If you want to remove 0 - 255 pulses per hour, I would use a second controller in an 8 pin DIL package. They are dirt cheap. You could convert the 2 binary switches (0-F) to an analog signal through two 4 bit R-2R networks, or just use a couple of weighted resistors for each bit. The controller reads them on analog inputs and converts both of them back to a single byte. I have used that method before to read the state of 4 switches through 1 pin and it works perfectly.
Michel On Apr 26, 6:53 am, "chuck richards" <[email protected]> wrote: > Hmmm. Interesting! Thanks. This is the reason I > always like to consult you guys. Someone always has > a unique method or a different view. > > Right now, on the first-off quickie prototype of this > new pulse-remover, it's a 3-package solution. > > It uses a 4040 ripple counter, a 4073 triple 3-input > AND gate, and one half of a 4013 D flip-flop. > > My first impression is that 3 packages is hard to beat. > But I will kick around the idea of removing one pulse > out of every 1008246 pulses. > > I did come up with a 6-package solution that's slightly > more complex. Have not built it yet, but it has the > addition of (2) hexadecimal rotary switches to use to > set in the number of pulses to remove every hour. > That number can be anywhere from 0 to 255 base ten. (FF hex) > That configuration can slow a clock down by about 68 seconds > per year max. That would pretty well cover the worst of > the Maxim TCXOs. To go any more than that, a ninth bit > would need to be decoded, and then up goes the package count. > > Or, the rotary switches could be assigned to the next higher > order bits starting at N=2 instead of N=1, and then > you'd have to play games figuring out how to set them! > > Not to mention that the resolution would then end > up being to the nearest 2 pulses, not to the nearest > single pulse. So, the 8-bit decoder using the switches > is the next thing I will build and start testing. > > The first simple one is hardwired to decode 117 and to remove > that many pulses. It's very simple, but changing that > integer is a pain. Moving a few wires around is fine > on a solderless board and during an experiment, but not > on a final solution. > > > > > > > > > > ---- Original Message ---- > From: [email protected] > To: [email protected] > Subject: Re: [neonixie-l] Dallas/Maxim TCXO > Date: Wed, 25 Apr 2012 00:13:39 -0400 > > >> That number turns out to be 117 pulses to somehow remove > >> every hour. > > >You could attack it a different way, and skip one pulse after every > >1008246. > >Shouldn't be hard to implement, as that's just 2 * 3 * 197 * 853. > >You could > >instead skip one out of 1008247, but that happens to be a prime > >number. > > >- John > > >-- > >You received this message because you are subscribed to the Google > >Groups "neonixie-l" group. > >To post to this group, send an email to [email protected]. > >To unsubscribe from this group, send email to > >[email protected]. > >For more options, visit this group athttp://groups.google.com/group/ > >neonixie-l?hl=en-GB. > > $4.95/mo. National Dialup, Anti-Spam, Anti-Virus, 5mb personal web space. 5x > faster dialup for only $9.95/mo. No contracts, No fees, No Kidding! > Seehttp://www.All2Easy.netfor more details! -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an 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/neonixie-l?hl=en-GB.
