16位高速DSP增强型同步串行口的设计

分析了一种16位高速DSP中增强型同步串口的帧格式及其接口和功能;详细讨论了同步串口的系统级和行为级的设计过程。利用Verilog,设计出同步串口的电路;并通过计算机仿真和实验,证明了设计的正确性。     

网络术语一点通

·波特率是数据的传输速率,单位为bit/s。波特率越大,数据传输速度就越快。·流量控制是指计算机串口进行数据流控制的方法。如果你的电脑使用硬件设备控制数据流,便可以选择“硬件”方式。Xon/Xoff是软件方法的标准,选择这种方式会降低串口数据处理速度。·串口缓冲是指计算机串行端口数据传输的缓存。增大串口缓存可以提高系统处理串行端口数据的速度,但串口缓存设置得过大,则可能影响其它应用程序的性能。·文件缓存(Name Cache) 是指系统文件名缓存的大小。较大的文件缓存可以提高文件系统的性能,进而改善     

USB2.0设备接口芯片从模式设计与实现

为了使USB接口能适应多样化的外围设备,以USB高速设备接口芯片的SoC模型为基础,设计并实现了一种从属结构的数据传输模式,详细分析了从模式传输原理、端点工作机制、固件程序设计、仿真平台设计及仿真结果。以Verilog硬件描述语言设计了仿真平台,包括例化Design Ware库中的USB主机验证IP核作为数据发送接收的主机端,外部数据存储器作为外设数据的中转站,并通过比较主机端的发送和回读数据验证了设计的正确性。结果表明,外部控制器可控制处于从模式的USB设备接口芯片,实现数据在主机与设备之间的交互,此模式下能够有效地提高数据的传输速率,改善数据传输系统的工作效率。     

一种基于状态机的串口通信协议的设计与实现

为解决串口通信中的数据传输容易出错、可靠性差、安全性不高且容错能力低等问题,设计并实现了一种基于状态机的串口通信协议,并将此协议应用到称重仪表的上位机通信中。本文介绍了串口通信协议的数据包格式以及其通信状态机,并给出了协议实现的部分示例代码及算法流程图。在数据包格式定义中通过设置起始标志、数据长度、校验、结束标志等字段,保证数据传输的正确性;并在数据包接收过程中引入状态机方法,简化编程模型的同时,提高了通信过程的可靠性、安全性以及数据传输的容错能力。     

在VC下利用Windows API进行异步串口通信软件的开发

串口是常用的计算机与外部串行设备之间的数据传输通道。为了提高串口通信的速度和资源利用率,软件采用Windows API函数并基于多线程技术和异步串口通信的设计理念,实现了温控器与上位机之间的数据交换,并且将采集到的数据保存到Excel中,便于分析和处理。     

基于Windows API的异步串口通信软件设计

串口是常用的计算机与外部串行设备之间的数据传输通道,在VC＋＋6.0中利用第三方控件实现串口通信时实时性较差,系统资源利用不足,为了提高串口通信的速度和资源利用率,软件采用Windows API函数并基于多线程技术和自定义消息机制的异步串口通信的设计理念,结合串口通信的机理和多线程同步技术,分析了Win32系统下多线程异步串口通信软件的开发方法。软件主线程是数据采集程序的管理者,串口监测线程（辅助线程）在后台对串口进行实时监视,获得了良好稳定的通信效果。     

基于FPGA的UART模块设计与实现

为了方便FPGA和CPU或者其他设备之间的数据传输,实现了一个可编程的通用异步收发器(UART)模块。采用Verilog HDL语言作为硬件功能的描述,硬件采用Alter公司的EP2C5T144C8N芯片,运用模块化设计方法分别设计了UART的发送器、接收器和波特率发生器。用Modelsim进行时序仿真,并用USB-Blaster在QuartusⅡ环境下进行设计、编译,经串口助手进行验证,数据传输快速、准确。     

8051单片机串口通信中的检错方法

为了保证微处理器芯片中串口传输数据内容的正确性,除了串口自带的奇偶校验外,采用信道编码也可以保证串口数据准确无误的传输。文中对应用较多的奇偶校验、CRC-8以及汉明纠错码三种方法进行检错分析,改进了数据传输的效率,同时比较了三种方法之间的性能差异。     

多串口并行通信数据传输系统设计

传统多串口并行通信数据传输系统无法自主获取串口号,需手动选择再打开串口,需要使用者事先了解接口编码,这无形增加了系统的工作时间。为此,设计一种基于FPGA的多串口并行通信数据传输系统,该系统中的串口数据接收模块采集多串口数据,并通过控制寄存器达到控制通信数据波特率的目的。系统利用NiosⅡ处理器使8种信道共同进行传输工作,其将数据传输到并串转换模块。并串转换模块对输出的8位并行数据添加通道标识、并串转换处理,再将处理后的并行数据传递到串口输出选择模块中。依据数据脉冲上升沿设计串口输出选择模块,该模块通过多路分配器将有数据通道的数据串行逐位送出。系统在软件中进行了传输设计、NiosⅡ处理器流程设计以及通信设备类的设计与封装。实验结果表明,所设计系统在FPGA上正确实现了8个串口数据的传输,并且具有较高的数据接收成功率。     

基于LPC2364的串口转网口专用协议卡的研制

给出了采用LPC2364芯片为处理器,并利用以太网中TCP协议来设计串口转网口模块．从而实现数据传输方式转换的一种设计方法。该方法中的软件采用FreerRtos实时多任务嵌入式系统和uIP协议栈来实现串口数据通讯和网口数据通讯两项任务。文中同时给出了系统框图和主程序流程图。     

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.     

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.     

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.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.