基于51单片机的函数信号发生器设计

设计思路：

1，波形在正弦波、锯齿波、方波中可选。
2 ，频率可选范围10Hz-990Hz，由按键阵列手动设置。每次设置时，在0-9的按键阵列中进行选择，按两次按键。例如0+1表示 10Hz，4+3表示430Hz,9+9表示990Hz。每次按键时，由一位数码管显示刚刚按下的按键序号。
3 ，每次在选择波形前，由1602液晶显示器提供文本提示，文本自拟。
4 ，每次在选择频率前，由1602液晶显示器提供文本提示，文本自拟。
5 ，在输出波形时，由1602显示目前的波形种类和频率。
6 ，用两个外部按键中断，一个实现暂停和继续输出波形的功能，另一个实现终止功能并进入下次波形设置。

实现工作流程：

①（开始仿真或按下停止工作按键后）1602提示：请选择波形种类。
② 在按键阵列中按键一次，对应的选择正弦波、锯齿波、方波之一。按键后，数码管显示刚才的按键编号。
③ 1602提示：请设置频率。
④ 在按键阵列中按键两次。输入的两位数，对应10到990Hz。每次按键后，数码管显示刚才的按键编号。
⑤ 通过DAC0832输出波形，在示波器中观察波形。
⑥ 1602显示目前波形的种类和频率。
⑦ 按下暂停按键，输出暂停，1602提示目前为暂停状态。
⑧ 再次按下暂停按键，恢复波形输出，1602继续显示波形的种类和频率。
⑨ 按下终止按键，波形停止输出，回到流程①。

 

仿真器件：

7SEG-BCD

AT89C51

BUTTON

CAP

CRYSTAL

DAC0832

LM016L

POT-HG

RES

RES16DIPIS

UA741

虚拟仪器模式：OSCILLOSCOPE , AC  VOL  TMETER

 

LCD显示部分代码封装：

#include <LCD1602.h>
#include "reg51.h" 
sbit RS = P2^6;
sbit RW = P2^5;
sbit EN = P2^7;


//输入：显示行数i,列数j，输出字符，输出字符长度n		
void LCD_send(unsigned char i,unsigned char j,unsigned char str[],unsigned char n)
{
	unsigned char x=0;
	if(i==1)
	{write_com(0x80+j);}
	else
	{write_com(0x80+0x40+j);}
    for(x=0;x<n;x++)
    {
         write_date(str[x]);
        delay(150);
    }
}
		
int LCD_init()//初始化函数体
{
    EN = 0;
    write_com(0X38);//设置16*2显示，5*7点阵，8位数据接口
    write_com(0X0C);//设置开显示，不显示光标
    write_com(0X06);//写一个字符时，整屏右移
    write_com(0X01);//显示清零
    return 0;
}

int write_com(unsigned char com)//写命令的函数体
{
    RS = 0;
    RW = 0;
    P0 = com;
    delay(5);
    EN = 1;
    delay(5);
    EN = 0;
    return 0;
}

int write_date(unsigned char data1)//写数据的函数体
{
    RS = 1;
    RW = 0;
    P0 = data1;
    delay(5);
    EN = 1;
    delay(5);
    EN = 0;
    return 0;
}

int delay(unsigned char xms)//延时函数
{
    unsigned char x,y;
    for(x=xms;x>0;x--)
        for(y=110;y>0;y--);
    return 0;
}

键值功能函数部分：

方式一；

void keyscan()//计算键值函数
{
	key=0x0f;
	if(key!=0x0f)
	{
		delay(1000);
		if(key!=0x0f)
		{
			key=0x0f;//测试列
		    switch(key)
		   {
			  case(0x07):keyvalue=15;break;
			  case(0x0b):keyvalue=14;break;
			  case(0x0d):keyvalue=13;break;
			  case(0x0e):keyvalue=12;break;

