毕业设计基于单片机的频率计数器设计

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1、设计内容与设计要求设计内容：本课题以单片机为核心，设计和制作一个频率计数器，来完成对输入的信号进行频率计数，计数的频率结果通过6位动态数码管显示出来。要求能够对0250KHZ的信号频率进行准确计数，计数误差不超过1HZ。设计要求：1. 设计方案要合理、正确；2. 系统硬件设计；3. 完成必要元器件选择；4. 系统软件设计及调试；5. 写出设计报告。主要设计条件1. MCS-51单片机实验操作台1台；2. PC机及单片机调试软件；3. 单片机应用系统板1套；4. 制作工具1套；5. 系统设计所需的元器件。说 明 书 格 式课程设计封面课程设计任务书目 录一、设计的内容、要求及目的二、系统总体方案

2、选择与说明三、系统方框图与工作原理四、各部分方案选定、功能及计算五、器件说明六、应用系统的程序设计七、调试说明、使用说明八、设计总结九、参考文献 附录：程序清单，设计电路原理图进 度 安 排设计时间分为二周第一周星期一、上午：布置课题任务，课题介绍及讲课。 下午：借阅有关资料，总体方案讨论。星期二、确定总体方案，学习与设计相关内容。星期三、各部分方案设计。星期四、各部分设计。星期五、设计及上机调试。第二周星期一：设计及上机调试。星期二：调试，中期检查。星期三：调试、写说明书。星期四-星期五上午：写说明书、完成电子版并打印成稿。星期五下午：答辩。目 录第1章 频率计数器设计 1.1设计内容、要求

3、及目的 1.2 基本原理与总体方框图第2章 硬件系统设计 2.1各部分方案及说明 2.1.1 单片机部分2.1.2 状态译码器2.1.3数据显示电路第3章 软件系统设计 3.1 应用系统的程序设计 3.1.1 1s定时 3.1.2 T1计数程序 3.1.3 进制转换 3.1.4 数码显示 3.2 程序调试第4章 设计总结体会 参考文献附录第1章 频率计数器设计1.1 设计的内容、要求及目的设计内容：本课题以单片机为核心，设计和制作一个频率计数器，来完成对输入的信号进行频率计数，计数的频率结果通过6位动态数码管显示出来。要求能够对0250KHZ的信号频率进行准确计数，计数误差不超过1HZ。 设计

4、要求：1. 设计方案要合理、正确；2. 系统硬件设计；3. 完成必要元器件选择；4. 系统软件设计及调试； 5.写出设计报告 实验目的本应用系统实验的目的是通过在“单片机原理及应用”课堂上学习的知识，以及查阅资料，培养一种自学的能力。并且引导一种创新的思维，把学到的知识应用到日常生活当中。在设计的过程中，不断的学习，思考和同学间的相互讨论，运用科学的分析问题的方法解决遇到的困难，掌握单片机系统一般的开发流程，学会对常见问题的处理方法，积累设计系统的经验，充分发挥教学与实践的结合。全能提高个人系统开发的综合能力，开拓了思维，为今后能在相应工作岗位上的工作打下了坚实的基础。1.2 基本原理与总体方

5、框图基本原理 频率计数器的主要功能是测量周期信号的频率。频率是单位时间（ 1S ）内信号发生周期变化的次数。如果我们能在给定的 1S 时间内对信号波形计数，并将计数结果显示出来，就能读取被测信号的频率。测量过程中定时/计数器T0和T1的工作方式设置，T1是工作在计数状态下，对输入的频率信号进行计数，在本次设计使用的98C51单片机，由于检测一个由“1”到“0”的跳变需要两个机器周期，前一个机器周期测出“1”，后一个周期测出“0”。故输入时钟信号的最高频率不得超过单片机晶振频率的二十四分之一，最大计数值为fOSC/24，由于fOSC12MHz，因此：T1的最大计数频率为0.5mHz。对于频率的概

6、念就是在一秒只数脉冲的个数，即为频率值。所以T0工作在定时状态下，每定时1秒中到，就停止T0的计数，而从T0的计数单元中读取计数的数值，然后进行数据处理。送到数码管显示出来。总体方框图 课题设计的是一种以单片机为主控制的频率计。数字频率计主要由以下几部分组成：定时计数、采集数据、进制转换和数码显示。 本课题主要是以单片机AT89C51 为核心, 通过计数电路, 以及软件程序的编写, 实现脉冲频率的显示。频率计系统总体框图如下： 外部脉冲信号关闭中断 1s定时 同时开始计数AT89C51单片机中断响应段选频率数据采集进制转换数码管显示74LS138译码电路位选 图1 频率计系统总体框图 第2章

