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Original question:

LVDS(FlatLink) to CSI-2 or 8bit+SYNC

DS90UB960-Q1: Multiple LVDS sensors to CSI-2 output

Petros Kavvathas
Prodigy 110 points
Part Number: DS90UB960-Q1


Hello,

I am working on a project and planning to use multiple cameras (https://e2e.ti.com/support/processors/f/791/t/779975). The main issue here is that the SoC on the market don't support a lot of inputs so a bridge is needed to combine the feeds. The SoC that I will most likely use has two CSI-2 4 Lanes input.

I just took a look at sensors from Sony (for example the IMX392), and the output is LVDS 8 channels. I can't find the actual outputs of the chip besides that both the 265 and 392 use sub-LVDS serial output (https://www.sony-semicon.co.jp/products_en/IS/sensor0/industry/products/industry.html)

I am planning to use 3 sensors and it's not clear to me if I can attach these sensors to a bridge like the UB960.

From the UB960 datasheet I see in 7.2 Functional Block Diagram (page 24) that each input is just one differential pair.

The questions I have now are:
Is FPD-Link III the same as LVDS or a variation on LVDS?
Since the output of one sensor has 8 channels, does that mean the output has 8 differential pairs?
- If yes, do I have to serialize that (if possible) to make it possible to feed it into the UB960?
- If no, what does a channel mean and how should I bridge the sensors?


If this all isn't an option, how do I deal with these sensors?

  • 0
    TI__Genius 12866 points
    The FPD-Link III interface is not compatible with sub-LVDS.
    To work with UB960, an FPD-Link III serializer need to be selected.

    We don't have any serializers that takes in sub-LVDS output from a imager.

    UB953/UB935 could take MIPI CSI-2 input and connect to UB960
    UB913/UB933 could take parallel input.

    Best Regards,
    Charley Cai
  • 0 in reply to Charley Cai
    Prodigy 110 points
    Thanks for the swift answer, I see that Lattice has a chip to convert from Sony's sub LVDS to CSI-2, so that could be used.

    I have two remaining questions:
    Is there a bridge to connect multiple CSI-2 inputs together or would I have to convert it first to the FPD-Link III and feed it into the UB960?

    For an alternative setup I could use cheaper rolling shutter sensors and those do support SLVS and Parallel, although I do see a problem. The UB933 supports 1MP at 60fps or 2MP at 30fps (and judging from the specs of the UB913, that one seems even less capable at 12 Bit). The sensors I plan on using are 1080p60 (which is roughly 2MP).
    Is there a chip that could convert the parallel or SLVS to FPD-Link III for these type of sensors?
  • 0 in reply to Petros Kavvathas
    TI__Genius 12866 points
    1. Yes, you could convert sub LVDS to CSI-2, then connect the output to a FPD-LINK III CSI-2 serializer, and feed it to UB960.

    2. Currently, we do not have any Serializer that could connect to multiple CSI-2 sensors. Each sensor would need it's own serializer and then connect to a deserializer hub (UB960).

    3. We don't have a parallel serializer that supports 1080p60fps.

    Best Regards,
    Charley Cai
  • 0 in reply to Charley Cai
    Prodigy 110 points
    Okay, I don't think that it's a good idea to use 3 chips just to convert and bridge the inputs since the Lattice Crosslink can do that.
    I don't see a different solution to that unfortunately.

    As for the second question, I did find a parallel serializer DS90UB953A that converts it to CSI-2, although the main issue is that there is no CSI-2 bridge chip available from TI
  • 0 in reply to Petros Kavvathas
    Prodigy 110 points
    I did find a partial solution to converting the sub-LVDS to something else, the TI SN65LVDS324 can convert it to parallel CMOS. Is this 1.8v parallel CMOS output something that the Toshiba TC358746AXBG can expect as an input?
  • 0 in reply to Petros Kavvathas
    TI__Genius 12866 points
    Reading the toshiba datasheet, it seems our SN65LVDS324 is compatible with the TC358746AXBG, but please also verify with Toshiba just to make sure.


    Best Regards,
    Charley Cai
  • 0 in reply to Charley Cai
    Prodigy 110 points
    It's not entirely what I am looking for. If it's the only answer, then it's the only solution with the use of TI products.