Hi Robert,
,,Double check how other do it. ''
thats what I am trying to do here
the thing is, I tried to look at the defkits, and finaly managed to get some orcad files into altium. then the confusion started. it did not make sense!
i recalculated the matching they did on the VCU190 and it did not match. not in a good way. that lead me to contact xilinx themselves, and the answer was that you should not trust the matching on the defkits, since they are not likely to be 100% correct.
But running ddr4 at 2400 Mhz, makes me a bit nervous. especially with this many in a 64 bits config (and that 4 times) . and it has to run at max speed for this project.
(It is kind of funny thinking about it..running transceivers @ 25 Gbps don't scare me at all)
this protoype will cost a lot of pennies, so i would prefer not waisting a pretty expensive FPGA and PCB.
yes there will be a compensation inside of the chips / tooling to get optimum preformance but still all documentation says you have to take internal wirebonds into account. so here I am doing that and there is no real guide of how to do it. it is going to be simulated, but does the simulation (post layout) take the timing of the internal wirebonds? or is it just pin to pin.? I am having a meeting about this today so hope to have a answer soon...
now i get the option in the schematic symbol to add the lengths of internal wirebond to the pins, and that is great. but the fun doesn't stop there.. how to match this..
I have broken down the 16 bits config to 2x8 to ease routing, so I can match the 16 bits on 2 layers making it possible. doing 16 bits and dqs / dm on one layer isn't even possible.
grouping signals in a control/ byte groups. and then i should match this over 64 bits.. thats sounds like impossible right?
I am at pre layout stage here, just figuring out on what layers to use... and still have a lot to do (see screenshot)
so any advice or experience is welcome.
in the end I will figure it out.. I always do, but having some help along the way is always nice!
anyway... Thanks for helping so far!
Best regards,
Paul..