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Overclocking Pinguino chip
04-01-2014, 12:36 PM,
#11
RE: Overclocking Pinguino chip
That's a different chip entirely.

Not applicable to any PIC32, is it?

Be sure to read Microchip's data sheet!!

John
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04-01-2014, 01:21 PM,
#12
RE: Overclocking Pinguino chip
(04-01-2014, 12:36 PM)pingotg Wrote: That's a different chip entirely.

Not applicable to any PIC32, is it?

Be sure to read Microchip's data sheet!!

John

Yes, you are right, it seems USB clock cannot be derived from secondary oscillator, at least not by reading datasheets. That didn't cross my mind and I wrongy assumed this should also be logical scenario like for that other chip. Thanks Wink
Dreaming in Code...
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04-01-2014, 02:58 PM,
#13
RE: Overclocking Pinguino chip
To overclock and keep USB you'd want to have (and change) the bootloader source to rebuild for the new xtal freq. Otherwise, a PICkit3 or the like.

You need to reflash the bootloader so need the PICkit3 (or 2) anyway I think.

John
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06-01-2014, 05:09 PM, (This post was last modified: 06-01-2014, 05:09 PM by regis.)
#14
RE: Overclocking Pinguino chip
I would not try to overclock a PIC if I didn't have a programmer (PicKit3) and another PIC under my hand Wink ...
For experimentation only, did you try to play with FPLLIDIV, PLLMULT and PLLODIV (see system.c) ?
If I had an external 8MHz crystal (OSCCONbits.NOSC = POSCPLL) then I would do :
DEVCFG2bits.FPLLIDIV = PLLIDIV2, OSCCONbits.PLLMULT = PLLMULT20 to get 80MHz=8/2*20
DEVCFG2bits.FPLLIDIV = PLLIDIV2, OSCCONbits.PLLMULT = PLLMULT24 to get 96MHz=8/2*24
DEVCFG2bits.FPLLIDIV = PLLIDIV1, OSCCONbits.PLLMULT = PLLMULT15 to get 120MHz=8/1*15
DEVCFG2bits.FPLLIDIV = PLLIDIV1, OSCCONbits.PLLMULT = PLLMULT16 to get 128MHz=8/1*16
DEVCFG2bits.FPLLIDIV = PLLIDIV1, OSCCONbits.PLLMULT = PLLMULT17 to get 136MHz=8/1*17
DEVCFG2bits.FPLLIDIV = PLLIDIV1, OSCCONbits.PLLMULT = PLLMULT18 to get 144MHz=8/1*18
etc ... up to 192MHz=8/1*24
All these configurations with OSCCONbits.PLLODIV = PLLODIV1;
The bootloader set DEVCFG2bits.FPLLIDIV to PLLIDIV2 so IMO, you can't reach more than 96MHz without modifying the bootloader config bits.
It's the same with USB which needs a PLL = 4MHz (PLL = 8MHz / PLLDIV2).
Remember that the Peripheral Clock is derivated from the System Clock. You can change it with : OSCCONbits.PBDIV = PBDIV8, PBDIV4, PBDIV2 or PBDIV1

I'm curious what you can get from that ...
It is easier to complain than it is to do, but it is better to do than it is to complain.
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