Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-30 Thread Clint Jay 
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 _ <bpl...@outlook.com> 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: cjaysh...@gmail.com
> > To: time-nuts@febo.com
> > 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 _ <bpl...@outlook.com> 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: cjaysh...@gmail.com
> > > > To: time-nuts@febo.com
> > > > 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 ev

Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-30 Thread Bryan _ 
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: cjaysh...@gmail.com
> To: time-nuts@febo.com
> 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 _ <bpl...@outlook.com> 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: cjaysh...@gmail.com
> > > To: time-nuts@febo.com
> > > 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

Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-30 Thread Clint Jay 
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 _ <bpl...@outlook.com> 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: cjaysh...@gmail.com
> > To: time-nuts@febo.com
> > 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 _ <bpl...@outlook.com> wrote:
> >
> > > Thanks Hal, that's interesting, wi

Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-30 Thread cfo 
On Sat, 26 Sep 2015 07:36:30 +0100, Clint Jay wrote:

*** SNIP 
> so it may be
> possible to modify the B version Bryan and I have.
*** SNIP 

Someone just published a 10Mhz writeup on eevblog
http://www.eevblog.com/forum/testgear/fe-5680b-1pps-to-10mhz/30/?
action=post;quote=767280;last_msg=767313

http://andrelubbock.blogspot.co.nz/2015/09/rubidium-frequency-
standard.html

CFO
Denmark

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Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-30 Thread Clint Jay 
I *think* that's the method posted by the seller of my unit and it's a
modification requiring an extra chip to divide the 20MHz signal down.

I am hoping to be able to re-enable the original 10MHz signal and use the
original filter as fitted to the board.

Still handy if you need 10MHz though.

On 30 September 2015 at 15:32, cfo  wrote:

> On Sat, 26 Sep 2015 07:36:30 +0100, Clint Jay wrote:
>
> *** SNIP 
> > so it may be
> > possible to modify the B version Bryan and I have.
> *** SNIP 
>
> Someone just published a 10Mhz writeup on eevblog
> http://www.eevblog.com/forum/testgear/fe-5680b-1pps-to-10mhz/30/?
> action=post;quote=767280;last_msg=767313
>
> http://andrelubbock.blogspot.co.nz/2015/09/rubidium-frequency-
> standard.html
>
> CFO
> Denmark
>
> ___
> 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.
>



-- 
Clint.

*No trees were harmed in the sending of this mail. However, a large number
of electrons were greatly inconvenienced.*
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Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-29 Thread Bryan _ 



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: cjaysh...@gmail.com
> To: time-nuts@febo.com
> 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 _ <bpl...@outlook.com> wrote:
> 
> > Thanks Hal, that's interesting, will try and see how far I can get.
> > -=Bryan=-
> >
> > > To: time-nuts@febo.com
> > > From: hmur...@megapathdsl.net
> > > Date: Fri, 25 Sep 2015 23:40:40 -0700
> > > CC: hmur...@megapathdsl.net
> > > 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 -- time-nuts@febo.com
> >

Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-29 Thread Don Latham 
definitely interested.   I'd especially like to know about using the 30 MHz
with the Chinese dds block.
Don

Clint Jay
> 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 _ <bpl...@outlook.com> wrote:
>
>> Thanks Hal, that's interesting, will try and see how far I can get.
>> -=Bryan=-
>>
>> > To: time-nuts@febo.com
>> > From: hmur...@megapathdsl.net
>> > Date: Fri, 25 Sep 2015 23:40:40 -0700
>> > CC: hmur...@megapathdsl.net
>> > 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 -- 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.
>>
>
>
>
> --
> Clint.
>
> *No trees were harmed in the sending of this mail. However, a large number
> of electrons were greatly inconvenienced.*
> ___
> time-nuts

Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-29 Thread Clint Jay 
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 _ <bpl...@outlook.com> wrote:

> Thanks Hal, that's interesting, will try and see how far I can get.
> -=Bryan=-
>
> > To: time-nuts@febo.com
> > From: hmur...@megapathdsl.net
> > Date: Fri, 25 Sep 2015 23:40:40 -0700
> > CC: hmur...@megapathdsl.net
> > 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 -- 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.
>



-- 
Clint.

