Specifications

Bluegiga Technologies Oy
Page 34 of 64
9 Audio Interfaces
9.1 Stereo Audio Codec Interface
Stereo audio CODEC operates from an internal 1.5V power supply. It uses fully differential architecture in
analog signal path for the best possible common mode noise rejection while effectively doubling the signal
amplitude.
The stereo audio bus standard I2S is supported and a software I2C interface can be implemented using
GPIOs to configure an external audio CODEC.
Figure 17: Stereo CODEC input and output stages
9.1.1 ADC
The ADC consists of two second-order sigma-delta converters and gain stages. The gain stage consists of
digital and analog gain stages which are controlled by iWRAP. The optimal combination of digital and analog
gain is automatically selected by iWRAP. The analog gain stage consist selectable 24 dB preamplifier for
selecting microphone or line input levels and an amplifier which can be configured in 3 dB steps. The iWRAP
gain selection values are shown in the Table 19.
Following sample rates are supported
 8kHz
 11.025kHz
 16kHz
 22.05kHz
 24kHz
 32kHz
 44.1kHz