Power Saving Technology Based on Overtimer Moment of Timers

针对通信系统中各定时器和网络端时钟频繁产生中断使系统过早进入工作状态的问题,结合移动终端的特点,提出一种基于定时器超时时刻调整的低功耗技术,并且从理论和实践上进行验证,该技术能够使设备尽可能地处于睡眠状态,有效地降低了系统功耗,对推动移动通信产业的发展具有重大意义.     

基于AT91R40008微处理器的软件定时器设计

软件定时器是嵌入式系统中使用较多的定时器。文中介绍了一种单链表的软件定时器的组织管理方法，避免了其余算法中的冗余和排序等操作，从而使软件定时器更有效率。     

vxWorks通用定时器设计与实现

在进行网络通信设备开发时,需要使用通用定时器。本文在研究vxWoks系统看门狗函数的基础上,提出了基于看门狗函数的定制定时器的设计方法,可以使定制定时器的最小周期满足网络通信设备开发的需要。本文给出了定制定时器实现的思想。     

实时嵌入式系统中高效定时器算法的实现

文章提出了一种实时嵌入式系统中高效定时器算法的实现手段：通过采用单循环队列定时器算法解决了在多队列计时算法中存在的冗余操作和排序操作的缺点。使定时器计时方法更有效率，更具有伸缩性，能适应不同规模的嵌入式系统。     

产品撷英

单节大电流锂离子/锂聚合物电池充电控制器集成了传输晶体管,具有电流检测和反向放电保护功能MCP73833/4可提供高达1A的充电电流,支持多档稳压输出(4.2V、4.35V、4.4V和4.5V),具备了充电时间控制、电池温度反馈和热电流调节等多种安全功能。MCP73833具有电源正常输出指示功能,而MCP73834具有定时器使能输入功能。当电流为系统供电,同时进行电池充电时,通过定时器使能输入可禁用定时器。这两种器件都采用低压差稳压器(LDO)测试模式,以保证应用系统即使在没有电池的情况下也可以进行测试。它们还有两种状态输出,可为用户提供关于电池充…     

工业控制机失控后从断点恢复运行的一种方法

工业控制机在工业现场使用时,大量的干扰源虽不会造成硬件系统的损坏,但常常使工业控制机不能正常运行,甚至控制失灵,造成严重后果。微机受干扰后,最常见的问题是程序执行进入一种“跑飞”或“死机”状态,引起程序失控。防止程序运行失控的主要对策是能及时发现程序运行的失控并引导系统正常运行。目前常用的方法是设置一个监视跟踪定时器,定时时间稍大于主控程序正常运行的一个循环周期,让主控程序运行过程中执行一次定时器的刷新操作。这样只要程序正常运行,定时器就不会产生溢出信号而发生中断。但当程序“跑飞”失控后,不能刷新定时器,导致定时器溢出产生中断,再利用定时中断服务程序将系统复位,重新初始化,重新执行主控程序或进入错误处理程序。这种方法在微机监测系统中,效果是明显的,但在某些工业控制系统中,特别在一些生产过程或流水线中,由于生产过程或工序的逻辑顺序性,当程序失控后,常要求系统     

德州仪器推出两款可编程系统定时器

德州仪器（TI）日前宣布推出两款能显著降低系统待机功耗的可编程系统定时器。支持看门狗定时器的TPL5000以及具有MOS驱动器的TPL5100，流耗仅30nA，与同类竞争解决方案相比，降低了90％。此外，它们还可替代微控制器（MCU）的内部定时器，使MCU始终保持在低功耗睡眠模式下。     

基于Local APIC的Windows 2000实时化改造

提出了一种用于提高Windows 2000的实时性改造方案,该方案首先通过设置Local APIC上的硬件定时器的中断向量来提升硬件定时器的中断优先级（IRQL）,从而使其高于系统时钟优先级,并使该定时器中断的中断服务程序运行动态加载的实时任务。由于中断服务程序运行实时任务是动态加载,无需重启操作系统。因此,该改造方案实现比较简便,适用于实时计算环境。     

红外传感信号处理器—BISS0001

<正> BISS0001为红外传感信号处理器集成电路,内含有运算放大器、电压比较器、状态控制器、延时定时器、封锁定时器及参考电压源等。它可与热释电红外传感器或其它各种传感器连接,只需极少外围元件就可构成自动延时控制或报警系统。     

