ATmega8/L datasheet, page 103. Найдено простым поиском по тексту за 1 минуту, включая время на поиск и скачивание самого даташита. http://www.atmel.com/Images/Atmel-2486-8-bit-AVR-microcontroller-ATmega8_L_datasheet.pdf
The double buffered Output Compare Register (OCR2) is compared with the Timer/Counter
value at all times. The result of the compare can be used by the waveform generator to generate
a PWM or variable frequency output on the Output Compare Pin (OC2). For details, see “Output
Compare Unit” on page 105.