The Digital Audio AES3 Pmod Compatible module is an interface to connect AES-3 / AES-EBU digital audio signals to an evalboard. It is designed to work with the Digilent Arty S-7, but because it is compatible with the Digilent PMod Interface Specification (6-Pin) and should also work with other boards.

The pin layout is as follows:

• 6: VCC (3,3V)
• 5: GND
• 4: not used
• 3: Output of a 24,576MHz clock signal
• 2: Output of the AES3 signal: From the module to the evalboard
• 1: Input of the AES3 signal: From the evalboard to the module

On pin 3 is the output clock of an 24,576MHz oscillator. This clock can be used to generate samplefrequencies like 48kHz, 96kHz and 192kHz. The board is tested to work with 192kHz. The maximum deviation of the oscillator is less than 10PPM.

Pin 3 connects to a Global Clock Pin of the Spartan-7 of the Arty-Board. Also the clock frequency is high enough to be routed into the PLL of the Spartan-7 for further treatment.

The oscillator can be removed. There is a large (5 x 7mm) empty pad for your own oscillator.

On the output of the RS485-Transceiver and the oscillators are series resistances. On the input of the RS485-Transceiver is a not populated AC-Termination.

I have a testcode to generate two audio signals of 200 and 1000Hz on the left and right channel of the AES3 output. The switches of the Arty-7 choose between the three samplerates. This code is based on XAPP1014 from Xilinx, which is closed source, so I can not post the sourcecode. Message me if you are interested.