在KEIL-MDK平台下，一步一步的搭建freemodbus移植到STM32F103单片机。主要讲解了哪些文件直接拷贝，不做任何修改；哪些移植的文件需要修改以及如何修改，修改过程中注意事项，最后提醒移植到MODBUS-RTU模式下应该注意的事项。(Under KEIL-MDK platform, freemodbus is built step by step and transplanted to STM32F103 single chip computer. This paper mainly explains which files are copied directly without any modification, which ported files need to be modified and how to modify them, and the matters needing attention in the process of modification. Finally, it reminds the matters needing attention when porting to MODBUS-RTU mode.)