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[ADV7613] Can ADV7613 output 480p or VGA via Dual-LVDS output?

Category: Datasheet/Specs
Product Number: ADV7613

Hi,

I have a question about ADV7613.

Question:
Can ADV7613 output 480p(720x480p) or VGA(640x480) via Dual-LVDS output?

There is a comment on the following thread:
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ez.analog.com/.../20746
using the dual output LVDS output transmitter the LVDS clock rate will be 1/2 that of input HDMI clock rate? For example:

Input: 148.5MHz HDMI 1080p ==> Output: 74.25MHz Dual LVDS
Input: 74.25MHz HDMI 720p ==> Output: 37.125MHz Dual LVDS
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I think these are possible for ADV7613.

But I don't know whether ADV7613 can be handle followings or not:
Input: 27MHz HDMI 480p ==> Output: 13.5MHz Dual LVDS
Input: 25MHz HDMI VGA ==> Output: 12.5MHz Dual LVDS

The datasheet says OpenLDI Output Clock Range is Min 25MHz - Max 92MHz.


When the input is 480p or VGA, can't we use "Dual LVDS" output because the output clock rate is less than 25MHz?

However, the script file "ADV7613-VER.1.1c.txt" inculdes following setting:
  ##01 Full Scripts - HDMI Input_LVDS Output script TMDS CLK Less Than or Equal to 27MHz##
  :01-03 HDMI Input_LVDS Output Port A and B:

HDMI input 480p and VGA meet "TMDS CLK is less than or equal to 27MHz".
So when we use the script ":01-03 HDMI Input_LVDS Output Port A and B:", can we use "Dual LVDS" output for 480p or VGA?
But in this case, I think that the datasheet spec "OpenLDI Output Clock Range, Min 25MHz" can not be kept.

Can ADV7613 output 480p(720x480p) or VGA(640x480) via Dual-LVDS output port?

Thank you!
Best regards.
Tamu

  • Hi Tamu San,

            Apologies for the delayed response, I was on leave. 

    Please find the below comments,

    Can ADV7613 output 480p(720x480p) or VGA(640x480) via Dual-LVDS output port ?

       As per specification, ADV7613 OpenLDI output clock range is between 25-92 MHZ, So we can support only within this range of resolution support.

       To achieve this, I beleive We can twice the pixel at source side (Set your HDMI source to output twice the pixels - Pixel Repeat Mode ).

       To carry Pixel repeat on the HDMI input - this increases the TMDS clock to 148.5 MHz, thus giving rise to LVDS output clock of 74.25 MHz.

      For example, If the input TMDS clock is at 54MHz. When dual LVDS transmitter enabled, the LVDS output clock to drive the identical panels will be running at half the input clock rate (27 MHz).

         HDMI Pixel repeated input for example: 0011223344......

            LVDS transmitter 1: 01234

            LVDS transmitter 2: 01234

    Thanks,

    Poornima

  • Hi Poornima-san,

    Thank you for your reply.

    >To achieve this, I beleive We can twice the pixel at source side (Set your HDMI source to output twice the pixels - Pixel Repeat Mode ).
    => I think this means that the changing to twice the pixel on HDMI source side is required.
    If this is not possible, Can't ADV7613 output 480p or VGA via Dual-LVDS output port?

    This time, not just one HDMI source device will be connected to the customer's HDMI sink system.
    There is a possibility that all of HDMI source can be connected to the customer's system.
    Of course, it includes HDMI source which can not support Pixel Repeat Mode.
    And HDMI 1.4 specification requires 480p and VGA support for HDMI sink.
    Please refer "6.2.1 Format Support Requirements" on HDMI 1.4 specification.
    The requirement for the 480p and VGA support of HDMI specification 1.4 does not include Pixel Repeat Mode.

    Again, my question is as follows:
    If HDMI source outputs normal 480p or VGA (it's not Pixel Repeat Mode), Can't ADV7613 output the 480p or VGA via Dual-LVDS output port?
    In this case, do we have to use Single-LVDS output port of ADV7613 for outputting the 480p or VGA which is not Pixel Repeat Mode?
    In other words, does the customer have to use Single-LVDS output port of ADV7613 for outputting the 480p or VGA in order to pass HDMI sink Compliance Test Specification?

    Thank you!
    Best regards.
    Tamu

  • Hi Tamu San,

    Please find the below comments,

    HDMI 1.4 specification requires 480p and VGA support for HDMI sink.
    Please refer "6.2.1 Format Support Requirements" on HDMI 1.4 specification.
    The requirement for the 480p and VGA support of HDMI specification 1.4 does not include Pixel Repeat Mode.

