| With the development of modern automotive technology, developers demand for better performance of powertrain functions, the traditional purely mechanical control system has been gradually fading out the stage of history and the electronic control systems take its place. The electronic control System is able to collects and samples other physical quantities into electrical signals, while the time control ability is more powerful than the traditional purely mechanical systems. In this background condition, more and more engineers took part in the development of automotive electronics, and gradually differentiate to driver engineers and the application-level engineers. Application-layer focuses on control strategy, they use the underlying drive to build the development of strategies. they do not need to know the detail of the drivers, and care only about their ability to achieve the established functions. Driver level engineers write low-level drivers to support the development of application-level engineers depending on the MCU hardware and application layer requirements.The author studyed the datasheet of the freescale MCU MC9S08SG8 focused on the need of the developer of the automotive electronic area. considering the real hardware conection environment, referring to the AUTOSAR driver structure and driver of other structures to design a series of basic driver software of the MC9S08SG8 ECU. including clock module. AD module. ACMP module.IO module. RTC module. MTIM module. SPI module and Flash module. The author analysesd the register of the modules and gave introduction and flow chart of the functions.The driver designed by the author covered the existing need of the user, which made it a complete driver platform, while the author considered the further need of the user and designed the drivers of the modules which is not ordered.Considering that in real condition the drivers are handled to the users as a library, the ability of checking error input value and return errors are improved. As the result of studing Autosar structure, author took in the DET function to facality the development of driver users.which can be disabled by Macro settings.The author researched on the SPI slave mode and compared two strategy of slave working mode, and a choice was made between them. The author also designed a self_test function and a filter function for the AD module. As the security of code is considered, the author made a severe test of the drivers designed, including function test and marginal test. According to the test result, the driver deisgned fits the designed requirement and can be handled to user.This paper developed a series of low-level driver software of ECU in automotive area, which is complete and able to be used in reality. The analysis of the module and registers of the MCU may be helpful for the following developer of the same MCU. The analysis of the Spi module is creative to some extent, which would meet the need of some special conditions. |
