基于FPGA的DRR2 SDRAM控制器接口的简化设计方法及实现

DDR2 SDRAM是由DDR SDRAM发展而来的一种新型大容量存储器,正在被越来越多的应用在高速存储系统中。文中介绍了利用MIG软件工具在Xilinx Spartan-3A系列FPGA中实现DDR2 SDRAM控制器的设计方法,详细叙述了其基本原理,并给出了硬件测试结果。     

基于Spartan-3A的DDR2接口数据采集

在高速、大容量存储的系统设计中,DDR2 SDRAM为设计者提供了高性价比解决方案。在FPGA中实现DDR2 SDRAM控制器,降低了系统功耗并节省空间,缩短开发周期,降低系统开发成本。详细介绍了在Xilinx Spartan-3A系列FPGA中实现DDR2控制器的设计原理．介绍利用MIG软件工具实现控制器设计,并给出硬件测试结果。     

基于Kintex-7 FPGA的DDR3 SDRAM接口应用研究

针对FPGA中使用DDR3进行大容量数据的缓存应用背景,采用模块化设计方法,提出基于Xilinx Kintex-7 FPGA的DDR3 SDRAM FIFO接口设计方案。在分析DDR3用户接口特点和用户接口时序的基础上,对不同读/写模式进行效率测试。借鉴标准FIFO的设计思想,结合DDR3 SDRAM控制器的特点,设计遍历状态机对该FIFO接口进行读/写测试。最后,原型机平台验证了该接口不仅具有标准FIFO简单易用的功能,而且具有存储空间大等优势。     

DDR SDRAM控制器的设计与实现

在分析DDR SDRAM基本特征的基础上,按照JEDEC DDR SDRAM规范提出了一个详细的DDR SDRAM控制器的设计方案.该方案采用Verilog HDL硬件描述语言实现,集成到高速SoC芯片中,然后使用Synopsys VCS对该控制器进行仿真,并在Stratix-Ⅱ开发板进行了FPGA验证.在阐述该控制器设计原理的基础上,进行模块划分和具体设计,提出了高效、稳定的处理方案,最后通过仿真和FPGA验证确保了设计的正确性.     

基于FPGA的DDR2 SDRAM接口信号完整性设计与验证

对高速DDR2 SDRAM接口信号进行完整性仿真分析,并根据仿真结果得到相应PCB设计规则,最终通过使用FPGA实现了对大容量DDR2 SDRAM的读写控制,板卡验证测试,达到了预期的效果。     

基于FPGA的DDR3 SDRAM控制器设计及实现

DDR3 SDRAM是第三代双倍数据传输速率同步动态随机存储器,以其大容量、高速率和良好的兼容性得到了广泛应用。文中介绍了DDR3的特点和操作原理,以及利用MIG软件工具在Virtex-6系列FPGA中实现DDR3 SDRAM控制器的设计方法,并进行硬件测试。验证了DDS3控制器的可行性,其工作稳定、占用资源少、可植性强等。     

一种基于FPGA的DDR SDRAM控制器的设计

对DDR SDRAM的基本工作特性以及时序进行了分析与研究,基于FPGA提出了一种通用的DDR SDRAM控制器设计方案。在Modelsim上通过了软件功能仿真,并在FPGA芯片上完成了硬件验证。结果表明,该控制器能够较好地完成DDR SDRAM的读写控制,具有读写效率较高、接口电路简单的特点。     

基于FPGA的DDR SDRAM控制器在高速数据采集系统中的应用

实现数据的高速大容量存储是数据采集系统中的一项关键技术。本设计采用Altera公司Cyclone系列的FPGA完成了对DDR SDRAM的控制，以状态机来描述对DDR SDRAM的各种时序操作，设计了DDR SDRAM的数据与命令接口。用控制核来简化对DDR SDRAM的操作，并采用自顶至下模块化的设计方法，将控制核嵌入到整个数据采集系统的控制模块中，完成了数据的高速采集、存储及上传。使用开发软件QuartusⅡ中内嵌的逻辑分析仪Signal TapⅡ对控制器的工作流程进行了验证和调试。最终采集到的数据波形表明，完成了对DDR SDRAM的突发读写操作，达到了预期设计的目标。     

DDR SDRAM控制器IP及其嵌入式应用

本文在介绍DDR SDRAM的工作原理基础上,提出了一种DDR SDRAM控制器的实现方法;DDRSDRAM的数据选通特性也在本文中给予了详细的讨论。本文提出的DDR SDRAM控制器实现方法通过了FPGA功能验证,并在LCD TV控制芯片中得到了成功地嵌入式应用。     

DDR2 SDRAM控制器IP功能测试与FPGA验证

完成挂载在AHB上对DDR2 SDRAM进行操作的DDR2控制器IP模块的设计,并通过了相关的读写测试。利用Altera的Qsys平台,将得到的DDR2控制器IP挂载到NiosII上,搭建SoPC系统,完成软硬件协同验证。验证结果表明,该IP在StratixIV的FPGA核心芯片上共占用287个逻辑单元,DDR2的工作频率可达200 MHz。同时,开发出了一套将AHB总线接口的IP挂载到NiosII Avalon总线上进行FPGA验证的通用方法。     

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.