pic18f1330 oscillator

[nicenoise]

hello,

We are testing a design using pic18F1330 with 40mhz.
compiler v4.065

Anyone test this function?

With 20mhz and 15pf works fine,
but with 40mhz and 15pf works 1/2 speed that 20mhz...
Whats happened?

I'm using HS fuse,
how works H4 fuse? 10mhz clock with x4 acelerator, right?
Should be working with this method?

Thanks a lot for your help,

/a

[Ttelmah]

40MHz, is not legal for the chip's oscillator. Read the data sheet...
Table 22-6 Fosc.

The chip supports:
40MHz _operation_ (not oscillation), with either:

10MHz crystal, and the PLL, or
40MHz _external oscillator_.

Yes. H4, with a 10MHz crystal, gives 40Mhz operation.

Best Wishes

[nicenoise]

hello,
thanks.
Of course i'm using external oscillator at 40mhz... but not works. Its very slow...
Any special configuration? Fuses?
compiler version?

/a