Can communication method and system for electric power-assisted bicycle

Abstract

The present invention provides a CAN communication method and system for an electric power-assisted bicycle, comprising: a master device / slave device transmitting a message generates content of an ID field, an ID extension field, and a data field of a CAN extended frame on the basis of a type of a CAN message to be transmitted, wherein the ID field and the ID extension field collectively comprise a protocol data unit format and a protocol data unit specific field; when the type of the CAN message is a broadcast message, configuring a message number in the protocol data unit format by setting the protocol data unit format to a second protocol data unit format, configuring extended content of the message number in the protocol data unit specific field, and configuring device information of a transmitting device in the data field; and when the type of the CAN message is a directed message, configuring a message number in the protocol data unit format by setting the protocol data unit format to a first protocol data unit format, configuring, in the protocol data unit specific field, a device node ID for receiving a message, and configuring instruction information in the data field. In the present invention, a bus device can be automatically identified and configured.

Description

CAN Communication Method and System for Electric-Assisted Bicycles Technical Field

[0001] This invention relates to the field of communication technology, and more specifically, to a CAN communication method and system for electric-assisted bicycles. Background Technology

[0002] Current electric-assist bicycle systems contain numerous electronic devices, such as instruments, controllers, and batteries. These devices communicate with each other according to a unified communication protocol, forming a complete communication network. Patent document CN112467847A discloses an energy-saving intelligent charging system for electric bicycles. The human-machine interface control center and the PLC charging control terminal communicate via a CAN bus. The human-machine interface control center transmits control commands for battery charging time and voltage to the PLC charging control terminal, which then executes these commands to charge the battery.

[0003] With the development of the e-bike industry, the user base has expanded, and product demands have diversified, making the communication network of e-bike systems increasingly complex. However, the current CAN communication protocol standard is not unified, which leads to the following problems: First, if the communication standard is not unified, it will cause duplication of software work and easily result in problems such as devices not receiving messages or data parsing errors; second, device compatibility is poor and there is no expansion capability. If users add devices from different manufacturers and models to the e-bike system, these devices may not be recognized. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the purpose of this invention is to provide a CAN communication method and system for electric-assisted bicycles.

[0005] A CAN communication method for an electric-assist bicycle provided by the present invention includes:

[0006] Frame structure generation steps: The master / slave device sending the message generates the contents of the ID segment, ID extension segment, and data segment of the CAN extended frame according to the type of CAN message to be sent;

[0007] The ID segment and ID extension segment include the protocol data unit format and the protocol data unit specific field;

[0008] When the type of the CAN message is a broadcast message, the message number is configured in the second protocol data unit format in the protocol data unit format, the message number extension content is configured in the protocol data unit specific field, and the device information of the transmitting device is configured in the data segment;

[0009] When the CAN message type is a directed message, the message number is configured in the first protocol data unit format in the protocol data unit format, the device node ID receiving the message is configured in the specific field of the protocol data unit, and the instruction information is configured in the data segment.

[0010] Furthermore, including:

[0011] Heartbeat broadcast: After the device is connected to the CAN bus of the electric-assist bicycle, the first CAN message is broadcast to the CAN bus using the frame structure generation step described above;

[0012] Parsing the heartbeat message: The master device parses the first CAN message to obtain the device information of the slave device;

[0013] Send configuration command: The master device sends a second CAN message to the slave device according to the device information of the slave device and using the frame structure generation step;

[0014] Parse configuration instructions: The slave device parses the second CAN message to obtain instruction information and executes the instruction information.

[0015] Furthermore, the ID field also includes: priority and reserved bits;

[0016] The master device / slave device sending CAN messages configures the priority of the CAN messages to be sent according to preset rules in the priority list;

[0017] The master device / slave device receiving the CAN message sorts and parses the received CAN message according to the priority.

[0018] The reserved bits are intended for the manufacturer of the slave device to configure independently.

[0019] Furthermore, the ID extension segment also includes: the source address;

[0020] When the master device or slave device that sends the CAN message sends a broadcast message, it configures the device node ID for sending the CAN message at the source address.

