说明：  实验名称: SPI接口实险，LED数据管显示。 实验目的: 学习AVR单片机的SPI功能 实验现象: 1、程序通过SPI接口输出数据到HC595芯片驱动LED数据管简单显示。 2、内部1 M晶振，程序采用单任务方式，软件延时。 环 境: ICCAVR6.31A
(Experiment name: SPI interface is dangerous, LED data display. Experimental Objective: To study the functional AVR MCU SPI experimental phenomena: 1, the program output data through the SPI interface to the HC595 chip data-driven pipe a simple LED display. 2, within 1 M crystal, single-task approach procedures, software delay. Environment: ICCAVR6.31A)