【導(dǎo)讀】語(yǔ)句通順，流利，專(zhuān)業(yè)用語(yǔ)較恰當(dāng)。意思表達(dá)合理，完整。單片機(jī)廣泛應(yīng)用于商業(yè)：諸如調(diào)制解調(diào)器，電動(dòng)機(jī)控制系統(tǒng)，空調(diào)控制系統(tǒng)，汽車(chē)發(fā)動(dòng)機(jī)和其他一些領(lǐng)域。這些單片機(jī)的高速處理速度和增強(qiáng)型外圍設(shè)備集合使。健壯的測(cè)試環(huán)境和用于驗(yàn)證這些無(wú)論在元部件層次還是系統(tǒng)級(jí)別的單片。機(jī)的合適的工具環(huán)境保證了高可靠性和低市場(chǎng)風(fēng)險(xiǎn)。Intel平臺(tái)工程部門(mén)開(kāi)發(fā)了一。種面向?qū)ο蟮挠糜隍?yàn)證它的AT89C51汽車(chē)單片機(jī)多線性測(cè)試環(huán)境。并重復(fù)用來(lái)驗(yàn)證其他幾種將來(lái)的單片機(jī)。MCS51單片機(jī)典型的應(yīng)用是高速事件控制系統(tǒng)。制，車(chē)輛動(dòng)態(tài)懸掛，反鎖制動(dòng)和穩(wěn)定性控制應(yīng)用。擁有操作不可預(yù)測(cè)的設(shè)備的經(jīng)濟(jì)和法律風(fēng)險(xiǎn)是很高的。設(shè)計(jì)的費(fèi)用可以高達(dá)500K美元，如果產(chǎn)品族享有同樣內(nèi)核或外圍設(shè)計(jì)缺陷的話，同時(shí)，AT89C51降至0Hz的靜態(tài)邏輯操作，并支持兩種可選的節(jié)電工作。行外部程序時(shí)，應(yīng)設(shè)置ALE無(wú)效。在此期間，當(dāng)訪問(wèn)外部數(shù)據(jù)存儲(chǔ)器，這兩次有效的PSEN信號(hào)不出現(xiàn)。

　　

【正文】 can be read back via the address and data lines for verification. The lock bits cannot be verified directly. Verification of the lock bits is achieved by observing that their features are enabled. Figure 211 Programming the Flash Figure 222 Verifying the Flash Chip Erase: The entire Flash array is erased electrically by using the proper bination of control signals and by holding ALE/PROG low for 10 ms. The code array is written with all “1”s. The chip erase operation must be executed before the code memory can be reprogrammed. Reading the Signature Bytes: The signature bytes are read by the same procedure as a normal verification of locations 030H, 031H, and 032H, except that and must be pulled to a logic low. The values returned areas follows. (030H) = 1EH indicates manufactured by Atmel (031H) = 51H indicates 89C51 (032H) = FFH indicates 12V programming (032H) = 05H indicates 5V programming Programming Interface Every code byte in the Flash array can be written and the entire array can be erased by using the appropriate bination of control signals. The write operation cycle is selftimed and once initiated, will automatically time itself to pletion. A microputer interface converts information between two forms. Outside the microputer the information handled by an electronic system exists as a physical signal, but within the program, it is represented numerically. The function of any interface can be broken down into a number of operations which modify the data in some way, so that the process of conversion between the external and internal forms is carried out in a number of steps. An analogtodigital converter(ADC) is used to convert a continuously variable signal to a corresponding digital form which can take any one of a fixed number of possible binary values. If the output of the transducer does not vary continuously, no ADC is necessary. In this case the signal conditioning section must convert the ining signal to a form which can be connected directly to the next part of the interface, the input/output section of the microputer itself. Output interfaces take a similar form, the obvious difference being that here the flow of information is in the opposite direction。 it is passed from the program to the outside world. In this case the program may call an output subroutine which supervises the operation of the interface and performs the scaling numbers which may be needed for digitaltoanalog converter(DAC). This subroutine passes information in turn to an output device which produces a corresponding electrical signal, which could be converted into analog form using a DAC. Finally the signal is conditioned(usually amplified) to a form suitable for operating an actuator. The signals used within microputer circuits are almost always too small to be connected directly to the outside world” and some kind of interface must be used to translate them to a more appropriate form. The design of section of interface circuits is one of the most important tasks facing the engineer wishing to apply microputers. We have seen that in microputers information is represented as discrete patterns of bits。 this digital form is most useful when the microputer is to be connected to equipment which can only be switched on or off, where each bit might represent the state of a switch or actuator. To solve realworld problems, a microcontroller must have more than just a CPU, a program, and a data memory. In addition, it must contain hardware allowing the CPU to access information from the outside world. Once the CPU gathers information and processes the data, it must also be able to effect change on some portion of the outside world. These hardware devices, called peripherals, are the CPU’s window to the outside. The most basic form of peripheral available on microcontrollers is the general purpose I70 port. Each of the I/O pins can be used as either an input or an output. The function of each pin is determined by setting or clearing corresponding bits in a corresponding data direction register during the initialization stage of a program. Each output pin may be driven to either a logic one or a logic zero by using CPU instructions to pin may be viewed (or read.) by the CPU using program instructions. Some type of serial unit is included on microcontrollers to allow the CPU to municate bitserially with external devices. Using a bit serial format instead of bitparallel format requires fewer I/O pins to perform the munication function, which makes it less expensive, but slower. Serial transmissions are performed either synchronously or asynchronously.