Application layer allocation method through utilization of two CAN (Controller Area Network) identifier divisions

Abstract

The invention discloses an application layer allocation method through utilization of two CAN (Controller Area Network) identifier divisions. According to an application layer, two different CAN identifier divisions are used for transferring process variables and non-process variables. Different bus competition ways are provided for the variables. According to the CAN identifier division for transferring the process variables, in a mode of extracting a plurality of bit segments in CAN identifiers and rearranging, splicing and combining the bit segments, a register base address segment for transferring the process variables in the application layer is formed, so the contradiction between variable segmented management and bus competition allocation imbalance is solved well. According to theapplication layer, division allocation and meaning allocation of the CAN identifiers have clear application protocol instruction meanings. A designed application layer protocol has good direct readingperformance and openness, is easy to analyze and is convenient for a user to establish application layer sub-protocols applicable to employing environments in a framework, and seamless compatibilitycan be carried out on a CAN-FD (CAN with Flexible Data rate) protocol.

Description

technical field [0001] The present invention relates to a Controller Area Network (CAN for short), in particular to a method for using and distributing CAN identifiers. Background technique [0002] Fieldbus CAN-bus is a new type of serial bus proposed by Bosch at the SAE (Society of Automotive Engineers) conference in February 1986 - Controller Area Network (CAN), which has multi-master and non-destructive arbitration The characteristics and excellent error detection mechanism, the reliability of the bus is generally recognized by the industry, widely used in the field of automobile manufacturing and industrial control production, and continues to expand, and now hundreds of millions of CAN chips are put into use every year. [0003] Field bus CAN-bus only defines the physical layer and data link layer in the ISO / OSI reference model, but does not define the application layer. For this reason, some institutions and organizations have defined a variety of application layer pr...

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Problems solved by technology

[0003] Field bus CAN-bus only defines the physical layer and data link layer in the ISO / OSI reference model, but does not define the application layer. For this reason, some institutions and organizations have defined a variety of application layer protocols for different application fields. Among them, use The most widely used are CANopen and DeviceNet. my country also released the national standard GB / T 18858.3 compatible with the DeviceNet protocol in 2002. Since both protocols use 11-bit CAN identifiers, their ID resources are limited, forcing the protocol to be compiled. is very complex and difficult to parse, and for some simple applications, the cost of using the protocol is too high

[0004] In 2006, Guangzhou Zhiyuan Electronics Co., Ltd. released the "iCAN Application Layer Protocol V1.0" with my country's independent intellectual property rights. At that time, it played a very important role in promoting the application of CAN bus in my country. Effective use of the resources of the 29-bit CAN identifier in the extended frame format of the CAN2.0b protocol and the command competition characteristics it provides, as well as the non-openness of the protocol itself, limit its application range and ultimately fail to be popularized

Due to the late appearance of CAN-FD, the traditional CAN application layer protocol cannot be directly compatible with CAN-FD, and a lot of adaptive transformation work is required

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