Guest Rudzz Posted February 8, 2012 Report Share Posted February 8, 2012 Hello everyone! I have been working on trying to create a nice audio interface wing for the Papilio one, and I thought I would share with you what I have come up with. I am using an AC '97 audio codec chip, namely the Cirrus Logic CS4202 (http://www.cirrus.com/en/products/cs4202.html). This chip has capabilities for 3 stereo and 2 mono line level inputs, and 2 mono mic inputs. It has stereo line out, headphone out (with amp), and mono out. 18-bit stereo A/D converter and 20 bit stereo D/A converter. More details can be found in the data sheet. I only utilize one line-in and one line-out in my first revision of the wing. I am unsure whether I should leave it like that, since it fits nicely in one wing slot, or expand it to utilize more inputs and outputs. The nice thing about the codec chip is that more inputs and outputs would not require any more i/o to the FPGA, but it would require a bigger wing for the audio jacks. I chose this chip because I have previously written the controller for an AC '97 codec in verilog, so I knew how to interface with it, and because of its capabilities. I currently only have a test project coded in verilog in Xilinx ISE, which brings the audio into the FPGA and outputs it without modification, using the AC '97 protocol. I would like to expand this to do some DSP, maybe an adaptive filter. There are a number of applications that this can be applied to. I am currently writing up a blog post detailing my circuit design, pcb design, soldering, and Verilog code to interface with it. When that is done I will follow up here with a link to the post. Any suggestions and comments are welcome! I would like to know also if anyone has any interests in using this design, so feedback is appreciated. Here is my dropbox gallery with a couple pics of my first smt prototype board: https://www.dropbox.com/gallery/2077246/1/AC97%20Wing?h=190c75 -John Ruddy Link to comment Share on other sites More sharing options...
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