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
標(biāo)簽： communications architecture Universal computer
上傳時(shí)間： 2015-12-08
上傳用戶：stvnash
從結(jié)構(gòu)上來說，實(shí)時(shí)多任務(wù)操作系統(tǒng)包括兩部分，一部分為操作系統(tǒng)內(nèi)核(kernel)，即實(shí)時(shí)執(zhí)行程序(Real Time Executive:RTX)，另一部分是輸入輸出部分(I/O)(注意開發(fā)系統(tǒng)不屬于操作系統(tǒng)的范疇)；嵌入式系統(tǒng)對(duì)I/O的需求通常比較小(無文件系統(tǒng)需求)，因此很多實(shí)時(shí)多任務(wù)操作系統(tǒng)本質(zhì)上就是一個(gè)實(shí)時(shí)執(zhí)行程序，如AMX(Kadak)，VRTX(Microtec)，iRMX(Intel)等(這里的X即:eXecutive)，如果純粹從kernel的角度來考察目前流行的各種實(shí)時(shí)多任務(wù)操作系統(tǒng)的性能，它們的效率差別都不大。 在市面上可以得到一些RTX的源代碼(有用C實(shí)現(xiàn)的，有用匯編實(shí)現(xiàn)的，還有用PL/M語言實(shí)現(xiàn)的)，從internet上也可以蕩一些下來(我介紹一個(gè)站點(diǎn)www.eg3.com，堪稱世界電子工程師資源寶庫(kù))，下面我要介紹的一個(gè)RTX版本(我命名為SRTX:short RTX)，可以說是RTX中的元老級(jí)產(chǎn)品了，來自某研究所，九十年代初他們到美國(guó)考察，從美國(guó)某公司購(gòu)得。五年以前，SRTX在國(guó)內(nèi)有售，許多搞工控的研究所利用SRTX開發(fā)了一些大型或小型的產(chǎn)品,這里介紹的SRTX我作了一些簡(jiǎn)化和改動(dòng).
標(biāo)簽：
上傳時(shí)間： 2015-12-09
上傳用戶：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.
標(biāo)簽： temperature Microcomputer real-tim control
上傳時(shí)間： 2015-12-10
上傳用戶：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.
標(biāo)簽： priority preemptive inversion problem
上傳時(shí)間： 2015-12-14
上傳用戶：氣溫達(dá)上千萬的
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(shè)計(jì)基於MSP430
標(biāo)簽： application describes Timer_A control
上傳時(shí)間： 2014-01-01
上傳用戶：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
標(biāo)簽： marvelous although language Matthew
上傳時(shí)間： 2014-01-22
上傳用戶：妄想演繹師
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.
標(biāo)簽： multilines LCDScreen component simulate
上傳時(shí)間： 2015-12-23
上傳用戶：invtnewer
對(duì)于單個(gè)控件,COMPONET-->INSTALL COMPONENT..-->PAS或DCU文件-->INSTALL。 2.對(duì)于帶*.DPK文件的控件包,FILE-->OPEN(下拉列表框中選*.DPK)-->INSTALL即可。 3.對(duì)于帶*.BPL文件的控件包,INSTALL PACKAGES-->ADD-->BPL文件名即可。 4.如果以上INSTALL按鈕為失效的話,試試COMPILE按鈕。 5.是RUN TIME LIB則在OPTION下的PACKAGES下的RUNTIMEPACKES加之。 如果編譯時(shí)提示文件找不到的話,一般是控件的安裝目錄不在DELPHI的LIB目錄中, 有兩種方法可以解決： 1.反安裝的源文件拷入到DELPHI的LIB目錄下。 2.或者TOOLS-->ENVIRONMENT OPTIONS中把控件源代碼路徑加入到DELPHI的LIB目錄中即可。
標(biāo)簽： INSTALL gt COMPONENT COMPONET
上傳時(shí)間： 2013-12-25
上傳用戶：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.
標(biāo)簽： Linux computer machines virtual
上傳時(shí)間： 2013-12-19
上傳用戶：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.
標(biāo)簽： Project Version Proxy going
上傳時(shí)間： 2014-08-10
上傳用戶：coeus
蟲蟲下載站版權(quán)所有 京ICP備2021023401號(hào)-1
