Structure and fun cti on of the MCS-51 seriesStructure and function of the MCS-51 series one-chip computer MCS-51is a nameof a piece of one-chip computer series which In tel Compa ny produces. This compa ny in troduced 8 top-grade on e-chip computers of MCS-51 series in 1980 after in troduc ing 8 on e-chip computers of MCS-48 series in 1976. It belong to a lot of kinds this line of one-chip computer the chips have,such as 8051, 8031,8751, 80C51BH, 80C31BH,etc., their basic compositi on, basic performa nee and in structi on system are all the same. 8051 daily representatives- 51 serialon e-chip computers .An one-chip computer system is made up of severalfollowi ng parts: ( 1) One microprocessor of 8 (CPU). ( 2) At slice data memory RAM (128B/256B),it use not depositti ng not can read ing /data that write, such as result not middle of operati on, final result and data wan ted to show, etc. ( 3) Procedure memoryROM/EPRC(4KB/8KB ), is used to preserve the procedure , some in itial data and form in slice. But does not take ROM/EPROM within some on e-chip computers, such as 8031 , 8032, 80C ,etc.. ( 4) Four 8 run side by side I/O in terface P0 four P3, each mouth can use as introduction , may use as export ing too. ( 5) Two timer / coun ter, each timer / coun ter may set up and count in the way, used to count to the exter nalin cide nt, can set up into a timi ng way too, and can accord ing to count or result of timing realize the control of the computer.(6) Five cut off cutting off the control system of the source .(7) One all duplexi ng serial I/O mouth of UART (un iversal asynchronous receiver/transmitter (UART) ), is it realizeon e-chip computer or on e-chip computer and serialcom muni cati on of computer to use for. ( 8) Stretch oscillator and clock produce circuit, quartz crystal finely tune electric capacity need outer. Allow oscillation frequency as 12 megahertas now at most. Every the above-me nti oned part was joined through the in side data bus .Am ong them, CPU is a core of the one-chip computer, it is the control of the computer and comma nd cen tre, made up of such parts as arithmetic unit and con troller , etc.. The arithmetic un it can carry on 8 pers ons of arithmeticoperati on and un it ALU of logic operati on while including one, the 1 storing device temporarilies of 8, storing device 2 temporarily, 8's accumulati on device ACC, register B and procedure state register PSW, etc. Pers on who accumulate ACCc ount by 2 in put ends en tered of check ing etc. temporarily as one operation often, comefrom person who store 1 operation is it is it make operati on to go on to count temporarily , operation result and loopback ACCwith another one. In addition, ACC is often regarded as the transfer station of datatran smissi on on 8051 in side . The same as gen eral microprocessor, it is the busiest register. Help rememberi ngthat agree ing with A expresses in the order. The con troller in cludes the procedure coun ter , the order is depositted, the order decipher, the oscillator and tim ing circuit, etc. The procedure coun ter is made up of coun ter of 8 for two, amounts to 16. It is a byte address coun ter of the procedure in fact,the content is the n ext IA that will carried out in PC. The content which cha nges it can cha nge the directi on that the procedure carries out . Shake the circuit in 8051 on e-chip computers, only n eed outer quartz crystal and freque ncy to fin ely tune the electric capacity, its freque ncy range is its12MHZ of 1.2MH Z. This pulse sig nal, as 8051 basic beats of work ing, n amely the mi nimum unit of time. 8051 is the same as other computers, the work in harm ony un der the con trol of the basic beat, just like an orchestra accord ing to the beat play that is comma nded.There are ROM (procedure memory , can only read ) and RAM in 8051 slices (data memory, can is it can write ) two to read, they have each in depe ndent memory address space, dispose way to be the same with general memoryof computer. Procedure 8051 memory and 8751 slice procedure memory capacity 4KB, address begi n from 0000H, used for preserv ing the procedure and form con sta nt. Data 8051- 8751 8031 of memory data memory 128B, address false00FH, use for middle result to deposit operation, the data are stored temporarily and the data are buffered etc.. In RAM of this 128B, there is un it of 32 byteses that ca n be appo in ted as the job register, this and gen eral microprocessor is different, 8051 slice RAMand job register rank one formation the same to arrange the locati on .It is not very the same that the memory of MCS-51 series one-chip computer and general computer disposes the way in additi on. Gen eral computer forfirst address space, ROMand RAMtan arrange in different space within the range of this address at will, namely the addressesof ROM and RAM, with distribut ing differe nt