Th working project is attached. what you have to take in to account when using this audio codecs with Digilent products is that you need to configure the codec (using I2C) as well as receive the samples using I2S IP core. Basically one is for the control of the codec and the other one is to receive the samples. I have written a small driver for both the I2S core and the I2C SSM2603 which is in the source files of the SDK project (in the sdk folder) which configures the registers for the codec and I2S IP core; the documentation for the codec can be found here. The IP core has not yet been documented which is the main reason we have not added it to the Digilent vivado-ip library, but it needs a 100MHz input for it to be able to synthesize the 12.228 MHz MCLK and the subsequent clocks for the I2S protocol.
The demo project reads the buttons and based on the ones you press it will:
BTN0 - Record 1s
BTN1 - Set Mic input
BTN2 - Set Line In input
BTN3 - Playback 1s
The project is not really optimized so it uses a variable "RecSamples", allocated to the stack memory which holds the recorded samples(48000 samples representing 1s at a 48KHz sampling rate) and it is also used fro play back, so don't press play back before record. The rest should be easily traceable from the comments in the driver and the main source code.
If you have any other questions feel fr to ask.