使用的是查表法：
1.c文件：
#include "reg52.h"
#include <intrins.h>
#include <i2c.h>
#define PCF8591 0x90
#define uint unsigned int
#define uchar unsigned char
#define arr_length 720 //正弦波數組長度
code unsigned char sin1[720]={0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87,0x88,0x8a,0x8b,0x8c,0x8d,0x8e,
0x8f,0x90,0x91,0x92,0x94,0x95,0x96,0x97,0x98,0x99,0x9a,0x9b,0x9c,0x9d,0x9e,0xa0,0xa1,0xa2,0xa3,0xa4,
0xa5,0xa6,0xa7,0xa8,0xa9,0xaa,0xab,0xac,0xad,0xae,0xaf,0xb0,0xb2,0xb3,0xb4,0xb5,0xb6,0xb7,0xb8,0xb9,
0xba,0xbb,0xbc,0xbd,0xbe,0xbf,0xbf,0xc0,0xc1,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xcb,0xcc,
0xcd,0xcd,0xce,0xcf,0xd0,0xd1,0xd2,0xd3,0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd8,0xd9,0xda,0xdb,0xdc,0xdc,
0xdd,0xde,0xdf,0xdf,0xe0,0xe1,0xe2,0xe2,0xe3,0xe4,0xe4,0xe5,0xe6,0xe6,0xe7,0xe8,0xe8,0xe9,0xea,0xea,
0xeb,0xeb,0xec,0xed,0xed,0xee,0xee,0xef,0xef,0xf0,0xf1,0xf1,0xf2,0xf2,0xf3,0xf3,0xf4,0xf4,0xf4,0xf5,
0xf5,0xf6,0xf6,0xf7,0xf7,0xf7,0xf8,0xf8,0xf9,0xf9,0xf9,0xfa,0xfa,0xfa,0xfb,0xfb,0xfb,0xfb,0xfc,0xfc,
0xfc,0xfc,0xfd,0xfd,0xfd,0xfd,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfd,0xfd,0xfd,0xfd,0xfc,0xfc,0xfc,0xfc,0xfb,0xfb,
0xfb,0xfb,0xfa,0xfa,0xfa,0xf9,0xf9,0xf9,0xf8,0xf8,0xf7,0xf7,0xf7,0xf6,0xf6,0xf5,0xf5,0xf4,0xf4,
0xf4,0xf3,0xf3,0xf2,0xf2,0xf1,0xf1,0xf0,0xef,0xef,0xee,0xee,0xed,0xed,0xec,0xeb,0xeb,0xea,0xea,
0xe9,0xe8,0xe8,0xe7,0xe6,0xe6,0xe5,0xe4,0xe4,0xe3,0xe2,0xe2,0xe1,0xe0,0xdf,0xdf,0xde,0xdd,0xdc,
0xdc,0xdb,0xda,0xd9,0xd8,0xd8,0xd7,0xd6,0xd5,0xd4,0xd3,0xd3,0xd2,0xd1,0xd0,0xcf,0xce,0xcd,0xcd,
0xcc,0xcb,0xca,0xc9,0xc8,0xc7,0xc6,0xc5,0xc4,0xc3,0xc2,0xc1,0xc0,0xc0,0xbf,0xbe,0xbd,0xbc,0xbb,
0xba,0xb9,0xb8,0xb7,0xb6,0xb5,0xb4,0xb3,0xb2,0xb0,0xaf,0xae,0xad,0xac,0xab,0xaa,0xa9,0xa8,0xa7,
0xa6,0xa5,0xa4,0xa3,0xa2,0xa1,0xa0,0x9e,0x9d,0x9c,0x9b,0x9a,0x99,0x98,0x97,0x96,0x95,0x94,0x92,
0x91,0x90,0x8f,0x8e,0x8d,0x8c,0x8b,0x8a,0x88,0x87,0x86,0x85,0x84,0x83,0x82,0x81,0x80,0x7e,0x7d,
0x7c,0x7b,0x7a,0x79,0x78,0x77,0x75,0x74,0x73,0x72,0x71,0x70,0x6f,0x6e,0x6d,0x6b,0x6a,0x69,0x68,
0x67,0x66,0x65,0x64,0x63,0x62,0x61,0x5f,0x5e,0x5d,0x5c,0x5b,0x5a,0x59,0x58,0x57,0x56,0x55,0x54,
0x53,0x52,0x51,0x50,0x4f,0x4d,0x4c,0x4b,0x4a,0x49,0x48,0x47,0x46,0x45,0x44,0x43,0x42,0x41,0x40,
0x40,0x3f,0x3e,0x3d,0x3c,0x3b,0x3a,0x39,0x38,0x37,0x36,0x35,0x34,0x33,0x32,0x32,0x31,0x30,0x2f,