		   }
		   key=0xf0;//测试行
		   if(key!=0xf0)
		  {
		     switch(key)
		    {
			    case(0x70):keyvalue=keyvalue;break;
			    case(0xb0):keyvalue=keyvalue-4;break;
			    case(0xd0):keyvalue=keyvalue-8;break;
			    case(0xe0):keyvalue=keyvalue-12;break;
		    }
		  }
		}
		while(key!=0xf0)	 //检测按键松手检测
		{
			delay(100);
		}
		switch(keyvalue)
		{
			    case(0):keyd();b=0;C=0;D=0;M=0;break;
			    case(1):keyd();b=0;C=0;D=0;M=1;break;
			    case(2):keyd();b=0;C=0;D=1;M=0;break;
			    case(3):keyd();b=0;C=0;D=1;M=1;break;
			    case(4):keyd();b=0;C=1;D=0;M=0;break;
			    case(5):keyd();b=0;C=1;D=0;M=1;break;
			    case(6):keyd();b=0;C=1;D=1;M=0;break;
			    case(7):keyd();b=0;C=1;D=1;M=1;break;
			    case(8):keyd();b=1;C=0;D=0;M=0;break;
			    case(9):keyd();b=1;C=0;D=0;M=1;break;
			    case(10):flg=1;LCD_send(1,5,"Sin       ",10); //正弦波
			                   LCD_send(2,5,"Select",6);div=0;
			                   b=1;C=0;D=1;M=0;break;
			    case(11):flg=2;LCD_send(1,5,"Square    ",10); //方波
			                   LCD_send(2,5,"Select",6);div=0;
			                   b=1;C=0;D=1;M=1;break;
			    case(12):flg=3;LCD_send(1,5,"Sawtooth  ",10); //锯齿波
			                   LCD_send(2,5,"Select",6);div=0;
          	                   b=1;C=1;D=0;M=0;break;
			    case(13):stop();b=1;C=1;D=0;M=1;z++;break;        //暂停
			    case(14):flg=4;LCD_init();init();b=1;C=1;D=1;M=0;break;;
			    case(15):b=1;C=1;D=1;M=1;break;
		}
	}
}

 

方式二：

uchar keyscan()   
{
	key=0xef;   //判断第一行       
    if(key!=0xef)
    {
    	delay(100);
    	switch(key)
    	{
    		case 0xee:{keyword=0;keyd();b=0;C=0;D=0;M=0;break;}   
		    case 0xed:{keyword=1;keyd();b=0;C=0;D=0;M=1;break;} 
	        case 0xeb:{keyword=2;keyd();b=0;C=0;D=1;M=0;break;} 		
	        case 0xe7:{keyword=3;keyd();b=0;C=0;D=1;M=1;break;} 
    	}
	} 
	key=0xdf;    //判断第二行       
    if(key!=0xdf)
    {
    	delay(100);
    	switch(key)
    	{
    		case 0xde:{keyword=4;b=0;C=1;D=0;M=0;keyd();break;}
			case 0xdd:{keyword=5;b=0;C=1;D=0;M=1;keyd();break;}
			case 0xdb:{keyword=6;b=0;C=1;D=1;M=0;keyd();break;}
			case 0xd7:{keyword=7;b=0;C=1;D=1;M=1;keyd();break;}
    	}    
    }
    key=0xbf;    //判断第三行       
    if(key!=0xbf)   
    {
        delay(100);     
        switch(key)
        {
          	case 0xbe:{keyword=8;keyd();b=1;C=0;D=0;M=0;break;}
			case 0xbd:{keyword=9;keyd();b=1;C=0;D=0;M=1;break;}
			
			case 0xbb:{
				keyword=10;flg=1;TR1=0;LCD_send(1,5,"Sin       ",10);LCD_send(2,5,"Select",6);TR1=1;
				b=1;C=0;D=1;M=0;break;}                         //正弦波
			case 0xb7:{
			    keyword=11;flg=2;TR1=0;LCD_send(1,5,"Square    ",10);LCD_send(2,5,"Select",6);TR1=1;
			    b=1;C=0;D=1;M=1;break;}                         //方波  
         }
        }
        key=0x7f;    //判断第四行       
        if(key!=0x7f)   
        {
          delay(100);     
          switch(key)
          {
          	case 0x7e:{
          	    keyword=12;flg=3;TR1=0;LCD_send(1,5,"Sawtooth  ",10);LCD_send(2,5,"Select",6);TR1=1;
          	    b=1;C=1;D=0;M=0;break;}                         //锯齿波
			case 0x7d:{
				keyword=13;wr=~wr;b=1;C=1;D=0;M=1;break;}        //暂停
			case 0x7b:{
				keyword=14;flg=4;TR1=0;LCD_send(1,0,"WAVE:Select",11);LCD_send(2,0,"FRE:       ",11);TR1=1;
				THHL=65536-3906;b=1;C=1;D=1;M=0;break;}                        //复位终止
			case 0x77:{keyword=15;b=1;C=1;D=1;M=1;break;}  
         }
        }
        return keyword;
}

 

