嵌入式RTC的设计与实现

实时时钟RTC(Real Time Clock)基本功能是提供时、分、秒等时间信息,并可提供闹铃功能.采用自项向下的正向高层次设计方法对RTC电路设计与实现进行了研究,对RTC电路的功能,原理及应用进行了介绍,并给出了比较详细的设计方案.该设计符合I2C总线接口规范.     

RTC平台中接入网关的设计与实现

设计并实现了RTC(Real-time communications)平台中接入网关模块。简要介绍了RTC平台的系统结构以及各个模块在平台中所处的位置及作用。接入网关提供给客户端统一的服务接口,用户终端无需关心后端具体的网络结构,服务实例,只需访问统一的服务接口即可获取服务。同时,具备大规模Web请求的接纳与分发能力,保证了系统的性能及设备的无缝扩容。在设计与实现上,主要考虑统一接口的设计并保证接入网关的高可靠性、高可用性和高效性。     

嵌入式处理器S3C2440 Windows CE的RTC模块驱动设计与实现

简要介绍了S3C2440嵌入式微处理器,分析了S3C2440的RTC(Real-time clock)硬件构架及其工作原理,在此基础上给出了RTC模块在WinCE下驱动程序的设计与实现.最后给出了部分驱动源代码.     

一种基于累积误差控制的RTC补偿算法及电路

介绍了晶体振荡器的温漂特性,提出了基于累积误差控制的RTC温度补偿算法,累积频率误差控制在15.3 ppm以内。设计了应用于微控制器中的RTC补偿电路,开发了自动调教电路,能很好地满足智能电表高精度、低功耗的计时要求。     

内置RTC作为电能表计时钟的应用

为降低电能表的成本,提高时钟的精确度,设计了一个基于ST微控制器的RTC时钟控制器.该时钟控制器采用内置RTC的原理,通过温度补偿晶体的频偏和校准秒脉冲的输出等方式得到精准的时钟.试验数据表明,通过温度补偿晶体的频偏和秒脉冲输出校准方法相结合,使RTC时钟在(-40℃,85℃)温度范围内的误差小于0.5 s/d.该RTC时钟控制器目前已应用于国网二代三相多功能电能表.     

可缩放应用程序

本文探讨了RTC客户端API中可用于提高RTC客户端应用程序的可缩放性的技术.介绍可以使用RTC客户端API来构建的应用程序类型,讨论了构建可缩放的RTC客户端应用程序时需要考虑的因素,并阐述了可以与RTC客户端API配套使用以提高可缩放性的技术.最后,按照其实现可缩放性的方式详细说明了三个示例应用程序.     

FatFS的水动力实验数据存储系统设计

针对在水动力实验研究中数据量集中、数量多的问题,提出了一种基于FatFS文件系统的SD卡存储系统设计方案。该系统以ST公司的STM32F103ZET6为核心,通过SDIO接口实现大量数据文件存储。详细讲解了系统的USB模块、RTC模块等硬件设计,探讨了在系统上移植FatFS文件系统的要点,并在SD卡上实现了FAT文件的读写功能。该系统传输速度快、可靠性强,具有一定的应用价值。     

软硬件双重保障的RTC电池电量监测技术研究

设计了一种基于软硬件双重保障的RTC电池电量监测电路，在硬件上设定低压检测阈值，利用比较器将电池电压与阈值电压进行比较，从而判断电量状态，在软件上监测和记录RTC电池工作时间，与评估的电池理论工作时间进行对比后判断电量状态。软硬件上只要其中一种方式达到低电量判断标准，即认为RTC电池电量低，需要更换电池。实验结果表明，该软硬件双重保障的RTC电池电量监测电路可有效监测电池状态，避免电池出现馈电。     

基于at91sam 9g 25的Linux下RTC设备驱动的设计与实现

I2C总线以其简单高效的方式被广泛的运用在嵌入式产品设计中,而实时时钟RTC则是其中应用的典型代表。在嵌入式Linux系统中,对其I2C驱动程序提供了较好的支持框架。但随着Linux内核版本的不断升级,对于I2C设备驱动的结构设计也趋于复杂,往往让开发者有些不知所措。本文以2.6.39版本Linux内核为背景,在分析该Linux版本I2C总线设备结构和RTC设备资源的基础上,结合RTC设备驱动模型和I2C/SMBus传输方式,对RTC设备在at91sam9g25上进行了具体的设备驱动设计实现,并通过在电力用户集中器设备中的应用,证明了驱动设计的可行性。     

面向控制器的实时组件技术研究

针对组件技术在控制系统设计中存在的建模问题、行为问题与定时问题 ,在系统的分析现有具有确定性行为组件技术的基础上 ,提出了实组件的概念 ,给出了一种面向控制器的实时组件模型 RTC,并对 RTC的结构、行为、通信、时态特性等方面进行了形式化的描述 .最后 ,以数控系统中运动控制的设计为例 ,验证了方法的有效性     

