Audio Serial Interface Configurations for Audio Codecs.pdf

An audio serial interface (ASI) provides a means to transfer non-buffered audio data between processors and/or audio converters. These data are typically encoded in PCM twos complement format, although other format variations may be possible to achieve companding for lower data rate transfers. Audio converters based on the delta-sigma (ΔΣ) architecture require an internal master clock that operates at a much faster rate than the target sample rate. Although there are several means to obtain this master clock, care must be taken to ensure that this clock does not drift with respect to the ASI. This report discusses several configurations that prevent such situations.