注：方式一比方式二多了有松手判断，方式二函数因为定义的数据类型不同可以返回键值keyword

 

主函数：

void main()
{
	LCD_init();
	init();
	while(1)
	{
		keyscan();
		switch(flg)   
			{   
				case 1: DAC0832=sin_tab[n];break;  //正弦波
				case 2: DAC0832=squ_tab[n];break;  //方波
				case 3: DAC0832=255-n;break;	   //锯齿波
				case 4: DAC0832=0xff;              //复位终止
			 }
	}
}

 

定时中断函数部分：

void time_intt1(void) interrupt 3   
{   
	TL1=THHL%256;
	TH1=THHL/256;  
//	if(n>=255) {n=0;} else {n++;}   
	n++;
}

 

数据段码部分：

unsigned code sin_tab[256]={   
0x80,0x83,0x85,0x88,0x8A,0x8D,0x8F,0x92,0x94,0x97,0x99,0x9B,0x9E,0xA0,0xA3,0xA5,0xA7,0xAA,0xAC,0xAE,0xB1,0xB3,0xB5,0xB7,0xB9,0xBB,
0xBD,0xBF,0xC1,0xC3,0xC5,0xC7,0xC9,0xCB,0xCC,0xCE,0xD0,0xD1,0xD3,0xD4,0xD6,0xD7,0xD8,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,0xE0,0xE1,0xE2,
0xE3,0xE3,0xE4,0xE4,0xE5,0xE5,0xE6,0xE6,0xE7,0xE7,0xE7,0xE7,0xE7,0xE7,0xE7,0xE7,0xE6,0xE6,0xE5,0xE5,0xE4,0xE4,0xE3,0xE3,0xE2,0xE1,
0xE0,0xDF,0xDE,0xDD,0xDC,0xDB,0xDA,0xD8,0xD7,0xD6,0xD4,0xD3,0xD1,0xD0,0xCE,0xCC,0xCB,0xC9,0xC7,0xC5,0xC3,0xC1,0xBF,0xBD,0xBB,0xB9,
0xB7,0xB5,0xB3,0xB1,0xAE,0xAC,0xAA,0xA7,0xA5,0xA3,0xA0,0x9E,0x9B,0x99,0x97,0x94,0x92,0x8F,0x8D,0x8A,0x88,0x85,0x83,0x80,0x7D,0x7B,
0x78,0x76,0x73,0x71,0x6E,0x6C,0x69,0x67,0x65,0x62,0x60,0x5D,0x5B,0x59,0x56,0x54,0x52,0x4F,0x4D,0x4B,0x49,0x47,0x45,0x43,0x41,0x3F,
0x3D,0x3B,0x39,0x37,0x35,0x34,0x32,0x30,0x2E,0x2D,0x2C,0x2A,0x29,0x28,0x26,0x25,0x24,0x23,0x22,0x21,0x20,0x1F,0x1E,0x1D,0x1D,0x1C,
0x1C,0x1B,0x1B,0x1A,0x1A,0x1A,0x19,0x19,0x19,0x19,0x19,0x19,0x19,0x19,0x1A,0x1A,0x1A,0x1B,0x1B,0x1C,0x1C,0x1D,0x1D,0x1E,0x1F,0x20,
0x21,0x22,0x23,0x24,0x25,0x26,0x28,0x29,0x2A,0x2C,0x2D,0x2F,0x30,0x32,0x34,0x35,0x37,0x39,0x3B,0x3D,0x3F,0x41,0x43,0x45,0x47,0x49,
0x4B,0x4D,0x4F,0x52,0x54,0x56,0x59,0x5B,0x5D,0x60,0x62,0x65,0x67,0x69,0x6C,0x6E,0x71,0x73,0x76,0x78,0x7B,0x7D};//正弦波段码  
unsigned code squ_tab[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,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
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,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,};//方波段码

 

初始化部分：

void init()//初始化
{
	THHL=65536-3906;
        TH1=THHL/256;
        TL1=THHL%256;   
        TMOD=0x11;
        ET1=1;
        TR1=1;
        EA=1;
        wr=0;
	b=0;
        C=0;
        D=0;
        M=0;
}

 

仿真图：

 

实现效果视频：

 

 

