Circuits and methods to reduce pin count of a single channel device with a multi-channel serial interface

摘要

A channel selection circuit in a serial audio communication device provides channel selection for insertion or extraction of data to or from a multiplexed serial data stream without the requirement of extra channel selection inputs. The channel selection circuit has multiple counters structured such that each counter represents a channel of the serial data stream. The input of each counter receives one of the multiple synchronizing timing signals. The input of the designated counter receives one timing signal that has the greatest frequency. The remaining counters receive the word select timing signals for determining which channel is being selected. A ready output of each counter is a channel indicator in communication with multiple signal selection circuits for selecting the multiple timing signals to be transferred to a data processing device for inserting or extracting data to or from the multiplexed serial data stream.