| Now, with the growth of complexity in embedded system, its development has always been based on the embedded operating system. It is embedded system's characteristic that hardware become diverse, so it's the main problem to resolve how to make the embedded system more efficient on many kinds of hardware. There is no BIOS in the embedded system commonly, therefore a effective bootloader must be given. BSP (Board Support Package) is the resolution and it is also the middleware between hardware and OS to make the hardware details transparent. In addition it can control the hardware, boot the embedded system and give OS hardware information complying with the OS requirement.During different development periods BSP has different purposes. In debug phase BSP is responsible for the target machines' communication with HOST and downloading OS from it. After analyzing the serial port working principle data can be transmitted from HOST to target and vice versa. And then raw SOCKET can be also used to do it only through Data-Link layer. In this phase a bootloader can be made at last to boot the kernel which has downloaded in the Target RAM. According to BSP's function request, completed the initialization of hardware, providing the condition which needed by running OS. Today, flash is the main storage for embedded system. After studying the flash character, kernel and files can be saved to flash if all write and erase operations of flash chip via the system bus follow the program flowchart.The embedded product's OS and files are saved to the flash generally, so BSP would be able to boot the OS from it. During product phase, BSP take charge of the initialization of lower hardware and OS running. bootloader loads OS from flash and hand over control to it. In order to save storage space BSP should be implemented in kernel. According to kernel structure and the requirement of boot steps, the design of kernel-included BSP is completed to initial hardware and run OS.
|
PDF Full Text Request