1、設計一個波形發生器，模擬心電信號。
#include<stc12c56.h>
#include<intrins.h>
#include<math.h>
#define  uchar unsigned char
#define  uint unsigned int
#define  NUM  2           //ADC channal
#define AD_SPEED1   0x60 //0110,0000   1      1     270個時鐘周期轉換一次，
#define AD_SPEED2   0x40 //0100,0000   1      0     540個時鐘周期轉換一次
#define AD_SPEED3   0x20 //0010,0000   0      1     810個時鐘周期轉換一次
#define AD_SPEED4   0x00 //0000,0000   0      0     1080個時鐘周期轉換一次
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
uchar code SacTab[256]={0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3e,0x3e,0x3f,0x40,0x41,0x43,0x45,0x46,
0x47,0x48,0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f,0x50,0x51,0x52,0x53,0x54,0x54,0x55,0x55,0x54,0x54,0x53,0x53,0x52,0x51,0x50,
0x4f,0x4e,0x4d,0x4c,0x4b,0x4a,0x49,0x47,0x45,0x42,0x3f,0x3d,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,
0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3b,0x39,0x37,0x35,0x32,0x2f,0x2c,0x3c,0x4c,0x5c,0x6d,0x7d,0x8d,0x9e,0xae,0xbe,0xcf,0xdf,
0xef,0xff,0xdb,0xb7,0x92,0x6e,0x4a,0x25,0x00,0x08,0x10,0x18,0x20,0x28,0x30,0x34,0x38,0x3a,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,
0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,
0x3c,0x3d,0x3e,0x3f,0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x48,0x4a,0x4c,0x4e,0x4f,0x50,0x51,0x52,0x53,0x53,0x54,0x54,0x55,
0x55,0x56,0x57,0x57,0x58,0x58,0x59,0x59,0x5a,0x5a,0x5b,0x5b,0x5c,0x5d,0x5d,0x5e,0x5e,0x5f,0x5f,0x5f,0x5e,0x5e,0x5d,0x5d,
0x5c,0x5c,0x5b,0x5b,0x5a,0x59,0x58,0x57,0x56,0x55,0x54,0x53,0x52,0x51,0x50,0x4f,0x4e,0x4d,0x4c,0x4b,0x4a,0x49,0x47,0x45,
0x44,0x42,0x40,0x3e,0x3d,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3d,0x3f,0x41,0x42,
0x43,0x43,0x42,0x41,0x3f,0x3d,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c,0x3c};
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
uchar code SinTab[256]={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 };
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
uchar AD_result=0,pwm_n=0,Freq=0;
uchar Wave=0;
float AD_n = 1.0;
/////////////////////////////////////////////////////////
void delay(uint delay_time);        // 延時函數
void  pwm_init(void);     //用ccap0_h設置占空比
void timer0_init(void);
void adc_init(void);
void pwm(uchar High);     //調節PWM輸出,波形發生函數
uchar  get_adc(uchar channel);     //AD 采樣
void button(uchar key);
void Key(void);
//////////////////////////////////////////////////////                                                                                                                     q/////////////////////////////////////
void delay(uint delay_time)        // 延時函數
{
    uint n;
    while(delay_time--)
    {
        n = 4000;
        while(--n);
    }
}
//////////////////////////////////////////////
void  pwm_init()     //用ccap0_h設置占空比
{
 CMOD = 0X02;  //時鐘為Fosc/2
 CL = 0X00;
 CH = 0X00;
 CCAP0H = 255 - 0x3c;      //基準電壓
 CCAP0L = 255 - 0x3c;
 CCAPM0 = 0X42;  //0100,0010 ECOM0=1使能比較器功能  PWM＝1，使能CEX0腳 作脈寬調節輸出
 CCAPM1 = 0X42;
 CR = 1;         //啟動pwm
