Driver Support; Audio Class 1.0 Mode And Fall-Back - XMOS xCORE-200 Multi-channel Audio board Design Manual

USB Audio Design Guide
Class devices are no longer limited to full-speed operation allowing greater channel
counts, sample frequencies and sample bit-depths. Additional improvement,
amoungst others, include:
Added support for multiple clock domains, clock description and clock control
Extensive support for interrupts to inform the host about dynamic changes that
occur to different entities such as Clocks etc

4.2.1 Driver Support

4.2.1.1 Audio Class 1.0
Audio Class 1.0 is fully supported in Apple OSX. Audio Class 1.0 is fully supported
in all modern Microsoft Windows operating systems (i.e. Windows XP and later).
4.2.1.2 Audio Class 2.0
Audio Class 2.0 is fully supported in Apple OSX since version 10.6.4. Audio Class
2.0 is not supported natively by Windows operating systems. It is therefore required
that a driver is installed. Documentation of Windows drivers is beyond the scope
of this document, please contact XMOS for further details.

4.2.2 Audio Class 1.0 Mode and Fall-back

The normal default for XMOS USB Audio applications is to run as a high-speed
Audio Class 2.0 device. However, some products may prefer to run in Audio Class
1.0 mode, this is normally to allow "driver-less" operation with Windows operating
systems.
To ensure specification compliance, Audio Class 1.0 mode always operates at
full-speed USB.
The device will operate in full-speed Audio Class 1.0 mode if one of the following
is true:
The code is compiled for USB Audio Class 1.0 only.
The code is compiled for USB Audio Class 2.0 and it is connected to the host
over a full speed link (and the Audio Class fall back is enabled).
The options to control this behavior are detailed in usb_audio_sec_custom_defines_api.
When running in Audio Class 1.0 mode the following restrictions are applied:
MIDI is disabled.
DFU is disabled (Since Windows operating systems would prompt for a DFU
driver to be installed)
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