PCM3168A: Controlling multiple parts in an audio mixer

Hi Glenn,
As far as using the PCM3168 goes, i assume we will need to make sure the clocks are synchronized for the system to work.

As far as the processor selection goes, I will need a bit more details on your overall system...maybe a block diagram may help to. I do not have a lot of background on processors for this type of application, but i can loop in some folks from the TI audio processor team for additional help if need.

I assume you would be feeding the 30 digital audio streams (from output of ADC??) for mixing etc. and route the same on one of the DAC inputs before feeding it to amp? Please do provide more details on the use case for the system and we can provide you more details. Thanks.

Best regards,
Ravi

Hi Ravi,

The system has approximately 30 audio inputs, and 20 audio outputs. At any given time each of the 20 outputs may be listening to a different mix of all 30 inputs, at different volume settings.

On the previous generation of the system we had an FPGA implement a crosspoint with a matrix of volume coefficients to MAC the incoming samples by for each output channel. Obviously we need to perform the 30x20 MAC each sample period to have all 20 output samples ready to go. The original mixer used twenty-two 48kHz. AC97 stereo codecs and the FPGA implemented the audio interface and control channel.

We're looking to replace the FPGA with an off-the-shelf processor, if such a thing exists. The processor would have to be able to handle all 5 PCM3168 to give us our 30 input channels and 20 output channels, be fast enough or have a DSP core to handle the 30x20 MAC each sample period, and have enough processing power to handle the business logic controlling which inputs are heard by which output.

It would be very nice if the processor had an SD card interface for loading configuration files and updating the business logic, and if it could host a basic web page (stored on the SD card) for online configuration that would be perfect.

In normal operation the system will be controlled either by a built-in front panel (channel select switches and volume pots), or by expansion panels connected over a UART, so we will have GPIO expanders for all the switches and ADCs to read the volume pots on either I2C or SPI bus (TBD). We are not planning on going to a touchscreen at this time.

I'll try and make a block diagram.

Regards,

Glenn

Hi Glenn,
This gives me lot more clarity and maybe there is no need for block diagram. Let me do some research on my end and also collaborate w processor team here to get you some answers.

Thanks for the details.

Best regards,
Ravi