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ADV7511 Audio Issue

Question asked by ChrisM Employee on Aug 21, 2013
Latest reply on Aug 21, 2013 by DaveD
We have designed-in the ADV7511 into a PCB for outputting HD video/audio to flat screens and projectors. Target market is quality-driven Electronic Cinema and high-quality advertisement applications. We are quite familiar with uncompressed audio/video data transfer and different protocols (HD-SDI, I2S, I2C, AES, ..) in electronic design.
We have made video out working with the ADV7511, but have problems getting audio out to work. The following is printed onto the ADV chip:
ADV7511
KSTZ-P
1219
236015.1
The audio input signal (actually coming from an FPGA) is a standard I2S signal. For now, we use only stereo only, but we want to extend it to 8 channels later, provided through 4x I2S lanes. For standard I2S, we use the following signals: I2S0, SCLK, LRCLK.
Sample rate (LRCLK frequency) is 48 kHz. 32 Bits of data are shifted per channel (between two LRCLK edges), of which only the 24 most significant bits are used (MSB first). We tried several register settings, but never could get audio out of a TV flat screen (also tried another HDMI monitor). The current setting is directly derived from the quick start guide of the programming guide and the presentation "HDMI-enabled Designs Using the ADV7511".
Through I2C read-modify-write cycles, we set the following registers/bits:

Register          Value      Comment

0x01[3:0]             0x0          N

0x02[7:0]             0x18        N

0x03[7:0]             0x00        N

0x0a[6:4]             '000'         I2S Input

0x0b[7]                '0'             SPDIF receiver: off

0x0c[5:2]             '0001'       Enable I2S0 input

0x0c[1:0]             '00'           Standard I2S

0x15[7:4]             0x2          48 kHz sampling frequency


Video mode is set to 24Bit/Pixel, 1920*1080*24p. We see a great video, but don't hear anything. Not even noise or the like ..
Is the chip we are using limited in functionality somehow? Any idea, what we're doing wrong (must be something very generic)?
Appreciate any feedback.

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