#include<reg51.h>
#define PCF8591 0x90 //PCF8591 地址
sbit P2_1=P2^1;
sbit P20=P2^0;
sbit key0=P1^0;//正弦按鍵
sbit key1=P1^1;//方波按鍵
sbit key2=P1^2;//三角波按鍵
sbit key3=P1^3;//鋸齒波按鍵
unsigned char flag;//1,2,3,4分別對應以上四個波形
unsigned char const code
SIN_code[256]= //正弦波字表
{0x80,0x83,0x86,0x89,0x8d,0x90,0x93,0x96,0x99,0x9c,0x9f,0xa2,0xa5,0xa8,0xab,0xae,0xb1,0xb4,0xb7,0xba,0xbc,0xbf,0xc2,0xc5,
0xc7,0xca,0xcc,0xcf,0xd1,0xd4,0xd6,0xd8,0xda,0xdd,0xdf,0xe1,0xe3,0xe5,0xe7,0xe9,0xea,0xec,0xee,0xef,0xf1,0xf2,0xf4,0xf5,
0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfd,0xfe,0xff,0xff,0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,0xff,0xff,0xfe,0xfd,0xfd,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,0xf6,0xf5,0xf4,0xf2,0xf1,0xef,0xee,0xec,0xea,
0xe9,0xe7,0xe5,0xe3,0xe1,0xde,0xdd,0xda,0xd8,0xd6,0xd4,0xd1,0xcf,0xcc,0xca,0xc7,0xc5,0xc2,0xbf,0xbc,0xba,0xb7,0xb4,0xb1,
0xae,0xab,0xa8,0xa5,0xa2,0x9f,0x9c,0x99 ,0x96,0x93,0x90,0x8d,0x89,0x86,0x83,0x80,
0x80,0x7c,0x79,0x76,0x72,0x6f,0x6c,0x69,0x66,0x63,0x60,0x5d,0x5a,0x57,0x55,0x51,0x4e,0x4c,0x48,0x45,0x43,0x40,0x3d,0x3a,
0x38,0x35,0x33,0x30,0x2e,0x2b,0x29,0x27,0x25,0x22,0x20,0x1e,0x1c,0x1a,0x18,0x16,0x15,0x13,0x11,0x10,0x0e,0x0d,0x0b,0x0a,
0x09,0x08,0x07,0x06,0x05,0x04,0x03,0x02,0x02,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x02,
0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0d,0x0e,0x10,0x11,0x13,0x15,0x16,0x18,0x1a,0x1c,0x1e,0x20,0x22,0x25,
0x27,0x29,0x2b,0x2e,0x30,0x33,0x35,0x38,0x3a,0x3d,0x40,0x43,0x45,0x48,0x4c,0x4e,0x51,0x55,0x57,0x5a,0x5d,0x60,0x63,0x66,
0x69,0x6c,0x6f,0x72,0x76,0x79,0x7c,0x80};
unsigned int t=0;
unsigned char keyscan()//鍵盤掃描函數
{
unsigned char keyscan_num,temp;
P1=0xff; //P1口輸入
temp=P1; //從P1口讀入按鍵值存入temp
if(~(temp&0xff)) //判斷是否有按鍵按下
{
if(key0==0) //正弦波
{
keyscan_num=1;
}
else if(key1==0) //方波
{
keyscan_num=2;
}
else if(key2==0) //三角波
{
keyscan_num=3;
}
else if(key3==0) //鋸齒波
{
keyscan_num=4;
}
else
{
keyscan_num=0; //沒有按鍵按下
}
return keyscan_num;
}
}
void init_PCF8591() //PCF8591初始化函數
{
P20=t;
}
void SIN()
{
unsigned int i;
do
{
P20=SIN_code; //由P2_0口輸出給PCF8591數據
i=i+1;
}while(i<256);
}
void Square()
{
EA=1;
ET0=1;
TMOD=1;
TH0=0xff; //裝入時間常數
TL0=0x83;
TR0=1;
}
void timer0(void) interrupt 1
{
P20=!P20;
TH0=0xff;
TL0=0x83;
TR0=1;
}
void Triangle()
{
P20=t;
do
{
P20=t+1; //上升沿
}while(t<0xff);
P20=0xff;
do
{
P20=t-1;
}while(t>0);
P20=0;
}
void Sawtooth()
{
P20=0;
do
{
P20=t;
t++;
}while(t<0xff);
}
#define _Nop() /*定義空指令*/
sbit SCL=P2^1; //I2C 時鐘
sbit SDA=P2^0; //I2C 數據
bit ack; /*應答標志位*/
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于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于4μs*/
_Nop();
_Nop();
_Nop();
_Nop();
SCL=0; /*鉗住I2C 總線，準備發送或接收數據 */
_Nop();
_Nop();
}
/*******************************************************************
結束總線函數
函數原型: void Stop_I2c();
功能: 結束 I2C 總線,即發送 I2C 結束條件.
