/** Macro to convert an ISP frequency to a number of timer clock cycles for the software SPI driver. */
#define TIMER_COMP(freq) (((F_CPU / 8) / 2 / freq) - 1)
/** Macro to convert an ISP frequency to a number of timer clock cycles for the software SPI driver. */
#define TIMER_COMP(freq) (((F_CPU / 8) / 2 / freq) - 1)