A program download method based on CAN bus

Abstract

The invention relates to a program download method based on a CAN bus. The program download method comprises that S1, when a system is powered on, whether a program update flag variable Up_Flg is effective or not and whether an object code program flag variable Code_ok is effective or not are judged, if the program update flag variable Up_Flg is ineffective and the object code program flag variable Code_ok is effective, the system enters an application mode, otherwise the system enters a BootLoad mode; S2, whether a FLASH driving code is received in a first predetermined time or not is judged, if the FLASH driving code is received in the first predetermined time, a step S3 is executed, otherwise the system returns to the step S1; S3, the object code program flag variable Code_ok is set to be zero; S4, an application program object code is erased; S5, a new program code is received; and S6, a new application program is executed. According to the invention, the program is downloaded based on the CAN bus and can be flashed at random, even if the programmed object code is wrong or the flashing process is interrupted accidentally, the flashing process can be executed again, whether the system enters the BootLoad mode or the application mode is judged through reading the flags, the system is powered on and enters an application program without time delay, and a zero speed starting effect is achieved.

Description

technical field [0001] The invention relates to the technical field of battery management systems for electric vehicles, in particular to a method for downloading programs based on a CAN bus. Background technique [0002] At present, in the field of electric vehicles, it is a common way to download programs to the battery management system through the CAN bus. However, in the existing CAN bus-based program downloading method, when the target code is wrong in the program programming process or the flashing process is accidentally interrupted, it cannot enter the flashing mode to flash again. After the battery management system is powered on, it needs to judge whether the system enters the BootLoad mode or the application program mode. In the prior art, it takes a certain amount of time to determine the mode after the system is powered on, resulting in a certain delay when the system is powered on and enters the application program, which affects the user's use. experience ef...

AI Technical Summary

Problems solved by technology

However, in the existing CAN bus-based program download method, when the target code is wrong during the program programming process or the flashing process is interrupted unexpectedly, it cannot enter the flashing mode and flash again

After the battery management system is powered on, it needs to judge whether the system enters the BootLoad mode or the application program mode. In the prior art, it takes a certain amount of time to determine the mode after the system is powered on, resulting in a certain delay when the system is powered on and entering the application program, which affects the user's use. experience effect

In addition, the existing program download based on CAN bus is prone to accidental operation of FLASH, resulting in wrong rewriting of FLASH

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