【正文】 al RAM in this event, but access to the port pins is not inhibited. To eliminate the possibility of an unexpected write to a port pin when Idle is terminated by reset, the instruction following the one that invokes Idle should not be one that writes to a port pin or to external memory.Powerdown ModeIn the powerdown mode, the oscillator is stopped, and the instruction that invokes powerdown is the last instruction executed. The onchip RAM and Special Function Registers retain their values until the powerdown mode is terminated. The only exit from powerdown is a hardware reset. Reset redefines the SFRs but does not change the onchip RAM. The reset should not be activated before VCC is restored to its normal operating level and must be held active long enough to allow the oscillator to restart and stabilize.中文譯文： 步進(jìn)電機(jī)的知識(shí)什么是步進(jìn)電機(jī)：步進(jìn)電機(jī)是一種把電脈沖轉(zhuǎn)化為角位移的執(zhí)行機(jī)構(gòu)。它由兩相和五相：。如果采用開關(guān)電源，?。一相接地。然后將信息發(fā)送到CPLD。步進(jìn)電機(jī)優(yōu)點(diǎn)和缺點(diǎn)優(yōu)勢(shì)1。5。高速操作難度較大3。此外，AT89C51支持頻率為0的靜態(tài)邏輯運(yùn)算，并支持兩種節(jié)電模式。作為輸入口時(shí)，由于內(nèi)部上拉電阻的作用，引腳被外部信號(hào)拉低時(shí)輸出一個(gè)電流，flash編程和校驗(yàn)時(shí)端口1也會(huì)接收到低地址信號(hào)。端口3輸出緩沖器可以驅(qū)動(dòng)四個(gè)TTL 輸入。但是請(qǐng)注意，在每次訪問外部數(shù)據(jù)存儲(chǔ)器都有一個(gè)ALE脈沖跳過。但是請(qǐng)注意，如果鎖存位1被編程，EA將鎖存位置上復(fù)位。 內(nèi)部振蕩電路 外部振蕩電路閑散模式在閑散模式下，CPU停止工作，而所有其他元件依然處于工作狀態(tài)。復(fù)位不能被激活，直到VCC恢復(fù)到其正常水平，以確保有足夠長(zhǎng)的時(shí)間使振蕩器重新啟動(dòng)并穩(wěn)定。掉電模式在掉電模式下，振蕩器停止運(yùn)行，斷電指令是最后一條要執(zhí)行的指令。時(shí)鐘振蕩器的特性時(shí)鐘振蕩器是可以設(shè)置為內(nèi)部振蕩器的反相放大器XTAL1和XTAL2分別為其出入端和輸出端，如圖1所示。PSEN程序儲(chǔ)存允許輸出是外部程序存儲(chǔ)器的讀選通信號(hào)，當(dāng)AT89C51由外部程序存儲(chǔ)器讀取指令時(shí)，每個(gè)機(jī)器周期兩次PSEN 有效，即輸出兩個(gè)脈沖。震蕩器運(yùn)行時(shí)，兩個(gè)運(yùn)行周期的高電平將使設(shè)備復(fù)位。作為輸入口時(shí)，由于內(nèi)部上拉電阻的做用，端口2引腳被外部信號(hào)拉至低電平時(shí)，將輸出電流，端口2在訪問使用16位地址的外部數(shù)據(jù)存儲(chǔ)器時(shí)發(fā)出的高位地址字節(jié)。作為一個(gè)輸出端口，每個(gè)引腳可以驅(qū)動(dòng)8個(gè)TTL輸入端。該設(shè)備是采用Atmel的高密度非易失性內(nèi)存技術(shù)并與工業(yè)標(biāo)準(zhǔn)的的MCS51指令集和引腳兼容。只是負(fù)載直接連接到電機(jī)軸也可以極其緩慢旋轉(zhuǎn)8。3。 電機(jī)驅(qū)動(dòng)器通過下面的電路來實(shí)現(xiàn)：R1?R8的電阻值為320Ω?？梢赞D(zhuǎn)移到控制電機(jī)勵(lì)磁是為了轉(zhuǎn)移如下：如果電機(jī)反轉(zhuǎn)的要求，傳輸?shù)募?lì)信號(hào)可以逆轉(zhuǎn)的。 3步進(jìn)電機(jī)具有快速啟動(dòng)和停止的優(yōu)良特性。 步進(jìn)電機(jī)精度為多少？是否累積　　一般步進(jìn)電機(jī)的精度為步進(jìn)角的35%，且不累積 如何確定步進(jìn)電機(jī)驅(qū)動(dòng)器直流電源混合式步進(jìn)電機(jī)驅(qū)動(dòng)器的電源電壓范圍較廣（比如IM483的供電電壓12?48VDC），電源電壓通常根據(jù)電機(jī)的轉(zhuǎn)速和響應(yīng)要求來選擇。步進(jìn)電機(jī)的種類：步進(jìn)電機(jī)分為三種：永磁式（PM），反應(yīng)式（VR）和混合式（HR）永磁式步進(jìn)電機(jī)一般為兩相，轉(zhuǎn)矩和體積較小。 6. Motor response only determined by the number of input pulses, which can be used open loop control, which makes the motor and control structure can be relatively simpleSystem cost 7. Just load directly connected to the motor shaft can also be extremely slow synchronous rotation. 8. Speed ??is proportional to the pulse frequency, and thus a relatively wide speed range.Shortings1. If not properly controlled prone to resonance。 if we adopt the switching power supply, power supply current is generally preferable to I, to times.The main characteristics of stepping motor： A stepper motor drive can be added operate pulse drive signal must be no pulse when the stepper motor at rest, such asIf adding the appropriate pulse signal, it will to a certain angle (called the step angle) rotation. Rotation speed and pulse frequency is proportional to. 2 Dragon step angle stepper motor version is degrees, 360 degrees around, takes 48 pulses to plete. 3 stepper motor has instant start and rapid cessation of superior characteristics.Change the pulse of the order of 4, you can easily change the direction of rotation.Therefore, the current printers, plotters, robotics, and so devices are the core of the stepper motor as the driving force.Stepper motor control exampleWe use fourphase unipolar stepper motor as an example. The structure shown in Figure 1: Four fourphase winding leads (as opposed to phase A1 A2 B1 phase phase B2) and two public lines (to the power of positive). The windings of one phase to the power of the ground. So that the windings will be inspired. We use fourphase eightbeat control, ie, 1 phase 2 phase alternating turn, would enhance resolution. 176。 reaction step is generally threephase, can achieve high torque output, step angle of degrees is generally, but the noise and vibration are large. 80 countries in Europe and America have been eliminated。 3. Since the accuracy of each step in the three per cent to five per cent, and the error will not accumulate to the next step and thus has better positional accuracy and repeatability of movement。通俗的說：當(dāng)驅(qū)動(dòng)程序收到一個(gè)步進(jìn)脈沖信號(hào)，將驅(qū)動(dòng)步進(jìn)電機(jī)軸旋轉(zhuǎn)一個(gè)固定的角度（步進(jìn)角）。是使用最廣泛的的步進(jìn)電機(jī)。步進(jìn)電機(jī)的主要特性