基于统计分析的多协议单片机数据通信系统EFT抗扰度研究

Research on EFT Immunity of MCU Data Communication System with Multi-protocol Based on Statistical Analysis

电快速瞬变脉冲群(EFT)易通过电源线与通信线间的耦合干扰电子系统或设备正常运行,通信协议直接影响数据通信的EFT抗扰度.本文设计了包含I2C、USART、SPI和RS232四种数据通信协议的单片机数据通信系统,采用线缆耦合方式对其进行EFT抗扰度试验,基于数理统计方法分析了不同通信协议下系统EFT抗扰度.根据试验中获取的阈值电压数据,运用最大似然法估计假设模型参数,再通过卡方拟合优度检验以及汉南-奎因信息准则选取最优拟合分布模型Gamma模型,以研究不同通信协议下的EFT干扰阈值电压分布规律.对单片机通信协议而言,在一定波特率下,EFT抗扰度由低到高依次为I2C、USART、SPI、RS232.

The electronic system or equipment can be easily disturbed by Electrical Fast Transient（EFT） induced by coupling between power lines and communication lines. EFT immunity of data communication is directly influenced by communication protocol. Hence, a MCU data communication system which contains four kinds of data communication protocol including I2C, USART, SPI and RS232 was designed for EFT immunity test by means of cable coupling. The test data was analyzed by mathematical statistics method for obtaining the EFT immunity of MCU data communication system under dif- ferent communication protocols. The optimal Gamma model is used for researching distribution law of EFT interference threshold voltage of MCU data communication system under different communication protocols, which was selected by chisquare goodness of fit test and Hannan Quinn information criterion through hypothetical models. The model parameters were estimated by maximum likelihood method based on test data. For MCU communication protocols, EFT immunity from low to high is in the order of I2C, USART, SPI, RS232 under the same baud rate.