问 本人是这样打算的：TWI读写EEPROM(AT24C512)放bootloader,片外flash放application,加SDRAM和有源晶振、复位芯片、9200、DC－DC做最小系统，不知有没有意义，如果可以要注意些什么。
另对9200data sheet 有句话不是太懂，敬请指点:
Main Oscillator Bypass
     The user CAN input a clock on the device instead of connecting a crystal.in this case,the user has to provide the external clock signal on the XIN.The programmer has to be sure not to modify the MOSCEN bit in the Main Oscillator Register.This bit must remain at 0,its reset value,for the external clock to operate properly.While this bit is at 0,the pin XIN is pulled down by a 500 k resistor in parallel with a 25 pF capacitor. 答 1: 24C512太大了点吧 答 2: 外接时钟谈的是外接时钟信号,不用芯片的内部时钟 答 3: 谢谢你啊，能更细一点吗我主要是说这句话的：While this bit is at 0,the pin XIN is pulled down by a 500 k resistor in parallel with a 25 pF capacitor.
还有这个描述是针对有源时钟之类的吧，对一般晶体（无源晶振）一样吗？