[0021] Furthermore, before the master device / slave device receiving the CAN message parses the data segment of the CAN message, it also includes verifying the data segment;

[0022] The verification includes: comparing the sum of the data from the first byte to the second-to-last byte of the data segment with the data of the last byte. If they match, the verification is successful; otherwise, the verification fails, and the master device / slave device receiving the CAN message re-receives the CAN message.

[0023] Furthermore, the master device identifies whether the slave device is online through heartbeat detection;

[0024] The first CAN message sent by the device after connecting to the CAN bus is a heartbeat broadcast message with a preset period.

[0025] A CAN communication system for an electric-assisted bicycle according to the present invention includes: a master device, a slave device, and a CAN bus;

[0026] The master device and the slave device are connected to the CAN bus;

[0027] The master / slave device sending the message generates the contents of the ID segment, ID extension segment, and data segment of the CAN extended frame according to the type of CAN message to be sent;

[0028] The ID segment and ID extension segment include the protocol data unit format and the protocol data unit specific field;

[0029] When the type of the CAN message is a broadcast message, the message number is configured in the second protocol data unit format in the protocol data unit format, the message number extension content is configured in the protocol data unit specific field, and the device information of the transmitting device is configured in the data segment;

[0030] When the CAN message type is a directed message, the message number is configured in the first protocol data unit format in the protocol data unit format, the device node ID receiving the message is configured in the specific field of the protocol data unit, and the instruction information is configured in the data segment.

[0031] Furthermore, the ID field also includes: priority and reserved bits;

[0032] The master device / slave device sending CAN messages configures the priority of the CAN messages to be sent according to preset rules in the priority list;

[0033] The master device / slave device receiving the CAN message sorts and parses the received CAN message according to the priority.

[0034] The reserved bits are intended for the manufacturer of the slave device to configure independently.

[0035] Furthermore, the ID extension segment also includes: the source address;

[0036] When the master device or slave device that sends the CAN message sends a broadcast message, it configures the device node ID for sending the CAN message at the source address.

[0037] Furthermore, before the master device / slave device receiving the CAN message parses the data segment of the CAN message, it also includes verifying the data segment;

[0038] The verification includes: comparing the sum of the data from the first byte to the second-to-last byte of the data segment with the data of the last byte. If they match, the verification is successful; otherwise, the verification fails, and the master device / slave device receiving the CAN message re-receives the CAN message.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] This invention can automatically identify and configure bus devices, so even devices from different manufacturers and models can operate smoothly in an electric-assist bicycle system as long as they follow the design scheme of this invention. This CAN communication method improves the compatibility and scalability of the electric-assist bicycle system to a certain extent, increasing the flexibility of its configuration. Simultaneously, the addition of data verification functionality during data transmission ensures the security of data transmission. Attached Figure Description

[0041] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0042] Figure 1 is a flowchart of the present invention;

[0043] Figure 2 is a schematic diagram of the CAN communication network structure of the present invention;

[0044] Figure 3 is a schematic diagram of the data frame of the CAN message of the present invention. Detailed Implementation

[0045] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0046] The CAN communication method for electric-assist bicycles of the present invention generates the frame structure of a CAN message through a frame structure generation step. Specifically, the master / slave device sending the message generates the contents of the ID segment, ID extension segment, and data segment of the CAN extended frame according to the type of CAN message to be sent. The ID segment and ID extension segment include the protocol data unit format and protocol data unit specific fields.

[0047] When the CAN message type is a broadcast message, the message number is configured in the second protocol data unit format in the protocol data unit format, the message number extension content is configured in the protocol data unit specific field, and the device information of the transmitting device is configured in the data segment. When the CAN message type is a directed message, the message number is configured in the first protocol data unit format in the protocol data unit format, the device node ID of the receiving message is configured in the protocol data unit specific field, and the instruction information is configured in the data segment. Thus, the master device can automatically identify and configure the bus device.