一种无线传感器网络中汇聚节点的本地时钟和传感器节点的RTC时钟同步校准的方法

为了降低传感器节点的功耗,应尽可能地让传感器节点在没有业务需求时进入休眠状态。由于传感器节点进入休眠状态后只有RTC时钟模块在运行,且RTC模块内部晶体振荡器受温度等因素的影响较大,造成RTC时钟精度不高进而可能会导致传感器节点不能准确地在预设的时间被自动唤醒,无法完成与汇聚节点的通信业务。为此,提出一种新的无线传感器网络中汇聚节点的本地时钟和传感器节点的RTC时钟同步校准方法,该方法摒弃了以往直接对传感器节点内部RTC模块的晶体振荡器进行温度参数补偿的做法,并由传感器节点根据汇聚节点的本地时钟来调整自己的RTC时钟,以便传感器节点和汇聚节点的时钟动态地保持一致。     

Performance evaluation of real time control in urban wastewater systems in practice: Review and perspective

Real time control (RTC) is generally viewed as a viable method for optimising the performance of urban wastewater systems. A literature review on the performance evaluation of RTC demonstrated a lack of consensus on how to do this. Two main deficiencies were identified: omitting uncertainty analysis and applying limited evaluation periods. A general methodology to evaluate the performance of RTC in practice, that takes into account these deficiencies, is proposed. The methodology is either data or model driven and the (dis)advantages of each are discussed. In a case study for a combined sewer system with limited discharge to a WWTP, it is demonstrated that the successful application of RTC and the possibility to determine a significant effect is very much dependent on the goal. It also clearly illustrates the need for taking uncertainties into account and that careful consideration in the chosen evaluation period is required.     

基于LPC2131的实时时钟控制设计

实时时钟在工业系统中具有良好的应用前景.本系统以微控制器LPC2131为核心控制器,控制内部实时时钟,实现对秒、分、小时等各个时间寄存器的准确操作,通过串口将采集到的数据发送到上位机.本文详细给出硬件设计总体框图、设计原理和软件实现的方法,得出了实验结果.这种实时时钟的控制方法,很容易应用到现代工业以及各种智能化应用系...     

基于RSSI均值的无线传感器网络拓扑控制算法

针对采用接收信号强度指示(RSSI)值构建拓扑存在误差的不足,提出一种分布式拓扑控制算法RTC。该算法基于RSSI均值计算节点间双向路径损耗,从而判断两节点间是否存在每跳通信链路代价都小于直接通信链路代价的两跳路径,以构建局部优化拓扑。理论分析了算法的通信复杂度和网络连通性,仿真分析了其节能特性,结果表明RTC在降低网络能量消耗的同时延长了网络生命周期。     

Lightweight runtime checking of C programs with RTC

The C Programming Language is known for being an efficient language that can be compiled on almost any architecture and operating system. However the absence of dynamic safety checks and a relatively weak type system allows programmer oversights that are hard to spot. In this paper, we present RTC, a runtime monitoring tool that instruments unsafe code and monitors the program execution. RTC is built on top of the ROSE compiler infrastructure. RTC finds memory bugs and arithmetic overflows and underflows, and run-time type violations. Most of the instrumentations are directly added to the source file and only require a minimal runtime system. As a result, the instrumented code remains portable. In tests against known error detection benchmarks, RTC found 98% of all memory related bugs and had zero false positives. In performance tests conducted with well known algorithms, such as binary search and MD5, we determined that our tool has an average run-time overhead rate of 9.7× and memory overhead rate of 3.5×.     

Fast over‐land atmospheric correction of visible and near‐infrared satellite images

A rapid atmospheric correction method is proposed to be used for visible and near‐infrared satellite sensor images over land. The method is based on a simplified use of a radiative transfer code (RTC), which is used only a priori, to generate Look‐Up‐Tables (LUTs) of the estimated surface reflectance. A typical scenario and ranges of values for the main atmospheric correction parameters are initially established. Each image pixel is treated as a slight deviation from the reference scenario defined by the vector of the typical values for the parameters. The assumption of the parameter's independence allows the use of one‐dimensional LUTs. The method is suitable for near real‐time processing or whenever a large number of data are to be handled rapidly. The operator intervention is minimal, and the computation time involved in the correction of a whole image is about 1000 times shorter than the full use of the base RTC. A test is performed with advanced very‐high‐resolution radiometer (AVHRR) visible and near‐infrared data, using the Second Simulation of the Satellite Signal in the Solar Spectrum (6S) RTC as the base code. The accuracy of the proposed method was compared with the standard use of the 6S RTC over the same dataset with resulting root mean square errors of 0.0114 and 0.0104 for AVHRR bands 1 and 2 for the estimated surface reflectance, respectively.