【正文】 ,芯片內(nèi)部集成ROM、PEPROM、RAM、總線、總線邏輯、定時(shí)P計(jì)數(shù)器、WatchDog、IPO、串行口、脈寬調(diào)制輸出、APD、 DPA、Flash RAM、E2PROM 等各種必要功能和外設(shè)。 PWM。關(guān)鍵詞：閉環(huán)調(diào)速；嵌入式；PWM；LM3S1138Abstract This design mainly for DC motor speed control system research and design. In the DC motor operation control, usually widely used pulse width modulation (P WM) technology, fast response, high accuracy, stability is good. DC motor speed and the motor is proportional to the voltage across, P WM modulation into the DC power supply has a frequency width (pulse duty cycle) square wave pulses with adjustable voltage, added to the DC motor armature, through changes in accounting space than the average voltage across the motor to regulate the duty cycle of the greater increase in the average voltage across the larger motor, the motor faster. DC motor drive based on the H bridge using a high voltage, high current motor drive chip L298, LM3S1138 microcontrollerbased embedded controller, driven by PWM to achieve in the L298 motor speed regulation. For the error rate, using simple, practical and adjust the ratio is better closedloop algorithm to adjust motor speed precision. Microcontroller to detect the motor speed pared with the speed set by adjusting the proportion of closedloop pulsewidth modulated square wave, thereby changing the average voltage across the motor to realize the feedback control of motor speed. Key word: Closed loop velocity modulation。對(duì)于速度的誤差，采用較為簡(jiǎn)單，實(shí)用且效果較好的閉環(huán)比例調(diào)節(jié)算法實(shí)現(xiàn)電機(jī)速度的精確調(diào)整。直流電機(jī)的轉(zhuǎn)速與電機(jī)兩端的電壓成比例，P WM 將直流電源調(diào)制成具有一定頻率的寬度( 脈沖占空比 ) 可調(diào)的方波脈沖電壓，加在直流電機(jī)的電樞上，通過(guò)改變占空比實(shí)現(xiàn)電機(jī)兩端平均電壓的調(diào)節(jié)，占空比越大，加在電機(jī)兩端平均電壓越大，電機(jī)速度越快。目 錄摘要 ..............................................................................................................................ⅠAbstract .......................................................................................................................Ⅱ引言 ................................................................................................................................11 嵌入式系統(tǒng)和 ARM 微處理器的概述 .....................................................................2 嵌入式系統(tǒng)概況 .................................................................................................2 嵌入式系統(tǒng)的發(fā)展歷史和現(xiàn)狀 ................................................................2 嵌入式系統(tǒng)的應(yīng)用 .....................................................................................3 LM3S1138 微控制器的介紹 ............................................................................4 LM3S1138 微控制器的特點(diǎn) .....................................................................4 EASYARM1138 開(kāi)發(fā)板的介紹 ................................................................6 直流電機(jī)的概述 .................................................................................................6 直流電機(jī)的特點(diǎn)和分類 ............................................................................6 有刷直流電機(jī)的工作原理 .........................................................................7 直流電機(jī)的電器特性 .................................................................................7 PWM 技術(shù)的簡(jiǎn)介 .................................................................................................8 直流電機(jī)的應(yīng)用 ...................................................................................................92 系統(tǒng)的總體方案設(shè)計(jì) ..............................................................................................10 系統(tǒng)分析 ..........................................................................................................10 系統(tǒng)功能分析 ...........................................................................................10 系統(tǒng)原理框架結(jié)構(gòu) ...................................................................................10 直流電機(jī) PWM 調(diào)速系統(tǒng)總體設(shè)計(jì) ................................................................11 直流電機(jī)的電樞的 PWM 調(diào)壓調(diào)速原理 .................................................11 PWM 控制方法的選擇 ............................................................................12 直流電機(jī)驅(qū)動(dòng)方案選擇 ...................................................................................13 直流電機(jī)速度控制算法選擇 ...........................................................................15 顯示方案選擇 ...................................................................................................17 基本方案的確定 ...............................................................................................173 系統(tǒng)硬件電路設(shè)計(jì) ..................................................................................................19 EASYARM1138 開(kāi)發(fā)板電路 ...........................................................................19 直流電機(jī)驅(qū)動(dòng)模塊電路設(shè)計(jì) ............................................................................19 測(cè)速模塊電路設(shè) ................................................................................................22 按鍵模塊電路設(shè)計(jì) ............................................................................................224 系統(tǒng)軟件設(shè)計(jì) ..........................................................................................................24 系統(tǒng)軟件設(shè)計(jì)的基本原則 ..............................................................................24 主程序的設(shè)計(jì) ..................................................................................................24 顯示子程序的設(shè)計(jì) ..........................................................................................25 LCD1602 顯示原理 ..................................................................................25 LCD1602 液晶顯示流程 ..........................................................................27 鍵盤子程序的設(shè)計(jì) ..........................................................................................27　調(diào)速程序流程圖 .............................................................................................28　正反轉(zhuǎn)程序流程圖 ...................................................................................28 加速減速程序流程圖 ...............................................................................29 比例調(diào)速流程圖 .........................................