I've done this but don't remember the detail on the wiring. The data sheet made it clear though. One thing I did notice is that the oscillator seemed to power the chip! If I were doing it again I'd probably use some kind of powered buffer on the oscillator input so that when I power down the circuit it actually stops.
-Bob On Thu, Nov 24, 2011 at 7:50 AM, Attila Kinali <att...@kinali.ch> wrote: > On Thu, 24 Nov 2011 14:41:24 +0000 > Stephen Farthing <squir...@gmail.com> wrote: > > > I have an Efratom 101 frequency standard with a 10 MHz TTL otput. I want > to > > use this to clock a PIC 16F628A so I can make a frequency counter with a > > resolution of 1 Hz. I am going to use the design by EI9GQ here > > http://homepage.eircom.net/~ei9gq/counter.html . What I need to know is > how > > i should go about electronically interfacing the TTL output from the > > rubidium standard so that it can clock the PIC. Has anyone on the list > > actually done this successfully? > > Have a look at the PIC 16F628 data sheet, it will tell you the requirements > for the clock input and there should be circuit for external clock signal > listed. If it's not in the datasheet, it should be in an appnote. > > Usually, chips accept sinusoidal and rectangular inputs up to 0V-VDD swing. > If i'm reading the schematic correctly and the PIC runs with 5V, then > you should be able to just feed the Efratom output directly to the PIC. > Maybe, a ceramic 100n capacitor in this line should be used to do > a DC isolation (1u cermaic should do as well). > > Attila Kinali > > -- > The trouble with you, Shev, is you don't say anything until you've saved > up a whole truckload of damned heavy brick arguments and then you dump > them all out and never look at the bleeding body mangled beneath the heap > -- Tirin, The Dispossessed, U. Le Guin > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.