基于单片机DA转换设计函数信号发生器

电路综合实习报告课程题目：基于单片机D/A转换设计函数信号发生器摘要：以51单片机为核心设计函数信号发生器，采用程序设计方法产生正弦波，方波，三角波，方波，锯齿波，波形的频率在一定频率范围内可任意改变。通过键盘来控制四种波形的类型选择与频率变化，并通过液晶屏1602显示其各自的类型及数值。主要包括信号发生局部、D/A转换局部以及液晶显示局部。关键词：D/A转换，液晶显示主要内容：1.实习原理2.实习内容系统设计设计要求方案设计〔各模块设计〕软件设计流程通过示波器对波形种类及频率进行测试测试说明测试过程测试结果3.实习的心得体会4.附录：源程序1.实习原理：系统总体框图主控芯片AT89S52DAC0832的内部结构：D/A转换原理图DAC0832是双列直插式8位D/A转换器。能完成数字量输入到模拟量(电流)输出的转换。其主要参数如下：分辨率为8位，转换时间为1μs，满量程误差为±1LSB，参考电压为-10V～+10V，供电电源为+5V～+15V，逻辑电平输入与TTL兼容。DAC0832中有两级锁存器，第一级锁存器称为输入存放器，它的允许锁存信号为ILE，第二级锁存器称为DAC存放器，它的锁存信号也称为通道控制信号/XFER。液晶屏的显示矩阵键盘2.实习内容：1〕系统设计利用AT89S52单片机采用程序设计方法产生锯齿波、正弦波、方波、三角波四种波形，再通过D/A转换器DAC0832将数字信号转换成模拟信号，滤波放大，最终由示波器显示出来，通过键盘来控制四种波形的类型选择、频率变化，最终输出显示其各自的类型以及数值。设计要求1)基于单片机的D/A转换用软件编程产生四种波形，分别为：锯齿波，正弦波，方波，三角波；2〕通过键盘选择四种波形类型；3〕波形频率可调；方案设计论证显示方案论证：方案一：采用LED数码管。LED数码管由8个发光二极管组成，每只数码管轮流显示各自的字符。由于人眼具有视觉暂留特性，当每只数码管显示的时间间隔小于1/16s时人眼感觉不到闪动，看到的是每只数码管常亮。使用数码管显示编程较易，但要显示内容多，而且数码管不能显示字母。方案二：采用LCD液晶显示器1602。其功率小，效果明显，显示编程容易控制，可以显示字母。以上两种方案综合考虑，选择方案二。键盘方案论证：

方案一：矩阵式键盘。矩阵式键盘的按键触点接于由行、列母线构成的矩阵电路的交叉处。当键盘上没有键闭合时，所有的行和列线都断开，行线都呈高电平。当某一个键闭合时，该键所对应的行线和列线被短路。方案二：编码式键盘。编码式键盘的按键触点接于74LS148芯片。当键盘上没有闭合时，所有键都断开，当某一键闭合时，该键对应的编码由74LS148输出。以上两种方案综合考虑，选择方案一。软件设计流程开始开始初始化N初始化有键按下有键按下YKey=BKey=AKey=CKey=BKey=AKey=CKey=9Key=8Key=7减频率增频率锯齿波正弦波方波三角波减频率增频率锯齿波正弦波方波三角波通过示波器对波形种类及频率进行测试测试说明：正弦波、矩形波、三角波和方波信号的输出，通过对独立键盘来实现其不同波形的输出以及改变其频率。测试过程：当程序下进去时经过初始化，液晶屏的上只显示“Starting，XinHaoFaSheng〞，然后显示“ClearAll,NothingHappened〞,当键盘4按下时开始显示频率，当键盘7按下时，此时输出波形为三角波，当键盘8按下时，此时输出波形为方波，当键盘9按下时，此时输出波形为正弦波，当键盘C按下时，此时输出波形为锯齿波。每按一次键盘4，再按键盘A,波形频率增加，每按一次键盘4，再按键盘B,波形频率减小。测试结果各种波形：输出波形为三角波输出波形为方波时输出为正弦波时输出为锯齿波时存在问题：得到的波形纹波比拟明显，波形相当不稳定，而且有时候出现了失真解决方法：修改程序中波形的幅值，使幅值减小，最后纹波变小，波形也比拟稳定。至于出现失真这个问题，经过检查，发现连接线路有所松动，处理完后，波形正常。3.实习心得体会通过这次实习，我学习了函数发生器设计的原理，用keil软件编程及调试，protues软件仿真，示波器的使用，加深了我对单片机的理解，也让我了解到专业知识的重要性。在实习过程中也碰到了很多困难，比方说对于写程序可以说是掌握得不是很好，用c语言写程序会出现很多错误；在用protues软件仿真时，由于第一次接触，所以一开始都不知道何从下手；在用示波器测试时纹波太大，而且波形不稳定等等，最后通过一些书籍，百度查看相关资料，询问同学，再修改程序，解决了困难。这次实习是对我们过去所学知识的系统提高和扩充的过程，很好的锻炼了我们解决问题的能力，同时也让我们了解到自己的缺乏，从而不断完善自己。