ATMEGA32保险丝位设置，低保险丝和高保险丝，16MHz，外部晶振？

Question

I am using ATMEGA32 with Crystal 16MHz .
I have written following code to generate 1kHz wave.

I tried writing Low- 0xFF High-0x99
But I am unable to get 1kHz wave . I am getting 250Hz wave . instead of 1kHz .

Please help.

#define F_CPU 16000000UL 
#include <avr/io.h> //io related 
#include <util/delay.h> //delay
#include "lcd.h" //custom lib for lcd
#include <stdlib.h> //for string handling
#ifndef sbit_h
#define sbit_h
int main(void)
{

    //All Declarations Go here.

   OCR0=p*127/100; //set pwm1 duty cycle
   OCR2=OCR0;      //set pwm2 duty cycle (Output compare register)

   while(1)
   { 
      if ((bit_is_set(PIND, 3 )))
       {
           pinChange(LED8,1); //Turn on solenoid valve
           pinChange(LED1,1);
           //PORTC|=(1<<PC3);
           _delay_ms(sq); //wait for squeeze time
           TCCR0 |= (1<<WGM00)|(1<<COM01)|(1<<WGM01)|(1<<CS01)|(1<<CS00); 
           //initialise timer in PWM mode 1kHz//cs00 and cs02
           _delay_us(500);//90 degree phase shift
           TCCR2 |= (1<<WGM20)|(1<<COM21)|(1<<WGM21)|(1<<CS22); //initialise timer2 in PWM mode 1kHz//CS22 for 1kHz
           _delay_ms(w1); //wait until weld time over
           TCCR0=0x00;  //stop PWM1
           TCCR2=0x00;  //Stop PWM2
           _delay_ms(h); //wait for hold time
           pinChange(LED8,0); //turn off solenoid valve
           pinChange(LED1,0);
           TCNT0=0x00; //Reset timer counter
           TCNT2=0x00; //reset timer counter
     }
}

Answer 1

Did you set clock selection fuse bits (and possibly clock divider) in the correct way? I'd start checking CKSEL0...3 and CKDIV8 .

By my experience, getting an exact multiple of the desired time/frequency is almost always based on a wrong clock setting.