我为了使用ATtiny45定时器1作每秒1000HZ的定时中断,编了以下程序,可是运行不了,想了好久也想不出解决的方法。请各位高手指导,看看问题出在哪里? 
#include <tiny45.h> 
 
#define uchar unsigned char 
#define uint unsigned int 
 
#define led PORTB.0 
#define LED_ON 0 
#define LED_OFF 1 
 
uint mark = 0; 
 
// Timer1 overflow interrupt service routine 
interrupt [TIM1_OVF] void timer1_ovf_isr(void) 
{ 
// Reinitialize Timer1 value 
TCNT1=0x64; 
// Place your code here 
mark++; 
} 
 
 
void main(void) 
{ 
PORTB=0x03; 
DDRB=0x01; 
 
// Timer/Counter 1 initialization 
PLLCSR=0x00; 
 
TCCR1=0x01; 
GTCCR=0x00; 
TCNT1=0x64; 
OCR1A=0x00; 
OCR1B=0x00; 
OCR1C=0x00; 
 
// Interrupt(s) initialization 
TIMSK=0x04; 
 
while(1) 
    { 
        if(mark==500)      
            led = LED_ON; 
        if(mark==1000)      
            led = LED_OFF; 
        mark = 0; 
    } 
} |   
     
  
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