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of electrons were greatly inconvenienced.*
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Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-26 Thread Hal Murray 

> 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.



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Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-26 Thread Clint Jay 
Bryan, I also found a stable 30MHz which I think is used to clock the
optional DDS board so I intend to experiment adding an AD9851 board with 6x
multiplier enabled but first I want to try and understand why the unit
locks and only outputs 10MHz from the XC9572, something in the firmware
appears to turn off the output, I may get around to experimenting a little
more soon and will of course share my findings if they're of interest. .

Bob, there are files which claim to be a dump of the firmware and also the
XC9572 along with a partial schematic but they're from a 5680A which, from
the pictures on the net, is a slightly different hardware version although
the major components appear identical so it may be possible to modify the B
version Bryan and I have.

On 26 September 2015 at 02:45, Bryan _ <bpl...@outlook.com> wrote:

> There is information on this thread on how you can tap into the unit at
> various points to get 20 and 60Mhz. Other owners have used a divider to
> bring it to the 10Mhz frequency desired. I have one of these units and
> haven't gone around to dividing it down. I purchased mine from Ebay and the
> seller notes that this particular version will output 10Mhz for a second or
> two and then disappear. I suspect you have the same version, maybe even the
> same seller, so the operation of these particular units appears to be
> normal. Mine will lock so I know it's working.
>
> http://www.eevblog.com/forum/testgear/fe-5680b-1pps-to-10mhz/msg556800/#msg556800
> 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 
>
> -=Bryan=-
>
> > From: kb...@n1k.org
> > Date: Fri, 25 Sep 2015 17:45:08 -0400
> > To: time-nuts@febo.com
> > Subject: Re: [time-nuts] FE-5680B Rubidium and DDS
> >
> > Hi
> >
> > There is no dump of the firmware. The problem you are most likely
> > having is not firmware related.
> >
> > If the VCXO i the unit drifts to far it needs to be re-tuned. Until this
> is done
> > the device simply sits in a “search for lock” loop forever and ever.
> >
> > Simple way to do it:
> >
> > Monitor the VCXO and bump the trimmer until the frequency goes above the
> intended
> > target (10 x N MHz depending on your monitor point) by at least 0.15
> ppm. The sweep is
> > slow enough that a counter running at a 0.1 second gate will easily show
> you what’s going on.
> >
> > Of course it can be other things. All of them are a bit more involved to
> fix.
> >
> > Bob
> >
> > > On Sep 25, 2015, at 11:34 AM, Clint Jay <cjaysh...@gmail.com> wrote:
> > >
> > > I've recently purchased one of the PPS Only FE Rubidium standards from
> eBay
> > > and, like many others I suspect, haven't been able to get a stable
> output
> > > frequency that lasts longer than a few seconds from the module.
> > >
> > > It appears that the 10MHz source vanishes after a few seconds but this
> is
> > > controlled by firmware.
> > >
> > > Which leads to my question, there is a dump of the firmware from the
> > > FE-5680, has anyone tried to reprogram one?
> > > --
> > > Clint.
> > >
> > > *No trees were harmed in the sending of this mail. However, a large
> number
> > > of electrons were greatly inconvenienced.*
> > > ___
> > > 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.
>
> ___
> 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.
>



-- 
Clint.

*No trees were harmed in the sending of this mail. However, a large number
of electrons were greatly inconvenienced.*
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Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-26 Thread Bryan _ 
Thanks Hal, that's interesting, will try and see how far I can get.
-=Bryan=-

> To: time-nuts@febo.com
> From: hmur...@megapathdsl.net
> Date: Fri, 25 Sep 2015 23:40:40 -0700
> CC: hmur...@megapathdsl.net
> 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 -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
  
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Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-26 Thread Bryan _ 
Clint, where are you seeing a 10Mhz output from the XC9752. That may be the 
easier approach if 10Mhz is the desired frequency. just send it to a buffer/ 
amplifier. Likely most users will want to do that anyways to add additional 
outputs.

