【正文】 ncluding group B and C port B mouth (low four, PC0 ~ PC3). A group can be set to give basic I/O mouth, flash control (STROBE) I/O flash controlled, twoway I/O3 modes, Group B can only set to basic I/O or flash controlled the I/O, and these two modes of operation mode entirely by controlling registers control word decision. 2. 8255 pins efficacy: (1). RESET: RESET input lines, when the input outside at high levels, all internal registers (including control registers) were removed, all I/O ports are denoting input methods. 附錄 4 (2). CS: chip choose a standard lamp line 1, when the input pins for low levels, namely/CS = 0, said chip is selected, allow 8255 and CPU for munications, / CS = 1, 8255 cannot with CPU do data transmission. (3). RD: read a standard lamp line 1, when the input pins for low levels, namely/RD = 0 and/CS = 0, allow 8255 through the data bus to the CPU to send data or state information, namely the CPU 8255 read from the information or data. (4). The WR: write a standard lights, when the input pins for low levels, namely/WR = 0 and/CS = 0, allows the CPU will data or control word write 8255. (5). D7: three states D0 ~ twoway data bus, 8255 and CPU data transmission channel, when the CPU execution input/output instruction, through its realization 8 bits of data read/write operation, control characters and status information transmitted through the data bus. (6). PA0 ~ PA7: port A input and output lines, A 8 bits of data output latches/buffers, an 8 bits of data input latches. (7). PB0 ~ PB7: port B input and output lines, a 8 bits of I/O latches, an 8 bits of input and output buffer. (8). PC0 ~ PC7: port C input and output lines, a 8 bits of data output latches/buffers, an 8 bits of data input buffer. Port C can through the way of working setting into two four ports, every 4 digit port contains A 4 digit latches, respectively with the port A and port B cooperate to use, can be used as control standard lights output or state standard lights input ports. (9). A0, A1: address selection line, used to select the PA 8255 mouth, PB mouth, PC mouth and controlling registers. When A0=0, A1= 0, PA mouth be chosen。 When A0=0, A1 = 1, PC mouth be chosen。 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。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). 附錄 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 附錄 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。 two Either according to the traffic rules, things direction 60 seconds, northsouth direction 40 seconds, time control are fix