[0048] Example 1

[0049] The electric-assist bicycle system includes devices such as an instrument panel, motor controller, battery, and ABS. Each device node is connected to the CAN bus via CAN_H and CAN_L ports, and the number of device nodes on the CAN bus can be increased or decreased as needed. Each device node has a device ID defined by the communication protocol standard. This ID is fixed and unique within the electric-assist bicycle system. Devices of the same type from different manufacturers and models will have the same ID if configured according to this CAN communication protocol standard. Special devices can have their own node IDs. If new devices other than those shown in Figure 2 are connected to the electric-assist bicycle system in the future, only the device node ID needs to be added to the CAN communication protocol standard, as shown in Figure 1. This invention provides a CAN communication method for electric-assist bicycles, including:

[0050] Heartbeat Broadcast: After the device is connected to the CAN bus of the electric-assist bicycle, the first CAN message is broadcast to the CAN bus.

[0051] Parsing the heartbeat message: The master device identifies whether the slave device is online through heartbeat detection. After obtaining the first CAN message, it parses the first CAN message to obtain the corresponding slave device information. The first CAN message can be a heartbeat broadcast message at a preset period.

[0052] Send configuration command: The master device sends the corresponding second CAN message to the slave device based on the slave device information.

[0053] Parse configuration instructions: The slave device parses the second CAN message to obtain instruction information and executes the instruction information.

[0054] As shown in Figure 3, the first and second CAN messages use CAN extended frames, which include an ID segment, an ID extension segment, and a data segment. The ID segment and the ID extension segment include the protocol data unit format, protocol data unit specific fields, and the source address.

[0055] Priority: Indicates the priority of this message frame. It is 3 bits long and ranges from 0 to 7, with smaller values ​​indicating higher priority. The receiving master / slave device sorts and parses the received messages according to their priority.

[0056] Reserved bit: This bit is reserved and undefined. It is 2 bits long and has a default value of 0. It can be configured by the device manufacturer.

[0057] Protocol Data Unit Format: This refers to the protocol data unit format type and also indicates the message number. It has a length of 8 bits, with 6 bits located in the ID field and 2 bits located in the ID extension field. Its data range is 0-255. Data between 0-239 indicates the selection of the first protocol data unit format, and data between 240-255 indicates the selection of the second protocol data unit format.

[0058] Protocol Data Unit (PDU) Specific Fields: These refer to bits specifically defined according to different PDU formats. Specifically, depending on the PDU format, there are two different definitions for these fields, both with a length of 8 bits. When the frame corresponds to the first PDU format, the PDU field is defined as the destination address, which refers to the device node ID receiving the message, i.e., the data destination of the current message. When the frame corresponds to the second PDU format, the PDU field is defined as the message number extension, with a data range of 0-255.

[0059] Source address: refers to the device node ID that sent the message, i.e. the data source of the current message, and has a length of 8 bits.

[0060] Message Number: This refers to the number of different CAN messages, including the reserved bits, the protocol data unit format, and the protocol data unit specific field. The reserved bits are 0 by default. When the message frame is a data frame for a specific destination address, its format is the first protocol data unit format, meaning there are 240 different message numbers, ranging from 0 to 239. When the data frame is a broadcast frame, its format is the second protocol data unit format. The protocol data unit format (240-255) * the protocol data unit specific field (0-255) equals 16 * 256 = 4096 different message numbers, ranging from 61440 to 65535. Regardless of the protocol data unit format, when the message number reaches the maximum number, the next message number for the same source address starts from the initial number.

[0061] When sending a broadcast message, the master / slave device selects the second Protocol Data Unit (PDU) format to configure the message number and configures the message number extension in the Protocol Data Unit specific field. When sending a directed message, the master / slave device selects the first PDU format to configure the message number and configures the receiving device node ID in the Protocol Data Unit specific field. The master / slave device receiving the message parses the message's data segments to obtain slave device information / instruction information.

[0062] To improve the security and integrity of message transmission, a verification process is performed on the data segment before the receiving master / slave device parses it. Specifically, as shown in Figure 3, the data segment consists of 8 bytes (64 bits), with the last byte being the security checksum. The security checksum is calculated by summing the first 7 bytes and taking the lower 8 bits; if they match, the verification is successful. When a device node receives a CAN message from another device node, it first verifies the data segment to determine its integrity and correctness, thus ensuring the security of data transmission. If the verification fails, the data is corrupted, and the device node must re-receive the data.

