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HDMI to VGA

Category: Hardware
Product Number: AD7611 and AD7512

I am making a PCB board for HMDI upstream to VGA downstream converter. I found AD7611 and AD7512 can do the Job. I would like to know is there any HDMI Rx IC that has integrated DAC in it. ALso, if HDMI Rx converts the video stream into RGB, why do we still need DAC. Also, Do i need microcontroller to control the EDID for sink device (Display) or should i connect the VGA DDC signals directly to the SDA and SCL input of HDMI Rx?



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[edited by: GenevaCooper at 5:14 PM (GMT -4) on 27 Apr 2023]
  • Hi,

      "ADV8005/ADV8003" single part can support HDMI to VGA with DAC integrated into it and note that "ADV8003 features a high speed digital-to-analog video encoder. Six 12-bit NSV, 3.3 V video DACs provide support for worldwide composite (CVBS), S-Video (Y-C), and component (YPrPb / RGB) analog outputs in standard definition (SD), enhanced definition (ED), or high definition (HD) video formats.

        Please refer below snap about primary functionality of ADV8003 part,

    Please note that, Most of our receiver part can support "ADV7610,ADV7611,ADV7612, ADV7619 ,ADV7625,ADV7604" RGB in Pixel bus output but if you want to go with integrated DAC then you have to choose another Video encoder part(ADV7341/ADV739x) along with ADV7611.

    Should i connect the VGA DDC signals directly to the SDA and SCL input of HDMI Rx ?

              If So, the EDID data is read by the DDC master on initial VGA connection to determine what formats the sink can handle.

     Do i need microcontroller to control the EDID for sink device (Display) ?

              Yes, We need microcontroller to control the EDID of sink device and It can read the EDID data at any time it wants to.

              The microprocessor can programs the EDID memory the way we want. In this mode the EDID memory must be connected to the board's 5V supply and it's SCL and SDA pins connected to microprocessors I2C bus.

    Regarding AD7512 is now under Obsolete.

    Thanks,

    Poornima

  • Hey, thank you for your answer. Could you please tell me an chip that can convert HDMI to VGA without the need of microcontroller?

    As VGA display accepts only analog signals, I do believe we need a DAC or do you have any video receiver that converts the TMDS signal to RGB pixel  analog directly?

  • Hi,

      By using ADV8003 as an single chip solution we can convert HDMI to VGA without the need of microcontroller. If you want to achieve using two chip solution then you can use "ADV7611(Receiver) & ADV739x/ADV734x (Encoder- DAC).

      Instead, Microcontroller, But you should use Off-board I2C Master device like AVES Tool to configure the ADV part registers using I2C.

      Please note that, If it is Off-board I2C master device then you need to initialize the I2C of ADV7611 at every run manually by running the script via AVES tool. then only you will get the video output. This case will suit for your application if you are not using the microcontroller.
      If it is On-board I2C master device (i.e MicroController) then no need to initialize the ADV7611 every time, Here Micro-controller software will take care this after power on.
     

    As VGA display accepts only analog signals, I do believe we need a DAC or do you have any video receiver that converts the TMDS signal to RGB pixel analog directly ?

        ADV8003 is the only part that can convert TMDS to RGB analog directly but we none of our receiver part can do this.

    Thanks,

    Poornima

  • FormerMember
    0 FormerMember

So you want to do HDMI -> VGA.  Is this digital VGA as in RGB or analog VGA.  The ADV7611 can convert HDMI to digital the the ADV7512 converts digital to HDMI.  All these devices need a I2C controller to configure them.  Another point is that only the ADV80xx parts can do format conversion, for the other parts the output timing is the same as the input timing.  Maybe a quick diagram would better explain what you are looking for.

  • Hello, I have just been given a requirements to convert HDMI upstream to VGA downstream. VGA uses analog signals to transmit video signals and HDMI uses digital to transit the video and audio. Do you know if ADV80xx can do the job without need of controller.

  • Hi,

      Instead of Microcontroller, Are you using any other Master device for controlling the ADV80xx part?

      As Stated, without I2C Master device its not possible to configure the ADV80xx registers to achieve the video output.

    Thanks,

    Poornima

  • Hello, Even using ADV80xx chip, do I still need to configuring ADV80xx using any Master device?