The Design And Implementation Of Bootloader Of Paperless Recorder’s Verification Platform

Embedded system usually refers to a variety of hardware processors, but there isn’t a universal BootLoader that can apply to all of the different processor platforms, because BootLoader isn’t universal and fully dependent on specific hardware platform. BootLoader program exists as the lowest part, it plays a vital role in embedded system device and it is indispensable.The key point of embedded system is to design and develop the corresponding BootLoader to ensure that the system can start loading the kernel and root file systerm normally.The main work of this paper is to build and design a BootLoader of the paperless recorder’s verification platform, to design and implement the suitable BootLoader program based on the specific hardware platform configuration.The BootLoader can complete the hardware and software environment initialization of the paperless recorder’s verification platform, loading Linux operating system and root file system, and ultimately the user authentication program can successful run on the platform.Through research and analysis of BootLoader, this paper gave the overview of the basic concepts of BootLoader, typical structure and main function, also gave the interactive mode with kernel.In the third part it involved the building process of software and hardware environment of verification platform’s BootLoader according to the requirements of the project, also gave the configuration process of system cross tool chain, NFS network file systerm, TFTP file transfer protocol and serial terminal program.The main realization method in this paper is to select U-boot as the basic program, then to achieve a simple BootLoader based on it, and gradually increased its expansion function to realize more complex function. First of all, the system can automatically identify where the code boots from, Nand Flash or Nor Flash, which can enhance the transplant flexibility of systerm. Secondly, this BootLoader supported DM9000NIC driver program, which can enable the system tol to transfer files through TFTP network protocol and greatly improved the efficiency of document transmission with host. Finally, the BootLoader realized the function of writing Yaffs2file system, the system can no longer through the JTAG interface to the Flash recording data, and can be directly using the BootLoader command operation.Eventually, in this paper realized a BootLoader which could initialize hardware platform, load the operating system kernel and the root file system, and also could support automatic identification Flash type at the booting time, could support DM9000chip and the writing of Yaffs2file system directly.