7、硬件系统设计 此次设计要求制作一频率计系统，需要使用的硬件主要包括51单片机芯片，74LS138译码器和数码管。另外还是用到排线若干，下载线及电源线。2.1 各部分方案选定、功能2.1.1 单片机部分 本次设计采用了AT89C51 单片机, AT89C51是一种带4K字节闪烁可编程可擦除只读存储器的低电压，高性能CMOS8位微处理器。如图2所示： 图2 AT89C52引脚图 AT89C51拥有五个中断源，当有外部脉冲到来时可实现中断的响应，另外AT89C51拥有定时/ 计数器（T0、T1），可实现定时与计数的功能。单片机AT89C51的P0、P2的4个8位并行I/O口可进行外部存储设备扩展。

8、2.1.2 状态译码器（74LS138） 图3 74LS138译码器 74LS138译码器输出的状态控制数码管的亮与灭，它有6个状态，连接到数码管的位选，达到点亮数码管点亮的要求。2.1.3 数据显示电路 图4 显示电路图 数据显示电路由限流电路和7段数码管组成,采用器件LED 显示器。本设计中采用了六个七段数码管进行数据显示, 将五个数码管串接起来进行显示, 显示数据即是对频率计的测量结果。系统板上硬件连线 ：（1） 把“单片机系统”中的P0.0P0.7口连接动态数码的段选ABCDEFGH端口。（2） 把“单片机系统”中的P2.0P2.2与译码器74LS138的A、B、C、引脚相连，再把译码

9、器经“非门”与“动态数码显示”区域中的1、2、3、4、5、6端口用6芯排线连接 。（3） 把“单片机系统”中的P3.5（T1）端子用导线连接到“频率源”的端子上。 (4) 把P3.2（/INT1）与按键连接。 第3章 软件系统设计3.1 应用系统的程序设 3.1.1 1s定时采用T0定时50，连续循环定时20次即可完成1定时，用一个计数单元20H存放循环的次数，每一次循环20H单元自减1，当20H单元为零时则1定时到时。其程序流程图如图5所示。 开始初始化T0 是否启动定时器等待中断NY启动定时器产生中断N20H-1=0？-重装初值Y关闭中断 结束 图5 1s定时流程图 3.1.2 T1计数程

10、序 设计中T1采用计数功能，思路是除了计数器T1的TH1和TL1用于计数外，再选用一个计数单元23H，每当计数器T1溢出回零时产生中断，中断程序执行23H单元自增1，这样，当一秒到时时采集的计数数据，23H单元存放的是数据的最高位，TH1存放的是数据的次高位，TL1存放的是数据的最低位。当然，这里所说的“最高位”“次高位”以及“最低位”都是针对十六进制而言的。T1计数程序的流程图如图6所示。 图6 T1计数流程图3.1.3 进制转换算法的基本思路是：第一步将最高位的高半字节提出来，除以10，把商存储起来，余数与最高位的低半字节组合成一个字节，再除以10，再存储商，余数以此类推，直到最后一次计算

11、得到的余数即为十进制数的个位；第二步把第一步存储的商组合成一个字节，依次除以10，仍然把每次得到的商存储起来，以此类推最后一次得到的余数即为十进制数的十位；以后也是以此类推得到十进制数的百位、千位以上算法必须要注意的一个为题是，每次得到的余数与低位的半字节组合成一个字节时，余数必须放在该字节的高半字节，否则计算错误。该本次频率计系待测的时钟信号的最高频率为460800Hz，对应的十六进制数为70800H，这里就以70800H转换为十进制数为例来说明这种算法。第一步：用7H除以10，商0H余7H，把商0存储在24H单元，余数7H与下一个字节08H的高半字节0H组合成一个字节70H。70H除以10

