OpenUAC2

An open-source audio streaming bridge compatible with USB Audio 2.0 specification

Features

• Full USB 2.0 HS support
• Asynchronous feedback
• Very low cost: no external programmable logic required
• Easy interfacing with DACs
• PCM supports: 44.1k, 48k, 88.2k, 96k, 176.4k, 192k, 352.8k, 384k, 705.6k, 768k (Not tested).
• DoP supports: DSD64, DSD128, DSD256 (Stability issue, to be fixed)

Current limitations

• DSD native is unsupported due to driver
• Manual reset may be required after reconnecting USB cable

Implementation details

For details of ST's USB device library, please refer to UM1734

These files contain the main work of this project

• audio_desc.c: USB configuration descriptor
• usbd_audio.c: USB interrupt callbacks
• audio_buffer.c: Circular buffer
• usbd_audio_if.c: Peripheral and external DAC interface

Note

There is currently a bug in CubeMX: when using LL for RCC, the PLLCFGR is not configured correctly. A workaround is manually add RCC->PLLCFGR |= 1 << 16; before LL_RCC_PLL_Enable(); after each code regeneration.