Understanding timer configuration

Using Arduino Programming Questions
1

I have this code that I am trying to understand , say -i- is looping from 0-100, then you have this (we already setup the timer stuff):

 TCNT1 = 0;
        ICR1 = i;
        OCR1A = i/2;

Say we also using a pre sacle of 1, with 16MHz clock , on timer 1.

According to the OCR1A , the values will be- 0,0,1,1,2,2,3,3,4,4,5,5... etc. Is that right ?
Is this means that the frequency is 16MHz,16MHz,8MHz, 8MHz ,4MHz, 4MHz, 2Mhz, 2Mhz... ?

What the ICR1 do, I could not really understand, and I also guess I dont get what frequencies will this code produce ?

Thank you.

2

we already setup the timer stuff

You have not provided the code which indicates the mode and other set up parameters of timer 1 which will determine the frequency and output.

In general, if the timer is in a mode using ICR1 as top value, ICR1 will be controlling the frequency, and OCR1A will be controlling the output duty cycle

3

Assuming the TimerCounter1 is set up for FastPWM with ICR1 as TOP the 'i' value is setting the frequency and the duty-cycle is set to (roughly) 50%. I think the formula is something like (16 MHz/(i+1))/2 so 0=8 MHz, 1=4 MHz, 2= 2.66 MHz, 3=2 MHz, 4=1.6 MHz