一种适用于恒定导通时间控制的高性能定时器电路

本文提出一种适用于恒定导通时间控制的开启时间定时器电路。电路中采用与输入电源电压成正比的电流对电容充电,从而实现定时器的定时时间与输入电源电压成反比,解决了传统恒定导通时间控制中系统工作频率随输入电源电压变化的问题。为了获得高的定时精度,开启时间定时器中的比较器采用了自适应偏置技术,根据输入电源电压的情况动态地设置定时器中比较器的偏置电流。基于0.6μmCD工艺,对所设计开启时间定时器电路进行仿真验证。结果表明,本文所设计的开启时间定时器电路,能够始终保证高的定时精度。同时由于定时时间与输入电源电压成反比,在系统中引入了前馈,极大地提高了系统的线性响应速度。     

Trading CDPD availability and voice blocking probability incellular networks

Cellular digital packet data (CDPD) offers mobile users access to a low-cost, ubiquitous, wireless data network. CDPD can be overlaid on existing AMPS analog cellular systems and share their infrastructure equipment on a noninterfering basis. Since CDPD utilizes the idle radio resources of AMPS, it is important to ensure that the normal AMPS activities are not affected by CDPD. Several timers and system parameters are defined in CDPD for this purpose. This article investigates how these timers and parameters affect the performance of AMPS/CDPD systems. Our study provides guidelines for the selection of input parameters to aid CDPD network planning. Specifically, we study the trade-off between CDPD availability and voice blocking probability. CDPD availability is defined as the proportion of time that the RF channels can be used to transmit CDPD data. We observe that selecting too large values for CDPD dwell time and the maximum number of CDPD channel streams will degrade the voice blocking probability without improving CDPD availability. On the other hand, selecting a too large value for the CDPD layoff time will degrade CDPD availability without improving voice blocking probability     

Performance of CDPD with Timed Hop and Forced Hop

Cellular Digital Packet Data (CDPD) offers mobile users access to a low-cost, ubiquitous, wireless data network. CDPD can be overlaid on existing AMPS analog cellular systems and share their infrastructure equipment on a non-interfering basis. To prevent interference with the voice activities, CDPD performs forced hop to a channel stream when a voice request is about to use the RF channel occupied by that channel stream. In addition, several timers and system parameters are defined in CDPD to ensure that the normal AMPS activities are not affected by CDPD. This article investigates how the channel selection algorithms, the timers and other parameters affect the performance of AMPS/CDPD systems. Specifically, we study the trade-off between mean CDPD channel holding time and voice incompletion probability. Our study indicates that if AMPS exercises the most-idle channel selection algorithm and CDPD exercises the least-idle channel selection algorithm, then the largest mean CDPD channel holding time is expected. On the other hand, if AMPS exercises the least-idle channel selection algorithm, then the smallest voice incompletion probability is expected.     

带延时功能的微波自动报警系统的设计

设计了一个由微波发射器、555定时器、电压比较器和继电器组成的具有延时功能的自动报警器。该报警器由微波探头检测活动物体,将波动的电磁场信号转化为波动的电压信号后输出给电压比较器,电压比较器比较后的高电平触发555定时器工作,经过延时后的信号触发继电器报警。该报警系统克服了一般报警器容易出现的漏报警现象和其他微波报警器容易受外界电磁场的干扰所引起的误报警的缺点,很好地解决了报警系统的灵敏性与可靠性之间的矛盾。     

一种基于消息方向的移动台状态转移方案

论文基于即时消息业务中上下行消息流之间的相关特性,提出了一种根据先前所处理消息的方向为移动终端状态定时器分配不同阈值的机制,并研究了其对下行包队列长度、下行消息时延和功耗节省等性能的影响。仿真结果表明,与传统单值状态定时器方案相比,该机制在保证相似服务质量的基础上显著降低了移动终端的功耗。     

USB外设计时控制器的设计

描述了-套基于单片机,能实现对电脑USB外围设备进行计时控制,同时兼具实时时钟显示功能的电路系统设计.很好地解决了长期困扰电脑使用者不能计时控制USB外设的难题.根据89S52单片机所具有的三路独立定时器资源,本设计对USB定时控制功能和计时功能进行了合理规划,相对于其它同类的设计仅束缚于两路定时器甚至一路有了很大的提高.本论文从设计方案、软硬件设计实现等多方面对设计进行了详细的阐述.实验结果证实本设计能满足各项设计功能并达到很好的效果.     

