A Kind Of Design And Implementation Of Embedded VoIP Terminal Based On I.MX51

With the development of the network and multimedia technology, the VoIP has been widely used in the Internet. The design of a VoIP teminal which has a simple hardware and software, good stability, high audio quality and affordable, will have a good practical significance. The paper proposes a design of the VoIP terminal based on the multimedia processor i.MX51 can meet the above requirements well. i.MX51 is a multimedia processor of Freescale semiconductor company and it is launched by the end of 2009. The processor uses the ARM Cortex-A8 core, and the maximun operating speed is 800MHz. In addition, its Video Processing Unit (VPU) has the intermal control block of the embedded video processing subsystem, which has low consumption of CPU resource when it is operating on the vedio encoding and decoding.The main research contents are as follows:(1)This thesis proposed a Linux-based design of VoIP based on i.MX51 according to the research status of VoIP at home and abroad.(2)In this paper analyze the theory and architecture of the VoIP. And analyze the oSIP protocol stack to its state machine module, the parser module and function modules.(3)VoIP terminal hardware design is completed in this paper. Its main tasks are peripheral chip selection, schematic design, PCB layout and soldering, hardware debugging and testing, hardware peripherals, includes memory expansion module circuit, ethernet interface, audio and video codec module and LCD interfaces Circuit.(4)Complete the VoIP terminal software design in the paper. Build a Linux-based embedded development platform. And VoIP terminal is composed by the terminal control module, SIP module, the media processing module and network transmission module, which is described separately. The terminal control module runs simultaneously on multiple tasks using the Linux multi-threaded.(5)Prove the correctness and rationality of the the proposed terminal design and development process by the test and results analysis of the terminal system in LAN.