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Information about input to TMS320DM365

Garfield Downes
Intellectual 330 points
Other Parts Discussed in Thread: TVP5158

I am a bit confused regarding multiple inputs to the DM365 DaVinci processor.

In the document SPRT516 that pitches the "DM365 Digital Video Recorder Reference Design: DM365DVR-UD1 @ U.S. $1,195"  a TVP5158 video decoder is shown taking 4 video channel inputs and interfacing to the DM365.

Of the 4 outputs, 2 can be used as cascaded inputs to be fed into a master device (from a slave).  The TVP5158 datasheet states:

 

TVP5158 provides a glueless audio and video interface to TI DaVinci™ video processors. Video output
ports support 8-bit ITU-R BT.656 and 16-bit 4:2:2 YUV with embedded synchronization. TVP5158
supports multiplexed pixel-interleaved and line-interleaved mode video outputs with metadata insertion.
TVP5158 and TVP5157 integrate 4-Ch audio ADCs to reduce the BOM cost for surveillance market.
Multiple TVP5158 devices can be cascade connected to support up to 8-Ch Video or 16-Ch audio
processing.

 

The DM365 datasheet does not mention anything about multiplexing inputs other than shared (multiplexed) pins and being able to accept 2 channels simultaneously.

In 8-bit mode, data lines YIN[7:0] and CIN[7:0] can be used for input. When using an 8-bit interface, the

CIN[7:0] inputs are typically used. However, either set of data inputs can be used or, alternately, two

separate imagers can be physically connected (but only one can be active at any given time, though).

 

Can someone please elaborate on this?  The information is spread across a few documents and is either very crpytic or not very helpful in explaining anything at all.

 

Thanks

  • 0
    TI__Mastermind 41665 points

    The TVP5158 allows for a single physical interface to carry multiple video channels through pixel or line interleaving, the idea being that you use a single 8 bit bus to put the video data from multiple sources on, this allows it to pipe multiple video sources into devices that are designed for taking in a single channel of video. For a diagram of what this looks like from a interleaved pixel perspective see figures 3-10 and 3-11 of the TVP5158 datasheet.

    The DM365 itself was not really designed to handle multiple video inputs, the VPFE video capture hardware is a single video channel design, however by using a device like the TVP5158 you can interleave multiple video streams into a single stream of data that looks like a single video stream to the DM365's VPFE port. This is why you see two sorts of explanations, the DM365 documentation assumes you are only using a single video channel, whereas the TVP5158 assumes you are using multiple video channels, but it can take those channels and interleave them on a single bus. This would mean that the DM365 captures a large frame containing multiple video streams within it which would be sorted out by software, which I suspect is something that is included with the DVR reference design, though I have not actually used one of these DVR boards yet myself.

  • 0 in reply to Bernie Thompson TI
    Prodigy 30 points

    Hi,

    I am having an application in which I have two video streams. One is analog composite video (From analog camera) and another is digital BT.656 (from an image processor). These two streams needs to be processed using DM365.

    I am planning to use TVP5158 for this. To use VIN_1 as one input and cascade input as second input. I am expecting the output stream to be a line interleaved one with the video data from the above two streams. Will this configuration work?