USB Audio 2.0 Reference Design, XS1-L1 Edition Hardware Manual (1.0)
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Introduction
The USB Audio 2.0 Reference Design, XS1-L1 Edition (hereafter "the board") is a
hardware reference design for a USB audio interface using the XMOS XS1-L1 event-
driven processor. It contains a single XS1-L1 device enabling implementation of a
complete USB 2.0 high-speed device compliant with release 2.0 of the audio USB
device class.
A block diagram of the design is shown below:
X
MOS
XS1-L1-128
XSYS
Debug
24 bit 192kHz
Stereo Audio
CODEC
CS4270
USB
Transciever
USB3318
13MHz
Oscillator
1Mbit
FLASH
USB
Series B
Receptacle
3.3V LDO
1.8V LDO
1.0V DC-DC
4.3V LDO
User
LEDs
Push-Button
Switches
Audio Master
Clock Oscillator
Produces
24.576MHz
or
11.2896MHz
Passive
LPF
Passive
LPF
3.5mm
Stereo
TRS Jack
3.5mm
Stereo
TRS Jack
Optical
Digital Audio
Transmitter
USB
High Speed
480Mb/s
ULPI
+5V VBus
CODEC
Analogue
Supply
L1 Core
Supply
+3V3D
I2S
Analog Out
1Vrms at
Full Scale
Analog In
2Vrms for
Full Scale
SPI
JTAG
Resync
MCLK
S/PDIF
The XS1-L1 event-driven processor communicates with the USB host via a ULPI USB
transceiver at the 480Mb/s high-speed rate. The XS1-L1 controls the streaming of
audio data over the USB connection and direct I
2
S interface to the audio CODEC. Multi-
ple additional functions (e.g. Mixers/DSP etc.) can be implemented by modifications
to the standard software.
Some key features of the board are listed below:
•
USB bus-powered. No external power supply required
•
Streams bit perfect audio data up to 24-bit @ 192kHz
•
Supports standard sample rates - 44.1kHz, 48kHz, 88.2kHz, 96kHz, 192kHz
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