I want to connect two codecs chips like AD 1938 to an ADAU 1452 dsp. Is it possible if so how?
Yes, you can connect two of the 1938 codecs to one ADAU1452 DSP. Have a look at the user guide for the 1452 evaluation board. The Eval board uses a 1938 and you will see that it only uses two of the four serial ports. If your application does not have a need to communicate with any other devices using I2S then you can just simply copy the way the 1938 is interfaced on the evaluation board and add the second one to the serial port 2 and 3. (They start with port 0).
If you do need to send I2S data to other devices then there are many different ways you could combine the two codecs. You can daisy chain the TDM lines to combine the four ADCs from each codec into one TDM8 data stream. Then for the DACs, you can run them in TDM16. There are lots of small details but the basic answer to your question is Yes, you can use two codecs.
Here is a link to the user guide with the evaluation board schematics.
Sorry for the late reply. The morning you answered was a national holiday so it took a while. I understand the inputs they are already there to use from the J2 and J3 connectors but what I don't understand is right now the codec on the eval board is working in self mode and all four outputs ( sdata_out 0 -4 ) are connected to it if I want to use two codecs and split the outputs for TDM mode do I have to reconfigure the codecs?
Yes, you will have to configure the codecs yourself. This codec only has a very basic mode for standalone operation and cannot do TDM modes without being programed by a system controller. The 1452 does have the ability to program external devices using the SPI master port but I do not have the details on exactly how to do that written up.
I do have an App Note that is almost ready to be published that details using a small microcontroller to boot up this family of codecs in TDM, or any other mode. I could share that with you if you want to go that direction.
Yes Dave that would most appreciated, thanks in advance.
Sorry to piggy-back onto this thread, but I would be interested to get your app note as well. Our next product will use an ADAU1452 plus two AD1938 and I would like info on how to configure them. (I did ask this in another thread that I started.)
Here is the link to the App note: http://www.analog.com/media/en/technical-documentation/application-notes/AN-1365.pdf
Since I wrote this note we have been working on expanding the cells in the library for controlling the master port. We have added cells that allow you to boot up other parts from the DSP using I2C. However, it does not work for SPI yet. It is on the list of things to update and I am not certain if it will be on the new upcoming release of SigmaStudio. I don't think it made in this release. So depending on your time schedule I would allow for this feature and I would design in the small "boot-up" processor I detailed in my App Note so you have the ability to use both methods.
I will go look for your other post and repeat this reply...
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