[Ftk_hardware] crates

Paola Giannetti paola.giannetti at pi.infn.it
Thu Mar 24 02:01:52 CDT 2011

I am sorry for the late answer, yesterday I couldn't see e-mails.

I think we cannot use ATCA for the core crates for a lot of reasons that 
I already explained, even at the review:
(1) we need early to test the system with the new chip, let's say next 
year and it is not realistic to have a new AMBoard, new LAMB and new CPU 
interface for the next year. It is very important to be able to measure 
currents, capability to work at 100 MHz and with the new chip, before 
the end of 2012. We will never do it if we change crate

(2) We are ahead designing the LAMB, the AMBoard and the AMchip. The 
suggestions of the reviewers are global, incoherent and do not take into 
account the fact that we have already done a lot of work and the budget 
will likely decrease not increase: (1) change package for the AMchip, 
(2) go to 130 nm IBM instead of 65 nm TSMC, (3) use serial links in the 
board instead of parallel buses, (4) get 30% more money (actually if we 
go to serial links we need 400% more money)......  all this is totally 
not realistic for our plan to be able to measure consumption, cooling 
and performances in 2012. Before doing production, we need probably 2-3 
AMChip prototypes, it requires time.

(3) using VME we are compatible with the vertical slice, what we do for 
the vertical slice is automatically good for the system. If we go to 
ATCA all the work we do with the vertical slice is unuseful. We do not 
have the manpower.

(4) we already have 2 new VME crates, 2 new CPUs  in the lab, we cannot 
put them in hold.

(5) we are measuring the consumption and it seems to be less than 
expected, may be a factor 2. This reduces a lot concerns  about 48 V (2 
pins could be enough and separate GND return could be available).

I really think ATCA for the core crate for 2015 is not feasible, 
especially if in the same time we have to take data with the vertical 
slice. Too much work in a too short time.
It is an interesting option for phase II. The LAMB will be redesigned 
for that time, with new chips, new packages and new serial links.


Mel Shochet wrote:
>      There are now two suggestions for moving to ATCA.  Interboard data 
> transfer in the Data Formatter crates could be made easier (the 
> alternative being fibers between boards).  The Initial Design Review 
> committee recommends that we consider ATCA for the core crates because 
> of the committee's concern about power (our 48-volt solution) and 
> cooling.  We will have to respond to this suggestion.  (A potential 
> disadvantage is ATCA's 8U vs VME's 9U size).  Could we have an initial 
> discussion of the issue at our meeting in 2 weeks (April 5)?  We could 
> hear what the DF issues are from Fermilab and what the core crate issues 
> are from someone in Italy working on the AM and associated 
> infrastructure.  Then we can decide on the next steps if any.
>                         Regards,
>                         Mel
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