基于单片机的数控车床xy工作台与控制系统设计翻译.pdf

Single Chip Microcomputer A microcontroller or MCU is a computer on a chip It is a type of microprocessor emphasizing self sufficiency and cost effectiveness in contrast to a general purpose microprocessor the kind used in a PC The majority of computer systems in use today are embedded in other machinery such as telephones clocks appliances vehicles and infrastructure An embedded system usually has minimal requirements for memory and program length and may require simple but unusual input output systems For example most embedded systems lack keyboards screens disks printers or other recognizable I O devices of a personal computer They may control electric motors relays or voltages and read switches variable resistors or other electronic devices Often the only I O device readable by a human is a single light emitting diode and severe cost or power constraints can even eliminate that In contrast to general purpose CPUs microcontrollers do not have an address bus or a data bus because they integrate all the RAM and non volatile memory on the same chip as the CPU Because they need fewer pins the chip can be placed in a much smaller cheaper package Integrating the memory and other peripherals on a single chip and testing them as a unit increases the cost of that chip but often results in decreased net cost of the embedded system as a whole Even if the cost of a CPU that has integrated peripherals is slightly more than the cost of a CPU external peripherals having fewer chips typically allows a smaller and cheaper circuit board and reduces the labor required to assemble and test the circuit board This trend leads to design A microcontroller is a single integrated circuit commonly with the following features central processing unit ranging from small and simple 4 bit processors to sophisticated 32 or 64 bit processors input output interfaces such as serial ports UARTs other serial communications interfaces like I C Serial Peripheral Interface and Controller Area Network for system interconnect peripherals such as timers and watchdog RAM for data storage ROM EPROM EEPROM or Flash memory for program storage clock generator often an oscillator for a quartz timing crystal resonator or RC circuit many include analog to digital converters This integration drastically reduces the number of chips and the amount of wiring and PCB space that would be needed to produce equivalent systems using separate chips and have proved to be highly popular in embedded systems since their introduction in the 1970s Some microcontrollers can afford to use a Harvard architecture separate memory buses for instructions and data allowing accesses to take place concurrently The single slice of the earlier period all of machines are 8 or 4 Among them the INTEL is most successful of 8031 because of in brief dependable but the function was quite good to acquire very big good opinion Henceforth at 8031 up developed MCS51 serieses a single slice machine system According to the single slice of this system machine system is still in the extensive usage till now Because the industry controls the exaltation of with realm request starting appearing 16 single slice machine but because sex price wanted to don t get a very extensive application than the disregard Develop greatly along with the consumption electronics product after 90 s the single slice machine technique got a huge exaltation Along with the extensive application of INTEL i 960 serieses especially later ARM series the 32 single slice machine replaces 16 single slice the high level position of the machine quickly and gets into an essential market And traditional of 8 single slice the function of the machine also got to fly to raise soon handling an ability to compare with to raise few a hundredfolds in 80 s Currently 32 single slice of the high level with main machine already over 300 MHzs the function keeps appropriation processor of making track for the mid 90 s and the common model number factory price drop into to USD 1 tallest carry of model number also only USD 10 The contemporary and single slice machine system has already no longer developed and used just under the naked machine environment the in great quantities appropriative built in operate system is applied extensively in the whole serieseses of the single slice is on board But Be ising the high level of handheld PC and cellular phone core processing single slice the machine even can use appropriative Windows and the Linux operate system directly Single slice the machine ratio appropriation processor is the most suitable to match to apply in the built in system so it got the most applications In fact the single slice machine is an amount the most calculators are in the world The modern mankind are living medium use of assemble in almost each electronics and machine product have a single slice machine All have 1 2 single slice machine in the computer accessorieses such as cellular phone telephone calculator home appliances electronics toy handheld PC and mouse etc And personal computer in would also capable number not a few single slice the machine be working Provide with more than 40 departments a single slice machine generally on the car complicated industry s controling the top of the system even may has single several hundred pedestalses slices machine to work in the meantime Single slice the amount of the machine not only far above the PC machine and other calculations of comprehensive even than the mankind s amount still want have another Singlechip study should be an important part in the five First the bus we know that a circuit is always from the components through wires connected and in analog circuits the connection does not become a problem because the devices are generally serial inter relationship between the various devices connection is not much but not the same as computer circuits which is based on the microprocessor as the core the device must be connected with the microprocessor the device must be between the mutual coordination and so on need to connect on a lot of If still the same as analog circuits in the microprocessor and a separate connection between the devices the quantity line will be many alarmingly so in the microprocessor introduced the concept of bus all devices share the connection All devices of all eight data lines from eight public online which is equivalent to all devices in parallel but only this is not enough if there is two devices send data simultaneously a 0 a 1 then the receiving party received what is it This situation is not allowed so to pass the line of control to control the device time job any time there can be only one device to send data which may have multiple devices simultaneously receiving Device s data lines will be referred to as data bus all the line of control devices known as control bus Singlechip at internal or external memory and other devices have memory cells these memory cells to be assigned addresses to use the allocation of addresses is of course to give the form of electrical signals and because memory cells are more so for address the allocation of more lines these lines were known as the address bus Second data address command The reason why these three together because these three are the essence is the same figure or are a string of 0 and 1 composed of sequence In other words addresses instructions are also data Command from single chip chip designer provides a figure it is consistent with our mnemonic commonly used commands have a strict one to one relationship not by the developer to change the MCU Address Singlechip are looking for internal external storage units input and output port based on the value of the internal unit s address has been provided for the chip designers and can not be changed the external unit can be single chip developers to decide but Yes there is some address must be the unit see procedures for the implementation process Data This is the object of treatment by the microprocessor in a variety of different applications in different circuits in general the data may be processed so have several situations 1 address such as MOV DPTR 1000H that address 1000h into the DPTR 2 the way the words or control characters such as MOV TMOD 3 3 which controls the characters 3 constants such as MOV TH0 10H 10H that is constant from time to time 4 The actual output value such as the mouth then P1 lantern light to light the whole then the implementation of instruction MOV P1 0FFH to light the whole dark then the implementation of instruction MOV P1 00H and 00H are here 0FFH actual output value Another example is the font code for the LED is the actual output value Understanding of the address the nature of instructions running is not difficult to understand why the process of running fly the data will be implemented as instructions Three P0 mouth P2 and P3 the mouth of the second function Usage often on P0 beginner I P2 and P3 mouth I use the second function puzzled think the second function and the original features have a switch between the process or that there have to be a directive in fact the port s second feature is completely automatic no need to use command to convert Such as P3 6 P3 7 respectively are WR RD signal when the micro chip RAM or external justifications machine has an external I O port they were used as the second function can not be used as general purpose I O port to use as long as one microprocessor implementation of the MOVX instruction 1 there will be a corresponding signal sent from the P3 6 or P3 7 no prior use instructions indicate In fact can not be used as general purpose I O port use is not should not but user not as a general purpose I O port to use At command you can arrange a Medium of Instruction SETB P3 7 and when the single chip implementation of this Article directions P3 7 will also become high but users will not do so because This usually will lead to the collapse of the system Four the program implementation process single chip power on reset in 8051 after the program counter PC in the value of 0000 so the procedure always 0000 unit begin implementation of that is to say the system s ROM must exist in the 0000 in this unit and 0000 in the storage unit must be a command Five the stack the stack is a region are used to store data the region does not have any unique position that is a part of internal RAM special is its data storage and access methods namely the so called advanced after that last in first out and the stack has a special data transmission command ie PUSH and POP there is a special unit specifically for its services that is the stack pointer SP when they first PUSH instruction the SP on at the origina