Re: [time-nuts] FE5680 missing PPS soln
I was hoping that pulling the lock LED from my setup would clear up my PPS signal, but no luck. I'm now getting a 4.545Khz sawtooth with 10Mhz noise. I need to peek at the input to the 74AC240. -Dave - Original Message - From: Attila Kinali att...@kinali.ch To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Friday, February 3, 2012 4:55:20 AM Subject: Re: [time-nuts] FE5680 missing PPS soln On Fri, 3 Feb 2012 09:50:52 - Rob Kimberley robkimber...@btinternet.com wrote: Mine was a green LED out of the junk box, but I did use 330R in series. 1k8 seems rather large. Then i'm not surprised that your FE-5680 refused to work :-) Just calculate: 5V supply, approx 2V LED voltage - 3V over the resistor. 3V/330R = 90mA. As i wrote already, the 74AC240 has it's absolute maximum rating at 50mA. For a general logic output, i wouldn't recomend to draw more than 10mA (as Bob Grant wrote, the lock signal doesn't seem to pass trough the 74AC240). Hence, i would say that 330R seems rather small :-) Keep in mind that you drove circuit at over current for quite a long time. The circuit is most likely damaged (if they dont have an over current limit, which i doubt). If for an unknown reason the lock signal fails in the future, it might be due to this. 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.
Re: [time-nuts] FE5680 missing PPS soln
Mine was a green LED out of the junk box, but I did use 330R in series. 1k8 seems rather large. I will probably put something between the 5680 and the LED later. I have a bin full of old 74xx, so should be easy. I've seen lots of threads about the 5680 and tweaks etc., but not much on actually building them into anything. I just built a very cheap dual unit (two 5680s bolted in). When I say cheap, the only thing bought were the 5680s. The rest was out of the junk box. The case is from an old Technics tape deck Front panel is cut down and drilled from an old PC side panel. The 5680s are bolted to the bottom of the case Main power (+15V) comes from a universal 5A laptop power supply (with selectable output voltage set to +15V). I used an old 10V brick to drive one of the 7805 sent by the Chinese supplier with the 5680s. The rest is the odd resistor and capacitor and wiring. Not pretty but very functional. Front panel has: 2 switches (+15V to the Rbs): 2 red LEDS - power ON to the RBs, 2 green LEDs - Lock, and two BNCs - 10 MHZ outout. The only thing left is where to fit the teddy bear they sent... Have fun with your projects! Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of bob grant Sent: 02 February 2012 23:20 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE5680 missing PPS soln The LEDs are common garden variety, tied to +5V and inline with 1k8...I was expecting 2ma or so. Note, whereas the PPS signal is buffered the LOCK signal for the DB9 is not passed though the 74ACT240 buffer. On Thu, Feb 2, 2012, at 11:10 PM, Attila Kinali wrote: On Thu, 02 Feb 2012 12:46:01 -0800 bob grant bobgr...@fastmail.fm wrote: Some info... Its tempting to attach an LED to the /LOCK signal on the DB9. However this signal is very weak and the LED does not seem very bright and PPS signal does not pulse...Hmm Internally the /LOCK pin is connected the 74AC240 buffer, but with an LED helping to keep the signal voltage high (2.3V) a logic low is never asserted. May i ask what kind of LED you connected and at which current you drove it? I don't know which 74AC240 the FE5680 units use, but Fairchild lists theirs with an absolute maximum rating of +/-50mA. I wouldn't use it to drive more than 20mA, which means that you need at least a current generation LED, or better a high efficiency LED. Such as John Lofgren used. Alternatively, use a small logic level P channel FET like the FDV302P or a small PNP. Attila Kinali [1] For those who don't know, Absolute Maximum Ratings should read as If you exceede these levels, your device will be dead for sure! -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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. -- http://www.fastmail.fm - The professional email service ___ 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.
