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DS90UB947 keeps streaming out some data when its input switch off

Hello,

I'm working on a repeater board that consists of one DS90UB948 deser. and one DS90UB947 ser. These two are connected 1:1 so D0 --> D0...D7-->D7 and CLK --> CLK (according to datasheet)  VIDEO_SOURCE_SER ---> DESER1 ----> SER -----> DESER2
 The board works good, the signal goes through, video after repeater is OK, but I have some problem. When the source of a signal is switched off, the deserializer (DESER1) stops generating CLK and data (correct), but the serializer still streams out a signal down to the link. When I connect another board to the output of the first, I see that its deserializer (DESER2) catches CLK signal and is LOCKed. The problem is that the serializer (SER) still streams a CLK with zero data in spite of its input (DESER1) streams nothing.

I tryed to set SOFT_SLEEP register in the serializer, but it did not help.


 My question:

Is that correct behaviour?

How can I detect that the source of the signal is switched off, when I have still LOCK signal on second deser asserted?

Thank you for any ideas.


Ondra