12、，商BH余2H，把商BH存储在25H单元，余数2H与8H组合成一个字节28H。28H除以10，商4H余0H，把商4H存储在26H单元，余数0H与0H组合成一个字节00H。00H除以10，商0H余0H，把商0H存储在27H单元，余数0H与0H组合成一个字节00H。00H除以10，商0H余0H，把商0H存储在28H单元，余数0即为所需十进制数的个位。第二步：把存储在24H与25H单元的商组合成一个字节0BH。0BH除以10，同第一步，存储商，余数与下一个商组合成一个字节，再除以10，一次类推得到十进制数的十位0。第三步：方法同第二步，得到十进制数的百位8。第四步：方法同第三步，得到十进制数的千位0

13、。第五步：方法同第四步，得到十进制数的万位6和十万位4。最后得到了十进制数460800。3.1.4 数码显示将十进制数转换为相应的LED显示的代码，最容易实现的编程方法就是查表，因数码管最多只需要显示六位，只需要查六次表就可以了，图7是将十进制数对应的LED显示代码存入以60H为首单元的流程图。 图7 十进制数转换为显示代码流程图3.2 程序的调试编写的频率计总体程序编译成HEX文件，写入51单片机内，在观察数码管显示的时候，发现高位的“0”仍然能够显示，而通常十进制的高位的“0”通常是省略的。为了解决这个问题，需要另外添加一段屏蔽高位的“0”的程序。具体程序编写如下：PINGBI: MOV

14、20H,#06H MOV R1,#55HPANDUAN:MOV A,R1 JNZ SCANNUM DEC R1 DEC 20H AJMP PANDUAN 程序经过调试以后，数码管从高位第一位不为“0”的数开始显示。 参考文献1、 单片机原理与应用 王迎旭等编 机械工业出版社2、 51系列单片机设计实例 楼然苗等编 北京航空航天大学出版社3、 计算机硬件技术基础实验教程 黄勤等编 重庆大学出版社4、微型计算机接口技术及应用 刘乐善主编 华中科技大学出版社5、单片微型计算机原理及接口技术陈光东等 华中科技大学出版社附录1源程序清单：ADD A,25HMOV B,#0AHDIV ABMOV 24H,

15、A ;存储第一位商MOV A,B M EQU 15N EQU 5ORG 0000HAJMP MAINORG 0003HAJMP CNINT0ORG 000BHAJMP T0INTORG 001BHAJMP T1INTORG 0030HMAIN:MOV SP,#70H MOV IE,#8BH ;开放EA、T1、T0中断 MOV TMOD,#51H;初始化程序 MOV TH0,#3DH MOV TL0,#71H MOV 20H,#20 MOV TH1,#00H MOV TL1,#00H MOV 21H,#00H MOV 22H,#00H MOV 23H,#00H SETB IT0 SJMP $CN

16、INT0:SETB TR0 SETB TR1 RETIT0INT:DJNZ 20H,NEXT1;定时中断服务程序 CLR TR1 CLR TR0 MOV 22H,TH1 MOV 21H,TL1 AJMP TRANSBDNEXT1:MOV TH0,#3CH MOV TL0,#0B0HEXIT:RETIT1INT:INC 23H;计数中断服务程序 RETITRANSBD:MOV SP,#70H;将十六进制数转换成十进制数MOV A,23HMOV B,#0AHDIV ABMOV 24H,A ;存储第一位商MOV A,BMOV 30H,22HANL 30H,#0F0HADD A,30HSWAP AMO

17、V B,#0AHDIV ABMOV 25H,A ;存储第二位商MOV A,BSWAP AANL 22H,#0FHADD A,22HMOV B,#0AHDIV ABMOV 26H,A ;存储第三位商MOV A,BMOV 30H,21HANL 30H,#0F0HADD A,30HSWAP AMOV B,#0AHDIV ABMOV 27H,A ;存储第四位商MOV A,BSWAP AANL 21H,#0FHADD A,21HMOV B,#0AHDIV ABMOV 28H,A ;存储第五位商MOV 50H,B ;存储十进制数个位MOV A,24HSWAP ASWAP AADD A,26HMOV B,#

18、0AHDIV ABMOV 25H,A ;存储第二位商MOV A,BSWAP AADD A,27HMOV B,#0AHDIV ABMOV 26H,A ;存储第三位商MOV A,BSWAP AADD A,28HMOV B,#0AHDIV ABMOV 27H,A ;存储第四位商MOV 51H,B ;存储十进制数十位MOV A,24HSWAP AADD A,25HMOV B,#0AHDIV ABMOV 24H,A ;存储第一位商MOV A,BSWAP AADD A,26HMOV B,#0AHDIV ABMOV 25H,A ;存储第二位商MOV A,BSWAP AADD A,27HMOV B,#0AHD