0x2e,0x2d,0x2c,0x2c,0x2b,0x2a,0x29,0x28,0x27,0x27,0x26,0x25,0x24,0x23,0x23,0x22,0x21,0x20,0x20,
0x1f,0x1e,0x1d,0x1d,0x1c,0x1b,0x1b,0x1a,0x19,0x19,0x18,0x17,0x17,0x16,0x15,0x15,0x14,0x14,0x13,
0x12,0x12,0x11,0x11,0x10,0x10,0xf,0xe,0xe,0xd,0xd,0xc,0xc,0xb,0xb,0xb,0xa,0xa,0x9,0x9,0x8,0x8,
0x8,0x7,0x7,0x6,0x6,0x6,0x5,0x5,0x5,0x4,0x4,0x4,0x4,0x3,0x3,0x3,0x3,0x2,0x2,0x2,0x2,0x1,0x1,0x1,
0x1,0x1,0x1,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,
0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x1,0x1,0x1,0x1,0x1,0x1,0x2,0x2,0x2,0x2,0x3,0x3,0x3,0x3,0x4,0x4,
0x4,0x4,0x5,0x5,0x5,0x6,0x6,0x6,0x7,0x7,0x8,0x8,0x8,0x9,0x9,0xa,0xa,0xb,0xb,0xb,0xc,0xc,0xd,0xd,
0xe,0xe,0xf,0x10,0x10,0x11,0x11,0x12,0x12,0x13,0x14,0x14,0x15,0x15,0x16,0x17,0x17,0x18,0x19,0x19,
0x1a,0x1b,0x1b,0x1c,0x1d,0x1d,0x1e,0x1f,0x20,0x20,0x21,0x22,0x23,0x23,0x24,0x25,0x26,0x27,0x27,
0x28,0x29,0x2a,0x2b,0x2c,0x2c,0x2d,0x2e,0x2f,0x30,0x31,0x32,0x32,0x33,0x34,0x35,0x36,0x37,0x38,
0x39,0x3a,0x3b,0x3c,0x3d,0x3e,0x3f,0x3f,0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,
0x4b,0x4c,0x4d,0x4f,0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5a,0x5b,0x5c,0x5d,0x5e,
0x5f,0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x6b,0x6d,0x6e,0x6f,0x70,0x71,0x72,0x73,
0x74,0x75,0x77,0x78,0x79,0x7a,0x7b,0x7c,0x7d,0x7e};
uchar code sin2[256]={
0x80, 0x83, 0x86, 0x89, 0x8c, 0x8f, 0x92, 0x95,
0x98, 0x9c, 0x9f, 0xa2, 0xa5, 0xa8, 0xab, 0xae,
0xb0, 0xb3, 0xb6, 0xb9, 0xbc, 0xbf, 0xc1, 0xc4,
0xc7, 0xc9, 0xcc, 0xce, 0xd1, 0xd3, 0xd5, 0xd8,
0xda, 0xdc, 0xde, 0xe0, 0xe2, 0xe4, 0xe6, 0xe8,
0xea, 0xec, 0xed, 0xef, 0xf0, 0xf2, 0xf3, 0xf4,
0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfc,
0xfd, 0xfe, 0xfe, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xfe,
0xfd, 0xfc, 0xfc, 0xfb, 0xfa, 0xf9, 0xf8, 0xf7,
0xf6, 0xf5, 0xf3, 0xf2, 0xf0, 0xef, 0xed, 0xec,
0xea, 0xe8, 0xe6, 0xe4, 0xe3, 0xe1, 0xde, 0xdc,
0xda, 0xd8, 0xd6, 0xd3, 0xd1, 0xce, 0xcc, 0xc9,
0xc7, 0xc4, 0xc1, 0xbf, 0xbc, 0xb9, 0xb6, 0xb4,
0xb1, 0xae, 0xab, 0xa8, 0xa5, 0xa2, 0x9f, 0x9c,
0x99, 0x96, 0x92, 0x8f, 0x8c, 0x89, 0x86, 0x83,
0x80, 0x7d, 0x79, 0x76, 0x73, 0x70, 0x6d, 0x6a,
0x67, 0x64, 0x61, 0x5e, 0x5b, 0x58, 0x55, 0x52,
0x4f, 0x4c, 0x49, 0x46, 0x43, 0x41, 0x3e, 0x3b,
0x39, 0x36, 0x33, 0x31, 0x2e, 0x2c, 0x2a, 0x27,
0x25, 0x23, 0x21, 0x1f, 0x1d, 0x1b, 0x19, 0x17,
0x15, 0x14, 0x12, 0x10, 0x0f, 0x0d, 0x0c, 0x0b,
