通讯实验程序。用到了IIC,SPI,UART和相应的中断,上位机通过UART将数据发送至主机,主机通过LED显示数据并将数据发送至从机,从机接收后通过SPI发送回主机。并再次显示数据。-communications experimental procedure. Use the IIC, SPI, UART and the corresponding disruption PC through UART send data to the mainframe, mainframe data thr