Copy#define DIAG_TIMER_FREQ (uint16_t) ((F_CPU/DIAG_TIMER_PRESCALER)/DIAG_TIMER_PER)
#define DIAG_TIMER_FREQ (uint16_t) ((F_CPU/DIAG_TIMER_PRESCALER)/DIAG_TIMER_PER)
The frequency of the TC is F_CPU divided by the prescaling factor.