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can davinci vpbe output to lcd and pal mode tv simultaneously?

feng15773
Prodigy 210 points

Hi, All

    Can davinci vpbe output to lcd and pal mode tv simultaneously? 

    In the vpbe user guide section 4.4.1.1:  "In this mode, the timing generator operates in the standard format. The support formats are 525/60 Hz  (NTSC-M) or 625/50 Hz (PAL-B/D/G/H/I) for SDTV and 525p or 625p for HDTV. The digital output from the LCD interface is also available simultaneously. Note, however, this is limited to LCDs, DACs, and encoders that support NTSC/PAL timing and the output will mirror the analog output display."   I'm confused about this clause.

   what's the exact meaning of "mirror the analog output display" ? does it mean some LCD PIN's output the same  cvbs signal as DAC? if it's true, then  which LCD PINS does the signal output to ?

   thanks.

  • 0
    TI__Mastermind 37340 points

    with regards to DM6446 (let us know if you are using a different platform), this means there is a single video timing generator that feeds both analog and digital video outputs.  This means that whatever resolution and refresh rate is defined for one video output (say analog PAL) must also be used for the other (digital LCD output).  You cannot define PAL for analog output and say 720p on digital side due to single hardware timing generator.  Let me know if this helps clear things up.

  • 0 in reply to Juan Gonzales
    Prodigy 210 points

    hi,  gonzales

          Thanks for your explaintion. It's very helpful for me to understand the digital and analog simultaneously output.

          I use DM6441 ,  not DM6446. and if I enable  vpbe working at PAL_COMPOSITE mode, then what's the output of digital lcd pins? will venc output the hsync/vsync/vclk/YCbCr signal to the pins according YCC8/rec656 output mode?or will venc just output the composite cvbs signal to one lcd pins?

         thanks

  • 0 in reply to Juan Gonzales
    Intellectual 270 points

    Hi Juan,

    One more question over this one. If the time for DLCD if from other board, can I make these two port different resolution and simultaneously?

    FYI, I've build a VGA board over DLCD, the timing is from the VGA board, 1024x768 supported.

     

    Yours sincerely

    David Chan

    blacksword.david@gmail.com

  • 0 in reply to feng15773
    TI__Mastermind 37340 points

    feng said:

          I use DM6441 ,  not DM6446. and if I enable  vpbe working at PAL_COMPOSITE mode, then what's the output of digital lcd pins? will venc output the hsync/vsync/vclk/YCbCr signal to the pins according YCC8/rec656 output mode?or will venc just output the composite cvbs signal to one lcd pins?

    DM6441 and DM6446 work in the same way.  When you define the output mode to be standard BT.656 mode and properly enable both analog and digital video output interfaces, you should see analog cvs output via DAC and digital BT.656 output via pins described in rec656 interface in VPBE User Guide; please note that hsyc /vsync. information is embedded in data stream in rec656 mode.

  • 0 in reply to blacksworddavid
    TI__Mastermind 37340 points

    blacksworddavid said:

    Hi Juan,

    One more question over this one. If the time for DLCD if from other board, can I make these two port different resolution and simultaneously?

    FYI, I've build a VGA board over DLCD, the timing is from the VGA board, 1024x768 supported.

    David,

    I am not sure I get your question, are you suggesting about feeding the pixel clock from a different board (one DM644x part) or are you talking about using two different DaVinci parts, one via a board.  If you are suggesting teo davinci parts, one for analog video output and the other for digital, then certainly.  Otherwise, with one part, I do not believe this is possible.

  • 0 in reply to Juan Gonzales
    Intellectual 270 points

    Hi Juan,

          When we use davinci to display. We put davinci into ether master or slave mode.

    Master means davinci himself should generate the timing.

    Slave means davinci can use the timing generated by somebody else.

    As for DM6446 I have to use slave mode to support resolution more than 1024x768.

    What I want to do is use DLCD to support an LCD, and analog(YPbPr) for a projector.   Projector can just work as a clone to the LCD.

    I want know is this a right way?

    If it is, what's the key point to make both of the DLCD and Analog ports work?

     


    Thanks

    Yours Sincerely

    David.

     

  • 0 in reply to blacksworddavid
    TI__Mastermind 37340 points

    David,

    On the analog side, DM6446 has built-in DACs that support NTSC/PAL, but will not be able to support 1024x768; in addition, in order to enable both analog and digital output simultaneously they need to both be configure for the same size since they share a single timing generator.  That said, when you put these two limitations together, the result is that if you wish to enable both analog and digital video output interfaces at the same time, then you are limited to standard timing mode (BT.656 NTSC/PAL).  If you configure your DLCD output to support 1024x768, then you loose the analog output capabilities.