Re: [time-nuts] FE-5680A GPS discipline board on sale now

Absolutely. There’s a standard AVR ISP header on the board and the firmware is open source - on github - so even if I didn’t do it, anyone else could. > On May 22, 2016, at 9:04 AM, GandalfG8--- via time-nuts > wrote: > > Nick, > > This looks very interesting but just

Re: [time-nuts] FE-5680A GPS discipline board on sale now

Nick, This looks very interesting but just wondering, will there be an option for end users to reprogram the board themselves just in case there does turn out to be any bugs in the software, and if so would you be making updates available? Regards Nigel GM8PZR

Re: [time-nuts] FE-5680A GPS discipline board on sale now

On Fri, 20 May 2016 07:03:10 -0700 Nick Sayer via time-nuts wrote: > > The discharge resistor of the integrator (R13) is with 10M way too high. > > The PCB resistance is usually in the same order of magnitude. Ie with > > a resistance that high, the actual resistance highly

Re: [time-nuts] FE-5680A GPS discipline board on sale now

All the more reason to just observe the log and manually select the value to burn in, IMHO. If you happen to see that the discipline is alternating between adjacent values, then you can "de-dither" by adding back the two lost resolution bits and selecting the correct low-bits by interpolation.

Re: [time-nuts] FE-5680A GPS discipline board on sale now

You SHOULD never have to write very frequently to the EEPROM. As long at the 5680 is connected to the GPS you don't have to write to the EEPROM at all. Only time you'd need to write is just before it is disconnected. Will you do that even three times a week. The unit that discipline the 5680

Re: [time-nuts] FE-5680A GPS discipline board on sale now

You're right. The EEPROM of concern is the one in the 5680. Since they're used, you have no idea how many writes they've already endured (likely a low number), and they're quite old. Sent from my iPhone > On May 20, 2016, at 3:20 PM, paul swed wrote: > > Mark > By

Re: [time-nuts] FE-5680A GPS discipline board on sale now

Mark By todays standards yes. But they were not that great 10 years ago. So I may be crossing wires. I am speaking off the eeprom in the 5680 and I think you are speaking to the one in the AVR. That would be of the modern type. Regards Paul WB8TSL On Fri, May 20, 2016 at 5:31 PM, Mark Sims

[time-nuts] FE-5680A GPS discipline board on sale now

I think the EEPROM in AVR chips is rated at 100,000 writes. Several people have tested them and most found they would survive at least 5 million writes... YMMV, of course. One write every 24 hours is still under 10K writes in a reasonable lifespan for a GPSDO. It’s a

Re: [time-nuts] FE-5680A GPS discipline board on sale now

Hello to the group. I would like to add a comment to this thread. I agree with Bobs comment on the eeprom writes. For modern units its 100K plus but does depend on the memory cell technology. However aren't the 5680s about 10 years old? If thats true then the write life cycle was much lower back

Re: [time-nuts] FE-5680A GPS discipline board on sale now

Hi If you go through the math on your eeprom, there is a point at which writes “don’t matter”. It depends a bit on the part you have and your target life. One write every 24 hours is still under 10K writes in a reasonable lifespan for a GPSDO. It’s a rare eeprom that is rated that low. Bob

Re: [time-nuts] FE-5680A GPS discipline board on sale now

Rather then a manual button, you might always burn in the EFC value after finding it stable for some number of hours. Then after that only burn it again under some strict conditions like being stable for twice as many hours and the value in the EEPROM is different from what it needs to be,

Re: [time-nuts] FE-5680A GPS discipline board on sale now

> On May 20, 2016, at 2:29 AM, Attila Kinali wrote: > > Hoi Nick! > > On Thu, 19 May 2016 10:08:10 -0700 > Nick Sayer via time-nuts wrote: > > >> This is a mash-up of my breakout board and GPSDO. You give it 30+W 18-24 >> VDC in (hack up a surplus

Re: [time-nuts] FE-5680A GPS discipline board on sale now

Hoi Nick! On Thu, 19 May 2016 10:08:10 -0700 Nick Sayer via time-nuts wrote: > This is a mash-up of my breakout board and GPSDO. You give it 30+W 18-24 > VDC in (hack up a surplus laptop power supply) and it supplies up to 2A @ 15 > VDC and 500 mA @ 5 VDC. In my testing I

[time-nuts] FE-5680A GPS discipline board on sale now

This is a mash-up of my breakout board and GPSDO. You give it 30+W 18-24 VDC in (hack up a surplus laptop power supply) and it supplies up to 2A @ 15 VDC and 500 mA @ 5 VDC. In my testing I see around 25 mV p-p of ripple on the 15V rail. The 5V rail is a bit noisier at around 35 mV.