GTA02: NavBoard V3 causing GPS interference

[joerg Reisenweber]

Am Friday 08 February 2013 17:10:00 schrieb Pascal Gosselin:
> I have found a good reference on how to best handle I2C cabling. It's a
> PowerPoint Presentation from Texas Instruments, I made a screenshot of
> the relevant image:
>
> http://s7.postimage.org/t9bfk47hn/Screen_Shot_2013_02_08_at_11_00_03_AM.png
>
> As I suspected, only one end of the shield gets grounded, individual
> coaxes for SCL and SDA.
>
> Google  I2C cable issues.ppt   to find the original document as the
> first hit.
>
> Now I have to source some extremely tiny minature coax, ideally with a
> solid core (for easier soldering to the pads on the NavBoard and the
> GTA02). Looking for recommendations, ideally something I can order from
> Digi-Key, Newark or Mouser in smaller quantities (it's not like a need a
> 1,000 foot roll!).
>
> It's not clear IF the power supply wires should be shielded.  I think I
> will try to see if it makes a difference for the GPS.
>
> -Pascal

You should use fine pitch flat ribbon connector or flat plastic connector like 
on LCM, and shield it with a metal braid sticky tape, again like originally 
done in GTA02 LCM connection.
For further crosstalk and EMI shielding run a GND wire as every 1., 3. aso 
wire in your ribbon cable.

Ulrathin coax is *extremely* expensive and hard to source

/j