Modbus协议在火牛开发板上的实现，通过串口进行开发板和PC的通信-The Modbus protocol in fire and Niu Kaifa board to achieve, through the serial port development board and PC communication

stm32操作SD卡znfat格式，在火牛开发板的已经试验成功，可以读取文件，创建文件-STM32SD znfat format, in the fire Niu Kaifa plate has been successfully tested, can read files, create file