【正文】 d modification based on PWM theory by the SCM. Showing some relative knowledge upon the DCmotor timing， the basic theory and the way to implement. This paper still provides a method for modifying the speed of DCmotor by way of time by numerical direct current PWM which bines direct current electrical engineering PWM to adjust soon principle to make into adjusts soon controller and the hardware which introduces that controller in detail constitute and the PWM direct current adjust soon function. The relay controls the machine’s positive and negative trun, and Using PWM direct current machine and the Hshape bridge circuit to adjust the speed and orientation of the automobile. The LED with the MAX7219 is used to display the time and the total distance. The former simulated control was replaced by Single Chip Micyoco control， which not only made the control precision higher without zero shift， but also facilitated the systematic improvement and upgrading， with flexibility and adaptability enhenced . Key words: DC motor speed regulating； sports in primary and middle schools； AT89C51 chip microp rocessor； LED Display 東華理工大學長江學院畢業(yè)設計（論文） 目錄 目 錄 前 言 ................................................................................................................................... 1 課題研究的意義、國內外有關課題的研究動態(tài)和自己的見解 ........................ 2 研究的意義 .................................................................................................. 2 國內外有關課題的研究動態(tài) ...................................................................... 2 課題研究的主要內容、擬解決的關鍵性問題和預期的成果 ............................ 2 課題的主要內容 .......................................................................................... 2 擬解決的關鍵性問題 .................................................................................. 2 預期的成果 ................................................................................................. 3 2 系統(tǒng)總體設計 ................................................................................................................. 4 系統(tǒng)設計任務和要求 ........................................................................................... 4 設計任務 ...................................................................................................... 4 設計要求 ..................................................................................................... 4 系統(tǒng)分析和總體設計思路 .................................................................................... 5 系統(tǒng)分析 ..................................................................................................... 5 系統(tǒng)總體設計思路 ...................................................................................... 5 系統(tǒng)組成框圖 ........................................................................................................ 5 3 系統(tǒng)方案的設計與論證 ................................................................................................. 7 電動機驅動方案的選擇 ........................................................................................ 7 信號檢測方案的選擇 ........................................................................................... 7 顯示模塊方案的選擇 ........................................................................................... 8 電源模塊的選擇 .................................................................................................... 8 4 系統(tǒng) CPU 的選擇 ......................................................................................................... 10 單片機開發(fā)系統(tǒng)的介紹 ...................................................................................... 10 單片機 AT89C51 的選擇 .................................................................................... 11 概述 ............................................................................................................ 11 主要功能特性 ........................................................................................... 11 AT89C51 單片機的結構 ........................................................................... 12 AT89C51 單片機最小系 ........................................................................... 13 AT89C51 的時鐘電路 ............................................................................... 14 AT89C51 的復位電路 ............................................................................... 15 5 系統(tǒng)硬件電路的模塊設計 ........................................................................................... 17 數(shù)據(jù)采集模塊 ...................................................................................................... 17 電機調速控制模塊 .............................................................................................. 18 PWM 調速原理分析 ................................................................................. 19 用 PWM 控制系統(tǒng)的電機調速電路 ........................................................ 22 PWM 調速下小車行駛狀態(tài)的變化顯示 ................................................. 23 路程檢測模塊 ..................................................................................................... 24 數(shù)碼管顯示部分 ................................................................................................. 25 東華理工大學長江學院畢業(yè)設計（論文） 目錄 MAX7219 芯片介紹 ................................................................................. 26 MAX7219 芯片的功能說明 ..................................................................... 26 MAX7219 的 基本工作原理及使用方法 ................................................. 27 MAX7219 在系統(tǒng)顯示模塊中的應用 ..................................................... 29 6 系統(tǒng)軟件設計 ................................................................................................................. 2 總 結 ...................................................................................