I am trying to input AC-3 audio through optical SPDIF. When I input digital stereo it is normal to play back but when I input AC-3 it doesn't decode. I see in Hardware Configuration there is a decoder. How do I turn it on?
Unfortunately, it does not decode AC-3.
Thanks, So what decoder I should buy or extra connection I can make it do it? I think the Sigma studio gives the option of this input there should be a way to do it that is intended.
As Dave mentioned, none of the SigmaDSP family are capable of doing AC-3 decoding. The S/PDIF receiver on the ADAU1452 reads the subcode of the stream and extracts the channel status, user data, validity and parity bits. In the consumer format, one of the standard flags specifies whether the data is "audio" or "non-audio." If the subcode indicates that it is non-audio, it then reads the bits that specify which non-audio format. That is why you see a reference to AC-3 in SigmaStudio.
This feature is included so that, if the incoming stream is non-audio, the SigmaDSP can pass the S/PDIF from input to output unchanged, and pass the data to en external processor to decode the compressed audio. The SigmaDSP can only process the data if it is PCM audio. This flag enables the SigmaDSP to detect and stop non-audio from being sent to a DAC as samples, which would be full scale noise.
There are a number of options available for decoding AC-3 including libraries for our SHARC and Blackfin families of DSPs. You will need to work with Dolby for licensing and approval for any decoder that you choose.
Thanks for the details reply. If you can kindly helping me with a bit more fundamental questions. I am building a consumer product that need to allow user to taking multi channel digital input and processing the signal. Ideally USB or ADAT, I only need I/O 8 channels max.
Can you kindly advice how I would to use TDM serial ports, how do i connect it to a USB to TDM convertor ? I find few USB to converter but I can't understand the physical connection parts. for example https://www.minidsp.com/products/usb-audio-interface/usbstreamer
Where and how do I take TDM from that and connect to ADAU 1452? Thanks.
Also I am nearly finished my design. Does your company help to make this a blank write only IC board with only ports I needed? I can program after use sigmastudio?
Thanks for your kind help. I know there are a lot questions probably very basic. Forgive me on lacking fundamental knowledge.
Have a nice day
Hi I am wondering if anyone from this company can help?? Or is there a number I can call to get help. I am need this I/O problem solved ASAP.
Yes, your questions are difficult to answer because I do not know where to start. The DSP takes in I2S or TDM and that is what it is setup for. You set that up with the serial port registers. The USB part of your question is a HUGE question and not an easy answer. You need something to be a USB host and this is even a bigger more complicated topic than using the SigmaDSP. The Blackfin has this capability but you would be even at a greater disadvantage trying to develop the application on a Blackfin yourself. We do not make "blank" PC boards, you would have to make your own PCB layout. That is yet another deep subject with lots to learn about.
So I respectably suggest you hire a design firm/person to do this design for you. I am not certain who would be the person to suggest, someone local to you in Australia might be a good start but someone on this forum might want to help you.
You could also look into using the Arduino. There is an active community of support for those boards and it can be interfaced with a SigmaDSP if needed. They have USB and Ethernet and Bluetooth etc. They use Linux to program them so there is a learning curve with that as well.
Thanks for be patient with me. I did more search and find some possible solutions for myself. It left me to small questions. Hope these are not too big as well. I couldn't find those or missed from manual.
what is the logic voltage on TDM input J2, J3 , 3.3V?
Which one is the TDM Master clock input MCLK? If I take clock from another board, I am guessing LRCLK but seems thats for I2S?
And the routing inside the sigmaDSP software?
The logic voltage is determined by IOVDD, which is 3.3V on the evaluation board.
The evaluation board is designed to be an inexpensive means to test code, and it is only capable of being an MCLK slave without major modifications. The schematics are in the User Guide: www.analog.com/ADAU1452
Please read about the serial input ports and TDM modes in data sheet. These signals on J2 and J3 are explained far in more detail than we can give here.
For anyone else reading this post, the questions were answered more fully on this thread:
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