crystal.h

GCC source code for do it yoursel a avr programer and jtagice debuger.

// Easy method: Set FREQ to crystal speed in Hz
// Set speed value to UBRRL value for given crystal at 19.2k data rate.

//#define FREQ	6000000 // 19200 has huge error rate
//#define FREQ	7372800
//#define FREQ	8000000
#define FREQ	12000000 //19200 has good error rate

/* - These are mathematically correct, preprocessor doesn't round right
#define N2400	((FREQ/16)/2400)-1
#define N4800	((FREQ/16)/4800)-1
#define N9600	((FREQ/16)/9600)-1
#define N14400	((FREQ/16)/14400)-1
#define N19200	((FREQ/16)/19200)-1
#define N28800	((FREQ/16)/28800)-1
#define N38400	((FREQ/16)/38400)-1
#define N57600	((FREQ/16)/57600)-1
#define N76800	((FREQ/16)/76800)-1
#define N115200	((FREQ/16)/115200)-1
*/
#if (FREQ != 7372800)
#define PATCH
#endif

#if (FREQ == 	7372800	)
#define N2400	191	
#define N4800	95	
#define N9600	47	
#define N14400	31	
#define N19200	23	
#define N28800	15	
#define N38400	11	
#define N57600	7	
#define N76800	5	
#define N115200	3	
#endif		


#if (FREQ == 	8000000	)
#define N2400	207	
#define N4800	103	
#define N9600	51	
#define N14400	34	
#define N19200	25	
#define N28800	16	
#define N38400	12	
#define N57600	8	
#define N76800	6	
#define N115200	3	
#endif		


#if (FREQ == 	12000000	)
#define N2400	312	
#define N4800	155	
#define N9600	77	
#define N14400	51	
#define N19200	38	
#define N28800	25	
#define N38400	19	
#define N57600	12	
#define N76800	9	
#define N115200	38		// 5 is the 'correct' speed here, but the error rate is too high and doesn't work	
#endif		

#if (FREQ == 	6000000	)
#define N2400	155	
#define N4800	77	
#define N9600	38	
#define N14400	25	
#define N19200	19	
#define N28800	12	
#define N38400	9	
#define N57600	6	
#define N76800	4	
#define N115200	2	
#endif