I am planning to purchase the EVAL-ADAU1966 for a project, but there are some issues I would like to be clarified.
The 12 channel audio input (192KBps 16bit) need approx. 4.5 MB/s bandwidth. How the evaluation board can input the regarded multichannel data by SPDIF through Optical and Coax In cables? because the industry standard S/PDIF can carry compressed 7.1 surround (such as DTS audio codec) in their maximum bandwidth, but the evaluation board seems to be able to input 16 channel by ADAU1966.
And if the above is possible, can the optical output in modern pc motherboards be able to transfer 12/16 multi channel audio input to the evaluation board or what is the appreciated source to make the SPDIF data in it for 12 channel audio.
The SPDIF receiver on the evaluation board is only a stereo devices with no ability to decode and encoded multichannel audio. It only is able to decode standard stereo audio transmitted on the SPDIF receiver. The receiver on this board we do not build. I think it can go up to 96kHZ but I am not certain about 192kHz. The DAC is capable of 192kHz but I would have to check the datasheet for the SPDIF receiver.
The receiver output is in I2S format that is buffered and sent to all the I2S inputs of the DAC so that the same signal will appear on all output pairs of the DAC. This is simply for testing and evaluation. To use this board for multichannel audio you would have to connect several I2S signals or some TDM signals into this evaluation board and change the configuration to accept these signals instead of the SPDIF receiver. This is the intention of the design to have a quick way to listen to the DACs via SPDIF and then more detailed evaluation by connecting it to a DSP board or some other source.
You would need some other SPDIF decoder that can decode the multi-channel audio and then send it to the DAC using TDM or multiple I2S lines. This is the way a product would use these DACs.