SPI接口与CRC算法在双DSP数据通信中的应用

提出了一种基于DSP28335片上SPI模块和CRC校验算法的数据通信方案。给出了接口电路设计、SPI模块驱动程序设计和求取CRC校验码的具体步骤,重点介绍了通信协议中从机发送请求机制和错误帧重发机制的实现,解决了SPI从机不能发起传输的问题,并提高了通信双方的差错检测能力。实验结果表明,该方案数据传输速度快,可靠性高,满足飞控计算机的性能要求。     

基于SPI的双DSP通信协议研究

提出了改进型SPI(Serial Peripheral interface,串行外围设备接口)协议,在标准SPI协议的基础上,增加了SPI从机主动发起通信的功能,并能指示数据/指令传输,设计了可靠的"帧"格式,帧带有序号和CRC校验,具有完善的出错重传机制。基于该SPI接口协议,设计了TMS320DM642和TMS320C6747之间的SPI通信接口,给出了接口电路设计和工作流程,并应用到课题组设计的水声通信机中。     

基于可重构SoC电路的验证和应用

文章介绍了一款新型可重构SoC电路,较详细地描述了它的内部结构和特点,并制定应用方案,分别重构SPI和DDS模块,对该电路进行验证.应用方案中,利用SPI与VS1003连接,通过该SPI接口控制并发送歌曲数据给VS1003,VS1003对数据进行解码处理,最后驱动功放播放歌曲.利用DDS模块产生信号数据,经过D/A转换...     

高可靠性SPI通信机制及其应用探讨

SPI总线系统拥有完善通信协议及高可靠性的应答重发机制,由于其占用的硬件资源较少、电路简单,在工业智能控制系统中应用较广。本文首先简单介绍了SPI总线通信的原理和特点,随后详细探究了主机和从机之间的双向通信应答和超时重传机制。     

一种通用从机同步串行接口电路的设计

根据I2C总线和SPI总线协议设计并实现了一种兼容I2C和SPI总线协议的从机同步串行接口电路。基于在传感器中的应用,介绍了该接口电路的整体结构和模块划分、时序、Verilog-HDL设计与实现,并给出了整个电路的仿真结果。验证结果表明,该接口电路可以实现与主机之间基于I2C总线和SPI总线的数据发送与接收,可满足物联网中传感器系统的通信需求。     

基于LEON3的SOC平台设计与SPI嵌入

提出了一种基于LEON开源微处理器软核的SOC平台构建方案,并通过对软核的重新配置完成了平台的构建.为扩展平台功能,对其加载嵌入了SPI接口模块;完成了VHDL和Verilog定义的接口之间的互相匹配,通过写wrapper的方法将SPI接口转化为AMBA APB定义的标准类型,成功地实现了两者之间的互连.FPGA验证和GRMON扫描结果表明,此SOC构建方案可行,并且完整实现了其特征要求.     

基于SPI互连的多串口系统

针对个人计算机只有1～2个串口,给同时连接多个串口设备进行联合测量带来的不便,提出了一种由多个单片机基于高速同步串行接口(SPI)才连的串口扩展方法.采用此方法所建的系统只需占用1个现有的串口或USB口,就可连接3个以上的串口设备.该系统由多个STC12C5410AD单片机构成主体,该型号单片机同时具有UART和SPI.系统中的单片机以"单主一多从"结构进行SPI总线互连,主机与从机通过SPI方式交换信息和数据,每个从机的串口可以连接1个外部串口设备并交换数据,同时主机的串口可与上位计算机相连,从而实现上位计算机通过该系统与多个下位串口设备交换数据.系统中,主机和从机都开辟有一定的数据缓存区,并且使主机的数据吞吐率高于从机的总和.此外,还介绍了教据交换协议、存储器的组织、软件结构等.     

基于智能卡标准的循环冗余校验码的研究与实现

分析了国内外智能卡应用中CRC校验方法的异同,深入研究了智能卡标准及CRC生成多项式,并把CRC的两种计算类型融合在一起,结合智能卡标准中CRC校验的特点提出了一种新的CRC计算模块的硬件实现方法．根据此方法完成了一种CRC计算模块的硬件设计,对设计进行了RTL仿真验证,通过了FPGA验证,并实施了投片．该芯片已经通过流片测试,结果表明模块功能和性能达到设计指标,性能良好．     

一种ARM的无线数据传输控制系统设计

串行无线通信传输方案,此方案廉价、开发方便、应用广泛,能解决目前许多无线串行传输价格昂贵、不易实现的问题.该方案成本低、开发方便,可广泛应用于条码扫描、无线抄表等.该文主要设计了系统的上位机和下位机,该方案介绍了一个基于LPC2148和nRF2401的短距离串行无线通信系统,其通过SPI同步串行接口传输,分析了该系统的...     

基于STM32的测井数据导出工具

石油测井中的原始数据往往可以给开采工作提供可靠的理论支持,在实际工作中,由于井下通信速率限制,随钻测井往往只能传输关键测井数据,原始数据导出只能在地面进行,需要一种高速可靠的通信协议,使测井数据导出更加高效,针对以上问题,提出了一种适用于随钻测井技术中的数据传输的改进SPI传输方法。该方法利用STM32F407的SPI通信和中断机制结合,能够提高数据传输效率和抗干扰能力。相比于传统的SPI应答机制,该方法不需要轮询等待SPI通信从机应答,而是通过从机向主机发送一个外部中断信号来告知SPI通信主机一帧数据已完成传输,从而准确控制下一帧数据传输的时机。该方法适用于大部分测井设备的主控芯片,不需要对测井设备做出较大的硬件改动,使用的数据传输线更少。同时,该方法避免了在系统SPI传输过程中数据移位错误发生后不可恢复等问题,降低了数据导出错误的可能性,为原始测井数据导出提供了新的思路。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.