[0063] Assuming the existing electric-assist bicycle system has a master motor controller but no slave ABS device, and an ABS device is connected to the system, and both the ABS device and the electric-assist bicycle system use the CAN communication protocol standard provided by this invention, the specific implementation steps for the electric-assist bicycle system to identify and match the ABS device are as follows:

[0064] The ABS device is connected to the CAN bus of the electric-assist bicycle system via its communication ports CAN_H and CAN_L. The ABS device sends heartbeat broadcast data to the CAN bus 1-2 seconds after power-on, once every 100ms. Assuming the CAN communication protocol standard defines all ABS type device node IDs as 0x20, and the heartbeat broadcast data priority is 6, this is the first broadcast data, message number 61440, and its data frame ID structure is as shown in the table below. Therefore, the data frame ID is 0x18F00120.

[0065] In addition, the 8-byte data segment of this frame message defines information such as the manufacturer, model and function of this ABS device. The first byte is the manufacturer code, the second byte is the device model code, the third byte is the device function code. If this device is ABS, the function code can correspond to functions such as single-channel front wheel, single-channel rear wheel, and dual-channel front and rear wheels. The fourth to seventh bytes are the heartbeat count, and the eighth byte is the safety check code.

[0066] Assuming the manufacturer code of the ABS device is 0xA1, the model code is 0x06, the function is dual-channel for front and rear wheels, and the corresponding function code is 0x11, this frame of data is the first heartbeat broadcast, and its data segment structure is as shown in the table below. The data segment is represented as 0xA10611000001B9.

[0067] If the master device's motor controller detects this message on the CAN bus, the device node ID code 0x20 in the data frame ID indicates that the newly added online device is an ABS device. After receiving this frame message, the master device first performs a security check on the data segment. The sum of the first 7 bytes is 0xB9, and the lower 8 bits are also 0xB9, which equals the value of the 8th byte security checksum, indicating successful verification. Subsequently, the master device parses the message data segment to identify the manufacturer, model, and function of this ABS device. Based on this information, the master device can subsequently send a working command signal adapted to its function to the newly added ABS device via a specific destination address data frame, enabling it to enter the working state.

[0068] Example 2

[0069] As shown in Figure 2, the present invention provides a CAN communication system for electric-assisted bicycles, comprising: a master device, a slave device, and a CAN bus.

[0070] The master device and the slave device are connected to the CAN bus. After the slave device is connected to the CAN bus of the electric-assist bicycle, it broadcasts and sends a first CAN message to the CAN bus. The master device parses the first CAN message to obtain the corresponding slave device information. The master device sends a corresponding second CAN message to the slave device based on the slave device information. The slave device parses the second CAN message to obtain the instruction information and executes the instruction information.

[0071] As shown in Figure 3, the first and second CAN messages use CAN extended frames, which include an ID segment, an ID extension segment, and a data segment. The ID segment and the ID extension segment include the protocol data unit format, protocol data unit specific fields, and the source address.

[0072] Priority: Indicates the priority of this message frame. It is 3 bits long and ranges from 0 to 7, with smaller values ​​indicating higher priority. The receiving master / slave device sorts and parses the received messages according to their priority.

[0073] Reserved bit: This bit is reserved and undefined. It is 2 bits long and has a default value of 0. It can be configured by the device manufacturer.

[0074] Protocol Data Unit Format: This refers to the protocol data unit format type and also indicates the message number. It has a length of 8 bits, with 6 bits located in the ID field and 2 bits located in the ID extension field. Its data range is 0-255. Data between 0-239 indicates the selection of the first protocol data unit format, and data between 240-255 indicates the selection of the second protocol data unit format.

[0075] Protocol Data Unit (PDU) Specific Fields: These refer to bits specifically defined according to different PDU formats. Specifically, depending on the PDU format, there are two different definitions for these fields, both with a length of 8 bits. When the frame corresponds to the first PDU format, the PDU field is defined as the destination address, which refers to the device node ID receiving the message, i.e., the data destination of the current message. When the frame corresponds to the second PDU format, the PDU field is defined as the message number extension, with a data range of 0-255.

