ATmega88 @ 8MHz LED fading 03

led-fading-03.c

/*
* LED_fading_03.c
* Controller: ATmega88 @ 8MHz
*/
#include <avr/io.h>
#include <util/delay.h>
#include        // Einbinden der Headerdatei math.h für mathematische Funktionen
 
int main(void)
{
    DDRB |= (1<<PB1); // OC1A = output
    ICR1 = 65535;       // ICR1 = Top Value
     
    // Mode 10: PWM, Phase Correct, Prescaler = 1, Clear OC1A on compare match
    TCCR1A = (1 << COM1A1) + (1 << WGM11);
    TCCR1B = (1 << WGM13) + (1 << CS10);
     
    while(1)
    {
        float result;                       // Datentyp float für Gleitkommaberechnungen
        uint8_t basis = 80, steps = 72;     // Basiswert und steps ausprobieren
         
        for(uint8_t i=0; i<= 254; i++)
        {
            result = ((pow(basis,(float)i/100))/(basis-1))*steps;   // Typecast i
            OCR1A = (uint16_t)result;       // Typecast result
            _delay_ms(100);
        }
         
        for(uint8_t i=255; i>= 1; i--)
        {
            result = ((pow(basis,(float)i/100))/(basis-1))*steps;   // Typecast i
            OCR1A = (uint16_t)result;       // Typecast result
            _delay_ms(100);
        }
    }
}