The ADAU1777 is a codec with four inputs and two outputs that incorporates a digital processing engine to perform filtering, level control, signal level monitoring, and mixing. The path from the analog input to the DSP core to the analog output is optimized for low latency and is ideal for noise canceling headsets. With the addition of just a few passive components, a crystal, and an EEPROM for booting, the ADAU1777 provides a complete headset solution. 

Note that throughout this data sheet, multifunction pins, such as SCL/SCLK, are referred to either by the entire pin name or by a single function of the pin, for example, SCLK, when only that function is relevant.