Virtex 5 Rocket IO design for reading in ADC data.

On Jun 30, 6:08=A0pm, "jgk2004"
<john.kauffman@n_o_s_p_a_m.n_o_s_p_a_m.uni-ulm.de> wrote:
> Hello Jon,
>
> You are completely correct, =A0I do not understand the virtex 5 at all!!
> What guide(since there are like 10) would you recommend reading to learn
> about LVDS. =A0Thank god i pinned out almost everything on my PCB to
> headers... just need to make a new socket board!
>
> Thanks
>
> Jgk
>
>
>
> >It seem to me as though you dont really understand the Virtex 5
> >architecture. You need to read the user guide and data sheet to get a
> feel
> >what is possible with a certain IO technology. Rocket IO uses CML type
> >drivers which are different to LVDS. LVDS upto 1.25 Gb/s is possible.
>
> >Jon =A0 =A0
>
> >--------------------------------------- =A0 =A0 =A0 =A0 =A0 =A0
> >Posted throughhttp://www.FPGARelated.com
>
> --------------------------------------- =A0 =A0 =A0 =A0
> Posted throughhttp://www.FPGARelated.com

Go through the Virtex-5 user guide i.e. UG190. There is a detailed
chapter on SelectIO (Chapter 6) which will help you in serialization/
de-serialization of your 250MHz LVDS lines. One important point to be
noted here is that GTPs won't work at lower frequencies (You need to
use the oversampling circuitry available in GTPs) like 250 MHz in your
case. . Anyway GTPs work with HSTL standard which is different from
LVDS.

For our 5Gsps PCIe Digitizers we use a Virtex-5 to read ADC-Data at
1.25Gbps per pin.
We can see that we still have a few hundred ps of sampling window, so
1.5Gbps probably would work as well.

Virtex-6 or Virtex-6 should be able to do higher rates.

See xapp860.pdf and xapp855.pdf for more.

Kolja Sulimma
cronologic

On Jun 30, 12:43=A0pm, "jgk2004"
<john.kauffman@n_o_s_p_a_m.n_o_s_p_a_m.uni-ulm.de> wrote:
> When you say that LVDS on the virtex 5 could easily be handled at 250MHz
> would I then need a core clock at above 250MHz? =A0Also what is hte max L=
VDS
> could be used on the virtex 5 without the rocket IOs? Can i use LVDS at
> 1GHz?