AVR 10ms timer with 8MHz clock
If you want to get periodic timer, you shall use CTC mode.

Check the datasheet page 99:

http://www.atmel.com/Images/Atmel-7766-8-bit-AVR-ATmega16U4-32U4_Datasheet.pdf

The formula is: F = F_CPU / (2 * N * (1 + OCR0))

OCR0 = (F_CPU / (F * 2 * N)) - 1 = (8000000 /(100 * 2 * 1024)) - 1 = 38.06 = 38

Timer 0 CTC mode (page 106): WGM02=0 WGM01=1 WGM00=0

To use TIMER0_COMP_vect interrupt, OCF0 &amp; OCIE0 flags must be set.