I think CPU's are built for a higher frequency. The question may be "what is that frequency?". The maker reduces the frequency to improve reliability.
Matt. On Mar 24, 11:23 am, vasile surducan <[email protected]> wrote: > On Wed, Mar 24, 2010 at 10:01 AM, vasile surducan <[email protected]>wrote: > > > > > > > On Wed, Mar 24, 2010 at 7:30 AM, m...@watty <[email protected]> wrote: > > >> Typically "over clocked" will fail at temperatures above 20C, or lower > >> than 5V supply and on a percentage of parts. > >> The amount possible to overclock will also be fewer devices, higher > >> voltage, lower temperature as you raise clock speed. > > >> It's not worth the risk on reliability grounds. The next one may not > >> work, there may be premature failure, or it will fail in summer. > > > This time you have right. However, since the question purpose was hobby and > > not production (my nose smell it) I can tell that 90% of the PIC works OK > > overclocked as suggested in the temperature range mentioned in the datasheet > > with external oscillator and external oscillator/internal PLL enabled > > combination. > > External oscillator above should not be undertand as an external HS/XT > crystal, but a stand alone oscillator. > > > > > The weak part of the PIC which is creating problems at high temperature is > > the internal oscillator and analogical stuff (reference, A2D and the > > comparator) > > Internal oscillator above is not only the RC INTOSC but also the HS/XT which > is using a logic gate inside the PIC. > > > > >> On Mar 24, 1:33 pm, vasile surducan <[email protected]> wrote: > >> > On Wed, Mar 24, 2010 at 3:22 PM, Sebastien Lelong < > > >> > [email protected]> wrote: > >> > > Hi guys, > > >> > > crystal. With 16 MHz Xtal, you have 16 * 4 = 64 Mhz, 4 being the black > >> magic > >> > > factor coming from PLL. > > >> > > Now, what if I use a 20 MHz Xtal ?... Will PIC gets burnt ? Or will it > >> just > >> > > won't work ? > > >> > 20MHz PICs works ok at 25MHz > >> > 40MHz PLL (10Mhz XTAL) works at 48Mhz (12MHz XTAL) > > >> > At 80MHz there is very low chance to work. > > >> > > Cheers, > >> > > Seb > > >> listen to Vasile! Assume in this case he is being kind! :-) > > >> -- > >> You received this message because you are subscribed to the Google Groups > >> "jallib" group. > >> To post to this group, send email to [email protected]. > >> To unsubscribe from this group, send email to > >> [email protected]<jallib%[email protected]> > >> . > >> For more options, visit this group at > >>http://groups.google.com/group/jallib?hl=en. -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
