Disclosed herein are systems and techniques for peripheral device diagnostics and control over a two-wire communication bus. For example, in some embodiments, a slave device may include circuitry to receive a synchronization control frame from an upstream device, receive audio data from the upstream device subsequent to receipt of the synchronization control frame, provide a synchronization response frame toward the upstream device, and provide first data representative of an operational characteristic of an audio device coupled to the slave device subsequent to provision of the synchronization response frame; circuitry to derive timing information from the synchronization control frame; and circuitry to provide the audio data to the audio device, and receive, from a sensor coupled to the slave device, second data representative of the operational characteristic of the audio device.