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Inserting VBI data using the DM649 PSP

Eddie3909
Guru 10385 points


Hi

I would like to insert data into the vertical blanking interval (VBI) but I have noticed that the frame descriptor does not have a pointer for VBI data. I reviewed the BIOS VPORT Driver users guide and couldn't find any info on how to do this.

I'm guessing that VBI isn't supported.[:(] Could you give me some ideas[*I] on how to implement it?


Thx

  • 0
    TI__Mastermind 41665 points

    Eddie said:
    I'm guessing that VBI isn't supported.Sad Could you give me some ideasIdea on how to implement it?

    I don't believe VBI is implemented in our software for DM648, but it should be possible. The only real suggestion for implementing it is given in section 4.5 of SPRUEM1, which discusses how the hardware would have to be configured to do this. Essentially you end up shifting the frame you are displaying beyond the sync event so that the DM648 is pumping out more data than the actual frame, the driver would have to be adjusted to deal with this larger frame and video port configuration and your software would have to deal with filling in the VBI data to each frame.

  • 0 in reply to Bernie Thompson TI
    Guru 10385 points

    Hi Bernie

    Thanks for pointing me to that section. Could you tell me what is meant by

    (Sec 4.5.2) ....."Note that the VBI data must be YCbCr separated."........

    Does it mean that the VBI "Y" data is tacked on to the end of the Y array, VBI Cb data tacked onto the end of Cb, etc. Assuming planar format.

    Cheers

  • 0 in reply to Eddie3909
    TI__Mastermind 41665 points

    Eddie said:
    Does it mean that the VBI "Y" data is tacked on to the end of the Y array, VBI Cb data tacked onto the end of Cb, etc. Assuming planar format.

    You could think of it as being tacked on to the end or the beginning, it depends on how you slide your frame, but generally it would be at the beginning and you would slide your frame upwards for vertical blanking data.

    As to the YCbCr seperation I think you have the right understanding, the planar format means that if you want contiguous data on the output you need to have your data divided up so it is sorted into the Y and Cb and Cr buffers. Since the output data is formed from the 4:2:2 CbYCrYCbYCrY... sequence your data needs to be put into the planar display buffers taking this into account, for example if you want your output VBI data to be 'ABCDEFGHIJK...' than your Y buffer should have 'BDFHJ...' your Cb buffer should have 'AEI...' and your Cr buffer should have 'CGK...'.

  • 0 in reply to Bernie Thompson TI
    Guru 10385 points

    Thanks a bunch Bernie[B*]