【正文】 會(huì) 本次實(shí)訓(xùn)設(shè)計(jì)使我對(duì)直流電機(jī)控制電路的設(shè)計(jì)與制作有所了解，盡管以前沒有接觸過，但都是通過查找資料大體了解了直流電機(jī)設(shè)計(jì)的大體思路。一個(gè)典型的例子發(fā)生在定時(shí)器使能并由預(yù)分頻器驅(qū)動(dòng) (6 CSn2:0 1)的時(shí)候：從計(jì)時(shí)器使能到第一次開始計(jì)數(shù)可能花費(fèi) 1 到 N+1 個(gè)系統(tǒng)時(shí)鐘周期， 其中 N 等于預(yù)分頻因子 ( 6 256 或 1024)。 若沒有實(shí)現(xiàn)功能則看是電路原因還是軟件程序的原因。 印制電路板 (PCB)是電子產(chǎn)品中電路元件和器件的支撐件．它提供電路元件和器件之間的電氣連接。 3 鍵盤電路的設(shè)計(jì) 由于系統(tǒng)要求功能簡(jiǎn)單，所以直接采用行式鍵盤進(jìn)行控制。設(shè)計(jì)中采用 STC89C52 芯片為主控制核心，鍵盤為控制部分，顯示部分采用 LED 顯示直流電機(jī)的正反轉(zhuǎn)、加減速。而光的波長(zhǎng)也就是光的顏色，是由形成 PN結(jié)的材料決定的。 本次實(shí)訓(xùn)采用專用芯片 L298N 作 為電機(jī)驅(qū)動(dòng)芯片且只驅(qū)動(dòng)一個(gè)電機(jī)。 其引腳排列如圖 2 所示 ： 圖 2 L298N 直流 電機(jī)的專用驅(qū)動(dòng)器 正常使用 L298N 驅(qū)動(dòng)直流電機(jī)時(shí)： 第 1 腳（ SENSING A）和 15 腳（ SENSING B）。 第 18引腳： XTAL1—— 反向振蕩放大器與 片內(nèi)時(shí)鐘操作電路的輸入端。有如下特點(diǎn)： 256 字節(jié)的 RAM； 4KB 的 ROM； 32 個(gè)通用 I/O 口線；為用戶提供了豐富的 I/O 口資源； 32 個(gè)通用工作寄存器； 2 個(gè)定時(shí)器 /計(jì)數(shù)器；具有 6個(gè)中斷源； ~； 1000 次可重復(fù)擦寫周期等。在軋鋼 機(jī)、礦井卷機(jī)、挖掘機(jī)、金屬切削機(jī)床、造紙機(jī)、高層電梯等領(lǐng)域中得到廣泛應(yīng)用。通電轉(zhuǎn)子繞組與定子磁體有相反的極性，通過相互吸引而產(chǎn)生轉(zhuǎn)矩使轉(zhuǎn)子轉(zhuǎn)動(dòng)。對(duì)有刷直流電機(jī)而言，轉(zhuǎn)子上的換向器和定子上的電刷在電機(jī)旋轉(zhuǎn)時(shí)為每個(gè)繞組供給電能。 關(guān)鍵詞： 直流電機(jī) ； STC89C52 單片機(jī) ； L298N 驅(qū)動(dòng)電路 . Abstract With the progress of the times and the development of science and technology, motor speed control system in the industrial and agricultural production, transportation and daily life plays an increasingly important role in. DC motor is acplished by a two magic field interactions which occur rotation. The stator by permanent mags or stimulated the electromag produces a fixed magic field, the rotor is posed of a series of winding and the magic materials formed, the current through each winding will generate a magic field. The brush DC motor, rotor and stator of the mutator brush in the motor rotates for each winding supplies electrical energy. Energized rotor winding and the stator mags have opposite polarity, through attraction to produce torque rotating the rotor. The speed of the motor and the applied voltage is proportional to the torque is proportional to the current, and the. For the DC motor control is a challenge, because must be at work during changing the speed of DC motor. The DC motor is the efficient operation of most monly used method is applied to a PWM ( pulse width modulation ) square wave, the onoff ratio corresponding to the desired speed. The motor has a low pass filter function, it will PWM signal is converted to an effective level. The design of STC89C52 monolithic integrated circuits to control the PID the direct pulse （ PWM ） machinery velocity modulation system, and elaborated on the system of control methods, structure and design, the application design problems. the system simple and good performance machinery velocity modulation prices are high, really to direct the electrical machinery velocity modulation control system of highprecision. Key words： monolithic integrated circuits, a direct motor, machinery velocity modulation system . 引言 ................................................................................................................................. 4 1 系統(tǒng)硬件介紹 .............................................................................................................. 4 硬件主控芯片概述及功能介紹 ................................................................... 4 STC89C52 單片機(jī)主控制電路圖 .................................................................. 4 L298N 直流電機(jī)的專用驅(qū)動(dòng)器 .................................................................. 6 硬件電路設(shè)計(jì) .................................................................................................. 7 顯示電路的設(shè)計(jì) ......................................................................................... 7 鍵盤電路的設(shè)計(jì) ......................................................................................... 8 電機(jī)驅(qū)動(dòng)電路 的設(shè)計(jì) ................................................................................... 8 2 系統(tǒng)軟件設(shè)計(jì) .............................................................................................................. 9 設(shè)計(jì)要求 ............................................................................................................. 9 總體設(shè)計(jì)方案 ...................................................................................................... 9 設(shè)計(jì)思路 ................................................................................................... 9 方案論證與設(shè)計(jì) ....................................................................................... 9 系統(tǒng)組成 ................................................................................................ 10 3 硬件制作、調(diào)試與軟件 .............................................................................................. 10 系統(tǒng) PCB板的設(shè)計(jì) ........................................................................................... 10 系統(tǒng)硬件調(diào)試 .................................................................................................... 11 主控程序 ........................................................................................................... 11 4 實(shí)訓(xùn)心得體會(huì) ............................................................................................................ 13 謝 辭 ............................................................................................................................ 14 參考文獻(xiàn) ........................................................................................................................ 15 附錄 A： ..........................