Dario Greggio wrote:
> Jan-Erik Soderholm wrote:
> 
>> Note that the PLL in these parts are a fixed 4 MHz -> 96 MHz
>> PLL. Other (non-USB PIC18) parts can use different input
>> frequencies to it's PLL circuit.
> 
> You say, Jan-Eirk?

No, the datasheet(s) does.

See the parameter F11/Fsys (On-Chip VCO System Frequency):

18F1230: Min/Max : 16/40 MHz.
18F4550: Typ: 96 MHz (*no* min/max specified)

> 
>> So 8 MHz xtal and 2/ PLL-prescaler is fine, but probebly not
>> a 9.8 MHz xtal, sice it can't be divided down to 4.0 MHz.
> 
> I made a 2550 work with a 8.867 (PAL Chroma XTal)...
> and it was fine 
> (actually, overclocked a bit :)
> I don't think that you need a actual 4MHz, I guess.

Well, it's all about the definition of "actual", right ? :-)

Jan-Erik.

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