单片机变频pwm实验程序设计与原理

#include<reg52.h>

sfr   CCON   = 0xD8;
sfr   CMOD   = 0xD9;
sfr   CL     = 0xE9;
sfr   CH     = 0xF9;
sfr   CCAP0L = 0xEA;
sfr   CCAP0H = 0xFA;
sfr   CCAPM0 = 0xDA;
sfr   CCAPM1 = 0xDB;

sbit  CR   = 0xDE;
sbit  led   = P2^0;

unsigned char duty = 0x80;
unsigned int fre = 0xffff;

void timer0_int (void) interrupt 1 using 1
{
 TH0 = fre >> 8;
 TL0 = fre & 0xff;
 led = ~led;
}

void timer0_init(void)
{  
    TMOD &= 0xf0; /* Set timer 0 */
 TMOD |= 0x1; /* mode 1 */
 TH0 = 0xff;  
 TL0 = 0xff;
 TR0 = 1; /* Enable timer 0 */
 ET0 = 1; /* Enable timer 0 interrupt */
 }

void pwm_init(void)
{
    CMOD = 0x4;  // Use timer0
    CL = 0x0;
    CH = 0x0;
    CCAP0H = duty;    //Duty Cycle
    CCAPM0 = 0x42;   // PWM mode
    CR = 1;   //Start PCA Timer.
}

void SOFt_delay(unsigned int _1ms)
{
 unsigned int tmp;
 while(_1ms--!=0) {
  for(tmp=0;tmp<144;tmp++);
 }
}
void check_key(void)
{
 unsigned char key1,key2;
 key1 = P1 & 0xf;
 soft_delay(20);
 key2 = P1 & 0xf;
 
 if(key1 == key2 && key1 != 0xf){
  if(key1 == 0xe)
   duty += 16;
  else if(key1 == 0xd)
   duty -= 16;
  else if(key1 == 0xb)
   fre += 0xff;
  else if(key1 == 0x7)
   fre -= 0xff;
  while((P1 & 0xf) != 0xf);
 }
}

void main (void)
{
 pwm_init();
 timer0_init();

 EA = 1; 
 while(1){
  CCAP0H = duty;
  check_key();  
 }

本文关键字：单片机  程序设计  51单片机，单片机-工控设备 - 51单片机