Method and device for increasing the data transmission capacity in a serial bus system
First Claim
1. A method for serial data transmission in a bus system having at least two subscribed data processing units that exchange messages via a bus in the bus system, each of the messages having a logical structure including a start-of-frame bit, an arbitration field, a control field, a data field, a Cyclical Redundancy Checking (“
- CRC”
) field, an acknowledge field and an end-of-frame sequence, the control field including a data length code, which contains information about the length of the data field, the method comprising;
interpreting, in a transmitted message, values of bits of the data length code;
i) in deviation from the Controller Area Network (“
CAN”
) standard International Organization for Standardization (“
ISO”
) 11898-1 for determining a number of bits of the data field when a first switchover condition is satisfied, and ii) in conformance with the CAN standard ISO 11898-1 for determining the number of bits of the data field when the first switchover condition is not satisfied,wherein satisfaction of the first switchover condition is determined based on at least one switchover bit included in a portion of the logical structure of the transmitted message, the portion not including the data length code.
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Accused Products
Abstract
A method is described for serial data transmission in a bus system having at least two subscribed data processing units that exchange messages via the bus, the transmitted messages having a logical structure in accordance with CAN standard ISO 11898-1, the logical structure including a start-of-frame bit, an arbitration field, a control field, a data field, a CRC field, an acknowledge field and an end-of-frame sequence, the control field including a data length code, which contains information regarding the length of the data field. When a first switchover condition is satisfied, the data field of the messages, in contrast to CAN standard ISO 11898-1, may comprise more than eight bytes, the values of the four bits of the data length code being interpreted at least partially in deviation from CAN standard ISO 11898-1 for determining the size of the data field when the first switchover condition is satisfied.
55 Citations
32 Claims
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1. A method for serial data transmission in a bus system having at least two subscribed data processing units that exchange messages via a bus in the bus system, each of the messages having a logical structure including a start-of-frame bit, an arbitration field, a control field, a data field, a Cyclical Redundancy Checking (“
- CRC”
) field, an acknowledge field and an end-of-frame sequence, the control field including a data length code, which contains information about the length of the data field, the method comprising;interpreting, in a transmitted message, values of bits of the data length code;
i) in deviation from the Controller Area Network (“
CAN”
) standard International Organization for Standardization (“
ISO”
) 11898-1 for determining a number of bits of the data field when a first switchover condition is satisfied, and ii) in conformance with the CAN standard ISO 11898-1 for determining the number of bits of the data field when the first switchover condition is not satisfied,wherein satisfaction of the first switchover condition is determined based on at least one switchover bit included in a portion of the logical structure of the transmitted message, the portion not including the data length code. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
- CRC”
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28. A device for serial data transmission in a bus system, comprising:
-
at least two subscribed data processing units that exchange messages via a bus in the bus system, each of the messages having a logical structure including a start-of-frame bit, an arbitration field, a control field, a data field, a Cyclical Redundancy Checking (“
CRC”
) field, an acknowledge field and an end-of-frame sequence, the control field including a data length code, which contains information about a length of the data field,wherein, when a first switchover condition is;
i) satisfied, values of bits of the data length code are interpreted by one of the at least two subscribed data processing units in deviation from the Controller Area Network (“
CAN”
) standard International Organization for Standardization (“
ISO”
) 11898-1 for determining a number of bits of the data field, and ii) not satisfied, values of the data length code are interpreted in conformance with the CAN standard ISO 11898-1 for determining the number of bits of the data field,wherein satisfaction of the first switchover condition is determined based on at least one switchover bit included in a portion of the logical structure of the transmitted message, the portion not including the data length code. - View Dependent Claims (29, 30, 31)
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32. A method for serially transmitting data over a bus of a bus system between two subscribed data processing units communicatively coupled by the bus, the method comprising:
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a first one of the two subscribed data processing units; determining a length of data to be included in a message in a data field, establishing, based on a first switchover condition;
(a) a correlation between a data length code and the determined length of data to be included in the data field that is one of;
i) in deviation from the Controller Area Network (“
CAN”
) standard International Organization for Standardization (“
ISO”
) 11898-1 when the first switchover condition is satisfied, and ii) in conformance with the CAN standard ISO 11898-1 when the first switchover condition is not satisfied, and (b) a polynomial that is of a length based on the determined length of data, the polynomial for calculating a checksum, andtransmitting a message including;
(a) the data length code having the established correlation to the determined length of data included in the data field, and (b) a Cyclical Redundancy Checking (“
CRC”
) field including the polynomial for calculating the checksum, over the bus to a second one of the two subscribed data processing units;wherein the message has a logical structure, the logical structure including;
a start-of-frame bit, an arbitration field, a control field, the data field, the CRC field, an acknowledge field and an end-of-frame sequence, the control field including the data length code that contains information about the length of the data field, andwherein satisfaction of the first switchover condition is determined based on at least one switchover bit included in a portion of the logical structure of the transmitted message, the portion not including the data length code.
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Specification