Function timer2_init

firmware/common/libs/timer/oscc_timer.cpp:109–194

#ifndef __AVR_ATmega32U4__
void timer2_init( float frequency, void (*isr)(void) )
{
    // disable interrupts temporarily
    cli();

    // clear existing config
    TCCR2A = 0;
    TCCR2B = 0;

    // initialize counter value to 0
    TCNT2  = 0;


    unsigned long prescaler = F_CPU / ((TIMER2_SIZE+1) * frequency);

    if ( prescaler > 256 )
    {
        prescaler = 1024;

        TCCR2B |= TIMER2_PRESCALER_1024;
    }
    else if ( prescaler > 128 )
    {
        prescaler = 256;

        TCCR2B |= TIMER2_PRESCALER_256;
    }
    else if ( prescaler > 64 )
    {
        prescaler = 128;

        TCCR2B |= TIMER2_PRESCALER_128;
    }
    else if ( prescaler > 32 )
    {
        prescaler = 64;

        TCCR2B |= TIMER2_PRESCALER_64;
    }
    else if ( prescaler > 8 )
    {
        prescaler = 32;

        TCCR2B |= TIMER2_PRESCALER_32;
    }
    else if ( prescaler > 1 )
    {
        prescaler = 8;

        TCCR2B |= TIMER2_PRESCALER_8;
    }
    else
    {
        prescaler = 1;

        TCCR2B |=  TIMER2_PRESCALER_1;
    }