文章目录
- (1)DA转换
- (2)DAC0832简介
- (3)电路设计
- (4)参考例程
- (5)参考文献
(1)DA转换
单片机作为一个数字电路系统,当需要采集外界模拟量的使用需要进行AD转换,将模拟量转换成数字量,供单片机使用。51单片机需要外部配置一个AD转换芯片来进行模拟量的采集,如我之前写了一篇ADC0832的使用。高级的单片机如STC12和STM32已经集成了AD转换功能,只需简单配置一下,便可以采集到AD转换后的数据。
AD转换(Analog to Digital)是模拟量转换数字量,那么DA转换(Digital to Analog)便是数字量转换成模拟量。
使用DAC0832进行数字到模拟的转换,再使用定时器控制输出波形的频率便可以制作一个函数信号发生器。
(2)DAC0832简介
CS:低电平有效,片选输入线
WR1:低电平大于500ms有效,输入锁存器
WR2:高电平有效,与XFER结合可将输入锁存器的8位数据传输到DAC寄存器中
XFER:低电平有效,数据传输控制输入线
DI0~DI7:8位数据位并行输入,有效时间大于90ns有效
VCC:电源输入5V-15V
VERF:基准电压输入线-10V~10V
RFB:反馈信号输入,可以看成一个反馈监测
IOUT1:电流输出1,其值随着输入线性变化
IOUT2:电流输出2,与OUT1值之和为一个常数
(3)电路设计
单片机最小系统
波形切换控制
(这里由于博主时间有限,例程代码的LED显示功能就没有写了)
(4)参考例程
#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int#define DI P0 //8位数据输入线//sbit sine_wave_LED1 = P1^0; //正弦波指示灯
//sbit square_wave_LED2 = P1^1; //方波指示灯
//sbit triangular_wave_LED3 = P1^2; //三角波指示灯
//sbit sawtooth_wave_LED4 = P1^3; //锯齿波指示灯
sbit change_wave_Key = P1^4; //更换波形uint freq = 3906; //定时数值×16^(-6)×256 = 波形频率 例程使用1KHZ
uint number=1,n=0,THHL,i;//正弦波段码
unsigned code sin[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 };
//三角波段码
unsigned code thr[256]={ 0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87, 0x88,0x89,0x8A,0x8B,0x8C,0x8D,0x8E,0x8F, 0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97, 0x98,0x99,0x9A,0x9B,0x9C,0x9D,0x9E,0x9F, 0xA0,0xA1,0xA2,0xA3,0xA4,0xA5,0xA6,0xA7, 0xA8,0xA9,0xAA,0xAB,0xAC,0xAD,0xAE,0xAF,0xB0,0xB1,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7, 0xB8,0xB9,0xBA,0xBB,0xBC,0xBD,0xBE,0xBF, 0xBF,0xBE,0xBD,0xBC,0xBB,0xBA,0xB9,0xB8, 0xB7,0xB6,0xB5,0xB4,0xB3,0xB2,0xB1,0xB0,0xAF,0xAE,0xAD,0xAC,0xAB,0xAA,0xA9,0xA8, 0xA7,0xA6,0xA5,0xA4,0xA3,0xA2,0xA1,0xA0, 0x9F,0x9E,0x9D,0x9C,0x9B,0x9A,0x99,0x98, 0x97,0x96,0x95,0x94,0x93,0x92,0x91,0x90, 0x8F,0x8E,0x8D,0x8C,0x8B,0x8A,0x89,0x88, 0x87,0x86,0x85,0x84,0x83,0x82,0x81,0x80, 0x7F,0x7E,0x7D,0x7C,0x7B,0x7A,0x79,0x78, 0x77,0x76,0x75,0x74,0x73,0x72,0x71,0x70, 0x6F,0x6E,0x6D,0x6C,0x6B,0x6A,0x69,0x68, 0x67,0x66,0x65,0x64,0x63,0x62,0x61,0x60, 0x5F,0x5E,0x5D,0x5C,0x5B,0x5A,0x59,0x58, 0x57,0x56,0x55,0x54,0x53,0x52,0x51,0x50, 0x4F,0x4E,0x4D,0x4C,0x4B,0x4A,0x49,0x48, 0x47,0x46,0x45,0x44,0x43,0x42,0x41,0x40, 0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47, 0x48,0x49,0x4A,0x4B,0x4C,0x4D,0x4E,0x4F, 0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57, 0x58,0x59,0x5A,0x5B,0x5C,0x5D,0x5E,0x5F, 0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67, 0x68,0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F, 0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77, 0x78,0x79,0x7A,0x7B,0x7C,0x7D,0x7E,0x7F }; //方波段码
unsigned code squ[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 };//10ms延时函数
void delay_10ms(uchar i)
{//毫秒级延时函数//在12MHZ下晶振下,大约延时10ms/次uchar a,b,c;for(c = i; c > 0; --c)for(b = 129; b > 0; b--)for(a = 38; a > 0; a--);
}//定时器0初始化
void Timer0Init(void)
{unsigned int THHL;TMOD &= 0xF0; //定时器1失效TMOD |= 0x01; //定时器0,16位计数THHL=65536-freq;TL0 =THHL%256; //设置定时初值TH0 =THHL/256; //设置定时初值TF0 = 0; //清除TF0标志TR0 = 1; //定时器0开始计时ET0=1; //开定时器0中断EA=1; //开总中断PT0=0; //定时器0中断最优
}void main()
{/*指示灯初始化,全部熄灭*/
// triangular_wave_LED3 = 1;
// square_wave_LED2 = 1;
// sine_wave_LED1 = 1;Timer0Init();//初始化定时器0while(1){if(change_wave_Key == 0){delay_10ms(1);//延时消抖if(change_wave_Key == 0){while(!change_wave_Key);//松手检测number++;if(number == 5){number = 0;}}}switch(number){case 1: {DI=sin[n]; break;}//正弦波case 2: {DI=thr[n]; break;}//三角波case 3: {for(i=0;i<256;i++){DI=squ[i];} break;}//方波case 4: {DI=256-n; break;}//锯齿波default:{break;}}}
}//定时器0中断处理函数
void Timer0_Routine() interrupt 1
{THHL=65536-freq;TL0=THHL%256;TH0=THHL/256; if(n>=255) {n=0;} else {n++;}
}
电路仿真及代码例程
链接:https://share.weiyun.com/ALLrnKTu 密码:cchvph
(5)参考文献
基于51单片机的DAC0832波形发生器
由于作者水平有限,如有错误望指摘。