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:
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 '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.