【正文】 終止掉電唯一的方式是硬件復位。如圖2所示要想通過外部時鐘來驅動它， XTAL1工作時XTAL2應懸空。EA/ VPP外部訪問允許。該引腳也是程序在Flash 編程時的PROG。在訪問使用8位地址的外部數(shù)據(jù)存儲器時，端口2也會收到一些高八位地址信號或者控制信號。在這種模式下， 在Flash編程期間也可以收到代碼字節(jié)，輸出程序改變的代碼字節(jié)。通過把一個多功能8位CPU與一個單一的芯片上的Flash相結合的，Atmel的AT89C51是一個功能強大微型計算機為許多嵌入式控制程序提供了高度靈活和成本效益的解決方案。如果沒有適當?shù)目刂?，容易共振?。 Q1?Q4作為達林頓401A，Q5Q8為S8550。它是與AT89C51兼容，但也增加了SPI接口和看門狗模塊，這不僅使調試變得更容易，也更穩(wěn)定。因此，目前的打印機，繪圖儀，機器人設備以步進電機作為動力核心。電源電流一般根據(jù)輸出相電流I來確定。在歐洲和美洲80個國家已被淘汰。 control the number of step pulses to connect the motor accurately. Stepper motor drive there are many, we should take a reasonable choice of power requirements of the drive, the following were introduced various types of typical drive.The latest technological developmentsDomestic and international research on the subdrive technology is very active, highperformance subdriver circuit can be broken down into thousands or even any subdivision. Now able to do plicated calculations to make after the breakdown of uniform step angle, which greatly improves the resolution of stepper motor pulses, reduce or eliminate the vibration, noise and torque ripple, the stepper motor is more class server feature.The actual role of step angle: in the absence of subdrive, the user select a different number of phases depends mainly on the stepper motor to meet their own requirements on the step angle，If you use the subdrive, the user can change the drive number of segments, can dramatically change the actual step angle stepper motor 39。s MAX7000 family. High impedance, electrically erasable and other characteristics, can be used for the 2500 unit, the working voltage of +5 V. CPLD receives information sent from the microcontroller after converted to the corresponding control signal output to the stepper motor drive. Put the control signal drives the motor windings after the input, to achieve effective control of the motor. The hardware structure of the motor driveMotor drive using the following circuit: R1R8 in which the resistance value of 320Ω. R9R12 resistance value . Q1Q4 as Darlington D401A, Q5Q8 for the S8550. J1, J2 and the stepper motor connected to the sixlead。山 東 建 筑 大 學 畢 業(yè) 設 計 外 文 文 獻 翻 譯 及 譯 文外文文獻：Knowledge of the stepper motorWhat is a stepper motor： Stepper motor is a kind of electrical pulses into angular displacement of the implementing agency. Popular little lesson: When the driver receives a step pulse signal, it will drive a stepper motor to set the direction of rotation at a fixed angle (and the step angle). You can control the number of pulses to control the angular displacement, so as to achieve accurate positioning purposes。Advantages and disadvantages of stepper motorAdvantages 1. The motor rotation angle is proportional to the number of pulses。phases39?；旌鲜讲竭M是混合了永磁式和反應的優(yōu)勢。如果采用線性電源，?。步進電機控制的例子我們以四相單極步進電機為例：四個相繞組引出四個相和兩個公共線（連接到正極）。單片機程序主要用于現(xiàn)場信號的采集和通過步進電機的運轉來計算的方向和速度信息。 J1，J2和步進電機連接到六個接口。優(yōu)良的啟動和制動特性_。2。功能特點AT89C51具有以下功能：4K字節(jié)的Flash，128字節(jié)RAM，32 I / O口，兩個16位定時器/計數(shù)器，一個五向量2級中斷機構，一個全雙工串行口，芯片振蕩器和時鐘電路。程序改變期間還要外部上拉電阻端口1端口1是一個具有內部上拉電阻的8位雙向I / O端口端口1輸出緩沖器可以驅動四個TTL 。端口3端口3是一個具有內部上拉電阻的8位雙向I / O端口。正常運行時ALE以恒定的速率發(fā)出振蕩頻率的1/6的脈沖信號，可用作外部時鐘或定時。 EA必須綁到GND才能使設備開始在0000H到FFFFH位取代碼。對外部時鐘信號的占空比沒有特殊要求，因為外部時鐘信號是通過一個2分頻觸發(fā)器后作為內部時鐘信號的，但最小高電平持續(xù)時間和最大的低電平持續(xù)時間應該符合要求。復位將重置SFR，但不改變RAM的內容。片上RAM和特殊功能寄存器保持原值，直到掉電模式終止。石英晶體或陶瓷諧振器都可以作為其材料。在此期間，當訪問外部數(shù)據(jù)存儲器時，這兩次有效的PSEN 信號不出現(xiàn)。ALE / PROG在訪問外部存儲器時地址鎖存使能輸出脈沖鎖存的低八位地址。在此應用中，它采用強大的內部上拉電阻，發(fā)光1S。當1寫入端口0引腳。芯片上的Flash允許程序存儲器通過系統(tǒng)或由傳統(tǒng)的非易失性存儲器編程重新編程。速度與的脈沖頻率成正比，因此，有相對較寬的調速范圍缺點1。由于每一步準確度為百分之三到五，而且誤差不會累積到下一步，因而具有更好定位精度和重復定位精度。 。 2控制方案控制系統(tǒng)框圖如下該方案采用AT89S51的主要控制裝置。4只要改變脈沖，可以很容易地改變電機軸旋轉的方向。如果要求較快的運行速度較高的響應速度就選用較高的電壓，但注意電源電壓的峰值不能超過驅動器的最大輸入電壓，否則可能會損壞驅動器。反應式一般有三相可以實現(xiàn)大轉矩輸出，但噪聲和振動大。2. Difficult operation to a higher speed.3. Difficult to obtain high torque4. There is no advantage in terms of volume weight, low energy efficiency.5. Over load will destroy the synchronization, the work will be issued when highspeed vibration and noise.Stepper motor drive requirements(1) to provide fast rise and fall of current speed, the current waveform as close as possible rectangle.For the period ended with the release of the loop