单片机8255扩展交通灯设计

Guangdong Institute of EducationBTEC CenterProgram: Electrical/Electronic Engineering (Electronic) Unit Title: Microprocessor SystemsUnit No: 10 Assignment Title: Design of traffic lights on public roads Assignment No.: 1002Issue Date: 10.19Submission Deadline: 12.13Assessor/Tutor: Sunny YaoInternal Verifier: Ricky ZhangStudent: Hong GuoStudent’s Reg. No: A233172NOTES TO STUDENTS●Check carefully the submission date and the instructions given with theassignment. Late assignments will not be accepted.●Ensure that you give yourself enough time to complete the assignment by the duedate.●Do not leave things such as printing to the last minute – excuses of this naturewill not be accepted for failure to hand-in the work on time.●You must take responsibility for managing your own time effectively.●If you are unable to hand in your assignment on time and have valid reasons suchas illness, you may apply (in writing) for an extension.●When you refer to the work of other authors in your assignment, you mustpractice citation by following Harvard System for Referencing.●If you are caught plagiarizing, you could have your grade reduced to zero, orat worst, you could be excluded from the course.STUDENT’S DECLARATION:I confirm that this is all my own work.Student’s Signature: Hong GuoAssignment DescriptionScenarioOn the bustling road of heavy traffic and endless stream of people,Safety guidelines for public roads are very important to ensure people against traffic injury. The traditional way is to equip traffic police or coordination and management personnel for the public roads. But this method is not only a waste of human and financial resources. Besides while the traffic police or the coordination and management personnel are working they usually have to withstand sunning, winding or raining. In addition, they must still face to security threats bringing from traffic accidents in every minute.Nowadays science and technology are in rapid development, this traditional practice can completely be replaced by advanced electronic products. The public road safety indicator lights which are design based on microprocessors are rightly such products. Not only these products can be designed flexibly and adjusted easily but also they are cost-effective in using and maintenance. In addition, they are really a beautiful landscape in city life.Now suppose you are an Electrical Engineer. You are assigned to design a type of traffic lights on public roads for Municipal Authority. The specific requirements are as follows:1.The product can absolutely guarantee the safe of traffic.2.Product should have no less than two guidelines so as to fit for different roadconditions.3.Please set aside a certain number of ports so that they can be upgraded insome day.As an electronics design engineer, you must complete the task as following: Task:1. (Pass Criterion 1.1) Compare types of microprocessor device families. Please compare no less then three types of microprocessor device families in parameters(word length, speed, memory space, timer/counters, i/o facilities, interrupt）in table and then select one type to do your design.2. (Pass Criterion3.1) Evaluate and choose programmable interface devices for a particular situation. Generally speaking, programmable interface device is a type of multi-purpose LSI chip. For example, 8279 is a common programmable interface device which can conveniently accomplish a design including microprocessor-based systems, keyboard and monitors. For another example, 8255 and 8155 are also programmable interface devices which are generally used for expanding ports of microprocessor-based systems. Please evaluate and choose appropriate programmable interface devices to accomplish your design.3. (Pass Criterion 3.2) Design, build program and test an interface for an external device to a microprocessor-based system. Design a schematic circuit, built an algorithm block flow diagram, write a program and test an interface for an external device to a microprocessor-based system. Please pay attention to their consistency and provide detail design steps. In addition, a detailed state description of the implementation phenomenon of your program should be given in text and g raphics or tables.Solution：1. According to the subject, I conpared the following table of the three different types2.Inside 8255, it is 3 parallel data input / output ports, two ways of working control circuit, a read / write control logic circuit and an 8-bit bus buffer. There are two work control circuit: one is group A control circuit, and another is group B control circuit. This two groups control circuit have a Control Command Register to accept the control word from CPU so that they can decide the working way of two ports. And they can also according to the control word requirements to clear exit "0" or by location "1" of the C bitwise.Group A control circuit is used to control upper part of A bitwise and C bitwise(PC7-PC4). Group B control circuit is used to control bottom half of B bitwise and C bitwise(PC3-PC0).Bus Data Buffer is a 3-state bi-directional 8-bit buffer, as a interface between 8255 and system bus, to transferring data, command, control, command, and external state information.Read / write control logic circuit accept the control signal RD,WR,RESEET, address signal AIA0 and so on. Then they according to the requirements of control signal to read out the port data and send that to CPU, or read the data from CPU in port.3. According to the title, I select 8051 and 8255 to design my traffic lights. First I will draw the statechart under reality.Second : The circuit connection diagram I designed：Third: According to the circuit diagram and the status flow, I give the Binary outputORG 00HPORTA EQU 7CFFHPORTB EQU 7DFFHPORTC EQU 7EFFHCADDR EQU 7FFFHLVB: MOV DPTR,#7FFFHMOV A,#80HMOVX @DPTR,AMOV DPTR,#7DFFHMOV A,#42HMOVX @DPTR,AMOV DPTR,#7EFFHMOV A,#49HMOVX @DPTR,AMOV R4,#12LCALL DELAYDebug results：The program of the second state: LVB1:MOV DPTR,#7DFFHMOV A,#08HMOVX @DPTR,AMOV DPTR,#7EFFHMOV A,#61HMOVX @DPTR,AMOV R4,#12LCALL DELAYMOV R7,#6Debug results：So the whole program is：ORG 00HPORTA EQU 7CFFHPORTB EQU 7DFFH PORTC EQU 7EFFH CADDR EQU 7FFFH LVB: MOV DPTR,#7FFFHMOV A,#80HMOVX @DPTR,AMOV DPTR,#7DFFHMOV A,#42HMOVX @DPTR,AMOV DPTR,#7EFFHMOV A,#49HMOVX @DPTR,AMOV R4,#12LCALL DELAY LVB1:MOV DPTR,#7DFFH MOV A,#08HMOVX @DPTR,AMOV DPTR,#7EFFHMOV A,#61HMOVX @DPTR,AMOV R4,#12LCALL DELAYMOV R7,#6LVB2:MOV DPTR,#7DFFH MOV A,#04HMOVX @DPTR,AMOV DPTR,#7EFFHMOV A,#51HMOVX @DPTR,AMOV R4,#3LCALL DELAYMOV DPTR,#7DFFHMOV A,#00HMOVX @DPTR,AMOV DPTR,#7EFFHMOV A,#41HMOVX @DPTR,AMOV R4,#3LCALL DELAYDJNZ R7,LVB2LVB3:MOV DPTR,#7DFFHMOV A,#03HMOVX @DPTR,AMOV DPTR,#7EFFHMOV A,#0CHMOVX @DPTR,AMOV R4,#12LCALL DELAYMOV R7,#6LVB4:MOV DPTR,#7DFFH MOV A,#02HMOVX @DPTR,AMOV DPTR,#7EFFHMOV A,#8AHMOVX @DPTR,AMOV R4,#3LCALL DELAYMOV DPTR,#7DFFHMOV A,#02HMOVX @DPTR,AMOV DPTR,#7EFFHMOV A,#08HMOVX @DPTR,AMOV R4,#3LCALL DELAYDJNZ R7,LVB4LJMP LVB1 DELAY: MOV R3,#0D2:MOV R2,#0D1:DJNZ R2,D1DJNZ R3,D2DJNZ R4,DELAYRETENDReference:Journal articles:Internet resource:。