The keil sofeware give too few example about AT91SAM7S64. The development of AT91SAM7S64 is not easy just like LPC22XX. If, post to godday@21cn.com. Thanks a lot!
The following should help: - in the product: Keil\ARM\Boards\Atmel\AT91SAM7S - http://www.keil.com/appnotes/docs/apnt_190.asp