【正文】 , energy feedback unit suitable to the large inertia load such as: fan, cement system pipe, dynamic balancing machines, centrifuge, etc。s study, development and application of puter application will create and intelligent control of scientists and engineers. SCM is widely applied in instrumentation, household appliance, medical equipment, aerospace, special equipment of intelligent management and process control and other fields, roughly can divide the following several categories: 1. In intelligent instruments on the application Singlechip microputer with small size, low power consumption, control function is strong, flexible, miniaturization and extended use convenience etc, which are widely used in instrumentation, bined with different kinds of sensors, which can realize such as voltage, power, frequency, humidity, temperature and flow rate, speed, thickness, Angle, length, hardness, elements and pressures, physical measurement. Adopting SCM control makes instrument digital, intelligent, miniaturization, and functional than by electronic or digital circuit stronger. For example precision measuring equipment (power meter, oscilloscope, various analyzer). 2. The application in industrial control MCU can constitute the various forms of control system, the data acquisition system. For example the production line of the intelligent pipe principle, the elevator intelligent control, various alarm system, work with puter constitute a secondary control system, etc. 3. The application in household appliances It can be said that now of household appliances basically adopts singlechip microputer control, from electric cooker, washing machines, refrigerators, air conditioner, color television, other audio video equipment, arrive again microelectronic quantity equipment, multifarious, omnipresent. 4. In puter work and munication in the field of application Modern singlechip generally have munication interface can be easily and puter data munications, for in the puter work and munication between devices applied to provide the excellent material conditions of present munication equipment basically realized the singlechip microputer intelligent control, from mobile, telephone, small pabx, building automatic train munication calling system, wireless munication, arrive again daily work deductionsfrom the mobile phone, cluster mobile munications, radios, etc. 5. Microputer in the medical device field of application Microputer in the medical equipment of use also is quite widespread, such as medical breathing machines, various analyzer, monitors, ultrasound diagnostic equipment and sickbed call system, etc. 6. In various largescale electric appliance of modular applications Some special MCU designed to acplish a specific function, and in various circuit of modular application, without asking using personnel understand its internal structure. If music integrated microcontroller, seemingly simple function, miniature in pure electronic chip (different from the principle of tape) be plex resemble puter principle. Such as: music signals in digital form stored in memory (ROM), similar to read by micro controller, into analog signals (similar to the music sound card). In large circuit, this modular application greatly reduced volume and simplify the circuit and reduce the damage, the error rate, also facilitate replacement. 7. Microputer in the application fields of auto equipment Microputer in the automobile electronic application is very wide, for example in the car engine control, based on CAN bus automobile engine intelligence electronic controllers, GPS navigation system, abs antilock brakes, braking system, etc. In addition, microputer in the industry and merce, finance, scientific research, education, national defence aerospace and other fields have a wide range of purposes. First, energy feedback unit work principle On frequencyvariable speedadjustable system, when the motor load is a load of potential energy type such as oil pumping unit, mine hoist, etc。and39。 in the storage unit must be a mand. Friday, 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 socalled 39。s ROM must exist in the39。0000 39。should not39。s address has been provided for the chip designers, and can not be changed, the external unit can be singlechip 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 port39。0 39。s fir