"PatC" <pato@REMOVETHISpatocarr.com> wrote in message 
news:CmWLk.6188$Zd.903@newsfe10.iad...
> Roger wrote:
>> I want to use 14 GTPs on a Virtex 5 each running a separate Aurora 
>> interface. The Aurora code from Coregen produces a clock_module process 
>> amongst all the others which contains a DCM.
>>
>> Previous experience of Virtex II Pro implementations allowed 1 clock 
>> module to be used with multiple Auroras. The Virtex 5 clock module is 
>> different in that it takes its clock input from the GTP Dual PLL together 
>> with a Lock signal.
>>
>> What's the best approach in this situation?
>>
>> A) Use 1 clock_module (DCM) per GTP_Dual i.e. 2 Auroras
>> B) Use 1 clock_module for all the Auroras with it being driven from one 
>> arbitrary GTP (same idea as the Virtex II Pro days).
>> C) Use 2 clock_modules for the top and bottom GTPs, again driven 
>> arbitrarily from 1 GTP in each half.
>
> You could do any and it would be fine, with caveats:
> a) you'd use 7 DCMs, lots of BUFGs and more power.
> b) the 'arbitrary' GTP_DUAL that is able to clock them all is the one in 
> the middle (ie. Y3)
> c) it's ok, just uses double clocking resources than b)
>
> Check out the RocketIO User Guide for more info.
>
> Cheers,
> -P@
>
>
>> Any help gratefully received.
>>
>> Roger.

Thanks Pat, that's one 'unknown' tackled. I'm regretting the day I started 
this as the Core Gen Aurora wizards (still don't know why there are 2) won't 
produce multiple independent Auroras. I have to specify a single lane 
version instead but that's particularly annoying as a GTP_dual is 
instantiated but only the ports of the GTP that's used are brought out. 
This, and the clocking issue, mean there's loads of hand editing to do which 
is disappointing and completely defeats the object of having Core Gen in the 
first place.

Thanks for your help with the clocking though.

Rog. 

Roger wrote:
> I want to use 14 GTPs on a Virtex 5 each running a separate Aurora 
> interface. The Aurora code from Coregen produces a clock_module process 
> amongst all the others which contains a DCM.
> 
> Previous experience of Virtex II Pro implementations allowed 1 clock 
> module to be used with multiple Auroras. The Virtex 5 clock module is 
> different in that it takes its clock input from the GTP Dual PLL 
> together with a Lock signal.
> 
> What's the best approach in this situation?
> 
> A) Use 1 clock_module (DCM) per GTP_Dual i.e. 2 Auroras
> B) Use 1 clock_module for all the Auroras with it being driven from one 
> arbitrary GTP (same idea as the Virtex II Pro days).
> C) Use 2 clock_modules for the top and bottom GTPs, again driven 
> arbitrarily from 1 GTP in each half.

You could do any and it would be fine, with caveats:
a) you'd use 7 DCMs, lots of BUFGs and more power.
b) the 'arbitrary' GTP_DUAL that is able to clock them all is the one in 
the middle (ie. Y3)
c) it's ok, just uses double clocking resources than b)

Check out the RocketIO User Guide for more info.

Cheers,
-P@


> Any help gratefully received.
> 
> Roger.

I want to use 14 GTPs on a Virtex 5 each running a separate Aurora 
interface. The Aurora code from Coregen produces a clock_module process 
amongst all the others which contains a DCM.

Previous experience of Virtex II Pro implementations allowed 1 clock module 
to be used with multiple Auroras. The Virtex 5 clock module is different in 
that it takes its clock input from the GTP Dual PLL together with a Lock 
signal.

What's the best approach in this situation?

A) Use 1 clock_module (DCM) per GTP_Dual i.e. 2 Auroras
B) Use 1 clock_module for all the Auroras with it being driven from one 
arbitrary GTP (same idea as the Virtex II Pro days).
C) Use 2 clock_modules for the top and bottom GTPs, again driven arbitrarily 
from 1 GTP in each half.

Any help gratefully received.

Roger.