Re: [time-nuts] FE5680 missing PPS soln
On Fri, 3 Feb 2012 09:50:52 - Rob Kimberley robkimber...@btinternet.com wrote: Mine was a green LED out of the junk box, but I did use 330R in series. 1k8 seems rather large. Then i'm not surprised that your FE-5680 refused to work :-) Just calculate: 5V supply, approx 2V LED voltage - 3V over the resistor. 3V/330R = 90mA. As i wrote already, the 74AC240 has it's absolute maximum rating at 50mA. For a general logic output, i wouldn't recomend to draw more than 10mA (as Bob Grant wrote, the lock signal doesn't seem to pass trough the 74AC240). Hence, i would say that 330R seems rather small :-) Keep in mind that you drove circuit at over current for quite a long time. The circuit is most likely damaged (if they dont have an over current limit, which i doubt). If for an unknown reason the lock signal fails in the future, it might be due to this. 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.
Re: [time-nuts] FE5680 missing PPS soln
9mA PaulG8GJA -Original Message- From: Attila Kinali [mailto:att...@kinali.ch] Sent: 03 February 2012 12:55 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE5680 missing PPS soln On Fri, 3 Feb 2012 09:50:52 - Rob Kimberley robkimber...@btinternet.com wrote: Mine was a green LED out of the junk box, but I did use 330R in series. 1k8 seems rather large. Then i'm not surprised that your FE-5680 refused to work :-) Just calculate: 5V supply, approx 2V LED voltage - 3V over the resistor. 3V/330R = 90mA. As i wrote already, the 74AC240 has it's absolute maximum rating at 50mA. For a general logic output, i wouldn't recomend to draw more than 10mA (as Bob Grant wrote, the lock signal doesn't seem to pass trough the 74AC240). Hence, i would say that 330R seems rather small :-) Keep in mind that you drove circuit at over current for quite a long time. The circuit is most likely damaged (if they dont have an over current limit, which i doubt). If for an unknown reason the lock signal fails in the future, it might be due to this. 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. This email, including any attachment, is a confidential communication intended solely for the use of the individual or entity to whom it is addressed. It contains information which is private and may be proprietary or covered by legal professional privilege. If you have received this email in error, please notify the sender upon receipt, and immediately delete it from your system. Anything contained in this email that is not connected with the businesses of this company is neither endorsed by nor is the liability of this company. Whilst we have taken reasonable precautions to ensure that any attachment to this email has been swept for viruses, we cannot accept liability for any damage sustained as a result of software viruses, and would advise that you carry out your own virus checks before opening any attachment. ___ 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] FE5680 missing PPS soln
Uhhh... last time I checked 3V/330 ohms is 9.1 milliamps, not 90 mA... - Just calculate: 5V supply, approx 2V LED voltage - 3V over the resistor. 3V/330R = 90mA ___ 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.
Re: [time-nuts] FE5680 missing PPS soln
Thank you Paul. :-) Rob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Reeves Paul Sent: 03 February 2012 12:59 To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] FE5680 missing PPS soln 9mA PaulG8GJA -Original Message- From: Attila Kinali [mailto:att...@kinali.ch] Sent: 03 February 2012 12:55 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE5680 missing PPS soln On Fri, 3 Feb 2012 09:50:52 - Rob Kimberley robkimber...@btinternet.com wrote: Mine was a green LED out of the junk box, but I did use 330R in series. 1k8 seems rather large. Then i'm not surprised that your FE-5680 refused to work :-) Just calculate: 5V supply, approx 2V LED voltage - 3V over the resistor. 3V/330R = 90mA. As i wrote already, the 74AC240 has it's absolute maximum rating at 50mA. For a general logic output, i wouldn't recomend to draw more than 10mA (as Bob Grant wrote, the lock signal doesn't seem to pass trough the 74AC240). Hence, i would say that 330R seems rather small :-) Keep in mind that you drove circuit at over current for quite a long time. The circuit is most likely damaged (if they dont have an over current limit, which i doubt). If for an unknown reason the lock signal fails in the future, it might be due to this. 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. This email, including any attachment, is a confidential communication intended solely for the use of the individual or entity to whom it is addressed. It contains information which is private and may be proprietary or covered by legal professional privilege. If you have received this email in error, please notify the sender upon receipt, and immediately delete it from your system. Anything contained in this email that is not connected with the businesses of this company is neither endorsed by nor is the liability of this company. Whilst we have taken reasonable precautions to ensure that any attachment to this email has been swept for viruses, we cannot accept liability for any damage sustained as a result of software viruses, and would advise that you carry out your own virus checks before opening any attachment. ___ 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.
