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ADV7511: we set HDMI mode (in 0xAF[1]), 0xC6[4] confirms HDMI mode, but no InfoFrames, not even SPD

Question asked by dszimmerman on Mar 7, 2014
Latest reply on Mar 10, 2014 by GuenterL

We have the ADV7511 connected to an FPGA on a working PCB -- we are outputting video successfully at 1920x1080p at 60Hz.


When trying to bring up audio (with use I2S, 16-bit samples, PCM only, frequencies in HDMI spec of 32KHz thru 192KHz), we notice on a Quantum 882-EA Analyzer that there are NO InfoFrames (sent in vertical blanking interval) of any kind - not even SPD (Specific Product Data), and the Analyzer believes the ADV7511 is NOT in HDMI mode.

As per "ADV7511 Hardware Users Guild" (Rev. D, pg  44/58, Sec 6.5.1 "DE, Hsync and Vsync Generation", we are controlling HSYNC, VSYNC, and DE (we don't use "embedded sync" or allow ADV7511 to generate any signals).


Of course we have verified our Quick Start Guide (main) I2C register settings (Programming Guide, Rev. G. pg 18), and have set monitor to HDMI with register 0xAF[1], and verified by reading 0xC6[4]:

4.2.2 HDMI DVI Selection

The HDMI Transmitter supports both HDMI and DVI modes. HDMI or DVI mode is selected by 0xAF[1]. In DVI mode no

packets will be sent, and all registers relating to packets and InfoFrames will be disregarded. DVI only supports the RGB color

space, so, if the input is not RGB, it is important to remember to set the color space conversion to output RGB when DVI is

enabled. See ▶ 0 for details about the Color Space Converter. The current mode of HDMI or DVI can be confirmed by the

read only (RO) bit 0xC6[4].


Other threads here suggest that the sink (monitor/analyzer) will say the source is DVI mode if it finds no InfoFrames.  So the question is, what could we do to suppress transmission of ALL info frames?  The only clue of a "master switch" turning all these InfoPackets and audio samples off is this statement:

In DVI mode no packets will be sent, and all registers relating to packets and InfoFrames will be disregarded.



We have these particular questions:


1. It appears most of the InfoFrames (e.g. Aux. Video Info, Audio Info) are enable by default with auto checksum generated.  With DEFAULT settings, shouldn't these InfoFrames be transmitted, even if they had errors?  We use default checksum generation.  We only use 24-bit RGB video data which works - as we understand it, HDMI spec requires monitors to accept 24-bit RGB with no AVI info frame.


2. The SPD InfoFrame appears to have nothing critical to operation of monitor -- we enabled the SPD InfoFrame (which is disabled by default) and again NO InfoFrames.  Shouldn't it be possible to send the SPD frame even if other frames were disabled, or incorrect?


3. Does the ADV7511 suppress transmission of all InfoFrames if any are invalid?  Does it not send any InfoFrames if valid Audio (e.g., on I2S lines) is present?  We cannot fathom what we could do to suppress sending of ALL InfoFrames.

4. Are we suppressing audio samples (in horizontal blanking data islands), and
InfoFrames (in vertical blanking periods), by controlling all of the ADV7511
timing as described above?

Many thanks,


Austin, TX

ATTACHMENT:  example of our Quantum 882-EA Analyzer output on working InfoFrames, and the ADV7511 case.