wave50%.c

利用ATmega16单片机的T2定时器产生方波的控制程序

//ICC-AVR application builder : 2007-9-8 下午 05:22:48
// Target : M16
// Crystal: 16.000Mhz

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

void port_init(void)
{
 PORTA = 0xFF;
 DDRA  = 0x00;
 PORTB = 0x00;
 DDRB  = 0xFF;
 PORTC = 0xFF; //m103 output only
 DDRC  = 0x00;
 PORTD = 0x00;
 DDRD  = 0xFF;
}

//TIMER0 initialisation - prescale:8
// WGM: Normal
// desired value: 15KHz
// actual value: 15.038KHz (0.3%)
void timer0_init(void)
{
 TCCR0 = 0x00; //stop
 TCNT0 = 0x7B; //set count
 OCR0  = 0x85;  //set compare
 TCCR0 = 0x12; //start timer
}

//TIMER1 initialisation - prescale:1
// WGM: 0) Normal, TOP=0xFFFF
// desired value: 125KHz
// actual value: 125.000KHz (0.0%)
void timer1_init(void)
{
 TCCR1B = 0x00; //stop
 TCNT1H = 0xFF; //setup
 TCNT1L = 0x80;
 OCR1AH = 0x00;
 OCR1AL = 0x80;
 OCR1BH = 0x00;
 OCR1BL = 0x60;
 OCR1CH = $OCR1CH$;
 OCR1CL = $OCR1CL$;
 ICR1H  = 0x00;
 ICR1L  = 0x80;
 TCCR1A = 0x50;
 TCCR1B = 0x01; //start Timer
}

//call this routine to initialise all peripherals
void init_devices(void)
{
 //stop errant interrupts until set up
 CLI(); //disable all interrupts
 port_init();
 timer0_init();
 timer1_init();

 MCUCR = 0x00;
 GICR  = 0x00;
 TIMSK = 0x00; //timer interrupt sources
 SEI(); //re-enable interrupts
 //all peripherals are now initialised
}


void main()
{
     init_devices(); 
}