Cross Platform Embedded System BSP Design

BSP is a hardware abstract layer between operating system and hardware, exactly a part of operating system. In embedded system the set of device drivers for a board is called Board Support Package (BSP). BSP includes the start-up codes as well as the drivers and programs related to system. BSP makes hardware transparent to operating system, so that embedded operating system (OS) and its applications can run on different hardware platform.The development of BSP is at the beginning of the whole system development. It is rather difficult to develop a good BSP package, since it requires all-around knowledge of both hardware and software. Because of the complexity, the BSP developers try to introduce the inheritance and derivation, component-based software engineering mechanisms to simplify the porting and development work of device drivers, by employing the similarity of hardware platforms and peripheral devices.During the recent years there has been more and more attention payed to this issue in both industry and academia. In this thesis, an agile BSP developing methodology for specific hardware platform is proposed, and a Cross Platform BSP Framework(CPBF) is implemented. CPBF is OS independent, thus all ANSI-C compatible operating systems including Linux, WinCE, PalmOS and Symbian can embed the APIs directly. It is separated into two major components: Cross Platform Low-Level Initialization (CPLI) and Cross Platform Low-Level Primitives (CPLP). CPLI is written in assembly source code, supplied for the initialization, mainly called by the bootloader. CPLP is mostly written in ANSI C, supplied for a reusable framework library that provides hardware-abstract peripheral access and control to AC97, USB, LCD, and UART etc, mainly called by the OS kernel and device drivers.As we can see, CPBF will reduce the duplication of effort through supplying a single, reusable code base for low-level access to device-specific hardware access and register modification; thereby it accelerates the development and testing process of embedded OS and device drivers, simplifies the maintenance and upgrading work. A result of this is quick time to market and quicker functionality of new drivers...