The 9851 will work with pretty much any clock and give an output but of course you need a decent speed clock to get a useful range of frequencies.
The handy feature of the 9851 is that it has a clock multiplier built in so that 30MHz can clock it at its maximum speed and give a useful DC-60MHz output. I'm a little past the point where the author is, I'm working my way through the CPLD dump.. On 30 September 2015 at 20:54, Bryan _ <[email protected]> wrote: > Clint, Yes, same seller. Yes schematic is partial, but it did answer a > question for me that I posted on eevblog where others suggested removing a > number of components to feed the 20Mhz to a divider. Looks like its a > resistor, cap and inductor from the schematic; R1,C1,L1. > I see, you want to make a easily reprogrammable frequency generator. I > haven't looked at the datasheet of the AD9851, but thought it needed a > 125Mhz crystal. Probably just easier to use a circuit like this. > http://www.perdrix.co.uk/FrequencyDivider/index.html > > http://www.ka7oei.com/FE-5680_diag_1c.gif (would still need to divide > first) > I was planning on the same, but just using the /2 for a 10Mhz out in the > first link. > Was always hoping for a easy mod inside the "B", but from the write up > that was just posted, the author has scoped it pretty well and it appears > the disappearing 10Mhz appears to be firmware driven. > Cheers > > -=Bryan=- > > > Date: Wed, 30 Sep 2015 11:45:49 +0100 > > From: [email protected] > > To: [email protected] > > Subject: Re: [time-nuts] FE-5680B Rubidium and DDS > > > > Bryan, I think we do, bought from an eBay seller named Fluke.I? > > > > I also found that schematic but it's a partial, very useful nonetheless. > > > > There's also a dump of the firmware and CPLD so I'm hoping I can make > some > > sense of that to work out the CPLD, I'd be happy with a solid 10MHz > output > > but to my mind, if I can clock an AD9851 with the 30MHz signal I can get > > 'as good as' with the same or better performance to the serially > > programmable DDS module. > > > > My thinking may of course be flawed, I'm new to the whole time nut game > and > > am learning as I go. > > > > The M09 chip seems to be in place of the MAX3232 chip, coupling RX/TX > from > > connectors to the CPU, it may be an opto but the package is tiny so it'd > > not offer much isolation, I'll take another look this evening and work > out > > the connections fully. > > > > On 29 September 2015 at 21:06, Bryan _ <[email protected]> wrote: > > > > > > > > > > > > > > Hi Clint: > > > Looks like we have the identical board. I suspect the XC9572 is turning > > > off the 10Mhz, although why would it wait for 6 seconds?. And as you > say > > > it's not related to the "lock" . Here is a schematic I found for a > FE-5680A. > > > > > > > http://www.rhodiatoce.com/pics/time-nuts/FE-5680A/FE-5680A_schematics_v0.1.pdf > > > I also note the same strange chip in the middle of the absent Max233, > > > wonder if it is some type of optoisolator to protect > > > inputs/outputs?Although not sure why one would be needed if the MAX232 > is > > > unpopulated. > > > > > > -=Bryan=- > > > > > > > Date: Tue, 29 Sep 2015 15:41:37 +0100 > > > > From: [email protected] > > > > To: [email protected] > > > > Subject: Re: [time-nuts] FE-5680B Rubidium and DDS > > > > > > > > I've made some investigations and re-confirmed my earlier findings > on the > > > > FE-5680B I have. > > > > > > > > It locks from cold in under five minutes and runs at approximately > 700mA > > > > steady with the expected PPS signal on the output connector when > locked. > > > > > > > > The particular 5680 I have has a Hi Density 15p male connector on the > > > > output and uses a single 15V supply, part number FE5680B UN 77672. > > > > > > > > The device does not have the optional DDS daughterboard which means > that > > > > it's not usable as a programmable signal source as it stands (but see > > > > later). > > > > > > > > For approximately six seconds after power is applied a 10MHz signal > > > > available on the output connector, this signal comes directly from > the > > > > XC9572 CPLD via a filter network and appears to be a clean sine wave. > > > > > > > > The 10MHz signal seems to be 'switched off' by some event in the > unit, I > > > > don't yet know if this is in response to an event or just a timed > > > shutdown > > > > but power cycling the unit re-enables the 10MHz output for a further > six > > > > seconds. It doesn't appear to be related to rubidium lock as it takes > > > > consdierably longer than