嵌入式技术
本文详细介绍了ATMage16的16位定时器的PWM应用。
//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
#include
#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《DDRD|=(1《init_devices(0x0f,0x45,0x0f,0xf0); //修改实参即可改变占空比,最大值为0X0FFF;
while(1);
}
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