• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 32 subscribers
  • Views 1159 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

DS90UB934-Q1: DS90UB953-Q1 / DS90UB934-Q1 Backwards Compatibility Mode - HSYNC / VSYNC

DS90UB934-Q1: Data output values outside active video when using CSI-2 serializer

Daniel Doonan
Prodigy 20 points
Part Number: DS90UB934-Q1
Other Parts Discussed in Thread: DS90UB935-Q1

I am using a CSI-2 image sensor, DS90UB935-Q1 serializer, DS90UB934-Q1 deserializer, and DVP input image processor.  The data is RAW10 with DVP backwards compatible mode.

I will include a timing diagram showing the active video as well as inactive and blanking periods.

According to the previous related thread:  The DVP HSYNC signal is generated based on "LP transitions" of CSI-2 input, which are part of the SOT/EOT in the CSI-2 timing diagram.  The DVP VSYNC signal is generated according to FS/FE.  The timing diagram is drawn on this basis.

What happens in periods B, C, G, H which are outside the active video but inside the HSYNC high time?  Are the PH/PF (packet header / packet footer) passed through to the deserializer output?

During blanking, will the data output have a fixed value (for example, all zeros) ?  Which periods on the timing diagram will be affected?

Also, can you confirm the HSYNC will stop running during frame blanking?

Your assistance is appreciated!

--

Daniel Doonan

  • 0
    TI__Guru** 103215 points

    Hello Daniel,

    Periods B, C, G, and H are not in the horizontal blanking. These are just the packet header and footer which is used for CSI-2 encoding. Packet header and footer are filtered out for DVP mode.

    During blanking RGB data is expected to be 0. This is basically all the time consumed by LPS states in the diagram above.

    During vertical blanking you may still have HSYNC pulses because you will still be getting long packet lines from the transmitter.

    Best Regards,

    Casey

  • 0 in reply to Casey McCrea
    Prodigy 20 points

    Hi Casey,

    That is a good point on HSYNC during vertical blanking and I will be alert for it - thank you.

    Since packet header and footer are filtered out for DVP mode, does this mean that the DVP data output is 0 during these times?  More generally, is there any output data which is "not active video" and "not 0" ?

    It will be easier to determine the location of the active video if everything else is 0.

    --

    Daniel

  • 0 in reply to Daniel Doonan
    TI__Guru** 103215 points

    Hello Daniel,

    The time during the packet header/footer is extremely small so I wouldn't get hung up on this portion. It is completely filtered out 

    If we are discussing generalities then it is possible for there to be non-zero data during the vertical blanking internal if the CSI-2 transmitter is sending packets still. This should depend on the sensor behavior. During the horizontal blanking I do not expect there to be any non-0 data 

    Best Regards,

    Casey