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ADV7625 - Audio In - 8 Channels on I2S in BPM Encoding

Question asked by BrianP on May 19, 2014
Latest reply on Jul 10, 2014 by mattp

Hi,

I would like to support sending audio  into the 7625 on the 4 I2S lines (along with the clocks) as BPM (bi-phase mark, essentially SPDIF) formatted audio data. In this question I am referencing section 5.3 of the Hardware Manual (rev PrB) for the audio input configuration options.

 

Looking at Table 9, it shows in the I2S/SPDIF Interface column that APx_IN1 through APx_IN4 can be configured for I2S or SPDIF.

 

Looking at Table 11, the summary of audio input formats, we see that in the Encoding column there are basically two encoding schemes supported, Normal and BPM. I equate Normal to I2S and SPDIF to BPM based on this table and the terminology used. Limiting this to sending Packet Type of Audio Sample Packet (not HBR), I do not see a combination of register settings that supports BPM on 4 audio input pins. I only see support for BPM on a single audio input AUD_IN[0] (5th row of the table) and everything above that row that supports multi-channel audio is limited to Normal encoding.

 

So Table 9 and Table 11 seem to be inconsistent with each other. What I need is basically the first row of the table 11, that supports multi-channel PCM on the I2S lines to be able to support BPM encoding. Is this possible with some combination of register settings that are not documented in this table?

 

Thanks,

Brian P.

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