The Well Synchronized Asynchronous FIFO buffer – USB interface

XMOS USB interface

The TWSAFB-USB is an asynchronous USB receiver intended to isolate the DAC from the source,
getting them operating in different and fully isolated time domains. This way the jitter of the source
cannot affect the DAC. Practically the incoming I2S/DSD data are processed by an XMOS
processor which works in slave mode. This means that the outgoing data are synchronized in a
different time domain managed by the master clock and optically isolated from the incoming data,
preventing source jitter from crossing the receiver and affecting the DAC. In practice, this allows
the output signals to be regenerated starting from a much more precise clock than that of the
The TWSAFB-USB receiver provides digital outputs to drive most of the DAC on the market,
sigma-delta and I2S DACs. It provides I2S and DSD output.


Input format: I2S/DoP/DSD

Inputs: USB port
Output format: PCM up to 768 kHz, DSD up to DSD512
Output phase: direct or reversed (dip-switches on board)
Galvanic isolation: all output signals are galvanic isolated from the XMOS processor to avoid interferences from the source
Master clock output: selectable (45.1584/49.152 MHz or 22.5792/24.576 MHz)
Power supply: 3V3DC/100 mA (isolated side)
External power supply: optional 5VDC/300 mA (USB side)
Software: ASIO driver for Windows provided
Board size: 109 x 52 mm