基于单片机的电子琴发声控制系统

2011年11月25日摘要本设计是基于单片机的模拟电子琴发声控制系统，该控制系统的主要控制部件是AT89S52，晶振频率为11.0592MHz，发声部件为蜂鸣器，显示部件为七段数码管，十个按键作为输入端。设计内容：设置8个音符按键发出1(do)、2(re)、3(mi)、4(fa)、5(so)、6(la)、7(xi)、1(do)，为一组八度音阶；设置1个按键调节音调高低（低八度音阶为一组，中八度音阶为一组，高八度音阶为一组），通过识别按键的次数来调出一组八度音阶，供人们演奏，在按键按下的同时由数码管输出对应的音阶数值；另外设置一个播放按键，当判断按键按下时，自动播放内存的音乐，可以随时中断音乐。设计方法：软件部分由扫描按键发声并显示和音乐自动播放两部分构成，故本设计通过判断一个按键的两种状态而在两个部分之间进行切换，每种状态对应一个指定部分，从而保证两种状态的正常切换。按键的扫描采用4*2矩阵形式，节省了输出端口。硬件部分的设计主要包括按键排列、数码管显示和蜂鸣器部分，本设计P1口用作对按键的扫描，P2口用作数码管显示，所以矩阵按键和数码管的排列均就近I/O口焊接，布局合理。数码管显示部分通过限流电阻接P2口，无译码器，考虑到输出的数值，本部分设计由软件部分实现指定数值输出。蜂鸣器通过PNP型三极管8550接P3口，8550可以实现音频的放大。蜂鸣器与数码管就近排列，以达到输出一致的效果。设计成果：按照本设计的设计理念，设计成功！该控制系统能准确实现按键扫描，音符、音阶的调用准确无误，同时能显示音符和音阶数值，但受数码管限制，无法同时显示音符1和高一阶音符1（本设计中以8代替）；能实现按键控制音乐的自动播放，当检测到控制按键按下时，即可启动音乐自动播放。本设计简单实用，方便操作，系统稳定，编程简单，能满足单片机初学者对单片机技术的追求，也能满足音乐初学者学习乐器的的基本需求。目录摘要·····························································································-0-1概述··························································································-1-1.1课题简介···········································································-1-1.2仿真技术与软硬件技术的结合················································-1-1.3单片机简介········································································-1-2系统总体方案及硬件设计······························································-3-2.1总体方案············································································-3-2.2按键矩阵············································································-4-2.3数码管显示·········································································-4-2.4蜂鸣器模块·········································································-4-3软件设计····················································································-5-3.1播放音乐部分······································································-5-3.2扫描按键部分······································································-7-3.3数码管显示·······································································-10-4Proteus软件仿真······································································-12-4.1键盘部分设计····································································-12-4.2蜂鸣器部分仿真·································································-12-4.3数码管部分仿真·································································-12-4.4整体仿真设计····································································-12-5课程设计体会············································································-14-5.1设计成果··········