摘要
本文研究一种基于嵌入式系统的Web服务器。本系统可以直接通过TCP/IP网络协议接入Internet实现远程访问,将传统测试仪器网络化,将传统仪器的信息通过通用异步串行口(UART)传输到本系统,然后远程客户端通过访问本系统获取信息,从而可以真正实现不受时间、地域限制的远程监控系统。本系统采用高性能RISC处理器S3C44B0X为CPU,外部扩展Flash和RAM,搭建系统硬件平台;软件方面,开发操作系统屏蔽层(Operating System Shielding,OSS),并在此基础上实现了两级调度机制,移植嵌入式实时操作系统(Real-time Operating System,RTOS)Nucleus PLUS和嵌入式TCP/IP网络协议栈Lwip,在此基础上编写应用程序。
硬件设计中采用以ARM7为内核的处理器S3C44BOX,外部扩展容量为2M字节数的Flash存储器AM29LV160和容量为8M字节数的SDRAM存储器HY57V641620,网络控制部分使用RTL8019AS网络控制器。软件设计中,为了便于软件开发,开发了操作系统屏蔽层,使得系统开发可以在稳定的Windows平台上进行,利用功能完善的开发工具Visual C++,待开发成熟后,可以方便地转移到嵌入式系统中进一步开发。在操作系统屏蔽层中设计了两级调度系统,避免了因为任务频繁切换造成的系统性能损失。在嵌入式系统硬件平台上移植嵌入式实时操作系统Nucleus PLUS和嵌入式TCP/IP协议栈Lwip。实现硬件驱动程序,完成整个系统功能。最后,对本文的研究工作做了总结和展望。
In this paper, it researched the Embedded System Web Server. The system can visit the traditional test instruments through the TCP/IP network protocol remotely access to the Internet, the information of traditional test instruments can transmit through the Universal Asynchronous Serial Port to the system, then the remote client access the information through the system, so that we can truly monitore and control the system any time and any where. The system uses high-performance RISC processor S3C44BOX for system CPU, with external expansion of RAM and Flash, to construct the hardware platforms. The development of operating system shielding layer, and on this basis to achieve the levels scheduling mechanisms, transplant embedded real-time operating system Nucleus PLUS, and embedded TCP/IP network protocol stack Lwip to the hard platform,and achive application program.
In hardware designment ,we use S3C44B0X which has a ARM7 core as system CPU, external expansion capacity of 2 M bytes of Flash memory AM29LV160 and capacity of 8 M bytes of SDRAM memory HY57V641620, use RTL8019AS as the network controller.When design software, in order to facilitate software development, first we developed the operating system shielding layer (Operating System Shielding), allowing the development of systems can be in the stable Windows platform, using good development tool Visual C++, when about finish the development, it will be convenient to transfer to the embedded system. In shielding layer above the operating system, level scheduling system designed to avoid frequent switching of the tasks because of the system performance loss. Then in the embedded systems hardware platform ,transplantat RTOS (Real-time Operating System) Nucleus PLUS and embedded TCP/IP protocol stack Lwip. Then, we develop the hardware drivers, to achieve system function. Finally, make summarizes and prospects about this paper.
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