An Efficient Time-Based Checkpointing Protocol for Mobile Computing Systems over Mobile IP

Time-based coordinated checkpointing protocols are well suited for mobile computing systems because no explicit coordination message is needed while the advantages of coordinated checkpointing are kept. However, without coordination, every process has to take a checkpoint during a checkpointing process. In this paper, an efficient time-based coordinated checkpointing protocol for mobile computing systems over Mobile IP is proposed. The protocol reduces the number of checkpoints per checkpointing process to nearly minimum, so that fewer checkpoints need to be transmitted through the costly wireless link. Our protocol also performs very well in the aspects of minimizing the number and size of messages transmitted in the wireless network. In addition, the protocol is nonblocking because inconsistencies can be avoided by the piggybacked information in every message. Therefore, the protocol brings very little overhead to a mobile host with limited resource. Additionally, by taking advantage of reliable timers in mobile support stations, the time-based checkpointing protocol can adapt to wide area networks.     

LOGO!和STEP7定时器功能的比较与分析

LOGO!和STEP7的定时器都具有接通延时、断开延时、保持接通延时、边缘触发延时和脉冲输出功能,LOGO!还有通/断延时定时器、对称时钟脉冲、异步脉冲和随机发生器功能。LOGO!应用于小型的自动化作业,对现场设备和过程集中控制,其功能专一,种类齐全,易于操作。STEP7有五种定时器,功能强大,不仅具有延时功能,还能实现或监控时间顺序,可提供等待时间、监控时间、测量时间,完成基于时间的计数功能,产生一定宽度的脉冲,可检验定时器的信号状态并组合布尔逻辑操作结果,适用于复杂的自动化控制系统。     

Priority-determined multiclass handoff scheme with guaranteed mobile QoS in wireless multimedia networks

The provision of multiclass services is gaining wide acceptance and will be more ubiquitous in future wireless and mobile systems. The crucial issue is to provide the guaranteed mobile quality of service (QoS) for arriving multiclass calls. In multimedia cellular networks, we should not only minimize the dropping rate of handoff calls, but also control the blocking rate of new calls at an acceptable level. This paper proposes a novel multiclass call-admission-control mechanism that is based on a dynamic reservation pool for handoff requests. In this paper, we propose the concept of servicing multiclass connections based on priority determination through the combined analysis of mobile movement information and the desired QoS requirements of multimedia traffic. A practical framework is provided to determine the occurrence time of handoff-request reservations. In our simulation experiments, three kinds of timers are introduced for controlling the progress of discrete events. Our simulation results show that the individual QoS criteria of multiclass traffic such as the handoff call-dropping probability can be achieved within a targeted objective and the new-call-blocking probability is constrained to be below a given level. The proposed scheme is applicable to channel allocation of multiclass calls over high-speed wireless multimedia networks.     

通信软件中定时器库的设计与实现

阐述了在通信软件中定时器库的需求以及现有定时器的缺陷，运用C＋＋高级编程技术STL和BOOST库，对系统底层的定时器库进行了设计与实现。     

Ad-hoc移动云环境下采取随机规划和买卖博弈的任务卸载方法

由于移动设备处理能力和能量的限制,近年来提出了一种新型移动云环境,通过Ad-hoc方式共享邻近设备的闲置资源完成数据处理、存储等需求。在此背景下,该文提出一个在源设备与邻近设备之间的任务卸载方案。考虑无线网络环境下移动设备的移动性导致连接时间随机性问题,采用随机规划方法补偿连接时间预测不精确对任务卸载带来的不利影响。同时,为了激励移动设备相互协作、最大化各自收益,提出基于买卖博弈的分布式多阶段随机买卖博弈任务卸载(SGWD)算法。仿真结果表明该算法在通信成本,时间延迟,能量消耗和收益性能上取得了有效提升。