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DS90CR286A: Using this Chip for an Arbitrary Serialized Data Stream

Part Number: DS90CR286A
Other Parts Discussed in Thread: DS90CR216A

Hello forum members, I was hoping to use this chip as a straight 1:7 receiver on each channel, but the input to output mapping doesn't seem to match up in the way I expected. I would have thought that the sequential RxOut pattern would continue in much the same way as in it's DS90CR216A 3 channel counterpart.

I figured each channel's sequence would map as:

[ RxOut6 RxOut5 RxOut4 RxOut3 RxOut2 RxOut1 RxOut0 ] for each channel such as in the DS90CR216A.

However the outputs observed in data sheet shows:

[ RxOut7 RxOut6 RxOut4 RxOut3 RxOut2 RxOut1 RxOut0 ] and some similar mappings for the other channels as well.

Is it possible to use this device for arbitrary data readouts of a serialized LVDS line? My serialized signal does not include HSYNC, VSYNC, or DE within the data, it only includes arbitrary values from an image sensor (all the frame start/stop and data types are baked into the individual pixels themselves, not represented as their own bit). Does this strobe just act as a simple 1:7 de-serializer with a non-sequential mapping scheme?

Also, I believe there is an error in the data sheet on pages 19-20, if any TI employees here see this, they might be interested in correcting it.

Table 2:

The mapping of RxIN0 shows only 6 positions mapped to it when TxIN7 should be included in that table section as seen from the timing diagram in Figure 6. I believe it most likely spilled over into RxIN1's section on the first entry. RxIN1 has 8 mappings instead of 7 like them rest of them, so this seems plausible.

Table 3:

This table has the same issue with RxIN0 as stated above for Table 2.

  • Hi Bryan, 

    Yes, the 3 channel and 4 channel variants will have different bit mapping between the two, as shown in Figure 6 and 7.

    s it possible to use this device for arbitrary data readouts of a serialized LVDS line? My serialized signal does not include HSYNC, VSYNC, or DE within the data, it only includes arbitrary values from an image sensor (all the frame start/stop and data types are baked into the individual pixels themselves, not represented as their own bit). Does this strobe just act as a simple 1:7 de-serializer with a non-sequential mapping scheme?

    This technically should be possible assuming you have something on the other side that can interpret the data and you are still staying within the "PCLK" limits of the device. 

    Also, I believe there is an error in the data sheet on pages 19-20, if any TI employees here see this, they might be interested in correcting it.

    Thanks for pointing this out. Appears that RxOUT7 is rolled over into RxIN1.

    Regards, 

    Logan

  • This, resolved my concerns, thank you.