+/** List of SPI prescaler masks for possible AVRStudio ISP programming speeds. */
+static uint8_t SPIMaskFromSCKDuration[] PROGMEM =
+{
+#if (F_CPU == 8000000)
+ SPI_SPEED_FCPU_DIV_2, // AVRStudio = 8MHz SPI, Actual = 4MHz SPI
+ SPI_SPEED_FCPU_DIV_2, // AVRStudio = 4MHz SPI, Actual = 4MHz SPI
+ SPI_SPEED_FCPU_DIV_4, // AVRStudio = 2MHz SPI, Actual = 2MHz SPI
+ SPI_SPEED_FCPU_DIV_8, // AVRStudio = 1MHz SPI, Actual = 1MHz SPI
+ SPI_SPEED_FCPU_DIV_16, // AVRStudio = 500KHz SPI, Actual = 500KHz SPI
+ SPI_SPEED_FCPU_DIV_32, // AVRStudio = 250KHz SPI, Actual = 250KHz SPI
+ SPI_SPEED_FCPU_DIV_64, // AVRStudio = 125KHz SPI, Actual = 125KHz SPI
+#elif (F_CPU == 16000000)
+ SPI_SPEED_FCPU_DIV_2, // AVRStudio = 8MHz SPI, Actual = 8MHz SPI
+ SPI_SPEED_FCPU_DIV_4, // AVRStudio = 4MHz SPI, Actual = 4MHz SPI
+ SPI_SPEED_FCPU_DIV_8, // AVRStudio = 2MHz SPI, Actual = 2MHz SPI
+ SPI_SPEED_FCPU_DIV_16, // AVRStudio = 1MHz SPI, Actual = 1MHz SPI
+ SPI_SPEED_FCPU_DIV_32, // AVRStudio = 500KHz SPI, Actual = 500KHz SPI
+ SPI_SPEED_FCPU_DIV_64, // AVRStudio = 250KHz SPI, Actual = 250KHz SPI
+ SPI_SPEED_FCPU_DIV_128 // AVRStudio = 125KHz SPI, Actual = 125KHz SPI
+#else
+ #error No SPI prescaler masks for chosen F_CPU speed.
+#endif
+};
+