Re: [time-nuts] FE5680 missing PPS soln
On Fri, 3 Feb 2012 13:02:11 + Mark Sims hol...@hotmail.com wrote: Just calculate: 5V supply, approx 2V LED voltage - 3V over the resistor. 3V/330R = 90mA Uhhh... last time I checked 3V/330 ohms is 9.1 milliamps, not 90 mA... Uhh... last time i checked... i should have used a calculator ^^; Sorry, please disregard what i wrote. 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.
Re: [time-nuts] FE5680 missing PPS soln
Hi, You need to check your maths... :-) Rob K -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila Kinali Sent: 03 February 2012 12:55 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE5680 missing PPS soln On Fri, 3 Feb 2012 09:50:52 - Rob Kimberley robkimber...@btinternet.com wrote: Mine was a green LED out of the junk box, but I did use 330R in series. 1k8 seems rather large. Then i'm not surprised that your FE-5680 refused to work :-) Just calculate: 5V supply, approx 2V LED voltage - 3V over the resistor. 3V/330R = 90mA. As i wrote already, the 74AC240 has it's absolute maximum rating at 50mA. For a general logic output, i wouldn't recomend to draw more than 10mA (as Bob Grant wrote, the lock signal doesn't seem to pass trough the 74AC240). Hence, i would say that 330R seems rather small :-) Keep in mind that you drove circuit at over current for quite a long time. The circuit is most likely damaged (if they dont have an over current limit, which i doubt). If for an unknown reason the lock signal fails in the future, it might be due to this. 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.
Re: [time-nuts] FE5680 missing PPS soln
I'm using a 556 dual timer, one section as an inverter to drive a lock led, and the other section as a pulse stretcher to drive a 1 pps led. Let's get on with it. Don Attila Kinali On Fri, 3 Feb 2012 09:50:52 - Rob Kimberley robkimber...@btinternet.com wrote: Mine was a green LED out of the junk box, but I did use 330R in series. 1k8 seems rather large. Then i'm not surprised that your FE-5680 refused to work :-) Just calculate: 5V supply, approx 2V LED voltage - 3V over the resistor. 3V/330R = 90mA. As i wrote already, the 74AC240 has it's absolute maximum rating at 50mA. For a general logic output, i wouldn't recomend to draw more than 10mA (as Bob Grant wrote, the lock signal doesn't seem to pass trough the 74AC240). Hence, i would say that 330R seems rather small :-) Keep in mind that you drove circuit at over current for quite a long time. The circuit is most likely damaged (if they dont have an over current limit, which i doubt). If for an unknown reason the lock signal fails in the future, it might be due to this. 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ 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] FE5680 missing PPS soln
Some info... Its tempting to attach an LED to the /LOCK signal on the DB9. However this signal is very weak and the LED does not seem very bright and PPS signal does not pulse...Hmm Internally the /LOCK pin is connected the 74AC240 buffer, but with an LED helping to keep the signal voltage high (2.3V) a logic low is never asserted. This logic low is needed to enable one half of the 74AC240 buffer (pin 1) that gates the PPS signal. Don't directly drive LEDs from the LOCK signal on the DB9 and, voila, the PPS signal reappears. Bob -- bob grant bobgr...@fastmail.fm -- http://www.fastmail.fm - Choose from over 50 domains or use your own ___ 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.
Re: [time-nuts] FE5680 missing PPS soln
I did the same thing when I first tested mine. I mounted the regulator and a pair of SMA jacks right to the board it came with using the big board copper as the heat sink for the regulator. I didn't want to build a driver for the LED so I wired it directly (with resistor, of course). Dim and logic low was way up at 2.3 volts. I solved the problem using a high efficiency LED (P/N C503B-RCS-CW0Z0AA1 from Digi-Key). It's running at a bit over half a mA using a 6.2k resistor to the 5 V supply. Now the logic low level is at about 700 mV (still a bit high) and the PPS output works. The LED is bright enough to see from way across the lab. The current generation of LED chemistries is really impressive. -John -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of bob grant Sent: Thursday, February 02, 2012 2:46 PM To: time-nuts@febo.com Subject: [time-nuts] FE5680 missing PPS soln Some info... Its tempting to attach an LED to the /LOCK signal on the DB9. However this signal is very weak and the LED does not seem very bright and PPS signal does not pulse...Hmm Internally the /LOCK pin is connected the 74AC240 buffer, but with an LED helping to keep the signal voltage high (2.3V) a logic low is never asserted. This logic low is needed to enable one half of the 74AC240 buffer (pin 1) that gates the PPS signal. Don't directly drive LEDs from the LOCK signal on the DB9 and, voila, the PPS signal reappears. Bob -- bob grant bobgr...@fastmail.fm -- http://www.fastmail.fm - Choose from over 50 domains or use your own ___ 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.
