XMOS USB Audio Driver Explanation¶
Overview¶
A common feature across all XMOS solutions is the use of the USB UAC2.0 protocol for audio transmission. Users developing USB sound card related products need to understand the XMOS USB Audio drivers, and this document mainly provides an explanation regarding USB Audio drivers.
Introduction to XMOS USB Audio Solution¶
The XMOS USB Audio solution's protocol accommodates both USB Audio Class 1.0 (UAC 1.0) and USB Audio Class 2.0 (UAC 2.0) standards, entirely adhering to the USB IF (USB Implementers' Forum) UAC2.0 and UAC1.0 protocol specifications.
The functions implemented by XMOS's USB Audio solution are as follows:
| Interface | Functional Parameters |
|---|---|
| USB | USB 2.0 (Full-speed and High-speed) USB Audio Class 1.0 USB Audio Class 2.0 USB Firmware Upgrade (DFU) 1.1 USB Midi Device Class 1.0 |
| audio | S/PDIF ADAT Direct Stream Digital (DSD) PDM Microphones DSD Over PCM MIDI |
| sample rate | 44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384, 705.6, 768 KHz |
| bit depth | 16-bit, 24-bit, 32-bit |
Users typically leverage XMOS's USB Audio solution with UAC2.0 high-speed protocol to meet requirements for high sampling rates and multiple audio channels, showcasing the high cost-effectiveness of the XMOS chip solutions. Transmission rates and bandwidth circumstances for UAC 1.0 and UAC 2.0 are as follows:
- UAC 1.0 transmission rate is 12Mbit/s
- UAC 2.0 maximum transmission rate reaches 480Mbit/s
The broad differences between UAC 1.0 and UAC 2.0 in XMOS's USB Audio solution are displayed in the table below:
| Feature | UAC 1.0 | UAC 2.0 |
|---|---|---|
| Application Scenarios | Stereo, standard sound card solutions | HiFi, multichannel, professional sound cards |
| Mac OS, Android, Linux, iOS | No driver installation required | No driver installation required |
| Windows (Win⅞/10) | No driver installation required | UAC 2.0 driver installation required |
| Number of Channels | Stereo | Multichannel |
| Functional Interfaces | Stereo input and output | Multichannel, SPDIF, MIDI, ADAT input and output |
| Maximum Sample Rate | PCM 96KHz@16-bit | PCM 768KHz@32-bit & DSD Native512 |
From the above, it is essential to note that:
- UAC 2.0 requires driver installation only on Windows systems. It is driver-free on Mac OS, Linux, and Android.
- If the user's product will be used on Windows systems, it is necessary to purchase the UAC 2.0 driver installation program for Windows.
- XMOS's UAC 2.0 solution supports multichannel, high sample rates, SPDIF, MIDI, and other functional interfaces.
Windows System UAC 2.0 Driver Explanation¶
When utilizing the XMOS UAC 2.0 solution, XMOS officially recommends several Windows system driver providers, with Thesycon drivers being a frequently used UAC 2.0 driver provider. According to XMOS's official document USB Audio 2.0 Driver for Windows - Overview, during XMOS USB Audio projects, users might employ various Thesycon drivers: Thesycon Evaluation driver, XMOS Stereo Driver, and Thesycon Commercial driver. The differences among these three drivers are described as follows:
| Evaluation Driver | XMOS Stereo Driver | Thesycon Driver | |
|---|---|---|---|
| Acquisition | Free download | No longer provided | Paid purchase |
| Max PCM Support | 768 KHz | 768 KHz | 768 KHz |
| DSD Support | DOP & Native DSD | DOP | DOP & Native DSD |
| MIDI | Supported | Not supported | Supported |
| Channel Support | Multichannel | Stereo | Multichannel |
Thesycon Evaluation Driver (Evaluation driver)¶
Users can download the evaluation board driver Thesycon Evaluation Driver (Evaluation driver) for testing and assessment when using our Hi-Fi evaluation board. The evaluation driver supports SPDIF, MIDI, multichannel, and Stereo output for PCM 768KHz and DSD Native512. However, there is a commercialization limitation with the evaluation driver -- it emits a beeping sound every five minutes after continuous playback for one hour. This evaluation driver is not authorized for commercial use and is provided only for user testing.
XMOS Stereo Driver (XMOS Stereo Driver)¶
No longer available.
Thesycon Driver (Thesycon Driver)¶
The Thesycon Driver is commercially licensed. Users can initially use the Thesycon Evaluation Driver, and after confirming the product's performance is satisfactory, they might decide to purchase the Thesycon Driver. In such cases, customers need to contact the driver provider, Thesycon, for business cooperation, covering functional requirements, License fees, and more.
Phytium Cloud does not participate in business negotiations between users and Thesycon or other third-party driver companies. Thesycon is one of the driver companies officially recommended by XMOS. For further details about the drivers, please visit the Thesycon official website.
USB Driver VID and PID Explanation¶
USB devices feature VID and PID descriptors, where VID stands for Vendor ID, and PID stands for Product ID. The USB IF assigns VIDs and PIDs based on brand registration.
In the XMOS USB Audio solution, you may opt to use Thesycon-assigned VID and PID or your own VID and PID (provided that you have registered with the USB IF and have obtained a certificate).