Hello Rafael,
If you refer to paragraph 3.8 of the datasheet, you will see that the maximum allowable crystal frequency is 16 MHz. However, assuming that FEE mode is used, even if you were to use a 25 MHz oscillator with a square wave output, this will not work because none of the RDIV settings available will give a reference frequency between the limits 31.25 to 39.0625 kHz.
For example, for a divider value of 512, the input frequency limits would be 16 to 20 MHz. For a divider value of 1024, the minimum input frequency would be 32 MHz.
Of course it is possible to use FBE mode, but the available bus frequencies would be limited to 12.5 MHz, 6.25 MHz, etc.
Regards,
Mac
Message Edited by bigmac on
2008-07-24 10:30 AM