0x09, 0x08, 0x07, 0x06, 0x05, 0x04, 0x03, 0x03,
0x02, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01,
0x02, 0x03, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
0x09, 0x0a, 0x0c, 0x0d, 0x0e, 0x10, 0x12, 0x13,
0x15, 0x17, 0x18, 0x1a, 0x1c, 0x1e, 0x20, 0x23,
0x25, 0x27, 0x29, 0x2c, 0x2e, 0x30, 0x33, 0x35,
0x38, 0x3b, 0x3d, 0x40, 0x43, 0x46, 0x48, 0x4b,
0x4e, 0x51, 0x54, 0x57, 0x5a, 0x5d, 0x60, 0x63,
0x66, 0x69, 0x6c, 0x6f, 0x73, 0x76, 0x79, 0x7c, };
sbit key1=P3^4;
sbit key2=P3^5;
uint speed=20; //正弦波變化速度
uint num=0;
uint time=0;
DACconversion(unsigned char sla,unsigned char c, unsigned char Val);
void Init_Timer1(void)//定時器一初始化程序
{
TMOD=0x01;
TH0=(65535-0)/256;
TL0=(65535-0)%256;
EA=1;//開總中斷
ET0=1;//開定時器0中斷
TR0=1; //啟動定時器0
}
void delay(uchar s){
uchar i,j;
for(i=s;i>0;i--)
for(j=110;j>0;j--);
}
void change_Speed(){
if(key1==0){
delay(10);
if(key1==0){
speed++;
}
}
if(key2==0){
delay(10);
if(key2==0){
if(speed>1)
speed--;
}
}
}
void time0() interrupt 1{
TH0=(65535-0)/256;
TL0=(65535-0)%256;
change_Speed();
for(num=0;num<arr_length;num=num+speed){
DACconversion(PCF8591,0x40,sin1[num]);
}
if(num==arr_length){
num=0;
}
}
void main()
{
Init_Timer1();
}
i2c.c文件
/*-----------------------------------------------
名稱：IIC協議
修改：無
內容：函數是采用軟件延時的方法產生SCL脈沖,固對高晶振頻率要作 一定的修改....(本例是1us機器
周期,即晶振頻率要小於12MHZ)
------------------------------------------------*/
#include "i2c.h"
//#include "delay.h"
#define PCF8591 0x90
#define _Nop() _nop_() //定義空指令
bit ack; //應答標志位
sbit SDA=P2^0;
sbit SCL=P2^1;
/*------------------------------------------------
啟動總線
------------------------------------------------*/
void Start_I2c()
{
SDA=1; //發送起始條件的數據信號
_Nop();
SCL=1;
_Nop(); //起始條件建立時間大於4.7us,延時
_Nop();
_Nop();
_Nop();
_Nop();
SDA=0; //發送起始信號
_Nop(); //起始條件鎖定時間大於4μ
_Nop();
_Nop();
_Nop();
_Nop();
SCL=0; //鉗住I2C總線，准備發送或接收數據
_Nop();
_Nop();
}
/*------------------------------------------------
結束總線
------------------------------------------------*/
void Stop_I2c()
{
SDA=0; //發送結束條件的數據信號
_Nop(); //發送結束條件的時鍾信號
SCL=1; //結束條件建立時間大於4μ
_Nop();
_Nop();
_Nop();
_Nop();
_Nop();
SDA=1; //發送I2C總線結束信號
_Nop();
_Nop();
_Nop();
_Nop();
}
/*----------------------------------------------------------------
字節數據傳送函數
函數原型: void SendByte(unsigned char c);
功能: 將數據c發送出去,可以是地址,也可以是數據,發完后等待應答,並對
此狀態位進行操作.(不應答或非應答都使ack=0 假)
