ADV7482: HDCP issue when input source switching.

Hi,

  Please crosscheck your 'HDMI input register settings' with reference configuration at ":01-11 HDMI to MIPI TxA CSI 2-Lane - YUV422 8-Bit, Up to 600Mbps"

  Also some of the recommended writes are not matched according to the reference script. Please refer below writes.

  If those writes are not included, I would not expect the part to work reliably (unless those values are default anyway).Those registers are generally internal settings that let us handle process variation which is why they are determined during characterization.

 94 72 11;  ADI Required Write // 0x72 0x33
 94 4 0A;  ADI Required Write are not provided in case 2 script

Thanks,

Poornima

Hi Poornima-san

Thank you for your reply.

Our customer is trying to evaluate with your recommended register setting.

if they completed it, i'll inform you.

Then, I have a question for you.

I referred recommended script on below URL.

http://www.analog.com/media/en/engineering-tools/design-tools/ADV7481ES3C-VER.3.6c.txt

But I could not find your recommended setting. "94 4 0A"

And there is no description on Data sheet, UG-747, hardware design guide etc... regarding TXA Map 0x04.

Could you disclose explanation of this register (TX A Map 0x04)?

Thanks,

Nishimoto.

Hi Hirotaka San,

  Please find the below comments,

  I could not find your recommended setting. "94 4 0A" .

     Sorry that was a typo error, the register address was C4 not 04 ( 94 C4 0A).

 Could you disclose explanation of this register (TX A Map 0x04) ?

       Those writes are generally determined at characterization and We don't disclose the details.
       These writes are for internal engineering reasons. We generally do not share these with customers.

Note: "ADI Recommended/Required write" register sequence should be followed as like as script file.We regard these writes as non user adjustments and hence their function is not documented. Please refer here ADI Recommended Setting

Thanks,

Poornima

Hi Poornima-san,

Thank you for your reply.

Customer had tried input source switching with 94 72 11 and 94 C4 0A but not improved this issue. I think above recommended registers are just for MIPI TXA, this issue occurred in HDCP block.

Could you please answer the first questions again?

Q1: What should the customer do to resolve this problem?

Q2: Is this phenomenon (case 2) a specification for the ADV7482?

Thanks,

Nishimoto.

Hi Hirotaka San,

       Please let us know, How long are you waiting during the Case2 Scenario (i.e How fast are you doing the HPD)?

       Generally the HDCP re-authentication when switching from one source to another (topology changes).  long delay Of these the HDCP is usually the slowest one to happen.

Also please note BCAPS register must be initialized appropriately if these features(HDCP 1.1_features, fast reauthentication, and fast_i2c speed ) are to be supported by the application that integrating the ADV748x.

Ensure with BCAPS[4] bit as "400KHz transfers are not permitted to any device unless all devices on the I2C bus are capable of 400KHz transfer"

Please refer below image about BCAPS register bit details,

Thanks,

Poornima

Hi Poornima-san,

>Please let us know, How long are you waiting during the Case2 Scenario (i.e How fast are you doing the HPD)?

As I mentioned my first message, customer doesn't do HPD when switch back to HDCP source from CVBS because they have to minimize mute period when input source switching.

In such case, once choose HDCP source, then switch to CVBS source and switch back to HDCP source, ADV7482 requires HDP again?

>Generally the HDCP re-authentication when switching from one source to another (topology changes).  long delay Of these the HDCP is usually the slowest one to happen.

Sorry, I could not understand. 

Let me clear ADV7482 design limitation during switching from HDCP source to CVBS source and switch back to HDMI/HDCP source, ADV7482 requires HDMI re-authentication and re-HPD from first part of authentication?

Thanks,

Nishimoto.

Hi Hirotaka San,

In such case, once choose HDCP source, then switch to CVBS source and switch back to HDCP source, ADV7482 requires HDP again ?

    Actually HPD is not required when switching the source between CVBS and HDCP but here we don't observe such issues in our eval board even when we increase the switching delay.

Thanks,

Poornima   

Hi Poornima-san,

Thank you for your comment.
How about below my question?

>Let me clear ADV7482 design limitation during switching from HDCP source to CVBS source and switch back to HDMI/HDCP source, ADV7482 requires HDMI re-authentication and re-HPD from first part of authentication.

Hi Hirotaka San,

       As stated earlier, Re-HPD/Reauthentication is not required when switching between HDCP and CVBS Source.

Thanks,

Poornima

Hi Hirotaka San,

       Please find our below connection setup in our eval board while switching between HDMI and CVBS source,

          "QD 804B(HDCP / CVBS)" --> EVAL ADV7482 --> VA1838 Analyzer.

Also Kindly note, In our software we are "Reauthenticating the HDCP" While switching between HDMI and CVBS Source and this we have confirmed by from our debug log (Debug Print "HDCP RESET" ).

Thanks,

Poornima