FE-5680A Rubidium oscillator - enable option 2?

[JJalling]

Hi all,

I have an old FE-5680A which, I think, doesn't have option 2 enabled (serial configuration).
When I send the command 0x2D 0x04 0x00 0x29 to read out the tuning register, it never replies. I have measured that the serial signal actually gets to the RX-pin on the DS80C323 processor, but no signal is returned on the TX pin.
Is there any way to enable option 2?

Thanks, Jonas

[JJalling]

... Actually I don't think this is related to option 2 - the calibration should, as far as I understand, be possible on all devices - can someone confirm this?

BR Jonas

[richnormand]

Have a look at these links:

http://www.leapsecond.com/time-nuts.htm
http://www.ko4bb.com/doku2015/doku.php?id=precision_timing:fe5680a_faq
http://www.ko4bb.com/doku2015/doku.php
https://hackaday.io/project/11514-hacking-a-fe-5680b-rubidium-reference-clock

First one is time nuts and search FE-5680. There are lots of references and hacks for these units.
Second and third is KO4BB site and the wiki. They also have a copy of the several x-rays I did when fixing my FE-5680A
(contact me should you need a specific x-ray of a region of interest. Files are huge)
Fourth is hacking to get other signals on the board.

Best of luck with it.

[JJalling]

Hey Rich,

Thanks for the info! If I have any luck fixing it, I'll report back here.
BR Jonas

[AlfBaz]

I don't suppose either of you happened to have downloaded the contents of the xilinx cpld in jedec format (*.jed file)?

I have a 5680B which appears identical to the A version and believe that flashing the A version of the jed file will keep the 10MHz signal on instead of turning it off after a few seconds, which is what the B version does.