Re: [time-nuts] FE5680 missing PPS soln
I've used an LED direct to the lock output. 330R resistor in series and the other end of the LED to the +5V rail. Works fine for me, but then, I'm not interested in the 1PPS (actually not even sure my bricks have that feature). Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of bob grant Sent: 02 February 2012 20:46 To: time-nuts@febo.com Subject: [time-nuts] FE5680 missing PPS soln Some info... Its tempting to attach an LED to the /LOCK signal on the DB9. However this signal is very weak and the LED does not seem very bright and PPS signal does not pulse...Hmm Internally the /LOCK pin is connected the 74AC240 buffer, but with an LED helping to keep the signal voltage high (2.3V) a logic low is never asserted. This logic low is needed to enable one half of the 74AC240 buffer (pin 1) that gates the PPS signal. Don't directly drive LEDs from the LOCK signal on the DB9 and, voila, the PPS signal reappears. Bob -- bob grant bobgr...@fastmail.fm -- http://www.fastmail.fm - Choose from over 50 domains or use your own ___ 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.
Re: [time-nuts] FE5680 missing PPS soln
YMMV but, if there's any chance of a PPS output it'll be arriving at pin 2 of the 74AC240 buffer. -- http://www.fastmail.fm - Accessible with your email software or over the web ___ 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.
Re: [time-nuts] FE5680 missing PPS soln
On Thu, 02 Feb 2012 12:46:01 -0800 bob grant bobgr...@fastmail.fm wrote: Some info... Its tempting to attach an LED to the /LOCK signal on the DB9. However this signal is very weak and the LED does not seem very bright and PPS signal does not pulse...Hmm Internally the /LOCK pin is connected the 74AC240 buffer, but with an LED helping to keep the signal voltage high (2.3V) a logic low is never asserted. May i ask what kind of LED you connected and at which current you drove it? I don't know which 74AC240 the FE5680 units use, but Fairchild lists theirs with an absolute maximum rating of +/-50mA. I wouldn't use it to drive more than 20mA, which means that you need at least a current generation LED, or better a high efficiency LED. Such as John Lofgren used. Alternatively, use a small logic level P channel FET like the FDV302P or a small PNP. Attila Kinali [1] For those who don't know, Absolute Maximum Ratings should read as If you exceede these levels, your device will be dead for sure! -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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.
Re: [time-nuts] FE5680 missing PPS soln
The LEDs are common garden variety, tied to +5V and inline with 1k8...I was expecting 2ma or so. Note, whereas the PPS signal is buffered the LOCK signal for the DB9 is not passed though the 74ACT240 buffer. On Thu, Feb 2, 2012, at 11:10 PM, Attila Kinali wrote: On Thu, 02 Feb 2012 12:46:01 -0800 bob grant bobgr...@fastmail.fm wrote: Some info... Its tempting to attach an LED to the /LOCK signal on the DB9. However this signal is very weak and the LED does not seem very bright and PPS signal does not pulse...Hmm Internally the /LOCK pin is connected the 74AC240 buffer, but with an LED helping to keep the signal voltage high (2.3V) a logic low is never asserted. May i ask what kind of LED you connected and at which current you drove it? I don't know which 74AC240 the FE5680 units use, but Fairchild lists theirs with an absolute maximum rating of +/-50mA. I wouldn't use it to drive more than 20mA, which means that you need at least a current generation LED, or better a high efficiency LED. Such as John Lofgren used. Alternatively, use a small logic level P channel FET like the FDV302P or a small PNP. Attila Kinali [1] For those who don't know, Absolute Maximum Ratings should read as If you exceede these levels, your device will be dead for sure! -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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. -- http://www.fastmail.fm - The professional email service ___ 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.