            YES, As per HDMI 1.4 specification "480P & VGA " doesn't require Pixel repeat mode because the Video formats with TMDS rates below 25 Mpixels/s require pixel repetition in order to be transmitted over the TMDS link. 

    >To achieve this, I beleive We can twice the pixel at source side (Set your HDMI source to output twice the pixels - Pixel Repeat Mode ).
    => I think this means that the changing to twice the pixel on HDMI source side is required.
    If this is not possible, Can't ADV7613 output 480p or VGA via Dual-LVDS output port ?

          No, Its not possible with single or dual LVDS port Since OpenLDI output clock range is between 25-92MHZ, So it can support only within this range of resolution support.

    Please refer this thread, Here expert given suggestion regarding minimum clock range at How to use ADV7613 to drive two identical LVDS display panels - Q&A - Video - EngineerZone (analog.com)

    Thanks,

    Poornima

  • Hi Poornima-san,

    Thank you for your reply.
    Sorry for many times.

    >>>To achieve this, I beleive We can twice the pixel at source side (Set your HDMI source to output twice the pixels - Pixel Repeat Mode ).
    >>=> I think this means that the changing to twice the pixel on HDMI source side is required.
    >>If this is not possible, Can't ADV7613 output 480p or VGA via Dual-LVDS output port ?
    >No, Its not possible with single or dual LVDS port Since OpenLDI output clock range is between 25-92MHZ, So it can support only within this range of resolution support.

    I think it's possible for outputting 480p or VGA with single LVDS port since the OpenLDI output clock range is between 25-92MHz.
    So I think as follows:
    - ADV7613 can output 480p or VGA via single-LVDS output port because the OpenLDI output clock is within between 25-92MHz.
    - But ADV7613 can not output 480p or VGA via Dual-LVDS output port because the OpenLDI output clock is less than 25MHz.
    Are these my understanding right?

    Also, I don't mention case that ADV7613 drives two identical LVDS display panels.
    I mention that ADV7613 drives one video image to only one LVDS display panel.

    Thank you!
    Best regards.
    Tamu

  • Hi Tamu San,

           Sorry that was a typo error.

           YES you are right, In Single mode LVDs the input pixel rate is equal to the HDMI pixel So we can support 480p or VGA via single-LVDS output port.

    Note:  Single mode LVDs, the input pixel rate is equal to the HDMI pixel.
                Dual mode LVDs, the pixel rate is half of the single or the HDMI pixel. 

    Thanks,

    Poornima

  • Hi Poornima-san,

    Thank you for your reply.

    - ADV7613 can output 480p or VGA via single-LVDS output port because the OpenLDI output clock is within between 25-92MHz.
    - But ADV7613 can not output 480p or VGA via Dual-LVDS output port because the OpenLDI output clock is less than 25MHz.
    I could understand these are right.

    I think this is the last question.

    However, the script file "ADV7613-VER.1.1c.txt" inculdes following setting:
    ##01 Full Scripts - HDMI Input_LVDS Output script TMDS CLK Less Than or Equal to 27MHz##
    :01-03 HDMI Input_LVDS Output Port A and B:

    ADV7613 can not output 480p or VGA via Dual-LVDS output port because the OpenLDI output clock is less than 25MHz.
    So I think that we can not use the script ":01-03 HDMI Input_LVDS Output Port A and B:".
    What condition / situation can we use this script?

    Thank you!
    Best regards.
    Tamu

  • Hi Tamu San,

            Please find the below comments,

    ADV7613 can not output 480p or VGA via Dual-LVDS output port because the OpenLDI output clock is less than 25MHz.
    So I think that we can not use the script ":01-03 HDMI Input_LVDS Output Port A and B:".
    What condition / situation can we use this script ?

      As per specification the OpenLDI output clock range is between '25-92MHZ' So there might be an mistake with the script but this need to be confirm with part specialist.

      Meanwhile could you please enable such configuration ":01-03 HDMI Input_LVDS Output Port A and B:" and check whether we can able to output 25MHZ in dual LVDS port.

    Thanks,

    Poornima

  • Hi Poornima-san,

    Thank you for your reply.

    >As per specification the OpenLDI output clock range is between '25-92MHZ' So there might be an mistake with the script but this need to be confirm with part specialist.
    => Thank you. When you get the feedback from the part specialist, please let me know it.

    Thank you!
    Best regards.
    Tamu

  • Hi Tamu San,

         Your question has been forwarded to Part Specialist.

    Thanks,

    Poornima