针对工业上使用的模拟量模块,大都直接采用模拟信号传输,或者使用Modbus通信协议传输,存在传输效率低,在传输距离上也受到了限制.为此设计了一个基于DeviceNet协议的模拟量模块,以STC15F2K60S2作为主控制器,采用独立CAN控制器模块和CAN收发器.设计4～20 mA电流信号的输入与输出电路,通过DeviceNet协议实现电流信号的采集与输出.最后通过CAN分析平台软件对模块的参数进行读写测试,结果表明本设计能够实现预期的功能.

According to the hardware structure and features of certain multimedia processing chip called PNX1700,the H.264 algorithm is replanted into PNX1700,ME and integer transform are also modified and optimized.The result indicates that,using this algorithm presented in the paper the fast H.264 codec are also modified and optimized,satisfying the requirement of real time video codec.

Based on the NEXPERIA PNXI700 DSP developed by Philips,this paper describes an embedded multimedia processing platform.The platform support real-time Audio/Video encoding and decoding,which use G.711/H.264.H.323 is also supported.Hardware design of this platform is described in this paper.

Based on the algorithm principle of H.263++ encoder and the architecture of multimedia chip PNX1500 invented by Philips Semiconductor, this paper describes a H.263++ encoder with high performance for real time signal processing. The result of experiment indicates that the encoder can encode all kinds of video data rapidly, and can fulfil the real time processing for all kinds of video signals.

Although the traditional compression method of video sequence is changeable coding based on DCT,the method of DCT brings some inevitable problems such as brink-effect and block-effect.This article provides a new model based on the second-wavelet.The coding method of the experiment in this article is update-wavelet transform combined with the split coding method and threshold quantization based on the protocol H.263.It is clear that this method really resolves the problem brought by traditional method DCT from the emulational result on PC,and meets the requirements of picture compression rate and real-time transmission.All of these conclusions provide a theoretical foundation for the high-qualified video sequence real-time transmission and parallel processing of pictures.

Gas monitor system based on wireless sensor network technology and IEEE802.15.4 overtakes the limitation of traditional system that the situation in mine is unknown in time.With this system,the security manager can real-time monitor the gas density of multi-location.Compared with traditional system,this system is portable and extensible and it also has advantage of physical size and power consumption.This paper describes both the whole system architecture and the structure of single node,furthermore,it also introduces the application method.

This paper describes design and implementation of a JTAG controller using PCI interface for Nexperia PNX1300/1500 series DSPCPU,mainly focuses on the JTAG standard and operation principle,the circuit design and the software development are also demonstrated.This control board has been used in the embedded system development based on PNX1300 and worked well.

针对嵌入式多媒体系统中资源的有限性和数据多样性的特点,设计了一种flash文件系统,并在基于PNX1500多媒体嵌入式系统中予以实现。该文件系统提出了两种文件管理策略相互协作的运行模式,在提高闪存的利用率的和可靠性的同时降低了文件系统的开销。适合于多媒体嵌入式系统的应用。

Aiming at the character of the multimedia processing chip called PNX1500[1],this paper describes the replan-tation of the G.729[2] algorithm into it,including its optimization.The result indicates that this arithmetic presented in the paper could implement the fast G.729 codec,and satisfies the requirements of audio realtime codec.

应用于PNX1500 DSP CPU的USB接口的JTAG控制器选用了CYPRESS公司的CY7C68013和TI公司的SN54ACT8990作为主控芯片,支持USB2.0协议,热插拔和即插即用,使用方便。此设计已实际应用在基于PNX1500的嵌入式系统调试中,取得了很好的效果。

Based on the architecture of multimedia chip PNX1500 invented by Philips Semiconductor,a design of a H.264 encoder with high performance for real time signal processing is presented in this paper,which chooses the advanced integer translation and searching algorithm,accomplishes the optimization and debugging for codes. The result of experiment indicates that the encoder can encode all kinds of video data rapidly and can fulfil the real time processing for all kinds of video signals.

The VLIW supported DSP is more and more widely used. However, because of inappropriate design of program structure and the use of redundant data structure, when H.264 video compression algorithm is transplanted to these kinds of DSP platforms, the cache hit ratio is low and the efficiency of DSP decreased. So the research of the optimization methods of the newest video compression algorithm H. 264/AVC on these kinds of DSP becomes more important. In this paper,the architecture of VLIW DSP is introduced, and based on the characters, the optimization methods are analyzed to accelerate the speed of integral transformation module of H. 264. At last, the H. 264 integral transformation module is optimized and simulated on the platform of VLIM DSP. The speed of integral transformation was successfully doubled after optimization.

本文介绍以Philips公司多媒体数字信号处理器PNX1500为核心的多媒体嵌入式平台,该平台具有较强的视频,音频处理能力和网络传输功能,支持H.323协议,对输入语音进行了G.711和输入视频进行H.263编码。本文重点阐述平台的硬件设计和底层驱动程序。

描述了PCI总线仲裁的原理和仲裁算法,阐述了用可编程器件实现总线仲裁的具体方法,并实现了一个双主设备仲裁器。

GUI(Graphic User Interface) based embedded applications are now widely in use.Common GUI products are usually large in size and complicated in detail.An embedded GUI system,which is more lightly weighted than most of current GUI products,was proposed in this paper.Due to adopting both object oriented modularized designing and a well-designed simulator,it is more convenient to develop this system.Its implementation in Video Conference Terminals was also introduced.In this implementation,this system took small memory size,and cost significantly short development time.It greatly reduced the cost of both product hardware and development labor.

由计算机USB接口启动的TUSB3210芯片,通过IIC总线实现对PAL/NTSC解码芯片SAA7113H、编码芯片SAA7121H的寄存器的初始化设置,同时分别从计算机串口、USB接口实现了对系统电路的在系统可编程功能。

Based on FPGA,we design and implement a four-channel-controled and hardware-implemented 2-D transpositional read/write memory module, which provides simultaneously 4-channel and 64-bit data for multiple arithmetic units,and realizes the four-channel parallel operations.The module has been put into practical applications.

Because of inappropriate design of program structure and the use of redundant data structure,when video compression algorithm is transplanted to DSP(digital signal processing) platforms,the cache hit ratio is low and the efficiency of DSP decreased.By analyzing the causes of cache miss and frequent jump operations,the data structure was redefined,the arithmetic was improved.The PNX1300's instruction set was used in DCT,Quantization,ME,Coding module of H.263 to increase the cache hit ratio and eliminate the frequent jump operations.The improved H.263 encoder can compress CIF-format video sequence at real-time with high definition.

This paper discusses and compares different algorithms for multiplication.Then,a 32-bit parallel multiplier,which adoptes tree structure and modularization,is designed and implemented using FPGA.

本文讨论了一种高吞吐量流水方式构建的MPEG-4可变长解码器的设计与仿真结果。在这种解码器中,我们采用了基于PLA的并行解码算法,这种算法能够实现每个时钟解码一个码字。同时,为了提高解码的效率,降低操作的延迟,我们在设计中还引入了流水线操作方式、码表分割等技术,这些技术有利于并行操作的实现。在文章的最后一部分,我们给出了FPGA的仿真结果,结果显示这种结构的解码器完全能够满足MPEG-4的可变长数据的解码需求。