[0076] Source address: refers to the device node ID that sent the message, i.e. the data source of the current message, and has a length of 8 bits.

[0077] Message Number: This refers to the number of different CAN messages, including the reserved bits, the protocol data unit format, and the protocol data unit specific field. The reserved bits are 0 by default. When the message frame is a data frame for a specific destination address, its format is the first protocol data unit format, meaning there are 240 different message numbers, ranging from 0 to 239. When the data frame is a broadcast frame, its format is the second protocol data unit format. The protocol data unit format (240-255) * the protocol data unit specific field (0-255) equals 16 * 256 = 4096 different message numbers, ranging from 61440 to 65535. Regardless of the protocol data unit format, when the message number reaches the maximum number, the next message number for the same source address starts from the initial number.

[0078] When sending a broadcast message, the master / slave device selects the second Protocol Data Unit (PDU) format to configure the message number and configures the message number extension in the Protocol Data Unit specific field. When sending a directed message, the master / slave device selects the first PDU format to configure the message number and configures the receiving device node ID in the Protocol Data Unit specific field. The master / slave device receiving the message parses the message's data segments to obtain slave device information / instruction information.

[0079] To improve the security and integrity of message transmission, a verification process is performed on the data segment before the receiving master / slave device parses it. Specifically, as shown in Figure 3, the data segment consists of 8 bytes (64 bits), with the last byte being the security checksum. The security checksum is calculated by summing the first 7 bytes and taking the lower 8 bits; if they match, the verification is successful. When a device node receives a CAN message from another device node, it first verifies the data segment to determine its integrity and correctness, thus ensuring the security of data transmission. If the verification fails, the data is corrupted, and the device node must re-receive the data.

[0080] Assuming the existing electric-assist bicycle system has a master motor controller but no slave ABS device, and an ABS device is connected to the system, and both the ABS device and the electric-assist bicycle system use the CAN communication protocol standard provided by this invention, the specific implementation steps for the electric-assist bicycle system to identify and match the ABS device are as follows:

[0081] The ABS device is connected to the CAN bus of the electric-assist bicycle system via its communication ports CAN_H and CAN_L. The ABS device sends heartbeat broadcast data to the CAN bus 1-2 seconds after power-on, once every 100ms. Assuming the CAN communication protocol standard defines all ABS type device node IDs as 0x20, and the heartbeat broadcast data priority is 6, this is the first broadcast data, message number 61440, and its data frame ID structure is as shown in the table below. Therefore, the data frame ID is 0x18F00120.

[0082] In addition, the 8-byte data segment of this frame message defines information such as the manufacturer, model and function of this ABS device. The first byte is the manufacturer code, the second byte is the device model code, the third byte is the device function code. If this device is ABS, the function code can correspond to functions such as single-channel front wheel, single-channel rear wheel, and dual-channel front and rear wheels. The fourth to seventh bytes are the heartbeat count, and the eighth byte is the safety check code.

[0083] Assuming the manufacturer code of the ABS device is 0xA1, the model code is 0x06, the function is dual-channel for front and rear wheels, and the corresponding function code is 0x11, this frame of data is the first heartbeat broadcast, and its data segment structure is as shown in the table below. The data segment is represented as 0xA10611000001B9.

[0084] If the master device's motor controller detects this message on the CAN bus, the device node ID code 0x20 in the data frame ID indicates that the newly added online device is an ABS device. After receiving this frame message, the master device first performs a security check on the data segment. The sum of the first 7 bytes is 0xB9, and the lower 8 bits are also 0xB9, which equals the value of the 8th byte security checksum, indicating successful verification. Subsequently, the master device parses the message data segment to identify the manufacturer, model, and function of this ABS device. Based on this information, the master device can subsequently send a working command signal adapted to its function to the newly added ABS device via a specific destination address data frame, enabling it to enter the working state.