19、IV ABMOV 26H,A ;存储第三位商MOV 52H,B ;存储十进制数百位MOV A,24HSWAP AADD A,25HMOV B,#0AHDIV ABMOV 24H,A ;存储第一位商MOV A,BSWAP AADD A,26HMOV B,#0AHDIV ABMOV 25H,A ;存储第二位商MOV 53H,B ;存储十进制数千位MOV A,24HSWAP AADD A,25HMOV B,#0AHDIV ABMOV 54H,B ;存储十进制数万位MOV 55H,A ;存储十进制数十万位 DISPLAY:MOV R0,#60H;对60H-65H清零 MOV R1,#06HNEXT2:

20、 MOV R0,#00H INC R0DJNZ R1,NEXT2MOV R0,#50H;将数码管要显示的频率送到60H开头的内存MOV R1,#5FHMOV R2,#06HMOV DPTR,#TABNEXT3: MOV A,R0 MOVC A,A+DPTRINC R0INC R1MOV R1,ADJNZ R2,NEXT3PINGBI: MOV 20H,#06H MOV R1,#55HPANDUAN:MOV A,R1 JNZ SCANNUM DEC R1 DEC 20H AJMP PANDUAN SCANNUM:MOV R0,#60H;将60H开始的数送到数码管显示 MOV R1,#00HMOV

21、 R2,20H LIGHT:MOV A,R0MOV P0,A MOV A,R1 MOV P2,AINC R0INC R1ACALL DELAYDJNZ R2,LIGHT AJMP SCANNUMDELAY:MOV R5,M WAIT:MOV R6,N WAITT:DJNZ R6,WAITT DEC R5DJNZ R5,WAITRETTAB: DB 0C0H,0F9H,0A4H,0B0H,99H,92H,82H,0F8H,80H,90HEND附录2设计电路原理图：电气信息学院课程设计评分表项 目评 价优良中及格差设计方案合理性与创造性（10%）开发板焊接及其调试完成情况*（10%）硬件设计或软件

22、编程完成情况（20%）硬件测试或软件调试结果*(10%)设计说明书质量(20%)答辩情况(10%)完成任务情况(10%)独立工作能力(10%)出勤情况(10%)综 合 评 分 指导教师签名：_ 日 期：_ 注：表中标*号项目是硬件制作或软件编程类课题必填内容； 此表装订在课程设计说明书的最后一页。课程设计说明书装订顺序：封面、任务书、目录、正文、评分表、附件（非16K大小的图纸及程序清单）。 g an employment tribunal claiEmployment tribunals sort out disagreements between employers and employe

23、es.You may need to make a claim to an employment tribunal if: you dont agree with the disciplinary action your employer has taken against you your employer dismisses you and you think that you have been dismissed unfairly.For more information about dismissal and unfair dismissal, seeDismissal.You ca

24、n make a claim to an employment tribunal, even if you haventappealedagainst the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any compensation awarded to you as a result of your failure to appeal.Remember that in most cases you must m

25、ake an application to an employment tribunal within three months of the date when the event you are complaining about happened. If your application is received after this time limit, the tribunal will not usually accept i.If you are worried about how the time limits apply to you, take advice from on

26、e of the organisations listed underFurther help.Employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation.Most people find making a claim to an employment tribunal challenging. If you are thinking abou

27、t making a claim to an employment tribunal, you should get help straight away from one of the organisations listed underFurther help.If you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your compensation if you win the case

28、. This is known as adamages-based agreement. In England and Wales, your solicitor cant charge you more than 35% of your compensation if you win the case.If you are thinking about signing up for a damages-based agreement, you should make sure youre clear about the terms of the agreement. It might be

29、best to get advice from an experienced adviser, for example, at a Citizens Advice Bureau. To find your nearest CAB, including those that give advice by e-mail, click onnearest CAB.For more information about making a claim to an employment tribunal, seeEmployment tribunals.The (lack of) air up there

30、Watch mCayman Islands-based Webb, the head of Fifas anti-racism taskforce, is in London for the Football Associations 150th anniversary celebrations and will attend Citys Premier League match at Chelsea on Sunday.I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC

