在计算机控制应用中直接开发单片机的一种方法

针对没有单片机开发系统或EPROM写入器无法对单片机进行开发的问题,设计了利用PC机对单片机进行直接简便开发的方法。详细介绍了80C31单片机为对象,利用PC机直接开发单片机的原理及步骤。通过PC机与单片机最小系统的异步通信,实现EPROM写入器功能。反向由单片机向PC机发送数据,使得PC机的监视器和存储器成为单片机的监视器和存储器。该方法节省了单片机开发系统和EPROM写入器等“必需品”,具有简单新颖,可灵活配置等特点,有较高的实用价值。     

Design,modelling, and simulation of a floating gate transistor with a novel security feature

This study proposes a new generation of floating gate transistors (FGT) with a novel built-in security feature. The new device has applications in guarding the IC chips against the current reverse engineering techniques, including scanning capacitance microscopy (SCM). The SCM measures the change in the C–V characteristic of the device as a result of placing a minute amount of charge on the floating gate, even in nano-meter scales. The proposed design only adds a simple processing step to the conventional FGT by adding an oppositely doped implanted layer to the substrate. This new structure was first analyzed theoretically and then a two-dimensional model was extracted to represent its C–V characteristic. Furthermore, this model was verified with a simulation. In addition, the C–V characteristics relevant to the SCM measurement of both conventional and the new designed FGT were compared to discuss the effectiveness of the added layer in masking the state of the transistor. The effect of change in doping concentration of the implanted layer on the C–V characteristics was also investigated. Finally, the feasibility of the proposed design was examined by comparing its I–V characteristics with the traditional FGT.     

基于RFID的供应链的信息与成本结构

针对供应链的信息共享和可视化管理,本文分析了如何更有效地将RFID技术应用在供应链管理中。本文介绍了RFID系统的组成,回顾了供应链管理的主要研究方向,建立了基于RFID技术的供应链管理信息模型,展望了应用RFID技术的供应链管理建模和商业应用的新方向,提出了基于RFID技术的供应链管理中所面对的以成本为中心的若干挑战。     

Another dimension in device characterization

Recent years have witnessed rapid progress in the area of high-resolution characterization of silicon devices by scanning capacitance microscopy (SCM). It is timely to discuss the applications of this technique in a broader context by addressing other types of devices and materials. This article represents a step towards this objective and will review our SCM work focusing on advanced InP-based laser structures. The basic principles involved in the SCM methodology are introduced, including resolution. The specific topics that will be covered include SCM analysis of regrowth on patterned substrates, different types of InP-based buried heterostructure (BH) lasers, and complex-coupled distributed feedback (CCCDFB) lasers. The behavior of the SCM signal in the different material and device-specific contexts is discussed, and device processing issues are highlighted. We also comment on the necessary factors for bringing the SCM technique to a level that can directly contribute to advanced III-V device technology     

Accurate modeling of the effects of fringing area interface traps on scanning capacitance microscopy measurement

Scanning capacitance microscopy (SCM) is a dopant profile extraction tool with nanometer spatial resolution. While it is based on the high-frequency MOS capacitor theory, there are crucial second-order effects which make the extraction of dopant profile from SCM data a challenging task. Due to the small size of the SCM probe, the trapped charges in the interface traps at the oxide-silicon dioxide interface surrounding the probe significantly affect the measured SCM data through the fringing electric field created by the trapped charges. In this paper, we present numerical simulation results to investigate the nature of SCM dC/dV data in the presence of interface traps. The simulation takes into consideration the traps' response to the ac signal used to measure dC/dV as well as the fringing field of the trapped charge surrounding the probe tip. In this paper, we present an error estimation of experimental SCM dopant concentration extraction when the interface traps and fringing field are ignored. The trap distribution in a typical SCM sample is also investigated.     

