【正文】 在編程時(shí)，EA/Vpp腳還需加上21V的編程電壓。如EA為低電平，則不管地址大小，一律讀取外部程序存儲(chǔ)器指令。Pin29：當(dāng)訪問外部程序存儲(chǔ)器時(shí)，此腳輸出負(fù)脈沖選通信號(hào)，PC的16位地址數(shù)據(jù)將出現(xiàn)在P0和P2口上，外部程序存儲(chǔ)器則把指令數(shù)據(jù)放到P0口上，由CPU讀入并執(zhí)行。更有一個(gè)特點(diǎn)，當(dāng)訪問外部程序存儲(chǔ)器，ALE會(huì)跳過一個(gè)脈沖。Pin30：ALE/當(dāng)訪問外部程序器時(shí)，ALE(地址鎖存)的輸出用于鎖存地址的低位字節(jié)。8051的復(fù)位方式可以是自動(dòng)復(fù)位，也可以是手動(dòng)復(fù)位，見下圖25。RESET由高電平下降為低電平后，系統(tǒng)即從0000H地址開始執(zhí)行程序。Pin9：RESET/Vpd復(fù)位信號(hào)復(fù)用腳，當(dāng)8051通電，時(shí)鐘電路開始工作，在RESET引腳上出現(xiàn)24個(gè)時(shí)鐘周期以上的高電平，系統(tǒng)即初始復(fù)位。INTEL的MCS51系列單片機(jī)采用的是哈佛結(jié)構(gòu)的形式。8. 時(shí)鐘電路：8051內(nèi)置最高頻率達(dá)12MHz的時(shí)鐘電路，用于產(chǎn)生整個(gè)單片機(jī)運(yùn)行的脈沖時(shí)序，但8051單片機(jī)需外置振蕩電容。6. 全雙工串行口：8051內(nèi)置一個(gè)全雙工串行通信口，用于與其它設(shè)備間的串行數(shù)據(jù)傳送，該串行口既可以用作異步通信收發(fā)器，也可以當(dāng)同步移位器使用。4. 定時(shí)/計(jì)數(shù)器(ROM)：8051有兩個(gè)16位的可編程定時(shí)/計(jì)數(shù)器，以實(shí)現(xiàn)定時(shí)或計(jì)數(shù)產(chǎn)生中斷用于控制程序轉(zhuǎn)向。2. 數(shù)據(jù)存儲(chǔ)器(RAM)8051內(nèi)部有128個(gè)8位用戶數(shù)據(jù)存儲(chǔ)單元和128個(gè)專用寄存器單元，它們是統(tǒng)一編址的，專用寄存器只能用于存放控制指令數(shù)據(jù)，用戶只能訪問，而不能用于存放用戶數(shù)據(jù)，所以，用戶能使用的RAM只有128個(gè)，可存放讀寫的數(shù)據(jù)，運(yùn)算的中間結(jié)果或用戶定義的字型表。 Communications. 2007. 5: 6264. 附錄A8051 contains the central processing unit, a program memory (ROM), several major unit of data memory (RAM), timer / counter, parallel interface, serial interface and interrupt system and data bus, address bus and control bus three bus Now we were to illustrate: 1 CPU: The central processor (CPU) is a the entire microcontroller core member, is an 8bit data width of the processor, able to handle 8bit binary data or code, coordination of the work of the CPU is responsible for controlling, manding and scheduling entire unit system, the pletion of the arithmetic and control input Output functions and other operations. 2 Data memory (RAM) 8051 internal 128 8 user data storage units and 128 special register unit, they are unified addressing the special register can only be used to store the data of the control mand, users can only access and can not be used to store user data, so , the user can use the RAM 128, can be stored for reading and writing data, intermediate results of operations or userdefined font table. 3 program memory (ROM): 8051 a total of 4096 8bit mask ROM used to store the user program, raw data, or form. 4 Timer / Counter (ROM): 8051 has two 16bit programmable timer / counter, to counter or timer interrupt is generated for the control program steering. 5 parallel input and output (I / O) port: 8051 a total of 4 groups of 8bit I / O port (P0, P1, P2 or P3) used for external data transfer. 6 fullduplex serial port: 8051 built a fullduplex serial munication port, serial data transfer used in conjunction with other devices, the serial port can be used for both asynchronous munication transceivers, when the synchronization shifter. 7 interrupt system: 8051 has better interrupt function, there are two external interrupts, two timer / counter interrupt and a serial interrupt, to meet the different control requirements, and has two priority selection. 