【正文】 36 參考文獻(xiàn) ［ 1］ EDA 技術(shù)實(shí)用教程 /潘松，黃繼業(yè)編著 . –2 版 . –北京：科學(xué)出版社， 2021 ［ 2］ 李軍法 ， Design of the lift operation controller based on CPLD， 陜西西16746236（ 2021） 07005903 附 錄 37 一、英文原文： 1 Introduction Motivation The original motivation for the Universal Serial Bus (USB) came from several considerations, two of the most important being: ? Easeofuse The lack of flexibility in reconfiguring the PC had been acknowledged as the Achilles’ heel to its further deployment. The bination of userfriendly graphical interfaces and the hardware and software mechanisms associated with newgeneration bus architectures have made puters less confrontational and easier to reconfigure. However, from the end user’s point of view, the PC’s I/O interfaces, such as serial/parallel ports, keyboard/mouse/joystick interfaces, etc., did not have the attributes of plugandplay. ? Port Expansion The addition of external peripherals continued to be constrained by port availability. The lack of a bidirectional, lowcost, lowtomid speed peripheral bus held back the creative proliferation of peripherals such as storage devices, answering machines, scanners, PDA’s, keyboards, and mice. Existing interconnects were optimized for one or two point products. As each new function or capability was added to the PC, a new interface had been defined to address this need. Initially, USB provided two speeds (12 Mb/s and Mb/s) that peripherals could use. As PCs became increasingly powerful and able to process larger amounts of data, users needed to get more and more data into and out of their PCs. This led to the definition of the USB specification in 2021 to provide a third transfer rate of 480 Mb/s while retaining backward patibility. In 2021, with wireless technologies being more and more capable, Wireless USB was introduced to provide a new cable free capability to USB. USB is the most successful PC peripheral interconnect ever defined and it has migrated heavily into the CE and Mobile segments. In 2021 alone over 2 billion USB 38 devices were shipped and there are over 6 billion USB products in the installed base today. End users “know” what USB is. Product developers understand the infrastructure and interfaces necessary to build a successful product. USB has gone beyond just being a way to connect peripherals to PCs. Printers use USB to interface directly to cameras. PDAs use USB connected keyboards and mice. The USB OnTheGo definition provides a way for two dual role capable devices to be connected and negotiate which one will operate as the “host.” USB, as a protocol, is also being picked up and used in many nontraditional applications such as industrial automation. Now, as technology innovation marches forward, new kinds of devices, media formats, and large inexpensive storage are converging. They require significantly more bus bandwidth to maintain the interactive experience users have e to expect. HD Camcorders will have tens of gigabytes of storage that the