The Automotive Audio Bus (A2B®) provides a multichannel, I2S/TDM link over distances of up to 15 m between nodes. It embeds bidirectional synchronous pulse-code modulation (PCM) data (for example, digital audio), clock, and synchronization signals onto a single differential wire pair. A2B supports a direct point to point connection and allows multiple, daisy-chained nodes at different locations to contribute and/or consume time division multiplexed (TDM) channel content.
A2B is a single-master, multiple-slave system where the transceiver at the host controller is the master. The master generates clock, synchronization, and framing for all slave nodes. The master A2B transceiver is programmable over a control port (I2C) for configuration and read back. An extension of this control port is embedded in the A2B data stream, which grants direct access of registers and status information on slave transceivers as well as I2C to I2C communication over distance.
The transceiver can connect directly to general-purpose digital signal processors (DSPs), field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), microphones, analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and codecs through a multichannel I2S/TDM interface. It also provides a pulse density modulation (PDM) interface for direct connection of up to four PDM digital microphones.
Finally, the transceiver also supports an A2B bus powering feature, where the master node supplies voltage and current to the slave nodes over the same daisy-chained, twisted pair wire cable as used for the communication link.