-=Bryan=-

> Date: Sat, 26 Sep 2015 07:36:30 +0100
> From: cjaysh...@gmail.com
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] FE-5680B Rubidium and DDS
> 
> Bryan, I also found a stable 30MHz which I think is used to clock the
> optional DDS board so I intend to experiment adding an AD9851 board with 6x
> multiplier enabled but first I want to try and understand why the unit
> locks and only outputs 10MHz from the XC9572, something in the firmware
> appears to turn off the output, I may get around to experimenting a little
> more soon and will of course share my findings if they're of interest. .
> 
> Bob, there are files which claim to be a dump of the firmware and also the
> XC9572 along with a partial schematic but they're from a 5680A which, from
> the pictures on the net, is a slightly different hardware version although
> the major components appear identical so it may be possible to modify the B
> version Bryan and I have.
> 
> On 26 September 2015 at 02:45, Bryan _ <bpl...@outlook.com> wrote:
> 
> > There is information on this thread on how you can tap into the unit at
> > various points to get 20 and 60Mhz. Other owners have used a divider to
> > bring it to the 10Mhz frequency desired. I have one of these units and
> > haven't gone around to dividing it down. I purchased mine from Ebay and the
> > seller notes that this particular version will output 10Mhz for a second or
> > two and then disappear. I suspect you have the same version, maybe even the
> > same seller, so the operation of these particular units appears to be
> > normal. Mine will lock so I know it's working.
> >
> > http://www.eevblog.com/forum/testgear/fe-5680b-1pps-to-10mhz/msg556800/#msg556800
> > 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 
> >
> > -=Bryan=-
> >
> > > From: kb...@n1k.org
> > > Date: Fri, 25 Sep 2015 17:45:08 -0400
> > > To: time-nuts@febo.com
> > > Subject: Re: [time-nuts] FE-5680B Rubidium and DDS
> > >
> > > Hi
> > >
> > > There is no dump of the firmware. The problem you are most likely
> > > having is not firmware related.
> > >
> > > If the VCXO i the unit drifts to far it needs to be re-tuned. Until this
> > is done
> > > the device simply sits in a “search for lock” loop forever and ever.
> > >
> > > Simple way to do it:
> > >
> > > Monitor the VCXO and bump the trimmer until the frequency goes above the
> > intended
> > > target (10 x N MHz depending on your monitor point) by at least 0.15
> > ppm. The sweep is
> > > slow enough that a counter running at a 0.1 second gate will easily show
> > you what’s going on.
> > >
> > > Of course it can be other things. All of them are a bit more involved to
> > fix.
> > >
> > > Bob
> > >
> > > > On Sep 25, 2015, at 11:34 AM, Clint Jay <cjaysh...@gmail.com> wrote:
> > > >
> > > > I've recently purchased one of the PPS Only FE Rubidium standards from
> > eBay
> > > > and, like many others I suspect, haven't been able to get a stable
> > output
> > > > frequency that lasts longer than a few seconds from the module.
> > > >
> > > > It appears that the 10MHz source vanishes after a few seconds but this
> > is
> > > > controlled by firmware.
> > > >
> > > > Which leads to my question, there is a dump of the firmware from the
> > > > FE-5680, has anyone tried to reprogram one?
> > > > --
> > > > Clint.
> > > >
> > > > *No trees were harmed in the sending of this mail. However, a large
> > number
> > > > of electrons were greatly inconvenienced.*
> > > > ___
> > > > 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.
> >
&g

Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-26 Thread Clint Jay 
The 10MHz output comes from the XC9572 CPLD but the fact that it's there
for a few seconds makes me thing it's possible to recover it, by fair means
or foul.

It's possible it's just a gate, certainly looks like it's bing switched off
and there's a file which claims to be a dump of the CPLD (as well as a few
other binaries) so it may be possible to trace it back but I'd want to try
and dump the CPLD contents from my FE so I'm going to build a JTAG cable.