********************************************************************/
void Stop_I2c()
{
SDA=0; /*發送結束條件的數據信號*/
_Nop(); /*發送結束條件的時鐘信號*/
SCL=1; /*結束條件建立時間大于4μs*/
_Nop();
_Nop();
_Nop();
_Nop();
_Nop();
SDA=1; /*發送I2C 總線結束信號*/
_Nop();
_Nop();
_Nop();
_Nop();
}
/*******************************************************************
字節數據發送函數
函數原型: void SendByte(UCHAR 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,并對 此狀態位進行操作.(不應答或非應答都使 ack=0) 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; /*置時鐘線為高，通知被控器開始接收數據位*/
_Nop();
_Nop(); /*保證時鐘高電平周期大于4μs*/
_Nop();
_Nop();
_Nop(); SCL=0;
}
_Nop();
_Nop();
SDA=1; /*8 位發送完后釋放數據線，準備接收應答位*/
_Nop();
_Nop(); SCL=1;
_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();
}
/*******************************************************************
字節數據接收函數
函數原型: UCHAR RcvByte();
功能: 用來接收從器件傳來的數據,并判斷總線錯誤(不發應答信號)，
發完后請用應答函數應答從機。
********************************************************************/
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; /*置時鐘線為低，準備接收數據位*/
_Nop();
_Nop(); /*時鐘低電平周期大于 4.7μs*/
_Nop();
_Nop();
_Nop();
SCL=1; /*置時鐘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
函數原型: void Ack_I2c(bit a);
功能: 主控器進行應答信號(可以是應答或非應答信號，由位參數 a 決定)
********************************************************************/
void Ack_I2c(bit a)
{
if(a==0)SDA=0; /*在此發出應答或非應答信號 */
else SDA=1;
_Nop();
_Nop();
_Nop(); SCL=1;
_Nop();
_Nop(); /*時鐘低電平周期大于 4μs*/
_Nop();
_Nop();
_Nop();
SCL=0; /*清時鐘線，鉗住I2C 總線以便繼續接收*/
_Nop();
_Nop();
}
/******************************************************************* DAC 變換, 轉化函數
*******************************************************************/
bit DAC(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);
}
#include<reg51.h>
#include <I2C.H>
#define PCF8591 0x90 //PCF8591 地址
unsigned char AD_CHANNEL;
unsigned long xdata LedOut[8];
unsigned int D[32];
/*******************************************************************
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);
}
void main()
{
init_PCF8591();
do
{
flag=keyscan();
}while(!flag);
while(1)
{
switch(flag)
{
case 1:
do
{
flag=keyscan();
DACconversion(PCF8591,0x40,SIN_code[256]);
}while(flag==1);break;
case 2:
DACconversion(PCF8591,0x40,0xff);
DACconversion(PCF8591,0x40,0x83);
do
{
flag=keyscan();
}while(flag==2);
TR0=1;
break;
case 3:
do
{
flag=keyscan();
if(t<=127)
DACconversion(PCF8591,0x40,t) ;
else
DACconversion(PCF8591,0x40,255-t) ;
}while(flag==3);
break;
case 4:
do
{
flag=keyscan();
DACconversion(PCF8591,0x40,t++);
}while(flag==4);
break;
}
}
}
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