Using a TXCO such as a DS1307 is by far the least muss and fuss. Stays accurate to within a second or two per month, which is really remarkable when you think about it.
That said, any properly designed (ie stable) quartz crystal oscillator circuit should give you similar accuracy once it is calibrated to an external source. You only need to do this once when per clock you build at the time you build it. I used to use a 1 pulse/second signal from a GPS receiver for the calibration. I then wrote a calibration routine which would start a counter in a 100hz interrupt service routine. I would count 60 pulses from the GPS then stop the counter. Then I subtracted the counter from 6000 and that would be the number of clocks I would add or subtract to per minute for my timekeeping. This calibration approach might be appropriate for someone who likes to code more than they like to solder, or wants the cost of the hardware kept to a bare minimum; The TXCO can cost more than the microcontroller ! ..c On Nov 2, 9:28 pm, Steve <sskillc...@gmail.com> wrote: > Group; > > I would love to hear your suggestions on the best way to keep a > microprocessor controlled clock accurate. > > The micro platform I'm using is an Arduino; which has a crystal > bundled onto the board, but it's not near accurate enough for a clock. > From my reading of this group there are RTC chips, TXCO crystals and > everything in between. There's the Taylor Edge RTC board, the > ChronoDot, the Maxim RTC1307 IC; so many choices! > > I only need accurate time keeping. This is for an HH:MM clock, no date > functions etc, so I'd like to keep it as simple (and cheap) as > possible. > > Thank you in advance. Your advice is greatly appreciated. > > Steve -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixi...@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