································································-14-5.2心得体会··········································································-14-参考文献·····················································································-15-书、专著：············································································-15-电子文献：············································································-15-附录1源程序代码······································································-16-附录2系统原理图······································································-27-附录3音乐简谱·········································································-28-河南理工大学本科课程设计报告-1-1概述1.1课题简介单片微型计算机室大规模集成电路技术发展的产物，属于第四代电子计算机它具有高性能、高速度、体积小、价格低廉、稳定可靠、应用广泛的特点。它的应用必定导致传统的控制技术从根本上发生变革。因此，单片机的开发应用已成为高科技和工程领域的一项重大课题。电子琴是现代电子科技与音乐结合的产物，是一种新型的键盘乐器。它在现代音乐扮演重要的角色，单片机具有强大的控制功能和灵活的编程实现特性，它已经溶入现代人们的生活中，成为不可替代的一部分。本课题的主要内容是用AT89S52单片机为核心控制元件，设计一个电子琴。以单片机作为主控核心，与键盘、扬声器等模块组成核心主控制模块，在主控模块上设有8个按键，2个控制按键和1个复位按键。一首音乐是许多不同的音阶组成的，而每个音阶对应着不同的频率，这样我们就可以利用不同的频率的组合，构成我们想演奏的那首曲目。对于单片机来说产生不同的频率非常方便，我们可以利用单片机的定时/计数器T0或T1来产生这样的方波频率信号，因此，我们只要把一首歌曲的音符对应频率关系编写正确，就可以达到我们想要的曲目。1.2仿真技术与软硬件技术的结合本设计中用到了软件Proteus，该软件是世界上著名的EDA工具(仿真软件)，从原理图布图、代码调试到单片机与外围电路协同仿真，一键切换到PCB设计，真正实现了从概念到产品的完整设计。是目前世界上唯一将电路仿真软件、PCB设计软件和虚拟模型仿真软件三合一的设计平台，其处理器模型支持8051、HC11、PIC10/12/16/18/24/30/DsPIC33、AVR、ARM、8086和MSP430等。在编译方面，它也支持IAR、Keil和MPLAB等多种编译，给我们做电路设计提供方便快捷的仿真效果。在编译的过程中用到了KeiluVision3,KeilC51是51系列兼容单片机C语言软件开发系统，与汇编相比，C语言在功能上、结构性、可读性、可维护性上有明显的优势，因而易学易用。Keil提供了包括C编译器、宏汇编、连接器、库管理和一个功能强大的仿真调试器等在内的完整开发方案，通过一个集成开发环境（uVision）将这些部分组合在一起。其方便易用的集成环境、强大的软件仿真调试工具令我们事半功倍。1.3单片机简介AT89S52是一种低功耗、高性能CMOS8位微控制器，具有8K在系统可编河南理工大学本科课程设计报告-2-程Flash存储器。使用Atmel公司高密度非易失性存储器技术制造，与工业80C51产品指令和引脚完全兼容。AT89S52具有以下标准功能：8k字节Flash，256字节RAM，32位I/O口线，看门狗定时器，2个数据指针，三个16位定时器/计数器，一个6向量2级中断结构，全双工串行口，片内晶振及时钟电路。另外，AT89S52可降至0Hz静态逻辑操作，支持2种软件可选择节电模式。空闲模式下，CPU停止工作，允许RAM、定时器/计数器、串口、中断继续工作。掉电保护方式下，RAM内容被保存，振荡器被冻结，单片机一切工作停止，直到下一个中断或硬件复位为止。片上Flash允许程序存储器在系统可编程，亦适于常规编程器。在单芯片上，拥有灵巧的8位CPU和在系统可编程Flash，使得AT89S52在众多嵌入式控制应用系统中得到广泛应用。图1.30图1.31AT89S52引脚图AT89S52实物图河南理工大学本科课程设计报告-3-2系统总体方案及硬件设计2.1总体方案开始播放音乐PLAY?显示1SWITCH?播放完毕？显示0显示3显示2无动作按2次扫描按键RESET显示键值调用音符(高八度)调用音符(中八度)调用音符(低八度)发音结束否是按1次按3次图2.1总体方案流程图本设计在音乐播放与键盘扫描之间切换，蜂鸣器能发出共计22个音符，共分三个八度音阶，数码管可显示0-8，由于数码管限制，此处用8代替高一级音符do。当系统运行时，默认进入键盘扫描，并不发音，数码管显示默认值1，即键盘默认可调用低八度音符。当音乐播放键(PLAY)按下时，音乐自动播放，数码管显示0，此间可按下复位键终止音乐。当播放停止时，跳出程序段，默认回到键盘扫描状态，数码管显示返回值1。每当音阶转换控制键(SWITCH)按下时，数码管显示的数值加1，设置最大显示值是3，循环显示；此处1代表可调用低八河南理工大学本科课程设计报告-4-度音符，2代表可调用中八度音符，3代表