Subcarrier multiplexed lightwave systems for broad-banddistribution

Microwave subcarrier multiplexing (SCM) is an important approach to the design of lightwave systems for broadband distribution. Recent progress in the design and performance of both analog and digital multichannel SCM systems is reviewed. The application of broadband SCM systems to both passive and optically amplified distribution networks is discussed. The discussion covers the general features of SCM systems; the electrooptic components that have been used in the system experiments described here, including laser intensity noise and noise due to intermodulation products; the carrier-to-noise ratio requirements; some multichannel FM systems experiments; and a 20-channel digital systems experiment; and a hybrid system carrying 60 FM SCM channels plus a 100-Mb/s baseband digital channel. Several approaches to broadband subscriber distribution networks are analyzed     

单片机软件模拟SPI接口的解决方案

SPI接口是一种同步串行通讯接口，具备SPI接口的外围芯片十分丰富，应用非常广泛。但是，具备SPI接口的单片机种类较少。介绍了一种基于单片机的模拟SPI接口的方法，使没有SPI接口的单片机扩展带有SPI接口的外围芯片成为现实。     

基于单片机的智能稳压电源

一种以单片机系统为核心的智能稳压电源，把开关电源的高效率特性与单片机系统自动检测和控制技术相结合，采用先进的传感器进行数据采样，运用适当的算法进行电压调整和电路保护。介绍了整体电路的设计和单片机系统的硬件及软件流程。     

AM－SCM光波技术的发展和展望

本文介绍了副载波复用光通信技术的基本原理，2种调制方式的性能比较，AM—SCM技术在CATV网上的应用和发展。     

Quantitative scanning capacitance microscopy analysis of two-dimensional dopant concentrations at nanoscale dimensions

We have applied the scanning capacitance microscopy (SCM) technique of twodimensional (2-D) semiconductor dopant profiling to implanted silicon cross sections. This has permitted the first direct comparison of SCM profiling scans to secondary ion mass spectroscopy (SIMS) depth profiles. The results compare favorably in depth and several readily identifiable features of the SIMS profiles such as peak concentration and junction depth are apparent in the SCM scans at corresponding depths. The application of dopant profiling to two dimensions is possible by calibrating the SCM levels with the one-dimensional (1-D) SIMS data. Furthermore, we have subsequently simulated the SCM results with an analytic expression readily derivable from 1-D capacitance vs voltage capacitance-voltage theory. This result represents a significant breakthrough in the quantitative measurement of 2-D doping profiles.     

单片机应用系统抗干扰问题的解决方案

单片机在应用过程中，干扰是必不可免的，因此，单片机抗干扰问题的解决、是单片机应用中的重要环节。在单片机应用系统设计中，通过硬件和软件设计都可以解决干扰问题，但软件解决方案，更经济、更有效，它可以提高应用系统的工作准确性、工作稳定性。即利用软件设计技术，全面提高应用系统的抗干扰能力。     

Synthesized Compact Models and Experimental Verifications for Substrate Noise Coupling in Mixed-Signal ICs

A synthesized compact modeling (SCM) approach for substrate coupling analysis is presented. The SCM is formulated using a scalable$Z$matrix approach for heavily doped substrates with a lightly doped epitaxial layer and using a nodal lumped resistance approach for lightly doped substrates. The SCM models require a set of process-dependent fitting coefficients and incorporate geometrical parameters of the substrate ports in a compact form that includes size, perimeter, and separation defined using the geometric mean distance to accommodate both far-field and near-field effects. The SCM approach is verified based on measurement data from two test chips, one in a custom lightly doped process and the other one using a 0.18-$muhbox m$BiCMOS lightly doped foundry process. The model accuracy is shown to be within 15% compared to measured data extracted from the test patterns. The SCM is exploited with application examples to show substrate model generation efficiency and accuracy at different levels of complexity, including a full chip substrate noise distribution analysis for a 2 mm by 2 mm chip with 319 substrate contacts.     

计算机控制智能小车的软件设计

本设计是采用单片机作为从机(也称下位机),而PC机作为中央控制机的主从式系统。主机同时根据从从机接收的过程参数进行判断处理并给从机发送各种控制命令。利用单片机的串行口与PC机的串行口进行串行通信,PC机可对远程前端单片机进行控制,将单片机采集的数据传送到PC中去,由PC机对数据进行处理和显示,同时把反馈信号发到单片机,实现闭环控制和管理。本设计在VC++6.0的环境下,编写使用C++语言,SQL数据库的串口通信程序,控制由单片机控制的智能小车。     

软件配置管理与UCM策略在移动终端项目中的实现

软件配置管理(SCM,Software Configuration Management)是一项基本的软件工程任务,用于管理当今复杂和快速发展的软件开发环境。本文介绍了SCM的最佳经验,并以SCM工具Rational CIearCase作为工具．展示了ClearCase在移动终端项目中如何通过统一变更管理(UCM,Unified Change Management)策略实现SCM的最佳经验。本文清晰地展示了如何通过Clear Case UCM简化和控制软件开发项目中的变更。     