[0085] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0086] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A CAN communication method for electric-assisted bicycles, characterized in that, include: Frame structure generation steps: The master / slave device sending the message generates the contents of the ID segment, ID extension segment, and data segment of the CAN extended frame according to the type of CAN message to be sent; The ID segment and ID extension segment include the protocol data unit format and the protocol data unit specific field; When the type of the CAN message is a broadcast message, the message number is configured in the second protocol data unit format in the protocol data unit format, the message number extension content is configured in the protocol data unit specific field, and the device information of the transmitting device is configured in the data segment; When the CAN message type is a directed message, the message number is configured in the first protocol data unit format in the protocol data unit format, the device node ID receiving the message is configured in the specific field of the protocol data unit, and the instruction information is configured in the data segment.

2. The CAN communication method for electric-assisted bicycles according to claim 1, characterized in that, include: Heartbeat broadcast: After the device is connected to the CAN bus of the electric-assist bicycle, the first CAN message is broadcast to the CAN bus using the frame structure generation step described above; Parsing the heartbeat message: The master device parses the first CAN message to obtain the device information of the slave device; Send configuration command: The master device sends a second CAN message to the slave device according to the device information of the slave device and using the frame structure generation step; Parse configuration instructions: The slave device parses the second CAN message to obtain instruction information and executes the instruction information.

3. The CAN communication method for electric-assisted bicycles according to claim 1, characterized in that, The ID field also includes: priority and reserved bits; The master device / slave device sending CAN messages configures the priority of the CAN messages to be sent according to preset rules in the priority list; The master device / slave device receiving the CAN message sorts and parses the received CAN message according to the priority. The reserved bits are intended for the manufacturer of the slave device to configure independently.

4. The CAN communication method for electric-assisted bicycles according to claim 1, characterized in that, The ID extension segment also includes: the source address; When the master device or slave device that sends the CAN message sends a broadcast message, it configures the device node ID for sending the CAN message at the source address.

5. The CAN communication method for electric-assisted bicycles according to claim 1, characterized in that, Before the master device / slave device receiving the CAN message parses the data segment of the CAN message, it also includes verifying the data segment; The verification includes: comparing the sum of the data from the first byte to the second-to-last byte of the data segment with the data of the last byte. If they match, the verification is successful; otherwise, the verification fails, and the master device / slave device receiving the CAN message re-receives the CAN message.

6. The CAN communication method for electric-assisted bicycles according to claim 2, characterized in that, The master device uses heartbeat detection to identify whether the slave device is online; The first CAN message sent by the device after connecting to the CAN bus is a heartbeat broadcast message with a preset period.

7. A CAN communication system for electric-assisted bicycles, characterized in that, include: Master device, slave device, and CAN bus; The master device and the slave device are connected to the CAN bus; The master / slave device sending the message generates the contents of the ID segment, ID extension segment, and data segment of the CAN extended frame according to the type of CAN message to be sent; The ID segment and ID extension segment include the protocol data unit format and the protocol data unit specific field; When the type of the CAN message is a broadcast message, the message number is configured in the second protocol data unit format in the protocol data unit format, the message number extension content is configured in the protocol data unit specific field, and the device information of the transmitting device is configured in the data segment; When the CAN message type is a directed message, the message number is configured in the first protocol data unit format in the protocol data unit format, the device node ID receiving the message is configured in the specific field of the protocol data unit, and the instruction information is configured in the data segment.

8. The CAN communication system for electric-assisted bicycles according to claim 7, characterized in that, The ID field also includes: priority and reserved bits; The master device / slave device sending CAN messages configures the priority of the CAN messages to be sent according to preset rules in the priority list; The master device / slave device receiving the CAN message sorts and parses the received CAN message according to the priority. The reserved bits are intended for the manufacturer of the slave device to configure independently.

9. The CAN communication system for electric-assisted bicycles according to claim 7, characterized in that, The ID extension segment also includes: the source address; When the master device or slave device that sends the CAN message sends a broadcast message, it configures the device node ID for sending the CAN message at the source address.

10. The CAN communication system for electric-assisted bicycles according to claim 7, characterized in that, Before the master device / slave device receiving the CAN message parses the data segment of the CAN message, it also includes verifying the data segment; The verification includes: comparing the sum of the data from the first byte to the second-to-last byte of the data segment with the data of the last byte. If they match, the verification is successful; otherwise, the verification fails, and the master device / slave device receiving the CAN message re-receives the CAN message.

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