Several Linux kernel drivers implement a standard bluetooth HCI API in the form of a device node and ioctls. Each of these drivers implements support for a specific HCI presenting and a list of them can be found in /sys/class/bluetooth/hci*
The Headset Profile (HSP) was encoropred in the initial Bluetooth specification for mono headsets. If a microphone is present on a stereo headphone device, it uses HSP for the audio channel. HSP uses a RFCOMM channel for control based on standard AT commands with bluetooth specific extensions for volume control and accept/reject buttons. The transport for audio is an SCO channel which allows a single (mono) 8kHz PCM encoded using Continuous Variable Slope Delta (CVSD) modulation amounting to 64kbps. This audio transferred over SCO can be provided to the HCI hardware driver (typical) or in highly embedded applications directly to an audio codec chip via a PCM back-channel depending on the bluetooth chipset.
Bluetooth canyon cn btu1 driver
2ff7e9595c
Comments