I'm trying to use two clock sources of mega88, internal rc oscillator for system clock and external crystal as timer. Usually external crystal is a watch crystal 32.768kHz, but I'll use different frequency of the crystal. Is it possible to use different frequency of crystal and what is the maximum frequency of crystal?
According to datasheet,
A crystal can then be connected between the TOSC1 and TOSC2 pins to serve as an independent clock source for Timer/Counter2. The Oscillator is optimized for use with a 32.768 kHz crystal.