}
///////////////////////////////////////////////
void timer0_init()
{
    TMOD |= 0x01;   //定時器設置 16位
    TH0 = -50000 / 256;
    TL0 = -50000 % 256;//初始化值
    ET0 = 1;
    TR0 = 1;
    EA = 1;
}
////////////////////////////////////////////
/*ADC初始化*/
void  adc_init()
 {
 P1M0 = 0x0f;      //設置模式 AD采樣10或11
 P1M1 = 0x00;
 ADC_CONTR = 0x80;      //打開電源
 delay(50);
 }
 //////////////////////////////////////////////////////////
 /*************定時器定時輸入波形***********************/
 void timer0_int() interrupt 1
{
 pwm_n = (pwm_n + 1)/255;
 switch(Wave)
 {
  case 0 : {pwm(SacTab[pwm_n]);break;}   //正常心電波
  case 1 : {pwm(pwm_n);break;}      //鋸齒波
  case 2 : {pwm(SinTab[pwm_n]);break;}   //正弦波
//  case 3 : {pwm(SanTab[pwm_n]);break;}
  default : pwm(0x3c);break;
 }
 TH0 = (-50000+Wave*200) / 256;
 TL0 = (-50000+Wave*200) % 256; 
}
////////////////////////////////////////////
void pwm(uchar High)     //調節PWM輸出
{
 CR = 0;
 CMOD = 0x02;    //setup PCA timer
 CL = 0x00;
 CH = 0x00;
 CCAP0L = 255 - High; //Set the initial value same as CCAP0H;
 CCAP0H = 255 - High; //高電平為  high/256
 CCAPM0 = 0x42;   //0100,0010 setup PCA module 0 in PWM mode
 CR = 1;     //start PCA timer
}
//////////////////////////////////////////////
uchar  get_adc(uchar channel)     //AD 采樣
{
    ADC_DATA = 0;
 ADC_LOW2 = 0;
    channel &= 0x07;                  //0000,0111 清0高5位
 _nop_();
    _nop_();
    _nop_();
    _nop_();
    ADC_CONTR |= AD_SPEED1;          //選擇速度
 _nop_();
    _nop_();
    _nop_();
    _nop_();
    ADC_CONTR |= channel;              //選擇 A/D 當前通
 _nop_();
    _nop_();
    _nop_();
    _nop_();
    delay(1);                        //使輸入電壓達到穩定
    ADC_CONTR |= 0x08;               //0000,1000 令 ADCS = 1, 啟動A/D轉換
 _nop_();
    _nop_();
    _nop_();
    _nop_();
 while(!(ADC_CONTR & 0x10));        //0001,0000 測試A/D轉換結束否
    ADC_CONTR &= 0x80;               //1000,0000 清 ADC_FLAG 位, 關閉A/D轉換,
  _nop_();
    _nop_();
    _nop_();
    _nop_();
    return (ADC_DATA); //返回 A/D 8 位轉換結果
}
/******************按鍵處理****************************/
void button(uchar key)
{
 if(key == 1)   
 {
  Wave=(Wave+1)%4;  
 }
 if(key == 2)
 {
  Wave=(Wave-1)%4;
 }
 if(key == 3)
 {
   Freq=(Freq+1)%50;
 }
 if(key == 4)
 {
   Freq=(Freq-1)%50;
 }
}
/////////////////////////////////////////////////
/******************AD做鍵盤**********************************/
void Key()
{
 AD_result = get_adc(NUM);   //獲取按鍵值
 if(abs(AD_result)< 240)   //判斷是否按鍵
 {
  delay(4);     //去抖動
  AD_result = get_adc(NUM);
  if(abs(AD_result)< 240)   //獲取穩定的按鍵值
  {
   AD_n=(255)/(254 - AD_result);   //獲取倍率，方便處理
   if((AD_n > 1.5)&&(AD_n <= 2.5))
    button(1);
   else if((AD_n > 2.5)&&(AD_n <= 3.5))
    button(2);
   else if((AD_n > 3.5)&&(AD_n <= 4.5))
    button(3);
   else if((AD_n > 4.5)&&(AD_n <= 5.5))
    button(4);
   else
    button(5);
  }
 }
 delay(25);
}
//////////////////////////////////////////////
main()
{
 adc_init();
 timer0_init();
 pwm_init();
 while(1)
 {
  Key();
 }
} 
2、設計波形采集回放系統。（待續）。。。