8 clock circuit: 8051 builtin frequencies up to 12MHz clock circuit used to generate the pulse timing of the entire operation of a microcontroller, but need an external oscillator capacitor 8051.There are two types of the structure of the microcontroller, a form that is separate from the program memory and data memory, ., the structure of Harvard (Harvard), another is the use of program memory and data memory into one of the widely used generalpurpose puter structure, . Princeton (Princeton) structure. INTEL MCS51 series MCU is used in the form of a Harvard architecture. MCS51 Pin Description: MCS51 series singlechip 8031,8051 and 8751 40Pin package the double row directly DIP structure to the right is the pin configuration 40 pin Power and ground two external crystal oscillator the clock line two, four groups of 32 8 I / O port, interrupt port line P3port line multiplexing. Pin9: the RESET / VPD reset signals are multiplexed with their feet, when the 8051 is powered on, the clock circuit to work, the RESET pin high of more than 24 clock cycles, the system is initially reset. After initialization, the program counter (PC) point 0000H, all P0P3 output is high, the stack pointer write 07H other special register is cleared to 0. RESET is low down from the high, starting from address 0000H program execution. In the initial reset, however, does not change the state of the RAM (working registers R0R7), the initial state of 8051. 8051 reset can be automatically reset, it can be manually reset, as shown in Figure 25. In addition, the the RESET / Vpd or a plex with their feet during Vcc powerdown, this pin can be connected to the standby power to ensure the microcontroller internal RAM data is not lost.Pin30: ALE / when access to external program, ALE (address latch) output is used to latch the low byte address. Access to the internal program memory, ALE end there will be a 1/6 clock frequency of positive pulse signal, this signal can be used to identify the microcontroller is working, but also can be used as a clock output externally. More a feature when accessing external program memory, ALE will skip a pulse. If the MCU EPROM, programming the meantime, will be used to enter the programming pulse. Pin29: When accessing external program memory, this pin outputs a negative pulse strobe signal, the PC39。 Automation Publication Group. 2004. 20( 4) : 3940. [18] HUANG Chengan. ZHANG Yue. YUN Huai zhong. The design of remotemeter control system based on GPRS[J]. Electrical Measurement amp。[7] 張毅剛,彭喜元,姜守達(dá),[N].哈爾濱工業(yè)大學(xué)出版社,2003年6月。[5] [M].北京航空航天大學(xué)出版社,1990年1月。[3] [M].清華大學(xué)出版社,1996。參考文獻(xiàn)[1] 張琳娜,[M].中國計(jì)量出版社,1999。感謝同組同學(xué)的默契配合，我從他們身上也學(xué)到了不少東西。李濤老師在設(shè)計(jì)過程提供了大量資料、修改意見及多次的參觀機(jī)會(huì)，讓我對(duì)所學(xué)知識(shí)有了較全面了解，為日后的工作和更進(jìn)一步的學(xué)習(xí)打下了堅(jiān)實(shí)的基礎(chǔ)，也積累了許多寶貴的設(shè)計(jì)經(jīng)驗(yàn)。再次感謝李濤老師長期以來悉心的指導(dǎo)，李濤老師的學(xué)識(shí)淵博、治學(xué)嚴(yán)謹(jǐn)。最后敬請(qǐng)各位專家、老師和同學(xué)對(duì)論文和今后的研究工作提出寶貴的指導(dǎo)意見和建議。（3）將單片機(jī)防盜報(bào)警系統(tǒng)擴(kuò)大其功能強(qiáng)度應(yīng)用于更廣的領(lǐng)域。目前系統(tǒng)中的一些功能如熱釋電紅外