用PIC单片机的PWM生产一个频率和幅值可调的正弦波

Terran

• #include "Head.h"
• void main (void)
• {
•      OSCCON=0b11110000;
•      TRISD=0;
•      PORTD=0;
•      TRISC=0b10000000;
•      OPTION_REG=0b10001000;
•      INTCON=0b11100000;
•      PIE1=0b00100000;//开串口中断
•      CCP1CON=0b00001100;
•      PR2=255;
•      T2CON=0b00000100;//  最大脉冲宽度 4*(255+1)=1024
•      TXSTA=0b00100100;     //SYNC=0;BRGH=1;
•      RCSTA=0b10010000;
•      BAUDCON=0b00001000;   //BRG16=1;
•      SPBRGH=0;
•      SPBRG=207;            //FOSC/[4(n+1)] (32000000/38400)/4-1=207
•      while(1)
•      {
•       Send();
•      }
• }
• //定时器中断程序
• void interrupt TMR0INT(void)//4/32*256=32us
• {
•     static unsigned char a=0,b=0,c=0;
•     static unsigned int pwm_duty=0;
•     const unsigned int pwm_1[PI_data]={0,13,25,37,50,62,74,85,96,107,118,127,137,146,154,162,
•     169,175,181,186,190,194,196,198,200,200,200,198,196,194,190,186,
•     181,175,169,162,154,146,137,127,118,107,96,85,74,62,50,37,
•     25,13};
•     const unsigned int pwm_2[PI_data]={0,31,63,94,124,155,184,213,241,268,294,319,342,364,385,405,
•     422,438,452,465,476,484,491,496,499,500,499,496,491,484,476,465,
•     452,438,422,405,385,364,342,319,294,268,241,213,184,155,124,94,
•     63,31};
•     const unsigned int pwm_3[PI_data]={0,63,125,187,249,309,368,426,482,536,588,637,685,729,771,809,
•     844,876,905,930,951,969,982,992,998,1000,998,992,982,969,951,930,
•     905,876,844,809,771,729,685,637,588,536,482,426,368,309,249,187,
•     125,63};
•     if(T0IF)
•     {
•         T0IF=0;
•         LATD6^=1;
•         if(++a==Pwm_frequency)  //1000000/(Pwm_frequency*32*50)=频率HZ  1000000/(6*32*50)=104HZ
•         {
•           a=0;
•           if(++b==PI_data)b=0;
•           switch(c)
•           {
•              case 1:  {pwm_duty=pwm_1;break;}
•              case 2:  {pwm_duty=pwm_2;break;}
•              case 3:  {pwm_duty=pwm_3;break;}
•              default: {pwm_duty=pwm_1;break;}
•           }  CCP1CON=(CCP1CON&0xcf)|((pwm_duty&3)<<4);CCPR1L=pwm_duty>>2;
•        }
•     }
•    if(RCIF)
•    {
•       static unsigned char temp=0;
•       if(OERR==1){CREN=0;asm("nop");CREN=1;}
•       temp=RCREG;
•       switch(temp)
•       {
•         case 'a':{Pwm_frequency++;break;}//频率加
•         case 'b':{if(Pwm_frequency)Pwm_frequency--;break;}//频率减
•         case 'c':{c++;if(c>3)c=1;break;}//振动幅度
•       }
•     }
• }
  

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dragongfly

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