Universal Serial Bus (USB) is a communications architecture that gives a personal computer (PC) the ability to interconnect a variety of devices using a simple four- wire cable. The USB is actually a two-wire serial communication link that runs at either 1.5 or 12 megabits per second (mbs). USB protocols can configure devices at startup or when they are plugged in at run time. These devices are broken into various device classes. Each device class defines the common behavior and protocols for devices that serve similar functions. Some examples of USB device classes are shown in the following table
标签： communications architecture Universal computer
上传时间： 2015-12-08
上传用户：stvnash
从结构上来说，实时多任务操作系统包括两部分，一部分为操作系统内核(kernel)，即实时执行程序(Real Time Executive:RTX)，另一部分是输入输出部分(I/O)(注意开发系统不属于操作系统的范畴)；嵌入式系统对I/O的需求通常比较小(无文件系统需求)，因此很多实时多任务操作系统本质上就是一个实时执行程序，如AMX(Kadak)，VRTX(Microtec)，iRMX(Intel)等(这里的X即:eXecutive)，如果纯粹从kernel的角度来考察目前流行的各种实时多任务操作系统的性能，它们的效率差别都不大。 在市面上可以得到一些RTX的源代码(有用C实现的，有用汇编实现的，还有用PL/M语言实现的)，从internet上也可以荡一些下来(我介绍一个站点www.eg3.com，堪称世界电子工程师资源宝库)，下面我要介绍的一个RTX版本(我命名为SRTX:short RTX)，可以说是RTX中的元老级产品了，来自某研究所，九十年代初他们到美国考察，从美国某公司购得。五年以前，SRTX在国内有售，许多搞工控的研究所利用SRTX开发了一些大型或小型的产品,这里介绍的SRTX我作了一些简化和改动.
标签：
上传时间： 2015-12-09
上传用户：wang5829
water temperature control system uses the Single Chip Microcomputer to carry on temperature real-time gathering and controling. DS18B20, digitized temperature sensor, provides the temperature signal by "a main line". In -10～+85℃ the scope, DS18B20’s inherent measuring accuracy is 0.5 ℃. The water temperature real-time control system uses the electricity nichrome wire carring on temperature increiseament and operates the electric fan to realize the temperature decrease control. The system has the higher measuring accuracy and the control precision, it also can complete the elevation of temperature and the temperature decrease control.
标签： temperature Microcomputer real-tim control
上传时间： 2015-12-10
上传用户：nairui21
In a preemptive priority based RTOS, priority inversion problem is among the major sources of deadline violations. Priority inheritance protocol is one of the approaches to reduce priority inversion. Unfortunately, RTOS like uC/OS can’t support priority inheritance protocol since it does not allow kernel to have multiple tasks at the same priority. Although it has different ways to avoid priority inversion such as priority ceiling protocol, developers still have some difficulties in programming real time applications with it. In this paper, we redesign the uC/OS kernel to provide the ability to support round robin scheduling and implement priority inheritance semaphore on the modified kernel. As result, we port new kernel with priority inheritance semaphore to evaluation board, and evaluate the execution time of each of the kernel service as well as verify the operations of our implementation.
标签： priority preemptive inversion problem
上传时间： 2015-12-14
上传用户：气温达上千万的
This application report describes the use of Timer_A3 to decode RC5 and SIRC TV IR remote control signals. The decoder described in this report is interrupt-driven and operates a background function using specific features the Timer_A3. Only a small portion of the MSP430 CPU?s nonreal-time resources is used. Specific hardware bit-latching capabilities of the Timer_A3 module are used for real-time decoding of the IR data signal, independent and asynchronous to the CPU. CPU activity and power consumption are kept to an absolute minimum level. The Timer_A3 decoder implementation also allows other tasks to occur simultaneously if required. The solutions provided are written specifically for MSP430x11x(1) and MSP430x12x derivatives, but can be adapted to any other MSP430 incorporating Timer_A3. 電視遙控器設計基於MSP430
标签： application describes Timer_A control
上传时间： 2014-01-01
上传用户：qq21508895
C++, although a marvelous language, isn t perfect. Matthew Wilson has been working with it for over a decade, and during that time he has found inherent limitations that require skillful workarounds. In this book, he doesn t just tell you what s wrong with C++, but offers practical techniques and tools for writing code that s more robust, flexible, efficient, and maintainable. He shows you how to tame C++ s complexity, cut through its vast array of paradigms, take back control over your code--and get far better results
标签： marvelous although language Matthew
上传时间： 2014-01-22
上传用户：妄想演绎师
LCDScreen is a couple of Delphi component which simulate a dot-LCD multilines screen. It is fully customizable and has animation and special effects capabilities for the displayed text. TLCDScreen is the display component and TLCDAnimator the animation one. Both have build-in Property editor making easier the development at design-time.
标签： multilines LCDScreen component simulate
上传时间： 2015-12-23
上传用户：invtnewer
对于单个控件,COMPONET-->INSTALL COMPONENT..-->PAS或DCU文件-->INSTALL。 2.对于带*.DPK文件的控件包,FILE-->OPEN(下拉列表框中选*.DPK)-->INSTALL即可。 3.对于带*.BPL文件的控件包,INSTALL PACKAGES-->ADD-->BPL文件名即可。 4.如果以上INSTALL按钮为失效的话,试试COMPILE按钮。 5.是RUN TIME LIB则在OPTION下的PACKAGES下的RUNTIMEPACKES加之。 如果编译时提示文件找不到的话,一般是控件的安装目录不在DELPHI的LIB目录中, 有两种方法可以解决： 1.反安装的源文件拷入到DELPHI的LIB目录下。 2.或者TOOLS-->ENVIRONMENT OPTIONS中把控件源代码路径加入到DELPHI的LIB目录中即可。
标签： INSTALL gt COMPONENT COMPONET
上传时间： 2013-12-25
上传用户：ljmwh2000
With User Mode Linux you can create virtual Linux machines within a Linux computer and use them to safely test and debug applications, network services, and even kernels. You can try out new distributions, experiment with buggy software, and even test security. Now, for the first time, the creator and maintainer of User Mode Linux shows how to put it to work hands-on. Jeff Dike covers everything from getting started through running enterprise-class User Mode Linux servers. You ll find authoritative advice on bootup, compilation, administration, specialized configurations, and much more.
标签： Linux computer machines virtual
上传时间： 2013-12-19
上传用户：xinzhch
JK Proxy Project - Version 0.1 ------------------------------ This was going to be a proxy server bu I stopped developing this program (maybe I will go on coding on this application again some time). The email part with spam filtering already works. Check out the numerous text files for additional information.
标签： Project Version Proxy going
上传时间： 2014-08-10
上传用户：coeus