six seconds to lock. > > > > > > > > There is a solid 30MHz signal inside the unit, stable once the > rubidium > > > has > > > > locked and the PPS output is also available once locked. > > > > > > > > Other observations show that the MAX3232 serial driver chip is > missing > > > and > > > > in it's place there is a tiny 8 pin device marked M09 or MO9 which is > > > > connected to the TXD/RXD pins on the output connector and the TXD/RXD > > > pins > > > > on the 80C323 CPU. > > > > > > > > I'd be very interested in suggestions as to the part number of that > > > device, > > > > it may yield clues as to the communication method needed. > > > > > > > > Attempts to communicate with it via a terminal program have given no > > > > responses at several 'standard' baud rates. Voltage levels are LVTTL. > > > > > > > > I'm wary of applying 5V to any of the pins on the interface connector > > > > directly and probing them with 3.3v via a 10K resistor has made no > > > > difference to any of the signals I can monitor (30MHz, PPS etc.) > with the > > > > exception of pin 13 which I *think* is reset, obviously this causes > the > > > > frequencies to skew for a few seconds until reset is completed. > > > > > > > > My intent is to use the 30MHz signal from the CPLD to clock a DDS > chip > > > > (probably one of the eBay DDS modules) that's controlled by a PIC > chip (I > > > > already have code to run a DDS VFO I developed earlier this and late > last > > > > year. Hopefully this will be small enough to fit inside the casing > > > though I > > > > don't see a problem with bringing the 30MHz signal out if necessary. > > > > > > > > My apologies if this is outside of the scope of this list, I will > also be > > > > writing up my findings and experiments with this standard on my blog > if > > > > anyone is interested? > > > > > > > > > > > > > > > > On 26 September 2015 at 11:23, Bryan _ <[email protected]> wrote: > > > > > > > > > Thanks Hal, that's interesting, will try and see how far I can get. > > > > > -=Bryan=- > > > > > > > > > > > To: [email protected] > > > > > > From: [email protected] > > > > > > Date: Fri, 25 Sep 2015 23:40:40 -0700 > > > > > > CC: [email protected] > > > > > > Subject: Re: [time-nuts] FE-5680B Rubidium and DDS > > > > > > > > > > > > > > > > > > > I as well wish there was a quick way of converting it back to > > > 10Mhz. I > > > > > am > > > > > > > sure it can be done, just not sure how or where to look > > > > > > > > > > > > If the 10 MHz is visible for a second or two, there is probably a > > > gate to > > > > > > turn it on/off. If I wanted 10 MHz, I'd open it up and trace the > > > wire > > > > > back. > > > > > > If it goes to a gate, you might be able to lift the pin for the > other > > > > > input > > > > > > and wire it hi/low. There is a good chance it goes to a FPGA > where > > > you > > > > > can't > > > > > > get at the gate. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > These are my opinions. I hate spam. > > > > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > > > > > time-nuts mailing list -- [email protected] > > > > > > To unsubscribe, go to > > > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > > > and follow the instructions there. > > > > > > > > > > _______________________________________________ > > > > > time-nuts mailing list -- [email protected] > > > > > To unsubscribe, go to > > > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > > and follow the instructions there. > > > > > > > > > > > > > > > > > > > > > -- > > > > Clint. > > > > > > > > *No trees were harmed in the sending of this mail. However, a large > > > number > > > > of electrons were greatly inconvenienced.* > > > > _______________________________________________ > > > > time-nuts mailing list -- [email protected] > > > > To unsubscribe, go to > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > and follow the instructions there. > > > > > > > > > _______________________________________________ > > > time-nuts mailing list -- [email protected] > > > To unsubscribe, go to > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > and follow the instructions there. > > > > > > > > > > > -- > > Clint. > > > > *No trees were harmed in the sending of this mail. However, a large > number > > of electrons were greatly inconvenienced.* > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Clint. *No trees were harmed in the sending of this mail. However, a large number of electrons were greatly inconvenienced.* _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
