51单片机波形发生器（本程序适用）其中独立按键1、2、3、4按下时会产生四个不同波形（矩形、三角波、梯形波、正弦波）主函数：Main.c#include <reg52.h>#include "i2c.h"#define AddWr 0x90 //写数据地址#define AddRd 0x91 //读数据地址/*unsigned char code tab[]={0,25,50,75,100,125,150,175,200,225,250 //表格数值越多，波形越平滑};*/unsigned char code tab1[]={0,10,20,30,40,50,60,70,80,90,100,110,120,130,140,150,160,170,180,190,200,210,220,230,240,250};unsigned char code juchi[64]={0,4,8,12,16,20,24,28,32,36,40,45,49,53,57,61,65,69,73,77,81,85,89,93,97,101,105,109,113,117,12 1,125,130,134,138,142,146,150,154,158,162,166,170,174,178,182,186,190,194,198,202,206,210,215,219,223,227,231,23 5,239,243,247,251,255};unsigned char code sin[64]={135,145,158,167,176,188,199,209,218,226,234,240,245,249,252,254,254,253,251,247,2 43,237,230,222,213,204,193,182,170,158,146,133,121,108,96,84,72,61,50,41,32,24,17,11,7,3,1,0,0,2,5,9,14,20,28,36,45,55,66,78,90,1 02,114,128};unsigned char code sanjiao[64]={0,8,16,24,32,40,48,56,64,72,80,88,96,104,112,120,128,136,144,152,160,168,176,184,192,200,208,216,224,232,240,248,248,240,232,224,216,208,200,192,184,176,168,160,152,144,136,128,120,112,104,96,88,80,72,64, 56,48,40,32,24,16,8,0};unsigned char code tixing[64]={0,13,26,39,52,65,78,91,104,117,130,143,156,169,182,195,208,221,234,247,247,247,247,247,247, 247,247,247,247,247,247,247,247,247,247,247,247,247,247,247,247,247,247,247,247,242,229,216,203,190,177,164,151,138,125,112,99,86,73,60,47,34,2 1,8};unsigned char code juxing[64]={255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,25 5,255,255,255,255,255,255,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};extern bit ack;bit WriteDAC(unsigned char dat,unsigned char num);/*------------------------------------------------主程序------------------------------------------------*/main(){unsigned char i;while (1) //主循环{// for(i=0;i<26;i++)// WriteDAC(tab1[i],1);while(P1==0xff){for(i=0;i<64;i++)WriteDAC(juxing[i]*6/10,1);if(P1!=0xff)break;}while(P1==0xfe){for(i=0;i<64;i++)WriteDAC(tixing[i]*6/10,1);if(P1!=0xfe)break;}while(P1==0xfd){for(i=0;i<64;i++)WriteDAC(sanjiao[i]*6/10,1);if(P1!=0xfd)break;}while(P1==0xfb){for(i=0;i<64;i++)WriteDAC(sin[i]*6/10,1);if(P1!=0xfb)break;}while(P1==0xf7){for(i=0;i<64;i++)WriteDAC(juchi[i]*6/10,1);if(P1!=0xf7)break;}}}/*------------------------------------------------写入DA转换数值输入参数：dat 表示需要转换的DA数值，范围是0-255 ------------------------------------------------*/bit WriteDAC(unsigned char dat,unsigned char num) { unsigned char i;Start_I2c(); //启动总线SendByte(AddWr); //发送器件地址if(ack==0)return(0);SendByte(0x40); //发送器件子地址if(ack==0)return(0);for(i=0;i<num;i++){SendByte(dat); //发送数据if(ack==0)return(0);}Stop_I2c();}IIC协议：IIC.C#include "i2c.h"#define _Nop() _nop_() //定义空指令bit ack; //应答标志位sbit SDA=P2^1;sbit SCL=P2^0;/*------------------------------------------------启动总线------------------------------------------------*/void Start_I2c(){SDA=1; //发送起始条件的数据信号_Nop();SCL=1;_Nop(); //起始条件建立时间大于4.7us,延时_Nop();_Nop();_Nop();_Nop();SDA=0; //发送起始信号_Nop(); //起始条件锁定时间大于4μ_Nop();_Nop();_Nop();_Nop();SCL=0; //钳住I2C总线，准备发送或接收数据_Nop();_Nop();}/*------------------------------------------------结束总线------------------------------------------------*/void Stop_I2c(){SDA=0; //发送结束条件的数据信号_Nop(); //发送结束条件的时钟信号SCL=1; //结束条件建立时间大于4μ_Nop();_Nop();_Nop();_Nop();_Nop();SDA=1; //发送I2C总线结束信号_Nop();_Nop();_Nop();}/*----------------------------------------------------------------字节数据传送函数函数原型: void SendByte(unsigned char c);功能: 将数据c发送出去,可以是地址,也可以是数据,发完后等待应答,并对此状态位进行操作.(不应答或非应答都使ack=0 假)发送数据正常，ack=1; ack=0表示被控器无应答或损坏。

------------------------------------------------------------------*/void SendByte(unsigned char c){unsigned char BitCnt;for(BitCnt=0;BitCnt<8;BitCnt++) //要传送的数据长度为8位{if((c<<BitCnt)&0x80)SDA=1; //判断发送位else SDA=0;_Nop();SCL=1; //置时钟线为高，通知被控器开始接收数据位_Nop();_Nop(); //保证时钟高电平周期大于4μ_Nop();_Nop();_Nop();SCL=0;}_Nop();SDA=1; //8位发送完后释放数据线，准备接收应答位_Nop();_Nop();SCL=1;_Nop();_Nop();_Nop();if(SDA==1)ack=0;else ack=1; //判断是否接收到应答信号SCL=0;_Nop();_Nop();}/*----------------------------------------------------------------字节数据传送函数函数原型: unsigned char RcvByte();功能: 用来接收从器件传来的数据,并判断总线错误(不发应答信号)，发完后请用应答函数。

------------------------------------------------------------------*//*unsigned char RcvByte(){unsigned char retc;unsigned char BitCnt;retc=0;SDA=1; //置数据线为输入方式for(BitCnt=0;BitCnt<8;BitCnt++){_Nop();SCL=0; //置时钟线为低，准备接收数据位_Nop();_Nop(); //时钟低电平周期大于4.7us_Nop();_Nop();_Nop();SCL=1; //置时钟线为高使数据线上数据有效_Nop();_Nop();retc=retc<<1;if(SDA==1)retc=retc+1; //读数据位,接收的数据位放入retc中_Nop();_Nop();}SCL=0;_Nop();_Nop();return(retc);}*//*----------------------------------------------------------------应答子函数原型: void Ack_I2c(void);----------------------------------------------------------------*//*void Ack_I2c(void){_Nop();_Nop();_Nop();SCL=1;_Nop();_Nop(); //时钟低电平周期大于4μ_Nop();_Nop();_Nop();SCL=0; //清时钟线，钳住I2C总线以便继续接收_Nop();_Nop();}*//*----------------------------------------------------------------非应答子函数原型: void NoAck_I2c(void);----------------------------------------------------------------*//*void NoAck_I2c(void){SDA=1;_Nop();_Nop();_Nop();SCL=1;_Nop();_Nop(); //时钟低电平周期大于4μ_Nop();_Nop();_Nop();SCL=0; //清时钟线，钳住I2C总线以便继续接收_Nop();}*//*----------------------------------------------------------------向无子地址器件发送字节数据函数函数原型: bit ISendByte(unsigned char sla,ucahr c);功能: 从启动总线到发送地址，数据，结束总线的全过程,从器件地址sla.如果返回1表示操作成功，否则操作有误。