Automobile ecu is the general name of automobile computer. At present, 90% of automobile ecu programming languages are basically written in C language, and some assembly languages and some C languages may also be used in automobile ecu. At present, the key of automobile ecu is only 16-bit single chip microcomputer, so the resources are limited and specific driving codes and configurations are needed. Most computer maintenance can be done by rewriting software and main parameters. If the circuit board is really damaged or other components are broken, only a new ecu can be replaced, and then the main parameters of software configuration can be written. Computer maintenance is not as complicated as mobile phone computer maintenance, and there is not much technical content. But it may not be long before the car becomes a big computer. At that time, maintenance will probably be the same as repairing mobile phones and computers, with a broad market and huge profits. Most products are written in C language and compiled into machine code by PICC compiler. In some cases, the compiled code is redundant and the execution efficiency cannot be optimal. In order to get the best execution efficiency, sometimes assembly code is nested in C language. For example, the remote control signal receiving program uses 3E code to encode the remote control signal. The receiving program needs to check the remote control signal input in the interrupt program, and the period is 100us. If written in C language, about 100us may take up more than 50us and spend less than half of its time on other logics. But if you deal with nested assembly, you only need 30us language. Remote control data is encrypted by rolling data number to prevent it from being intercepted, cracked or attacked again by people in the air. However, due to the large dose shift operation, it takes a long time to decrypt the data, so the decryption code is also written in assembly language. These functions are very demanding, for example, the regulator has LIN and CAN CAN communication functions. We choose ROM/RAM with richer resources and faster operation speed, from Freescale's 8-bit processor DZ96 and 16-bit processor DZ 128. Because of the improvement of performance, all codes are basically developed in C language, and no assembly code is embedded. Considering the requirement of real-time self-reliability, all regulators are basically not developed based on freeRTOS, linux and other operating systems. This was basically a few years ago. In recent years, with the rapid development of electronic technology, 32-bit cortex-Mx single chip microcomputer has swept everything with high cost performance. PIC series processors, which were all the rage before, should have gradually withdrawn from the historical stage. I think so. LIN bus should be the current standard, and the electrical condition of the car can be easily diagnosed by diagnostic instrument and driving computer. The so-called automobile electronic maintenance has become using diagnostic tools and replacing parts, which is less and less technical and has become pure manual labor.