| With the fast developing of Information Technology, especially the popularization of Internet, the accelerating process of combination of 3C(including Computer, Communication and Consumption electronics), the Digital Times have become true. Embedded connected device is the one of the most popular product in Digital Times. To get a leading position in this field, different countries conduct a serious competition with each together. Embedded software is the kernel part of digital product. As the foundation and the leader of Embedded software, Embedded Operation system plays a more and more important role in the developing process of this industry. This article made a deeply research concentrated on the application of source code exploitation μC/OS, which is widely used in the Embedded Operation System, on the SPCA 720A. At the same time, a windows -like Graphical User Interface and some graphic operation have been achieved on this foundation. And a tiny file system that is used to save the files has been achieved.Jean J.Labrosse, an expert on embedded system form United States, invented μC/OS. It was designed for embedded application, and most of the source code is made by C language. The part related with the CPU hardware is made by assembly language, which is about 200 lines. The part that is made by assembly language has been compressed to thelowest limit in order to transplant it to any other CPU. The users could embed μC/OS to the product only if they have standard ANSI C compiler and some software for compiling and linking.(μC/OS, a preemptive multi-task real time kernel, is based on the priority. That means the task own the highest priority in all tasks that is in ready state, will always run firstly. Task scheduler is completed by check table.Different task have different priority. There are 64 priorities in μC/OS, and it support no more than 64 tasks.μC/OS could be cut; it means that only the useful function to users will be embedded. In this way, some function or all function could be included into the product, and the ROM/RAM resource occupied by the kernel could be adjusted depend on the product. The cut is achieved by the conditional compiling. The author tried his best to make sure that the kernel will occupy the least resource.SPCA720A is a MIPS instruction system IC, and is support the GCC compiler in the Linux, so in the transplanting process of μC/OS, we choose MIPS instruction to accomplish the hardware-related part in the μC/OS. For example: Function IRQTrap OSDisableInt OSEnableInt OSCtxSw OSStartHighRdy, IRQEnable etc. Meanwhile, we could transplant the other useful application achieved by C language directly, such as: Task scheduler, memory management, signals amount management, mailbox management etc.We construct a windows-like Graphical User Interface based on theμC/OS. Firstly, we achieved the support for mouse and keyboard. Because SPCA720A have PS2 interface, we achieved the input from mouse and keyboard after installed their drivers. Secondly, we achieved the function to draw point and line. Because SPCA720A doesn't support float calculation itself, and the color level and the luminance level ofevery point on TV screen is related with the other 4 point around it, it's hard to draw curve and slash. In fact, we choose to draw vertical line and horizontal line the approximate the curve and slash. Finally, to achieve an windows-like Graphical User Interface, we save the position, size, and other parameters by defining great deal of data structure, and use Binary tree and Graph to record the relationship between different graphs. Refers to the Traversing Graph, we divided it into many Traversing of Binary tree. We have achieved the many operation to the graph such as: display, insert, delete, and efface the overlay of graphs, at the same time we achieved the function of the select of graphic menu and input of characters.In order to save our operations, we take use of the SPCA720A function to support Flash memory to achieve a tiny file...
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