31、 Sport.For me its about how he felt and I would like to speak to him first to find out what his experience was.Uefa hasopened disciplinary proceedings against CSKAfor the racist behaviour of their fans duringCitys 2-1 win.Michel Platini, president of European footballs governing body, has also order

32、ed an immediate investigation into the referees actions.CSKA said they were surprised and disappointed by Toures complaint. In a statement the Russian side added: We found no racist insults from fans of CSKA.Age has reached the end of the beginning of a word. May be guilty in his seems to passing a

33、lot of different life became the appearance of the same day; May be back in the past, to oneself the paranoid weird belief disillusionment, these days, my mind has been very messy, in my mind constantly. Always feel oneself should go to do something, or write something. Twenty years of life trajecto

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35、od, think lucky money and new clothes are necessary for New Year, but as the advance of the age, will be more and more found that those things are optional; Junior high school, thought to have a crush on just means that the real growth, but over the past three years later, his writing of alumni in p

36、eace, suddenly found that isnt really grow up, it seems is not so important; Then in high school, think dont want to give vent to out your inner voice can be in the high school children of the feelings in a period, but was eventually infarction when graduation party in the throat, later again stood

37、on the pitch he has sweat profusely, looked at his thrown a basketball hoops, suddenly found himself has already cant remember his appearance.童年时，觉得压岁钱和新衣服是过年必备，但是随着年龄的推进，会越来越发现，那些东西根本就可有可无；初中时，以为要有一场暗恋才意味着真正的成长，但三年过去后，自己心平气和的写同学录的时候，突然就发现是不是真正的成长了，好像并没有那么重要了；然后到了高中，觉得非要吐露出自己的心声才能为高中生涯里的懵懂情愫划上一个句点，但

38、毕业晚会的时候最终还是被梗塞在了咽喉，后来再次站在他曾经挥汗如雨的球场，看着他投过篮球的球框时，突然间发现自己已经想不起他的容颜。Originally, this world, can produce a chemical reaction to an event, in addition to resolutely, have to do, and time.原来，这个世界上，对某个事件能产生化学反应的，除了非做不可的坚决，还有，时间。A persons time, your ideas are always special to clear. Want, want, line is cle

39、ar, as if nothing could shake his. Also once seemed to be determined to do something, but more often is he backed out at last. Dislike his cowardice, finally found that there are a lot of love, there are a lot of miss, like shadow really have been doomed. Those who do, just green years oneself give

40、oneself an arm injection, or is a self-righteous spiritual.一个人的时候，自己的想法总是特别地清晰。想要的，不想要的，界限明确，好像没有什么可以撼动自己。也曾经好像已经下定了决心去做某件事，但更多的时候是最后又打起了退堂鼓。嫌恶过自己的怯懦，最终却发现有很多缘分，有很多错过，好像冥冥之中真的已经注定。那些曾经所谓的非做不可，只是青葱年华里自己给自己注射的一支强心剂，或者说，是自以为是的精神寄托罢了。At the moment, the sky is dark, the air is fresh factor after just rai

41、ned. Suddenly thought of blue plaid shirt; Those were broken into various shapes of stationery; From the corner at the beginning of deep friendship; Have declared the end of the encounter that havent start planning. Those years, those days of do, finally, like youth, will end in our life.此刻，天空是阴暗的，空

42、气里有着刚下过雨之后的清新因子。突然想到那件蓝格子衬衫；那些被折成各种各样形状的信纸；那段从街角深巷伊始的友谊；还有那场还没有开始就宣告了终结的邂逅计划那些年那些天的非做不可，终于和青春一样，都将在我们的人生中谢幕。Baumgartner the disappointing news: Mission aborted. r plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipi

43、tation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the crui

44、sing altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.The supersonic descent could happen as early as Sunda.The weatheThe balloon will slowly drift to the edge of space at

45、 120,000 feet ( Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, hell be traveling fast, so despite the distance, it will not be like d

46、iving into the deep end of a pool. It will be like he is diving into the shallow end. Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches th

47、e more dense air closer to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes its not needed. Instead, he plans to deploy his 270-square-foot (25-square-meter) m

48、ain chute at an altitude of around 5,000 feet (1,524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it wont. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).cause there27