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

Digital converter to PIC, allows to send SPI data to PIC

After sending one byte over SPI, you have to clear one byte in the data register (DR) again. In SPI you always send and receive a byte You cannot just send OR receive a byte, it's always AND. The technical explanation is that there is only one clock