4.附录源程序：#include"regX51.h"#include"intrins.h"#include<absacc.h>#include"1602.h"#include"DAC0832.h"#include<math.h>#defineucharunsignedchar#defineuintunsignedintucharKey,keytemp,flag=20,i;ucharfreq,baiwei,shiwei,gewei;uintcodepinlv[]={400,227,214,200,190,178,170,160,153,147,140,134,130,125,121,117,112,108,105,101,99,96,92,90,88,86,83,81,80,78,76,74,72,70,78,76,74,72};ucharcodevalue[16]= //矩阵键盘中每个键对应的P0口值{0x0e7,0x0d7,0x0b7,0x077,0x0eb,0x0db,0x0bb,0x07b,0x0ed,0x0dd,0x0bd,0x07d,0x0ee,0x0de,0x0be,0x07e};ucharcodetable[]={0x30, //0在1602中的十六进制码0x31, //1在1602中的十六进制码0x32, //2在1602中的十六进制码0x33, //3在1602中的十六进制码0x34, //4在1602中的十六进制码0x35, //5在1602中的十六进制码0x36, //6在1602中的十六进制码0x37, //7在1602中的十六进制码0x38, //8在1602中的十六进制码0x39, //9在1602中的十六进制码0x41, //A在1602中的十六进制码0x42, //B在1602中的十六进制码0x43, //C在1602中的十六进制码0x44, //D在1602中的十六进制码0x45, //E在1602中的十六进制码0x46 //F在1602中的十六进制码};ucharcodesanjiaobo[128]={0x00,0x04,0x08,0x0c,0x10,0x14,0x18,0x1c,0x20,0x24,0x28,0x2c,0x30,0x34,0x38,0x3c,0x40,0x44,0x48,0x4c,0x50,0x54,0x58,0x5c,0x60,0x64,0x68,0x6c,0x70,0x74,0x78,0x7c,0x80,0x84,0x88,0x8c,0x90,0x94,0x98,0x9c,0xa0,0xa4,0xa8,0xac,0xb0,0xb4,0xb8,0xbc,0xc0,0xc4,0xc8,0xcc,0xd0,0xd4,0xd8,0xdc,0xe0,0xe4,0xe8,0xec,0xf0,0xf4,0xf8,0xfc,0xfe,0xfa,0xf6,0xf2,0xee,0xea,0xe6,0xe2,0xde,0xda,0xd6,0xd2,0xce,0xca,0xc6,0xc2,0xbe,0xba,0xb6,0xb2,0xae,0xaa,0xa6,0xa2,0x9e,0x9a,0x96,0x92,0x8e,0x8a,0x86,0x82,0x7e,0x7a,0x76,0x72,0x6e,0x6a,0x66,0x62,0x5e,0x5a,0x56,0x52,0x4e,0x4a,0x46,0x42,0x3e,0x3a,0x36,0x32,0x2e,0x2a,0x26,0x22,0x1e,0x1a,0x16,0x12,0x0e,0x0a,0x06,0x02,};ucharcodefangbo[256]={0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,};ucharcodezhengxianbo[128]={0x80,0x86,0x8c,0x92,0x98,0x9f,0xa5,0xab,0xb0,0xb6,0xbc,0xc1,0xc7,0xcc,0xd1,0xd5,0xDA,0xde,0xe2,0xe6,0xea,0xed,0xf0,0xf3,0xf6,0xf8,0xfa,0xfc,0xfd,0xfe,0xff,0xff,0xff,0xff,0xff,0xfe,0xfd,0xfc,0xfa,0xf8,0xf6,0xf3,0xf0,0xed,0xea,0xe6,0xe3,0xde,0xDA,0xd6,0xd1,0xcc,0xc7,0xc1,0xbc,0xb6,0xb1,0xab,0xa5,0x9f,0x99,0x92