stm32通过spi口与74hc595相连，然后由74hc595控制8盏灯的闪灭，注意该工程所用外接高速晶振为12MHZ,而大部分板子为8M赫兹，使用时需要修改锁相环倍频系数。-stm32 through spi port is connected with 74hc595 and eight lights are ocontrolled by the 74hc595 , note that works with an external high-speed oscillator is 12M