We are designing a board based on SabreSD. We are planning to use all, i.MX6 Solo, Dual-lite and Quad processor on the same board with 1GB, 2GB, and 4GB DDR3 RAM respectively while the PCB remains same for all the three configurations.
When using i.MX6 Quad, we'll mount four 8Gb DDR3 (MT41K512M16HA-125 IT).
In case of i.MX6 Dual-lite, we'll mount two 8Gb DDR3 (MT41K512M16HA-125 IT) &
In case of i.MX6 Solo, we'll mount single 8Gb DDR3 (MT41K512M16HA-125 IT).
In the reference layout (LAY-27392_C), balanced T topology has been used for connecting all 4 DDR3 RAMs back to back.
I would like to know if I should go with fly-by topology or balanced T topology as in the case of balanced T topology when 3 RAMs are not mounted (with i.MX Solo configuration). Will there be any effect of noise due to the stubs in the absence of other 3 RAMs?
Also, do let me know what precautions to be taken care while migrating from quad to dual lite and solo processor. I have referred to Application Note AN4397 for schematics design.
Any help is appreciated@ in advance.igorpadykov