volatile long speed_counter = 0;
void increment_speed_counter()
{
     speed_counter++;
}
END_OF_FUNCTION(increment_speed_counter);

no main():
install_timer();
    LOCK_VARIABLE(speed_counter);
    LOCK_FUNCTION(increment_speed_counter);
    install_int_ex(increment_speed_counter, BPS_TO_TIMER(10));

no while:
while(speed_counter>0){
//logica
speed_counter--;
}
//draws