附件1：外文文献原文
BASED ON MCU INTERSECTION TRAFFIC LIGHTS THE CONTROLLER DESIGN
Because of the rapid development of our economy resulting in the car number of large and medium-sized cities surged and the urban traffic, is facing serious test, leading to the traffic problem increasingly serious, its basically are behaved as follows: traffic accident frequency, to the human life safety enormous threat, Traffic congestion, resulting in serious travel time increases, energy consumption increase; Air pollution and noise pollution degree of deepening, etc. Daily traffic jams become people commonplace and had to endure. In this context, in combination with the actual situation of urban road traffic, develop truly suitable for our own characteristics of intelligent signal control system has become the main task.
Preface
In practical application at home and abroad, according to the actual traffic signal control application inspection, planar independent intersection signal control basic using set cycle, much time set cycle, half induction, whole sensor etc in several ways. The former two control mode is completely based on planar intersection always traffic flow data of statistical investigation, due to traffic flow the existence of
variable sex and randomicity, the two methods have traffic efficiency is low, the scheme, the defects of aging and half inductive and all the inductive the two methods are in the former two ways based on increased vehicle detector and according to the information provided to adjust cycle is long and green letter of vehicle, it than random arrived adaptability bigger, can make vehicles in the parking cord before as few parking, achieve traffic flowing effect In modern industrial production,current,voltage,temperature, pressure, and flow rate, velocity, and switch quantity are common mainly controlled parameter. For example: in metallurgical industry, chemical production, power engineering, the papermaking industry, machinery and food processing and so on many domains, people need to transport the orderly control. By single chip microcomputer to control of traffic, not only has the convenient control, configuration simple and flexible wait for an advantage, but also can greatly improve the technical index by control quantity, thus greatly improve product quality and quantity. Therefore, the monolithic integrated circuit to the traffic light control problem is an industrial production we often encounter problems.
In the course of industrial production, there are many industries have lots of traffic equipment, in the current system, most of the traffic control signal is accomplished by relays, but relays response time is long, sensitivity low, long-term after use, fault opportunity increases greatly, and adopts single-chip
microcomputer control, the accuracy of far greater than relays, short response time, software reliability, not because working time reduced its performance sake, compared with, this solution has the high feasibility.
About AT89C51
random翻译(1)function characteristics description:
AT89C51 is a low power consumption, high performance CMOS8 bit micro-controller, has the 8K in system programmable Flash memory. Use high-density Atmel company the beltpassword nonvolatile storage technology and manufacturing, and industrial 80S51 product instructions and pin fully compatible. Chip Flash allow program memory in system programmable, also suitable for conventional programmer. In a single chip, have dexterous 8 bits CPU and in system programmable Flash, make AT89C51 for many embedded control application system provides the high flexible, super efficient solution. A T89C51 has the following standard function: 8k bytes Flash, 256 bytes RAM, 32-bit I/O mouth line, the watchdog timer, two data pointer, three 16 timer/counter, a 6 vector level 2 interrupt structure, full-duplex serial port, piece inside crystals timely clock circuit. In addition, AT89C51 can drop to 0Hz static logic operation, support two software can choose power saving mod
e. Idle mode, the CPU to stop working, allowing the RAM, timer/counter, serial ports, interruption continue to work. Power lost protection mode, RAM content being saved, has been frozen, microcontroller all work stop, until the next interruption or hardware reset so far. As shown in figure 1 for the AT89C51 pins allotment.
Figure 1 the A T89C51 pins allotment
(2)interrupt introduction
AT89C51 has six interrupt sources: two external interruption, (and), three timer interrupt (timer 0, 1, 2) and a serial interrupts. Each interrupt source can be passed buy bits or remove IE the relevant special register interrupt allow control bit respectively make effective or invalid interrupt source. IE also includes an interrupt allow total control bit EA, it can be a ban all interrupts. IE. Six is not available. For AT89C51, IE. 5 bits are also not be used. User software should not give these bits write 1. They AT89 series for new product reserved. Timer 2 can be TF2 and the T2CON registers EXF2 or logical triggered. Program into an interrupt service, the sign bit can be improved by hardware qing 0. In fact, the interrupt service routine must determine whether TF2 or EXF2 activation disruption, the sign bit must also by software qing 0. Timer 0 and 1 mark
a timer TF0 and TF1 has been presented in the cycle count overflow S5P2 074 bits. Their value until the next cycle was circuit capture down. However, the timer 2 marks a TF2 in count overflow of the cycle of S2P2 074 bits, in the same cycle was circuit capture down
Table 1
Table 2
About 8255 chip
1.8255 features:
(1)A parallel input/output LSI chips, efficacy of I/O devices, but as CPU bus and peripheral interface.
(2)It has 24 programmable Settings of I/O mouth, even three groups of 8 bits I/O mouth to mouth, PB mouth and PA PC mouth. They are divided into two groups 12 I/O mouth, A group including port A an
d C mouth (high four, PC4 ~ PC7), including 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, two-way 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.
(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 communications, / 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 ~ two-way 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, PB mouth be chosen;
When A0=0, A1 = 1, PC mouth be chosen;
When A0=1, A1= 1, control register is selected.
Concerning seven section LED display introduction Through light emitting diode chip appropriate link (including series and parallel) and appropriate optical structure. May constitute a luminous display light-emitting segments or shine points. By these luminous segments or shine point can be composed digital tube, symbols tube, m word pipe, tube, multilevel matrix display tube etc. Usually the digital tube, symbols tube, m word tube were called stroke display, but the stroke displays and matrix tube collectively referred to as character displays.
1. The LED display classification
(1) by word high marks: stroke monitors word high least 1mm (monolithic integrated type more digital tube word high in commonly 2 ~ 3mm). Other types of stroke display tiptop 1.27 mm (0.5 inch) even up to hundreds of mm.
(2) color-coded score red, orange, yellow, green and several kinds.
(3) according to the structure points, reflecting cover type, a single point-elastic and monolithic integrated type.
(4) from the luminous section electrode connection mode of points of anode and cathode two kinds.
2. LED display parameters
Due to the LED display is LED based, so its light, and the electrical characteristics and ultimate meaning of the parameters with most of the same light emitting diode. But because the LED monitor containing multiple light emitting diode, it must has the following specific parameters:
(1) the luminous intensity ratio
Due to the digital tube paragraphs in the same driving voltage, each are not identical, so positive current each different. The luminous intensity All segments of the luminous intensity values the ratio of the maximum and minimum values for the luminous intensity ratio. The ratio between 2.3 in 1.5 ~, the maximum cannot exceed 2.5.
(2) pulse positive current
IF each segment of typical strokes displays for positive dc working current IF, then the pulse, positive current can be far outweigh.someotherwordpeopledontthinkoffirst. Pulse 390v 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 network 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 network coordination control surface controlling; -- According to the control principle differentiates: timing control, induced control and adaptive control.
About watch-dog circuit
By single-chip computers.the micro computer system, because of single chip work often can be affected by external electromagnetic interference, causing program run fly while into dead circulation, the program's normal operation be interrupted by single chip microcomputer control system was unable to work, can cause the whole system of come to a standstill, happen unpredictable consequences, so out of microcontroller running status real-time.according consideration, they generate a specially used for monitoring microcontroller program running state of the chip, commonly known as "watchdog" (watchdog).

版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。