—— Overview
Application software is the most important component of automotive ECU, and the function and reliability of ECU depend largely on its application software. With the continuous development of automobile electronics technology, ECU electronic control system code is increasingly complex, and ECU software is frequently faced with the problem of change and upgrade. In the early stage of research and development, hardware physical interfaces such as JTAG, BDM or Nexus are generally used to download programs. However, with the in-depth development of technology and the production and after-sales phase of products, the way of physical hardware interface downloading can no longer meet the needs of Oems and suppliers.
Currently CAN bus has been widely used in vehicle network applications, so the online software swiping function based on CAN bus is also widely used. In the development stage, it is convenient for software developers to design, debug and test the ECU code online through CAN bus, so as to improve work efficiency and development progress. In the production stage, batch download CAN be realized by online writing programs through CAN bus, which facilitates the update of software version and avoids the cost and complexity of physical hardware interfaces such as JTAG and BDM. In the after-sales phase, the software in ECU CAN be directly upgraded through CAN bus by using diagnostic instruments and other devices to avoid huge losses caused by product recalls caused by software defects, and provide an upgradable platform for ECU functions.
—— Flash Bootloader Software Architecture
CAN Driver
CAN driver module realizes CAN message sending and receiving and CAN controller hardware operation.
CAN is driven mainly by the following features:
• Initialize the CAN controller
• CAN send and receive message
• CAN feedback message events
Flash Driver
Flash is used to operate Flash's erase, write, and read functions.
Flash driver has the following characteristics:
• Flash hardware initialization
• Erase Flash sector
• Flash block data is written to
• Flash block of data read
• Data check
Transport Protocol Layer
The transport layer implements the following (using different transport layer protocols depending on the scenario) :
• Transport protocol specification based on huahai custom protocol
• Transport protocol specification based on ISO 15765-2
• Transport protocol specification based on CCP
The transmission layer mainly provides data grouping and unpacking function service, able to realize message transmission in segmented transmission: subcontracting and sending of long message, as well as assembly and receiving of subcontracted message. The transport layer has the following characteristics:
• The subcontract and assembly data from the data link layer
• Long message flow control and timing parameters adjustment
• In the process of data transmission error detection and handling overtime
Diagnostics Layer
When the transport layer adopts the ISO 15765-based protocol specification, the diagnostic layer is integrated into the Bootloader program code as an option.
The diagnostic layer implements the Bootloader program write process defined in ISO 15765-3/ISO 14229-1, including: diagnostic session switch, security state switch, identifier read and write, program write and ECU reset, etc.
The diagnostic layer has the following characteristics:
• Implement ISO 14229 in flash diagnosis of the related services
• Calls Flash Driver
Watch Dog
In order to prevent the bootloader from operating overtime, the watchdog module can reset the ECU after a certain period of time to improve the reliability of the software.
Watchdog timing has the following characteristics:
• Monitor bootloader timeout or crash, reset ECU
• Timing parameters can be configured arbitrarily
• Real time is guaranteed
Security Algorithm
The security algorithm is used to process the software encryption and secure access related diagnostic service content and realize the legitimacy and integrity of program download.
The encryption algorithm module has the following characteristics:
• According to different user needs, as an option
• Download tool, check the legality of Seed & Key diagnostic services
• The integrity of the program download check, such as the CRC check
—— Flash Bootloader Solution
To realize the online writing function of CAN bus, we need to develop the Bootloader function software for the target ECU, including the necessary CAN driver, Flash driver, communication protocol and other components. Bootloader software generally has the following requirements:
• Bootloader and application software must be put in different ROM space
• Using nonvolatile storage unit to store the information such as flags
• Need to support different communication protocols
• Bootloader and application software cannot at the same time have the hardware resources
• Program caused by ECU power, and so on and so forth flash fault repair function of the fault
• To download program verification
• Security access modules and encryption algorithm
• Watch dog
Based on existing products and solutions, combined with years of Bootloader development experience, We can customize Flash Bootloader software (including Bootloader and Flash Driver) according to customers' target needs and hardware platform, and deliver it to customers in the form of C source code. Combined with domestic CAN bus-based ECU online writing requirements, Huahai Technology CAN provide three different Flash Bootloader complete solutions to help customers efficiently and safely carry out ECU online writing, customers CAN choose suitable solutions according to their own needs.
Flash brush tool adapter can use USBCAN, CANCard, CANcase and other hardware.
Flash brush Tool software can be used CANape/MeCa/Flash Tool and other upper computer software. MeCa is a general ECU measurement and calibration tool independently developed by Huahai Technology, which integrates Flash program swiping function and is an easy-to-use software product with a simple and reliable Flash swiping interface. As shown in the figure below:
Solution 1
Based on many years of Bootloader development experience, referring to ISO 15765 relevant specifications, the transport layer protocol streamlined Flash Bootloader online write scheme, including Flash brush tools, Bootloader embedded source code, Flash driver and Bootloader application source code, etc..
Solution 2
Flash Bootloader program solution fully meets ISO 15765 specification. The Bootloader module is developed based on ISO 15765-2 and ISO 15765-3 standards. The software architecture of each functional module is shown in the figure below:
Solution 3
Flash Bootloader solution scheme based on CCP protocol and Bootloader module is developed based on CCP protocol standard.
—— Code Integration Services
The integration service mainly includes the integration and delivery of source code, training and technical support.
Code integration and delivery
According to the needs of customers, we will help customers do the following work:
• Integration of Flash Bootloader software with user hardware platforms
• Integration of online writing software with user applications
• Integration of Flash drivers with user applications
• Delivery of source code
• Submit process documentation and instructions
Training
In the process of service integration, in order to enable users to better master the use of codes and tools, we will provide knowledge training related to FlashBootloader integration, including Bootloader principle, Bootloader integration method, tool use method and so on.
Technical Support
Provide technical support for software source code, including email, telephone communication and on-site service.
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