完整程序：

#include <reg51.h>
#define uchar unsigned char
#define uint unsigned int
#define key P1
#define DAC0832 P3
sbit b = P2^0;
sbit C = P2^1;
sbit D = P2^2;
sbit M = P2^3;           //LCD的BCD码输入口
sbit wr = P2^4;          //暂停口
sbit RW = P2^5;
sbit RS = P2^6;
sbit EN = P2^7;
uchar flg = 0;          //波形功能判断标志位
uchar keyvalue=16;      //键值
uchar n=0;
uchar z=1;
uchar fre[11] ="000Hz      "; 
uint div=0;
uint data THHL=65536-3906;      //初始频率为1Hz
uint write_com(unsigned char);  //声明写命令函数
uint write_date(unsigned char); //声明写数据函数
void LCD_send(uchar i,uchar j,uchar str[],uchar n);//声明LCD封装函数

unsigned code sin_tab[256]={   
0x80,0x83,0x85,0x88,0x8A,0x8D,0x8F,0x92,0x94,0x97,0x99,0x9B,0x9E,0xA0,0xA3,0xA5,0xA7,0xAA,0xAC,0xAE,0xB1,0xB3,0xB5,0xB7,0xB9,0xBB,
0xBD,0xBF,0xC1,0xC3,0xC5,0xC7,0xC9,0xCB,0xCC,0xCE,0xD0,0xD1,0xD3,0xD4,0xD6,0xD7,0xD8,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,0xE0,0xE1,0xE2,
0xE3,0xE3,0xE4,0xE4,0xE5,0xE5,0xE6,0xE6,0xE7,0xE7,0xE7,0xE7,0xE7,0xE7,0xE7,0xE7,0xE6,0xE6,0xE5,0xE5,0xE4,0xE4,0xE3,0xE3,0xE2,0xE1,
0xE0,0xDF,0xDE,0xDD,0xDC,0xDB,0xDA,0xD8,0xD7,0xD6,0xD4,0xD3,0xD1,0xD0,0xCE,0xCC,0xCB,0xC9,0xC7,0xC5,0xC3,0xC1,0xBF,0xBD,0xBB,0xB9,
0xB7,0xB5,0xB3,0xB1,0xAE,0xAC,0xAA,0xA7,0xA5,0xA3,0xA0,0x9E,0x9B,0x99,0x97,0x94,0x92,0x8F,0x8D,0x8A,0x88,0x85,0x83,0x80,0x7D,0x7B,
0x78,0x76,0x73,0x71,0x6E,0x6C,0x69,0x67,0x65,0x62,0x60,0x5D,0x5B,0x59,0x56,0x54,0x52,0x4F,0x4D,0x4B,0x49,0x47,0x45,0x43,0x41,0x3F,
0x3D,0x3B,0x39,0x37,0x35,0x34,0x32,0x30,0x2E,0x2D,0x2C,0x2A,0x29,0x28,0x26,0x25,0x24,0x23,0x22,0x21,0x20,0x1F,0x1E,0x1D,0x1D,0x1C,
0x1C,0x1B,0x1B,0x1A,0x1A,0x1A,0x19,0x19,0x19,0x19,0x19,0x19,0x19,0x19,0x1A,0x1A,0x1A,0x1B,0x1B,0x1C,0x1C,0x1D,0x1D,0x1E,0x1F,0x20,
0x21,0x22,0x23,0x24,0x25,0x26,0x28,0x29,0x2A,0x2C,0x2D,0x2F,0x30,0x32,0x34,0x35,0x37,0x39,0x3B,0x3D,0x3F,0x41,0x43,0x45,0x47,0x49,
0x4B,0x4D,0x4F,0x52,0x54,0x56,0x59,0x5B,0x5D,0x60,0x62,0x65,0x67,0x69,0x6C,0x6E,0x71,0x73,0x76,0x78,0x7B,0x7D};//正弦波段码  
unsigned code squ_tab[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,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
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,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,};//方波段码

void stop()
{
	if (z%2==1){wr=1;LCD_send(2,5,"stop      ",11);}
    else{wr=0;LCD_send(2,5,fre,11);}
}

void keyd()
{
    if(div<100){div*=10;div+=keyvalue%10;THHL=65536-3906/div;}
    if(div>=100){div=0;THHL=65536-3906;}
    fre[0]=div/10%10 + '0';fre[1]=div%10 + '0';fre[2]='0';
    LCD_send(2,5,fre,11);
}

void delay(uchar xms)//延时函数
{
    uchar x,y;
    for(x=xms;x>0;x--)
        for(y=110;y>0;y--);
}

void init()//初始化
{
	THHL=65536-3906;TH1=THHL/256;TL1=THHL%256;   
    TMOD=0x11;ET1=1;TR1=1;EA=1;wr=0;
	b=0;C=0;D=0;M=0;
}

