[time-nuts] Easy-to-use TDC to compare PPS

[Attila Kinali]

On Tue, 15 Sep 2015 16:30:59 +0200
Xavier Bestel <xavier.bestel at free.fr> wrote:

> I'd like to do some PPS comparisons on an SBC (like a Beaglebone or RPi) 
> using a TDC. So far the ones I've seen which could be suitable are 
> ACAM's TDC-GPX and TI's THS788:
> http://www.acam.de/fileadmin/Download/pdf/English/DB_GPX_e.pdf
> http://www.ti.com/lit/ds/symlink/ths788.pdf
> However these chips don't look so simple to connect to a standard SBC. 
> Would anyone of you already have attempted that journey, or simply have 
> a reasonably good idea about how to do that ?

Why don't they connect easily to SBCs? (beside, is there such a thing as
a standard SBC?) Yes, they both use differential inputs (for obvious reasons)
but this easy to solve with a single gate.

Alternatively you can try the PICTIC-II [1] which you can extend to do
more than just timestamping and to multiple ports. For this application
it should be precise/accurate enough.

			Attila Kinali

[1] http://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:pictic

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