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When a device has Bluetooth host and controller clocks that reside on different clock domains, the clocks may drift apart over time (not be synchronized). This can cause communication between the two domains to experience dropped or missed packets, leading to problems such as audio drops, glitches, etc. that affect any protocols that use software codecs which rely on precise timing and clock synchronization. This disclosure describes techniques to reduce the impact of clock drift. These include use of a trigger by the Bluetooth controller, e.g., a general purpose input/output (GPIO) trigger or a hardware interrupt from a host controller interface (HCI); use of the Bluetooth controller chip as the single clock source of the Bluetooth audio interface; synchronization of clocks via the audio hardware abstraction layer (audio HAL); and the use of asynchronous sample rate converter. With the use of one or more of these techniques, the audio interface can consistently deliver packets, thereby eliminating the impact of clock drift when two different clock sources are available.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.