocol, said full duplex communication means including a receive bus and a transmit bus for handling said second communication protocol, and said receive bus being provided via said bi-directional communication means; and means for detecting connection of a diagnostic tool to the interface circuit and selecting one of the communication protocols for said diagnostic tool. - View Dependent Claims (14)
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Specification