,0x8c,0x86,0x80,0x79,0x73,0x6d,0x67,0x61,0x5b,0x55,0x4f,0x49,0x43,0x3e,0x39,0x33,0x2e,0x2a,0x25,0x21,0x1d,0x19,0x15,0x12,0x0f,0x0c,0x09,0x07,0x05,0x03,0x02,0x01,0x00,0x00,0x00,0x00,0x00,0x01,0x02,0x03,0x05,0x07,0x09,0x0c,0x0e,0x12,0x15,0x18,0x1c,0x20,0x25,0x29,0x2e,0x33,0x38,0x3d,0x43,0x48,0x4e,0x54,0x5a,0x60,0x66,0x6c,0x73,0x79,};ucharcodejc[128]={0x00,0x02,0x04,0x06,0x08,0x0a,0x0c,0x0e,0x10,0x12,0x14,0x16,0x18,0x1a,0x1c,0x1e,0x20,0x22,0x24,0x26,0x28,0x2a,0x2c,0x2e,0x30,0x32,0x34,0x36,0x38,0x3a,0x3c,0x3e,0x40,0x42,0x44,0x46,0x48,0x4a,0x4c,0x4e,0x50,0x52,0x54,0x56,0x58,0x5a,0x5c,0x5e,0x60,0x62,0x64,0x66,0x68,0x6a,0x6c,0x6e,0x70,0x72,0x74,0x76,0x78,0x7a,0x7c,0x7e,0x80,0x82,0x84,0x86,0x88,0x8a,0x8c,0x8e,0x90,0x92,0x94,0x96,0x98,0x9a,0x9c,0x9e,0xa0,0xa2,0xa4,0xa6,0xa8,0xaa,0xac,0xae,0xb0,0xb2,0xb4,0xb6,0xb8,0xba,0xbc,0xbe,0xc0,0xc2,0xc4,0xc6,0xc8,0xca,0xcc,0xce,0xd0,0xd2,0xd4,0xd6,0xd8,0xda,0xdc,0xde,0xe0,0xe2,0xe4,0xe6,0xe8,0xea,0xec,0xee,0xf0,0xf2,0xf4,0xf6,0xf8,0xfa,0xfc,0xfe};voidScanKey();voidDly_mS(unsignedintms) //延时函数{unsignedinti;while(ms--)for(i=0;i<75;i++);}voidIniSys(){Dly_mS(200);EA=0;TCON=0x00;/*中断标志清0*/IT1=0;/*中断1边缘触发*/EX1=0;/*中断1暂时关闭*/ET0=0;/*定时器0中断关闭*/TMOD=0x01;/*定时器0方式1*/TH0=0x0FC;TL0=0x18;//定时1msEA=1;/*开中断*/ET0=1;/*开定时器0中断*/}voidCT0Server()interrupt1 //定时器中每1MS扫描一次键盘{TH0=(65536-1000)/256;TL0=(65536-1000)%256;//定时10msTR0=1;keytemp=Key;ScanKey();}voiddelay_nus(ucharn){while(--n){;}}voidScanKey(){ucharP0Buf,scan,j;P0=0x0f;P0Buf=P0;if(P0Buf!=0x0f){P0=0xf0;scan=P0Buf;P0Buf=P0;scan=scan+P0Buf;for(j=0;j<16;j++){if(value[j]==scan){Key=j;break;}}}}voidfunction0(){Display(0,0,"ClearAll");Display(0,1,"NothingHappened");DAC0832=0x00;}voidfunction4(){for(i=0;i<128;i++)//循环送255个三角波数据{ DAC0832=sanjiaobo[i];delay_nus(freq); }}voidfunction5(){for(i=0;i<128;i++)//循环送255个方波数据{ DAC0832=fangbo[i];delay_nus(freq);}}voidfunction6(){for(i=0;i<128;i++)//循环送255个正弦波数据{ DAC0832=zhengxianbo[i];delay_nus(freq);}}voidfunction7(){for(i=0;i<128;i++)/