外文翻译---基于单片机的十字路口交通灯控制器的设计-单片机(编辑修改稿)

外文翻译---基于单片机的十字路口交通灯控制器的设计-单片机(编辑修改稿)内容摘要：

smaller, pulse positive current can be bigger. Traffic signal control type The purpose of the traffic signal control are three: first,in time and space space intersection traffic in different directions,control traffic operation order。 Second, make on planar cross the road work on the people and objects of transport at the highest efficiency, Third, as the road users to provide necessary information, and help them to effectively use the traffic facilities. Road traffic signal control of basic types have many points method. According to the control geometry characteristic is divided into: single intersection control point control, the traffic trunk lines of coordinated control wire, traffic work coordination control surface controlling。 According to the control principle differentiates: timing control, induced control and adaptive control. About watchdog circuit By singlechip micro puter system, because of single chip work often can be affected by external electromagic interference, causing program run fly while into dead circulation, the program39。 s normal operation be interrupted by single chip microputer control system was unable to work, can cause the whole system of e to a standstill, happen unpredictable consequences, so out of microcontroller running status consideration, they generate a specially used for monitoring microcontroller program running state of the chip, monly known as watchdog (watchdog). 附录 6 MAX692 was slightly system monitoring circuit chip, have backup battery switching, power lost discriminant functions monitoring, the watchdog. The encapsulation and pin instructions as figure2shows. Figure 2 MAX692 encapsulation and pins Watchdog circuit application, make SCM can in no condition to achieve continuous work, its working principle is: the watchdog chip and MCU an I/O pins are linked together, the I/O pins through program control it regularly to the watchdog of the pins on into high level (or the low level), this program statement is scattered on SCM other control statements, once among singlechip due to the interference makes application run into a fly after the procedures section into dead circulation state, write the watchdog pins program cannot be executed, this time, the watchdog circuit will be without microcontroller sent signals, then at it and MCU reset pin connected pin reset signal give out a a, make SCM reposition occurs, namely the program from program memory splittext started, so we realized the MCU automatic reset. Infrared detection circuit The infrared radiation photon in semiconductor materials stimutes the nonequilibrium carriers (electronic or holes), cause electrical properties change. Because carrier does not escape in vitro, so called within the photoelectric effect. Quantum photoelectric effect high sensitivity, response speed heat detectors much faster, is optional detectors. In order to achieve the best performance, generally need worked in low temperature. Photoelectric detector can be divided into: (1) optical type: also called photoconductive resistance. The incident photon stimulate the valence band uniform semiconductor electronic across forbidden band into the conduction band and left in valence band, cause cavitation increases, for electric conductance eigen light conductivity. From the band gaps of impurity level also can stimulate light into the conduction band or born carriers valence band, and for impurities light conductivity. The cutoff wavelength by impurity ionization energy (ie) decision. Quantum efficiencies below eigen optical and require lower working temperature. (2) photovoltaic type: mainly p n knot of light born volts effect. Energy more than the 附录 7 width of infrared photonic band gaps in area and its nearby of electrons cavitation. Existing electric field make hole into p area, electronic into n area, two parts appear potentials. Deoxidization device have voltage or current signal. Compared with optical detectors, pv detector detect rate more than forty percent of figure limit, Don39。 t require additional bias electric field and load resistance, no power consumption, having a high impedance. These characteristics of preparation and use of the focal plane array bring great benefits. (3) light emitting Schottky potential barrier detector: metal and semiconductor contact, typically include PtSi/Si structure and form was Schott potential barrier, infrared photon through Si layer for PtSi absorption, electronic Fermi level, obtain energy leap over left cavitation potential barrier into the Si substrate, PtSi layer of electronic was collected, plete infrared detection. Make full use of Si integration technology, facilitate production, with lower cost and good uniformity wait for an advantage, but make it mass (1024 x 1024 even greater) focal plane array to make up for the defect of quantum low efficiency. Have strict low temperature requirements. With this kind of detector, both at home and abroad has already produced as qualitative good thermography. Pt Si/Si structure made of FPA is the earliest IRFPA. Timing counting and traffic calculation Using MCS 51 internal timer/counter for timing, cooperate software delay realizes the timer. This method hardware cost saving, cut allows the reader in timer/counter use, disruptions and programming get exercise and improve. Computation formula is as follows: TC = M C Type in, M for counter touch value, the value and the counter working way concerned. For a traffic intersection, it can in the shortest possible time to achieve maximum traffic, even reached the best performance, we call in unit of time to achieve the maximum flow multienergy for cars. Use the equation: (traffic = traffic/time) to represent. Intersection traffic lights used to create the general though。