Research Of Bootloader Technology Of Embedded System

With the development of embeded technology, embeded system has been widely used in many files of society. In the initial developing stage of embedded system, Bootloader is used to complete the initialization of target board and provide support to hardware platform, and can provide a good development and debug environment for OS and Application. Traditional Bootloader can only boot OS, and some can provide Serial Port for communicating with PC. With the development of Embeded system,this is far from enough. So design a Bootloader with network communicating function is important.In this topic, Bootloader technology of embedded system is researched, using EP9315 with an Ethernet controller and RTL8201 as hardware environment, and the Open Source embedded network communication protocol LwIP and real time operating systemμC/OS-II as software environment. On this basis,a Bootloader with powerful function and strong interactive ability is implemented.After the analysis of the working mechanism of LwIP, this article implements the transplantation of LwIP intoμC/OS-II, including the files correlated with CPU and Operation System Emulation Layer, then the Programming model of the upper layer API and lower layer Network Interface is given. Then on the basis of analysis of working mechanism of Ethernet controller and PHY, Ethernet Network Driver is implemented, including ethernet network initialization, interrupt service routine, receiving and sending data. And then TFTP is implemented upon the Network Communication Protocol, adding the function of Network Download for Bootloader. Eventually, the embedded system is tested.