address space in a formatio n. While visit ing the memory, corresp onding and only an address Memory un it, can ROM, it can be RAM too, and by visiting the order similarly. This kind of memorystructure is called the structure of Prin cet on. 8051 memories are divided into procedure memoryspace and data memoryspace on the physics structure, there are four memory spaces in all: The procedure stores in one and data memoryspace outside data memoryand one in procedure memory space and one outside one, the structureforms of this kind of procedure device and data memoryseparated form data memory, called Harvard structure. But use the an gle from users, 8051 memory address space is divided into three kin ds: (1) In the slice, arran ge blocks of FFFFH , 0000H oflocation , in unison outside the slice (use 16 addresses). (2) The data memoryaddress space outside one of 64KB, the address is arran ged from 0000H 64 KB FFFFH (with 16 addresses ) too to the locati on. (3) Data memory address space of 256B (use 8 addresses). Three above-mentioned memory space addresses overlap, for dist in guish ing and desig ning the order symbol ofdifferent data transmission in the instruction system of 8051: CPU visit slice, ROM order spe nd MOVC , visit block RAM order uses MOVX outside the slice, RAM order uses MOV to visit in slice.8051 on e-chip computer have four 8 walk abreast I/O port, call P0, P1, P2 and P3. Each port is 8 accurate two-way mouths, accounts for 32 pins altogether. Every one I/O line can be used as introduction and exported independently. Each port includesa latch (n amely special fun cti on register ), one exports the driver and a in troductio n buffer . Make data can latch whe n outputting, data can buffer whenmaking introduction , but four fun cti on of passway these self-same. Expa nd among the system of memory outside hav ing slice, four port these may serve as accurate two-way mouth of I/O in com mon use. Expa nd among the system of memory outside hav ing slice, P2 mouth see high 8 address off; P0 mouth is a two-way bus, send the in troductio n of 8 low addresses and data / export in timeshari ngOutput grade , P3 of mouth , P1 of P1 , connect with in side have load resista nee of draw ing , every one of they can drive 4 Model LS TTL load to output. As while in putt ing the mouth,any TTL or NMOSCircuit can drive P1 of 8051 one-chip computers as P3 mouth in a no rmal way . Because draw resista nee on output grade of them have, can open a waycollector too or drain-source resista nee is it urge to ope n a way, do not n eed to have the resista nee of draw ing outerly . Mouths are all accurate two-way mouths too. Whe n the con duct is in put, must write the corresp onding port latch with 1 first . As to 80C51 on e-chip computer, port can on ly offer milliampere of output electric currents, is it output mouth go when urging one ordinary basing of tran sistor to regard as, should con tact a resista nee among the port and transistor base , in order to the electricity while restraining the high level from exporting P1~P3Being restored to the throne is the operati on of in itializ ing of an on e-chip computer. Its main function is to turn PCinto OOOOHinitially , makethe on e-chip computer beg in to hold the con duct procedurefrom unit 0000H. Except that the ones that enter the system are initialized normally,as because procedure operate it make mistakes or operate there aren't mistake, in order to extricate on eself from a predicame nt , n eed to be pressed and restored to the throne the key restarti ng too. It is an in put end which is restored to the throne the sig nal in 8051 China RST pin. Restore to the throne sig nal high level effective , should sustain 24 shake cycle (namely 2 machine cycles ) the above its effective times. If 6 of frequency of utilization brilliant to shake, restore to the throne sig nal durati on should exceed 4 delicate to finish restoring to the throne and operating. Produce the logic picture of circuit which is restored to the throne the sig nal:Restore to the throne the circuit and in clude two parts outside in the chip en tirely. Outside that circuit produce to restore to the throne sig nal (RST ) hand over to Schmitt's trigger, restore to the throne circuit sample to output , Schmitt of trigger con sta ntly in each S5P2 , mach ine of cycle in hav ing one more , the n just got and restored to the throne and operated the necessary signal insidly. Restore to the thro ne resista nee of circuit gen erally, electric capacity parameter suitable for 6 brilliant to shake, can is it restore to the throne signal high level duration greater than 2 machine cycles to guarantee. Being restored to the throne in the circuit is simple, its fun cti on is very importa nt. Pieces of on e-chip computer system could normal running,should first check it can restore to the throne not