Evaluation of scanning capacitance microscopy sample preparation by focused ion beam

Due to the continuous reduction of the critical dimensions of semiconductor devices, it becomes very important to know the two dimensional (2D) doping profile for electrical performance of devices. Scanning Capacitance Microscopy (SCM) is a powerful technique for qualitative analysis of 2D doping species distribution, measuring small capacitance variations with high spatial resolution. For 2D carrier profiling, the region of interest must be accessible to the profiling instrument. SCM samples require cross-sectioning to expose the inner sample at a visible surface. In some analysis, the failure is localized at a very accurate address up to hundreds of nanometers. With the traditional polishing method of sample preparation it is very difficult to reach the exact location. For this reason we are investigating a new way to prepare SCM sample with Focused Ion Beam (FIB) and plasma etch in order to accurately choose the scanning zone. This paper presents a method to obtain SCM scans after a sample preparation by FIB and the influence of the FIB and the Plasma etcher on cross-sectioned SCM samples.     

基于双单片机的数据通信模块的设计

介绍一种基于双单片机技术的数据通信模块,他主要由2个AT89C2051单片机,调制解调芯片和RS 485总线接口芯片构成.该模块通过普通铁路电话线实现了车站信号的接力式传输,通过软件模拟SPI总线实现了两单片机之间的数据通信.该设计方法不仅简化了系统结构,分散了单片机的工作任务,而且增强了系统的实时性和可靠性,提高了通信效率.     

Proteus虚拟仿真在单片机实验教学中的应用研究

为了解决单片机实验教学中实验类型单一、实验设备更新快和成本高等问题,在单片机实验教学中引入Proteus软件仿真,获得了很好的教学效果,同时将该仿真软件用在学生的电子设计竞赛和课程设计中,提高了学生的动手能力。以数字电压表实验为例,介绍了如何利用Proteus软件进行单片机实验教学的方法。实践证明：该方法可提高单片机实验教学的效果,加深学生对单片机原理及应用的理解,激发学生学习的兴趣,锻炼学生进行软硬件开发的能力。     

Degree-of-polarization-based PMD monitoring for subcarrier-multiplexed signals via equalized carrier/sideband filtering

We demonstrate a method for differential-group-delay (DGD) and polarization-mode-dispersion (PMD) monitoring using the degree-of-polarization (DOP) in subcarrier-multiplexed (SCM) systems. Traditional SCM signal show very little DOP sensitivity to DGD/PMD due to the low modulation depth used for generating SCM signals. We use a narrow-band optical filter to equalize the power of the carrier and one of the sidebands by offsetting the filter from the carrier, enabling PMD and DGD monitoring and more than tripling the DOP sensitivity to DGD/PMD. Our technique is simple, uses only a single optical filter, and can be applied to both single- and double-sideband (SSB and DSB) SCM signals as well as single and multisubcarrier systems. Additionally, we show that our monitoring technique is robust to the chromatic dispersion-induced radio-frequency (RF) power fading effect seen in DSB SCM signals. Using this technique to enhance the DOP sensitivity to DGD/PMD and generate a feedback signal to a PMD compensator (PMDC), we obtain an 11-dB improvement in the 5% RF power tail.     

脊髓纵裂畸形的外科治疗

目的探讨脊髓纵裂的外科治疗。方法回顾性分析2005年1月-2009年1月收治的21例脊髓纵裂患者。男性9例,女性12例。依照脊髓纵裂Pang分型,Ⅰ型12例,Ⅱ型9例。纵裂位于胸段6例,胸腰段6例,腰段7例,腰骶段2例。21例中12例I型SCM患者行骨嵴切除、硬膜囊成型和终丝切断;5例II型SCM患者行纵裂纤维束松解1例,终丝切断术4例。结果17例手术患者15例获3～48个月(平均15个月)随访,术前症状得到明显改善5例,部分改善6例,无变化4例,加重0例。结论I型SCM患者应早期手术治疗,即使无症状也建议手术;II型SCM患者手术适用于有进展性神经功能障碍者,手术方式应针对造成脊髓栓系的原因行纤维束松解或终丝切断术。     

单片机微控制器中断处理算法改进

以LPC2132微控制器电源控制电路为例,分析了使用该微控制器进行中断处理算法遇到的中断嵌套及伪中断等问题,并根据LPC2132微控制器中断性能的特点,提出了具有针对性的有效简易改进算法,为微控制器中断处理算法设计提供了参考。