發送數據正常，ack=1; ack=0表示被控器無應答或損壞。
------------------------------------------------------------------*/
void SendByte(unsigned char c)
{
unsigned char BitCnt;
for(BitCnt=0;BitCnt<8;BitCnt++) //要傳送的數據長度為8位
{
if((c<<BitCnt)&0x80)SDA=1; //判斷發送位
else SDA=0;
_Nop();
SCL=1; //置時鍾線為高，通知被控器開始接收數據位
_Nop();
_Nop(); //保證時鍾高電平周期大於4μ
_Nop();
_Nop();
_Nop();
SCL=0;
}
_Nop();
_Nop();
SDA=1; //8位發送完后釋放數據線，准備接收應答位
_Nop();
_Nop();
SCL=1;//控制線
_Nop();
_Nop();
_Nop();
if(SDA==1)ack=0;
else ack=1; //判斷是否接收到應答信號
SCL=0;
_Nop();
_Nop();
}
/*******************************************************************
DAC變換,轉化函數
*******************************************************************/
bit DACconversion(unsigned char sla,unsigned char c, unsigned char Val)
{
Start_I2c();//啟動總線
SendByte(sla);//發送器件地址
if(ack==0)return(0);
SendByte(c);//發送控制字節
if(ack==0)return(0);
SendByte(Val);//發送DAC的數值
if(ack==0)return(0);
Stop_I2c();//結束總線
return(1);
}
/*----------------------------------------------------------------
字節數據傳送函數
函數原型: unsigned char RcvByte();
功能: 用來接收從器件傳來的數據,並判斷總線錯誤(不發應答信號)，
發完后請用應答函數。
------------------------------------------------------------------*/
/*unsigned char RcvByte()
{
unsigned char retc;
unsigned char BitCnt;
retc=0;
SDA=1; //置數據線為輸入方式
for(BitCnt=0;BitCnt<8;BitCnt++)
{
_Nop();
SCL=0; //置時鍾線為低，准備接收數據位
_Nop();
_Nop(); //時鍾低電平周期大於4.7us
_Nop();
_Nop();
_Nop();
SCL=1; //置時鍾線為高使數據線上數據有效
_Nop();
_Nop();
retc=retc<<1;
if(SDA==1)retc=retc+1; //讀數據位,接收的數據位放入retc中
_Nop();
_Nop();
}
SCL=0;
_Nop();
_Nop();
return(retc);
}
*/
/*----------------------------------------------------------------
應答子函數
原型: void Ack_I2c(void);
----------------------------------------------------------------*/
/*void Ack_I2c(void)
{
SDA=0;
_Nop();
_Nop();
_Nop();
SCL=1;
_Nop();
_Nop(); //時鍾低電平周期大於4μ
_Nop();
_Nop();
_Nop();
SCL=0; //清時鍾線，鉗住I2C總線以便繼續接收
_Nop();
_Nop();
}*/
/*----------------------------------------------------------------
非應答子函數
原型: void NoAck_I2c(void);
----------------------------------------------------------------*/
/*void NoAck_I2c(void)
{
SDA=1;
_Nop();
_Nop();
_Nop();
SCL=1;
_Nop();
_Nop(); //時鍾低電平周期大於4μ
_Nop();
_Nop();
_Nop();
SCL=0; //清時鍾線，鉗住I2C總線以便繼續接收
_Nop();
_Nop();
}
*/
/*----------------------------------------------------------------
向無子地址器件發送字節數據函數
函數原型: bit ISendByte(unsigned char sla,ucahr c);
功能: 從啟動總線到發送地址，數據，結束總線的全過程,從器件地址sla.
