#include <avr/io.h>
#include <avr/interrupt.h>

// Ringpuffer für den Timer Interrupt
uint8_t nextPulseState[256];
uint16_t ticksToNextInterrupt[256];
uint8_t bufferPointer = 0;

// Variablen der 8 Kanaele
uint8_t portFrequency[8];

ISR (TIMER1_COMPA_vect) {

    // Setze Ports
    PORTD = nextPulseState[bufferPointer];
    bufferPointer++;

}

void setBaseFrequencyDivident(uint16_t baseDivident) {
    OCR1AH = (uint8_t) (baseDivident >> 8);
    OCR1AL = (uint8_t) baseDivident;
}

int main(void)
{

    // PORTD fuer Pulse-Kanaele
    DDRD = 0xFF;

    // Timer1 mit vollem CPU Takt und OCIA im CTC Modus
    TCCR1B = (1 << WGM12) | (1 << CS10);
    TIMSK1 = (1 << OCIE1A);
    sei();

    // Setze default Frequenzbereich
    setBaseFrequencyDivident(160); // 16MHz / 160 -> 100.000 Hz

    // Debuging
    portFrequency[0] = 2;
    portFrequency[1] = 2;
    portFrequency[2] = 2;
    portFrequency[3] = 2;
    portFrequency[4] = 2;
    portFrequency[5] = 2;

    while (1) {

        // Berechne werte fuer PROTD and the OCR
        for (uint8_t i = 0; i < 256; i++) {
            uint16_t bufferPosition = ((uint16_t) bufferPointer + i);
            uint8_t nextState = 0;
            nextState |= ((bufferPosition % portFrequency[0] == 0) << 0);
            nextState |= ((bufferPosition % portFrequency[1] == 0) << 1);
            nextState |= ((bufferPosition % portFrequency[2] == 0) << 2);
            nextState |= ((bufferPosition % portFrequency[3] == 0) << 3);
            nextState |= ((bufferPosition % portFrequency[4] == 0) << 4);
            nextState |= ((bufferPosition % portFrequency[5] == 0) << 5);
            nextState |= ((bufferPosition % portFrequency[6] == 0) << 6);
            nextState |= ((bufferPosition % portFrequency[7] == 0) << 7);
            nextPulseState[(uint8_t) bufferPosition] = nextState;
        }

    }

}