Method for transmitting data via a serial communication bus, bus interface, and computer program

Patent metadata

Field	Value
Publication number	US-10530606-B2
Application number	US-201816029054-A
Country	US
Kind code	B2
Filing date	Jul 6, 2018
Priority date	Jul 11, 2017
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

An extension of the existing CAN FD data transmission protocol. The extension enables the use of the IPv6 protocol for the CAN bus. The CAN FD protocol is further developed in an incompatible way. One modification measure relates to the lengthening of the Data Field, which is positioned in the transmission frame after an Arbitration Field. An arbitrary number of bytes can be entered in the extended Data Field within a specified upper limit. Since the Data Field is transmitted at a higher bit rate field than the Arbitration Field, the data throughput is increased dramatically.

First claim

The invention claimed is:

1. A bus interface for transmitting data over a serial communication bus,
wherein a transmission frame transmits the data, wherein the transmission frame has at least one arbitration field and one data field,
wherein the arbitration field controls a bus access according to the Carrier Sense Multiple Access with Collision Resolution method by prioritization of messages based on an identifier,
wherein a low bit rate is set for the arbitration phase and a higher bit rate is set in the data field for the transmission of the data,
wherein the data field has a variable length for an arbitrary number of bytes within a specified upper limit which is greater than 64 bytes,
wherein in the transmission frame a CRC field is provided, wherein at least one section is allocated to a CRC check code,
wherein a start field is provided in the transmission frame and the CRC check code is calculated over the fields Start Field, Arbitration Field, Control Field, and Data Field, and
wherein the data transmission takes place asynchronously and ensures the synchronization of the data transmitting station and data receiving station, a resynchronization is performed according to a bit-stuffing rule, wherein the bit-stuffing rule is applied over the areas from the start field until the end of the data field, wherein the bit-stuffing rule states that a stuff-bit is only inserted after a defined number of successive bits with the same bus level, wherein the defined number is a natural number greater than the number 5, wherein the number of inserted stuff-bits is entered in one section of the CRC field.

2. The bus interface of claim 1 , wherein the specified upper limit is the value of 4096 bytes.

3. The bus interface of claim 1 , wherein the length of the arbitration field is set to 32 bits.

4. The bus interface of claim 1 , wherein a control field is provided in the transmission frame between the arbitration field and the data field, wherein at least one section is allocated for a length specification in terms of the data field.

5. The bus interface of claim 1 , wherein an End Field is provided in the transmission frame and at least one end-of-frame code is entered in the End Field, wherein the end-of-frame code has a length of 11 bits.

6. The bus interface of claim 1 , wherein a stuff-bit is inserted at fixed specified positions in the CRC field.

7. The bus interface of claim 6 , wherein the CRC field starts with a fixed specified stuff-bit and the other fixed specified stuff-bits are each inserted at an interval of 9 bits of the CRC field.

8. The bus interface of claim 1 , wherein the identifier field in the arbitration field is sub-divided into sections “Message Content” identifier and “Device” identifier.

9. The bus interface of claim 8 , wherein a section with the higher order bits is reserved for the prioritization of the message content and a section with the lower order bits is allocated to the device identification.

10. The bus interface of claim 9 , wherein the identifier has a length of 32 bits and the section with the higher order bits has a length of 24 bits and the section with the lower-order bits has a length of 8 bits.

11. A non-transitory computer program product including computer code to execute the transmitter-side operations and/or the receiver-side operations of a method for transmitting data over a serial communication bus, wherein the data is transmitted with a transmission frame when processed in a computation unit wherein the transmission frame has at least one arbitration field and one data field, wherein the arbitration field controls a bus access according to the Carrier Sense Multiple Access with Collision Resolution method by prioritization of messages based on an identifier, wherein a low bit rate is set for the arbitration phase and a higher bit rate is set in the data field for the transmission of the data, wherein the data field has a variable length for an arbitrary number of bytes within a specified upper limit which is greater than 64 bytes,
wherein in the transmission frame a CRC field is provided, wherein at least one section is allocated to a CRC check code,
wherein a start field is provided in the transmission frame and the CRC check code is calculated over the fields Start Field, Arbitration Field, Control Field, and Data Field, and
wherein the data transmission takes place asynchronously and ensures the synchronization of the data transmitting station and data receiving station, a resynchronization is performed according to a bit-stuffing rule, wherein the bit-stuffing rule is applied over the areas from the start field until the end of the data field, wherein the bit-stuffing rule states that a stuff-bit is only inserted after a defined number of successive bits with the same bus level, wherein the defined number is a natural number greater than the number 5, wherein the number of inserted stuff-bits is entered in one section of the CRC field.

12. A non-transitory computer program product of claim 11 , wherein the specified upper limit is the value of 4096 bytes.

13. A non-transitory computer program product of claim 11 , wherein the length of the arbitration field is set to 32 bits.

14. The non-transitory computer program product of claim 11 , wherein a control field is provided in the transmission frame between the arbitration field and the data field, wherein at least one section is allocated for a length specification in terms of the data field.

15. A non-transitory computer program product of claim 11 , wherein an End Field is provided in the transmission frame and at least one end-of-frame code is entered in the End Field, wherein the end-of-frame code has a length of 11 bits.

16. A non-transitory computer program product of claim 11 , wherein a stuff-bit is inserted at fixed specified positions in the CRC field.

17. A non-transitory computer program product of claim 16 , wherein the CRC field starts with a fixed specified stuff-bit and the other fixed specified stuff-bits are each inserted at an interval of 9 bits of the CRC field.

18. A non-transitory computer program product of claim 11 , wherein the identifier field in the arbitration field is sub-divided into sections “Message Content” identifier and “Device” identifier.

19. A non-transitory computer program product of claim 18 , wherein a section with the higher order bits is reserved for the prioritization of the message content and a section with the lower order bits is allocated to the device identification.

20. A non-transitory computer program product of claim 19 , wherein the identifier has a length of 32 bits and the section with the higher order bits has a length of 24 bits and the section with the lower-order bits has a length of 8 bits.

21. A method for transmitting data over a serial communication bus, wherein the data is transmitted with a transmission frame, wherein the transmission frame has at least one arbitration field and one data field, wherein the arbitration field controls a bus access according to the CSMA-CR method (Carrier Sense Multiple Access with Collision Resolution) by prioritization of messages based on an identifier, wherein a low bit rate is set for the arbitration phase and a higher bit rate is set in the data field for the transmission of the data, wherein the data field has a variable length for an arbitrary number of bytes within a specified upper limit which is greater than 64 bytes,
wherein in the transmission frame a CRC field is provided, wherein at least one

Assignees

• Volkswagen Ag

Inventors

• Meier Alexander

Classifications

• H04L12/40156

  by using dedicated slots associated with a priority level · CPC title

• H04L12/40084

  Bus arbitration · CPC title

• G06F13/4282 Primary

  on a serial bus, e.g. I2C bus, SPI bus (on daisy chain buses G06F13/4247) · CPC title

• G06F13/376

  using a contention resolving method, e.g. collision detection, collision avoidance · CPC title

• H04L12/4135 Primary

  using bit-wise arbitration · CPC title