如果返回1表示操作成功，否則操作有誤。
注意： 使用前必須已結束總線。
----------------------------------------------------------------*/
/*bit ISendByte(unsigned char sla,unsigned char c)
{
Start_I2c(); //啟動總線
SendByte(sla); //發送器件地址
if(ack==0)return(0);
SendByte(c); //發送數據
if(ack==0)return(0);
Stop_I2c(); //結束總線
return(1);
}
*/
/*----------------------------------------------------------------
向有子地址器件發送多字節數據函數
函數原型: bit ISendStr(unsigned char sla,unsigned char suba,ucahr *s,unsigned char no);
功能: 從啟動總線到發送地址，子地址,數據，結束總線的全過程,從器件
地址sla，子地址suba，發送內容是s指向的內容，發送no個字節。
如果返回1表示操作成功，否則操作有誤。
注意： 使用前必須已結束總線。
----------------------------------------------------------------*/
/*bit ISendStr(unsigned char sla,unsigned char suba,unsigned char *s,unsigned char no)
{
unsigned char i;
for(i=0;i<no;i++)
{
Start_I2c(); //啟動總線
SendByte(sla); //發送器件地址
if(ack==0)return(0);
SendByte(suba); //發送器件子地址
if(ack==0)return(0);
SendByte(*s); //發送數據
if(ack==0)return(0);
Stop_I2c(); //結束總線
DelayMs(1); //必須延時等待芯片內部自動處理數據完畢
s++;
suba++;
}
return(1);
}
*/
/*----------------------------------------------------------------
向無子地址器件讀字節數據函數
函數原型: bit IRcvByte(unsigned char sla,ucahr *c);
功能: 從啟動總線到發送地址，讀數據，結束總線的全過程,從器件地
址sla，返回值在c.
如果返回1表示操作成功，否則操作有誤。
注意： 使用前必須已結束總線。
----------------------------------------------------------------*/
/*bit IRcvByte(unsigned char sla,unsigned char *c)
{
Start_I2c(); //啟動總線
SendByte(sla+1); //發送器件地址
if(ack==0)return(0);
*c=RcvByte(); //讀取數據
NoAck_I2c(); //發送非就答位
Stop_I2c(); //結束總線
return(1);
}
*/
/*----------------------------------------------------------------
向有子地址器件讀取多字節數據函數
函數原型: bit ISendStr(unsigned char sla,unsigned char suba,ucahr *s,unsigned char no);
功能: 從啟動總線到發送地址，子地址,讀數據，結束總線的全過程,從器件
地址sla，子地址suba，讀出的內容放入s指向的存儲區，讀no個字節。
如果返回1表示操作成功，否則操作有誤。
注意： 使用前必須已結束總線。
----------------------------------------------------------------*/
/*bit IRcvStr(unsigned char sla,unsigned char suba,unsigned char *s,unsigned char no)
{
unsigned char i;
Start_I2c(); //啟動總線
SendByte(sla); //發送器件地址
if(ack==0)return(0);
SendByte(suba); //發送器件子地址
if(ack==0)return(0);
Start_I2c();
SendByte(sla+1);
if(ack==0)return(0);
for(i=0;i<no-1;i++)
{
*s=RcvByte(); //發送數據
Ack_I2c(); //發送就答位
s++;
}
*s=RcvByte();
NoAck_I2c(); //發送非應位
Stop_I2c(); //結束總線
return(1);
}
*/
原理圖：
效果：
單片機課程設計~