main.c

// --------------------------------------------------------------------------

// an OC1A

// ATTiny2313

// --------------------------------------------------------------------------

#include <avr/io.h>

#include <avr/interrupt.h>

int main()

{

    DDRB = (1 << PB3);

    TCCR1A = (1 << COM1A0);             // Toggle OC1A at TOP

    TCCR1B =

        (1 << WGM12) |                  // CTC mode 4

        (1 << CS10);                    // Prescaler = 1

    OCR1A = 105;

    for (;;)

    {

    }

}