SPI(Serial Peripheral Interface——串行外设接口)串行通信简单实用,控制方便,通信速率快。作为主机传输,它的传输速率最高可达单片机工作频率的二分之一,作为从机则最高可达单片机工作频率的四分之一。文章分析了基于AVR单片机的SPI串行通信原理,并给出SPI串行通信程序实例。 SPI (Serial Peripheral Interface) serial communication is simple and practical, easy to control, fast communication speed. As a host transmission, its transfer rate up to one-half the operating frequency of the microcontroller, as a slave up to a quarter of the operating frequency of the microcontroller. The paper analyzes SPI serial communication principle based on AVR microcontroller and gives an example of SPI serial communication program.