girino_optimization.md

womai

Two ideas to make the code more efficient (run faster):

The calculation

ADCCounter = ( ADCCounter + 1 ) % ADCBUFFERSIZE;

involves an integer division which tends to be time consuming (at least on a Microchip PIC - I do not know Atmel as well). Instead, try

if (++ADCCounter >= ADCBUFFERSIZE) ADCCounter = 0;

Second, you can completely avoid the time required to evaluate

if(wait)

and live without the wait variable if you simply set stopIndex to a value that the counter never reaches, as long as you aren't yet in the post-trigger phase. I.e. during initialization (when starting a new sweep) set

stopIndex = ADCBUFFERSIZE + 1;

and when the trigger event happens then just do as you did so far, but without the boolean wait variable:

ISR(ANALOG_COMP_vect)
{
    // Disable Analog Comparator interrupt
    cbi( ACSR,ACIE );
    
    // Turn on errorPin
    //digitalWrite( errorPin, HIGH );
    sbi( PORTB, PORTB5 );
    
    stopIndex = ( ADCCounter + waitDuration ) % ADCBUFFERSIZE;
}

and the ADC ISR routine becomes

ISR(ADC_vect)
{
    if (++ADCCounter >= ADCBUFFERSIZE) ADCCounter = 0;
    
    if ( stopIndex == ADCCounter )
    {
        cbi( ADCSRA, ADEN );
        freeze = true;
    }
}