On Thu, Mar 11, 2010 at 8:16 AM, mattschinkel <[email protected]>wrote:
> > Yes, I've worked even with 2.5ppm VTCXO.(output frequency may be slighty > > modified using a voltage) > > However some of them are so expensive ($75 up to $150) that are > prohibitive. > > I've seen 3.3V TCXO with 5ppm at $2.5 or so, I think at Digikey. > > I don't think you would need a hardware RTCC if you can get a nice > 32.768MHz oscillator. Matt, RTCC it's already in the PIC. It needs only the 32768 connected at T1OSI/T1OSO. Why writing clock-calendar when is already implemented with hardware registers? Of course it works with TMR1 as well. Any reasonable 32768 TCXO or crystal I found in the neighbourhood is 5ppm, no less so be it. > You could use this oscillator allong with timer1 > or timer3 to get correct time. I think the reason they have an RTCC is > that you can then run your main PIC at any speed you wish, while still > having a accurate RTC. > > As you know, 32.768MHz or 32.768KHz devide by 65536 well to get > seconds. > 32.768MHz / 65536 = 500hz.... 500hz / 500 = 1hz > > Matt. > > -- > 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.