succeeding. Checking andean pop one'shead and mon itor the pin with the oscillograph ten tatively, push and is restored to the throne the key, the wave form that observes and has eno ugh range is exported (in sta ntan eous),can also through is it restore to the throne circuit group holding value carry on the experime nt to cha nge.At prese nt,MCU to in filtrate all areas of our lives, which is almost difficult to find traces of the field without SCM. Missile navigation equipment, aircraft, all types ofin strume nt con trol, computer n etwork com muni cati ons and data tran smissi on, in dustrial automati on, real-time process control and data processing, extensive use of various smart IC card, civilia n luxury car security system, video recorder, camera, fully automatic washi ng mach ine con trol, and program-c on trolled toys, electro nic pet, etc., which arein separable from the microc on troller. Not to men ti on the area of robot con trol, i ntellige nt in strume nts, medical equipme nt was. Therefore, the MCU learning, development and application of the large nu mber of computer applicati ons and in tellige ntcon trol of the scie ntists, engin eers.SCM is widely used in instruments and meters, household applia nces, medical equipme nt, aerospace, specialized equipment, intelligent managementand process control fields, roughly divided into the followi ng several areas:(1)In the application of Intelligent InstrumentsSCM has a small size, low power con sumpti on, con troll ingfun cti on, expa nsion flexibility, the adva ntages of miniaturization and ease of use, widely used instrument,comb ining differe nt types of sen sors can be realized Zhuru voltage, power, frequency, humidity, temperature, flow, speed, thick ness, an gle, len gth, hard ness, eleme ntal, physical pressure measureme nt. SCM makes use of digital in strume nts, in tellige nee, mini aturizati on, and fun cti on ality tha n electro nic or digital circuits more powerful. Such as precisi on measuri ng equipme nt (power meter, oscilloscope, various an alytical in strume nt).(2)In the in dustrial con trol applicati onWith the MCican constitute a variety of control systems, data acquisition system. Such as factory assembly line ofin tellige nt con trol,all kinds of alarm systems,a nd computer n etworks con stitute a sec on dary con trol system.(3)In the Applianee of Household appliancesIt can be said that the appliances are basically using SCM, praise from the electric rice, washing machines, refrigerators, air con diti on ers, color TV, and other audio video equipme nt, to the electronic weighing equipment, varied, and omnipresent. (4)In the field of computer n etworks and com muni cati ons applicati onsMCU gen eral with moder n com muni cati on in terface, can be easy with the computer data com muni cati on, n etwork ing and com muni cati ons in computer applicati ons betwee n devices had excelle nt material con diti ons, are basically all com muni cationequipme nt to achieve a con trolled by MCU from mobile pho ne, teleph one, min i-program-c on trolled switchboards, buildi ng automated com muni catio ns call system, train radiocom muni cati on, to the daily work can be see n everywhere in the mobile phon es, trun ked mobile radio, walkie-talkies, etc..(5 ) Microcomputer in the field of medical device applicati onsMCU in the use of medical devices is also quite extensive, such as medical respirator, the various an alyzers, mon itors, ultraso und diag no stic equipme nt and hospital beds, etc. call system.(6 ) In a variety of major appliances in the modular applicati onsDesigned to achieve some special single specific functionto be modular in a variety of circuit applicati ons, without requiring the use of personnel to understand its internal structure. If music in tegrated sin gle chip, seem in gly simple fun cti on, mini ature electr onic chip in the net (the principle is different from the tape machine), you need a computer similarto the prin ciple of the complex. Such as: music sig nal to digital form stored in memory (like ROM), read by the microc on troller, an alog music in to electrical sig nals (similar to the sound card).In large circuits, modular applications that greatly reducethe volume, simplifies the circuit and reduce the damage, errorrate, but also easy to replace.(7) Microcontroller in the application field of automotive equipme ntSCM in automotive electro nics is widely used, such as avehicle engine controller, CAN bus-based IntelligentElectronic Control Engine, GPS navigation system, absan ti-lock braki ng system, brake system, etc..In additi on, the MClih bus in ess, finan ce, research, education,n ati onal defe nse, aerospace and other fields has a very widerange of applicati ons.译文51系列单片机的功能和结构结构和功能的监控监-51系列之一--计算机芯片监控监-51名是一幅一个电脑晶片，英特尔公司生产系列.这家公司推出8级一个计算机芯片监控监-51系列之后，于1980年8引入一个计算机芯片监控监，于1976年48系列.。