#endif\r
\r
/* Preprocessor Checks and Defines: */\r
- #if (F_CPU == 8000000)\r
+ #if !defined(F_CLOCK)\r
+ #error F_CLOCK is not defined. You must device F_CLOCK to the frequency of the unprescaled input clock in your project makefile.\r
+ #define F_CLOCK 0\r
+ #endif\r
+ \r
+ #if (F_CLOCK == 8000000)\r
#if (defined(__AVR_AT90USB82__) || defined(__AVR_AT90USB162__))\r
#define USB_PLL_PSC 0\r
#elif (defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || \\r
#elif (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))\r
#define USB_PLL_PSC 0\r
#endif\r
- #elif (F_CPU == 16000000)\r
+ #elif (F_CLOCK == 16000000)\r
#if (defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_ATmega32U6__))\r
#define USB_PLL_PSC ((1 << PLLP2) | (1 << PLLP1))\r
#elif (defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__))\r