void LCD_send(uchar i,uchar j,uchar str[],uchar n)//输入：显示行数i,列数j，输出字符，输出字符长度n
{
	uchar x=0;
	if(i==1)
	{write_com(0x80+j);}
	else
	{write_com(0x80+0x40+j);}
    for(x=0;x<n;x++)
    {
        write_date(str[x]);
        delay(150);
    }
}
		
void LCD_init()//LCD初始化函数体
{
    EN = 0;
    write_com(0X38);//设置16*2显示，5*7点阵，8位数据接口
    write_com(0X0C);//设置开显示，不显示光标
    write_com(0X06);//写一个字符时，整屏右移
    write_com(0X01);//显示清零
	LCD_send(1,0,"WAVE:Select    ",15);
	LCD_send(2,0,"FRE:           ",15);
}

uint write_com(uchar com)//写命令的函数体
{
    RS = 0;
    RW = 0;
    P0 = com;
    delay(5);
    EN = 1;
    delay(5);
    EN = 0;
    return 0;
}

uint write_date(uchar data1)//写数据的函数体
{
    RS = 1;
    RW = 0;
    P0 = data1;
    delay(5);
    EN = 1;
    delay(5);
    EN = 0;
    return 0;
}

void keyscan()//键值功能判断
{
	key=0x0f;
	if(key!=0x0f)
	{
		delay(1000);
		if(key!=0x0f)
		{
			key=0x0f;//测试列
		    switch(key)
		   {
			  case(0x07):keyvalue=15;break;
			  case(0x0b):keyvalue=14;break;
			  case(0x0d):keyvalue=13;break;
			  case(0x0e):keyvalue=12;break;

		   }
		   key=0xf0;//测试行
		   if(key!=0xf0)
		  {
		     switch(key)
		    {
			    case(0x70):keyvalue=keyvalue;break;
			    case(0xb0):keyvalue=keyvalue-4;break;
			    case(0xd0):keyvalue=keyvalue-8;break;
			    case(0xe0):keyvalue=keyvalue-12;break;
		    }
		  }
		}
		while(key!=0xf0)	 //检测按键松手检测
		{
			delay(100);
		}
		switch(keyvalue)
		{
			    case(0):keyd();b=0;C=0;D=0;M=0;break;
			    case(1):keyd();b=0;C=0;D=0;M=1;break;
			    case(2):keyd();b=0;C=0;D=1;M=0;break;
			    case(3):keyd();b=0;C=0;D=1;M=1;break;
			    case(4):keyd();b=0;C=1;D=0;M=0;break;
			    case(5):keyd();b=0;C=1;D=0;M=1;break;
			    case(6):keyd();b=0;C=1;D=1;M=0;break;
			    case(7):keyd();b=0;C=1;D=1;M=1;break;
			    case(8):keyd();b=1;C=0;D=0;M=0;break;
			    case(9):keyd();b=1;C=0;D=0;M=1;break;
			    case(10):flg=1;LCD_send(1,5,"Sin       ",10); //正弦波
			                   LCD_send(2,5,"Select",6);div=0;
			                   b=1;C=0;D=1;M=0;break;
			    case(11):flg=2;LCD_send(1,5,"Square    ",10); //方波
			                   LCD_send(2,5,"Select",6);div=0;
			                   b=1;C=0;D=1;M=1;break;
			    case(12):flg=3;LCD_send(1,5,"Sawtooth  ",10); //锯齿波
			                   LCD_send(2,5,"Select",6);div=0;
          	                   b=1;C=1;D=0;M=0;break;
			    case(13):stop();b=1;C=1;D=0;M=1;z++;break;        //暂停
			    case(14):flg=4;LCD_init();init();b=1;C=1;D=1;M=0;break;;
			    case(15):b=1;C=1;D=1;M=1;break;
		}
	}
}

void main()
{
	LCD_init();
	init();
	while(1)
	{
		keyscan();
		switch(flg)   
			{   
				case 1: DAC0832=sin_tab[n];break;  //正弦波
				case 2: DAC0832=squ_tab[n];break;  //方波
				case 3: DAC0832=255-n;break;	   //锯齿波
				case 4: DAC0832=0xff;              //复位终止
			 }
	}
}

void time_intt1(void) interrupt 3   
{   
	TL1=THHL%256;
	TH1=THHL/256;  
//	if(n>=255) {n=0;} else {n++;}   
	n++;
}