The other option which may be more practical would be to add my own DDS
(already designed and built for another application but would need to be
modified a little and repackaged) and use the 30MHz CPLD output that's
always present when the unit is locked to get programmable spot
frequencies.

On 26 September 2015 at 07:40, Hal Murray  wrote:

>
> > 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 -- time-nuts@febo.com
> 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.*
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Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-25 Thread Bryan _ 
There is information on this thread on how you can tap into the unit at various 
points to get 20 and 60Mhz. Other owners have used a divider to bring it to the 
10Mhz frequency desired. I have one of these units and haven't gone around to 
dividing it down. I purchased mine from Ebay and the seller notes that this 
particular version will output 10Mhz for a second or two and then disappear. I 
suspect you have the same version, maybe even the same seller, so the operation 
of these particular units appears to be normal. Mine will lock so I know it's 
working.
http://www.eevblog.com/forum/testgear/fe-5680b-1pps-to-10mhz/msg556800/#msg556800
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 

-=Bryan=-

> From: kb...@n1k.org
> Date: Fri, 25 Sep 2015 17:45:08 -0400
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] FE-5680B Rubidium and DDS
> 
> Hi
> 
> There is no dump of the firmware. The problem you are most likely 
> having is not firmware related.
> 
> If the VCXO i the unit drifts to far it needs to be re-tuned. Until this is 
> done
> the device simply sits in a “search for lock” loop forever and ever.
> 
> Simple way to do it:
> 
> Monitor the VCXO and bump the trimmer until the frequency goes above the 
> intended
> target (10 x N MHz depending on your monitor point) by at least 0.15 ppm. The 
> sweep is
> slow enough that a counter running at a 0.1 second gate will easily show you 
> what’s going on.
> 
> Of course it can be other things. All of them are a bit more involved to fix. 
>  
> 
> Bob
> 
> > On Sep 25, 2015, at 11:34 AM, Clint Jay <cjaysh...@gmail.com> wrote:
> > 
> > I've recently purchased one of the PPS Only FE Rubidium standards from eBay
> > and, like many others I suspect, haven't been able to get a stable output
> > frequency that lasts longer than a few seconds from the module.
> > 
> > It appears that the 10MHz source vanishes after a few seconds but this is
> > controlled by firmware.
> > 
> > Which leads to my question, there is a dump of the firmware from the
> > FE-5680, has anyone tried to reprogram one?
> > -- 
> > Clint.
> > 
> > *No trees were harmed in the sending of this mail. However, a large number
> > of electrons were greatly inconvenienced.*
> > ___
> > 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.
> 
> ___
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> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Re: [time-nuts] FE-5680B Rubidium and DDS

2015-09-25 Thread Bob Camp 
Hi

There is no dump of the firmware. The problem you are most likely 
having is not firmware related.

If the VCXO i the unit drifts to far it needs to be re-tuned. Until this is done
the device simply sits in a “search for lock” loop forever and ever.

Simple way to do it:

Monitor the VCXO and bump the trimmer until the frequency goes above the 
intended
target (10 x N MHz depending on your monitor point) by at least 0.15 ppm. The 
sweep is
slow enough that a counter running at a 0.1 second gate will easily show you 
what’s going on.

Of course it can be other things. All of them are a bit more involved to fix.  

Bob

> On Sep 25, 2015, at 11:34 AM, Clint Jay  wrote:
> 
> I've recently purchased one of the PPS Only FE Rubidium standards from eBay
> and, like many others I suspect, haven't been able to get a stable output
> frequency that lasts longer than a few seconds from the module.
> 
> It appears that the 10MHz source vanishes after a few seconds but this is
> controlled by firmware.
> 
> Which leads to my question, there is a dump of the firmware from the
> FE-5680, has anyone tried to reprogram one?
> -- 
> Clint.
> 
> *No trees were harmed in the sending of this mail. However, a large number
> of electrons were greatly inconvenienced.*
> ___
> 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.

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