user will want to move to their PC for editing, viewing, and archiving. Furthermore existing devices like still image cameras continue to evolve and are increasing their storage capacity to hold even more unpressed images. Downloading hundreds or even thousands of 10 MB, or larger, raw images from a digital camera will be a time consuming process unless the transfer rate is increased. In addition, user applications demand a higher performance connection between the PC and these increasingly sophisticated peripherals. USB addresses this need by adding an even higher transfer rate to match these new usages and devices. Thu。 他 一絲不茍的作風(fēng)，嚴(yán)謹(jǐn)求實(shí)的態(tài)度， 孜孜不倦的授業(yè)精神 ， 不但教我如何完成畢業(yè)設(shè)計(jì)，還 教我 不怕麻煩，注意細(xì)節(jié)的做人法則， 使 我 終生受益。 本課題在選題及研究過程中 都 得到 了朱治國 老師的悉心指導(dǎo)。 本文中設(shè)計(jì)的電梯控制器 以 CPLD 為實(shí)現(xiàn)載體，以 VHDL 為描述語言實(shí)現(xiàn)了電梯的升降舒適感和運(yùn)行的可靠性， 相信在以后的智能建筑中 會(huì) 得到廣泛的應(yīng)用和 推廣 致 謝 35 畢業(yè)設(shè)計(jì)順利完成了，在此次實(shí)踐過程中，我學(xué)到了很多東西。 本次三層電梯控制器的設(shè)計(jì)采用VHDL 語言 ， 源程序經(jīng) MAX+plus II 軟件仿真，目標(biāo)器件選用 CPLD 器件。 表 引腳的鎖定 端口 結(jié)構(gòu)圖上的信號(hào)名 引腳號(hào) 結(jié) 論 34 在本學(xué)期做畢業(yè)設(shè)計(jì)的過程中，我學(xué)習(xí)了 VHDL 語言的基本語法， 熟悉了MAX+plus II的 VHDL文本設(shè)計(jì)流程全過程， 掌握了 三層電梯控制器的設(shè)計(jì)方法，及它 的仿真和硬件測試。 33 第五章 硬件測試 第一節(jié) 程序的下載實(shí)現(xiàn) 在驗(yàn)證仿真波 形無誤后，可以把程序下載到實(shí)驗(yàn)箱上進(jìn)行觀察，進(jìn)一步驗(yàn)證其功能的實(shí)現(xiàn)情況。 第四節(jié) 本章小結(jié) 本章對(duì) VHDL 源程序進(jìn)行了仿真，分別對(duì)只有一個(gè)上升請求，只有一個(gè)下降請求，有多個(gè)下降請求，有多個(gè)停站請求，只有二樓有下降請求，同時(shí)有上升和下降請求這六種基本情況進(jìn)行了驗(yàn)證。這樣可以大大簡化程序，但要注意的是 abc 向量作為判斷依據(jù)，需實(shí)時(shí)更新 ，可以單獨(dú)寫一個(gè)進(jìn)程，觸發(fā)時(shí)鐘周期要設(shè)置得很小 。在電梯的上升模式時(shí)， 如果有本層請求信號(hào)，則電梯開門；如果沒有任何請求信號(hào)，則 電梯停在當(dāng)前層；否則 用 stoplight 和 fuplight 與全局變量 abc 作比較，如果 stoplight 或 fuplight 比abc 大，則說明更高層還有上升 或停站請求，電梯需繼續(xù)上升；如果 abc 更大，則用 abc 與 fdnlight 作比較，如果 fdnlight 更大，則說明更高層有下降請求，電梯繼續(xù)上升，否則電梯下降。039。139。 在電梯的關(guān)門狀態(tài)中，應(yīng)把 position=3 改為 position=n，關(guān)鍵是修改 position=2 的部分，如果按照原方法把每層羅列，則隨著樓層的增加，程序會(huì)非常復(fù)雜，所以得尋求各 32 中間層的共性。 本設(shè)計(jì) 在信號(hào)定義時(shí) 就 使 用了二進(jìn)制向量，而 非 整數(shù) ， 并且使用狀態(tài)機(jī)的設(shè)計(jì)方法，因此 擴(kuò)展性較好。 同時(shí)有上升和下降請求的仿真波形 從前面所有的仿真波形來看，電梯的的運(yùn)行 情況 完全符合它的運(yùn)行規(guī)則，電梯的位置變化合情合理 。 圖 有多個(gè)停站請求的仿真波形 圖 所示 ，當(dāng)只有二層有下降請求時(shí)，電梯上升至二層，然后下降，顯然正確。 29 圖 有下降請求的仿真波形 圖 所示 的波形是二層和三層都有下降請求的仿真波形，當(dāng)電梯在一層關(guān)門后，檢測到 fdnlight 為“ 110”，則直接上升到三層，開門后 fdnlight(3)清零，等待 4s 后，關(guān)門下降到二層停止， 開門后 fdnlight(2)和 stoplight(2)清零， 再下降到 一層。 當(dāng)電梯時(shí)鐘上升沿檢測到 一層上升請求信號(hào)fuplight(1)為‘ 1’時(shí)，電梯開門， fuplight(1)清零， 等待 4s，關(guān)門檢測到二層停站請求，于是電梯上升到二層 停止， 開門 stoplight(2)清零， position 信號(hào)由 1 變?yōu)?2，電梯最終停在 二層。fuplight,fdnlight,stoplight 是三位二進(jìn)制向量，波形圖中的 1代表“ 001”，表示一層有請求， 2代表“ 010”，表示二層有請求， 4代表“ 100”，表示三層有請求。 doorlight 信號(hào)邏輯‘ 1’表示開門，邏輯‘ 0’表示關(guān)門。 第二節(jié) 波形仿真 在波形仿真中，根據(jù)實(shí)際，我 們有必要做一些假設(shè)，即是： ○ 1 外部請求上升的乘客，進(jìn)入電梯后一定是按更高層的停站按鈕 ； ○ 2 外部請求下降的乘客，進(jìn)入電梯后一定是按更低層的停站按鈕 ； ○ 3 如果 有乘客進(jìn)入電梯，則一定有停站請求 ； ○ 4 同一時(shí)刻有很多人按鍵