【正文】 simple and the easy be imitators. Investigate its reason, may be stuck in product without using SCM or other programmable logic devices. . Microcontroller history 1971 Intel pany developed the world39。s first microputer. 1976 the Intel pany develop MCS 48 series of 8 bits of single chip microcontroller, this also is published. Zilog pany in 1976 development Z80 microprocessor, widely used in microputer and industrial automatic control equipment. At that time, Zilog, Motorola and Intel microprocessor field in Japan. In the early 1980s, the Intel pany in MCS 48 series microcontroller, on the basis of launched MCS 51 series 8 bits of highgrade microcontroller. MCS 51 series microcontroller whether pieces (RAM capacity, I/O mouth function, system extension aspects had the very big enhancement. Singlechip the bus: we know that a circuit is always from the ponents through wires connected, and in analog circuits, the connection does not bee a problem, because the devices are generally serial interrelationship between the various devices connection is not much, but not the same as puter 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). Device39。139。can not be used as generalpurpose I / O port use39。not39。000039。in this unit, and39。, and the stack has a special data transmission mand, ie39。, 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 original value of the foundation on) automatically add one, whenever the implementation of a POP instruction, SP on (at the original value basis) minus one automatically. Because of the value of SP can be used to change directions, so as long as the stage at the beginning of the proceedings to change the value of the SP, you can put the stack set up the required memory units, such as at the beginning of the proceedings, with a MOV SP, 5FH instructions when put on the stack from the memory modules installed in the unit 60H start. The normal procedure at the beginning of the total that there is a stack pointer of the instruction set, because at startup, SP initial value of 07H, thus the stack from the beginning the next unit 08h, and 08h to 1Fh in the region 8031 is the second, Three, four working registers area, often used, this will lead to data chaos. The author has prepared a different program, not exactly the same instructions to initialize the stack, which is the author39。 And rolling mill, large longmen planer, spindle etc need fast brake class load, the motor is inevitably exists generating process, namely of motor rotor in external drag or load inertia maintain itself under the actual, making the motor speed is greater than the synchronous speed inverters, motor power will be issued by stored in inverter with dc bus filter capacitance, if you don39。t achieve motor precision braking . Five. With the development of the technology of puter and control， the temperature control of electric heating furnace is being fully developed, the technology has been an important part of industry. To meet the requirement of industrial control, the thesis designs a system which is constituted of temperature detecting device, A/D conversion, monolithic processor keyboard and display apparatus, alarming circuit and D/A conversion based on the control of electric heating furnace. The thesis explains the principle, the concept of design, constitution and characteristic. Because of the great developing speed of automatic temperature controlling, the thesis try to explain the system in detail, and the thesis also reflect the direction of the development of temperature controlling system. This design controlled member is an electric heating stove, adds through the control in the resistance wire beginnings and ends voltage operating time operating time, es the average power which outputs to the resistance wire to perform to control. Automatic temperature control of the electric furnace is realized by a temperature control circuit of solid state relay on the basis of the singlechip puter. This article put PID algorithm applies in the resistance furnace temperature control system, elaborated PID controller design, the hardware constitution and the software design, have realized set of temperatures gathering and the control design proposal. This control system has such advantages as low cost .control accuracy, good reliability and good resistance to interference. application of single chip in electronic scale The development of the modern society has put forward higher request on weighing technology. The desktop electronic scales have been great application in mercial trade, but they have many shortings such as large volume, high cost, AC supply power and not cove nince to carry, so they are restricted to use. The usual portable scales are lever scales which are mostly used by residents, and spring balance which measure through pression or drawing of spring. They are being rejected for their big measuring errors. People have be