AVR Freaks

Alright I think I got it to work with the RTC for LFO modulation! Let me know if you see something that needs to be improved:

void TCA0_init(void)
{
    /* set pin 0 of PORT A as output */    
    PORTA.DIR |= PIN0_bm;
    
    /* set waveform output on PORT A */
    PORTMUX.TCAROUTEA = PORTMUX_TCA0_PORTA_gc;
    
    TCA0.SINGLE.INTCTRL = TCA_SINGLE_OVF_bm | TCA_SINGLE_CMP0_bm; // Overflow Interrupt
    
    TCA0.SINGLE.CTRLB = TCA_SINGLE_CMP0EN_bm            /* enable compare channel 0 */
                      | TCA_SINGLE_WGMODE_SINGLESLOPE_gc;    /* set single PWM mode */
    
    /* disable event counting */
    TCA0.SINGLE.EVCTRL &= ~(TCA_SINGLE_CNTEI_bm); 
    
    TCA0.SINGLE.PER  = 999;  // Periodic value
    TCA0.SINGLE.CMP0 = 300;  // Duty cycle
    
    TCA0.SINGLE.CTRLA = TCA_SINGLE_CLKSEL_DIV16_gc        /* set clock source (sys_clk/16) */
                      | TCA_SINGLE_ENABLE_bm;           /* start timer */
}

void RTC_init(void)
{
    
    while(RTC.STATUS > 0);  /* Wait for all registers to be synchronized */
	RTC.CTRLA = RTC_PRESCALER_DIV4_gc | RTC_RTCEN_bm; /* Enable RTC, 4 prescaler */
	RTC.CLKSEL = RTC_CLKSEL_INT32K_gc; /* Select 32.768 kHz internal RC oscillator */
	RTC.PER = 100;
	while(RTC.STATUS > 0);  /* Wait for all registers to be synchronized */
    RTC.INTCTRL |= RTC_OVF_bm;
}


ISR(TCA0_OVF_vect)
{
    msturns++;	//ms increment if TCA0 overflow
	ledturns++;
    TCA0.SINGLE.INTFLAGS = TCA_SINGLE_OVF_bm;
}

ISR(TCA0_CMP0_vect)
{
    cli();		//updates mod pwm duty cycle
	TCA0.SINGLE.CMP0 = pwm;
    TCA0.SINGLE.INTFLAGS = TCA_SINGLE_CMP0_bm;
	sei();
}

ISR(RTC_CNT_vect)
{
    inc++;		//increment position in wavetable
	cli();
	RTC.PER = speed;	//update mod speed
	sei();
    RTC.INTFLAGS = RTC_OVF_bm;
}

int main(void)
{
    CCP = CCP_IOREG_gc; // No clock division (full 16Mhz)
    CLKCTRL.MCLKCTRLB = 0; // No clock division (full 16Mhz)
    TCA0_init();
    RTC_init();
    sei();
    
    uint16_t offset;
    
    while (1)
    {
            
        //---------PWM OUTPUT

            
        if (abs(depthvalue) >= 13)
        {
             offset = (300 - ((depthvalue * 300)/255));  //updating mod pwm value
        }
        
        pwm = (((100 + currentinc) * depthvalue)/255) + offset;
        
        if (abs(speedvalue) >= 13)
        {
            speed = 255 - speedvalue; //updating mod speed
        }
        
        //update mod waveform value
        currentinc = (int)((sin(((2 * PI) / 255) * inc)*200) + 200);  //Sine
        
    }