MCS51系列、MCS96系列等单片机由于都不带SPI串行总线接口而限制了其在SPI总线接口器件的使用。文中介绍了SPI串行总线的特征和时序，并以串行E2PROM为例，给出了在51系列单片机上利用I/O口线实现SPI串行总线接口的方法和软件设计程序(汇编语言)。 -MCS51 series, Processor MCS96 such as SCM carry SPI serial bus interface and are restricted in their SPI Bus Interface use. This paper introduces the SPI serial bus characteristics and timing, and serial E2PROM example, presented in 51 MCU use I / O Line SPI serial bus interface software design methods and procedures (assembly language).