DS90UB949-Q1: APB interface to interact with HDMI

Hi Renan,

No, typically APB registers are not shared as no access to APB registers are needed for normal device operation.

Best Regards,

Charley Cai

Hi Charley,

The issue I have encountered is for my application using the DS90UB949 I need to provide some sort of notification that the monitor is still active, even if no valid video source is attached.  I am using the Test Pattern Generator to achieve this.  When no video is attached the Pattern Generator is enabled and the user knows that the monitor is still functioning, but does not have a valid video input. Then once a valid input is applied the pattern generator turns off and normal operation resumes.  In order to verify that a supported resolution is being applied, I am using the HDMI_FREQ register at address 0x5F and confirming that the value matches the supported video input frequency.

The problem is when I turn on the pattern generator, the HDMI_FREQ register begins to report the internal oscillator's frequency instead so I can never determine if a valid video has been applied.

I found in the Analog Launchpad software that messages were being sent to the HDMI APB to get the input resolution values.  I was able to use an I2C packet sniffer to find out the commands and registers being read to get the information and using them have been able to determine that a valid resolution has been applied, even when the pattern generator is enabled.  I went on to do a register dump of the APB to see if there were any more critical values being reported that I could use for this function, but going through all of the data has been very tedious and it is very possible I will miss something. 

With information on the registers and their functions I could determine if I can use any other information that is reported there and also confirm that I am using the current registers I found properly.

Thanks,
Adam

Hi Adam,

Thanks for the clarification. I have sent you a private message to follow up.

Best Regards,

Charley Cai

Hi Charley,

I don't believe I have received the private message.  I'm not seeing it in my inbox.

Thanks,

Adam