timer1.c

MEGA16 开发包3

//ICC-AVR application builder : 2007-5-6 21:30:57
// Target : M16
// Crystal: 8.0000Mhz
//TIMER1 initialize - prescale:64
// WGM: 10) PWM phz correct, TOP= ICRn
// desired value: 1Hz
// actual value:  1.000Hz (0.0%)


#include <iom16v.h>
#include <macros.h>

#define PWM1A     PORTD5  //OC1A   PD5
#define PWM1B     PORTD4  //OC1B   PD4
unsigned char OCAH;
unsigned char OCAL; 
unsigned char OCBH; 
unsigned char OCBL; 
 
void timer1_init(void)
{
TCCR1B = 0x00;          //stop
TCNT1H = 0x00;          //setup
TCNT1L = 0x01;
OCR1AH = OCAH;
OCR1AL = OCAL;
OCR1BH = OCBH;
OCR1BL = OCBL;
ICR1H = 0xff;          // pwm 的计数顶值
ICR1L = 0xFF;
TCCR1A = 0xA3;         // 匹配清零 top置位 
TCCR1B = 0x0B;         // start Timer
}

void init_devices(unsigned char valueah,unsigned char valueal,unsigned char valuebh,unsigned char valuebl)
{

 OCAH=valueah;
 OCAL=valueal;
 OCBH=valuebh;
 OCBL=valuebl;
 CLI();
                         //disable all interrupts
 timer1_init();
 MCUCR = 0x00;
 GICR  = 0x00;
 TIMSK = 0x04;           //timer interrupt sources
 SEI();                  //re-enable interrupts

}


void main(void)
{
 PORTD&=(0<<PWM1A)&(0<<PWM1B);
 DDRD|=(1<<PWM1A)|(1<<PWM1B);
 init_devices(0x0f,0x45,0x0f,0xf0);       //修改实参即可改变占空比,最大值为0X0FFF;
 while(1);
}