Tool/software:
Can the CSI output of the DS90UB954 be used as the input to the UB953?
This would enable it to act as a repeater (as per the UB947/8 pair) but also provide a replicating capability.
MIPI -> UB953 -> FPD Link -> UB954 -> MIPI(A) -> UB953 -> FPDLink
UB954 -> MIPI(B) -> UB953 -> FPDLink
