LITE ON TECHNOLOGY AWOXMII2, AWOXMII0 User Manual

AWOX, S.A.
93 Place Pierre Duhem
34000 MONTPELLIER, France
Tel: [phone], Fax: [phone]

www.awox.com [e-mail]

Technical Note

Digital Mozart II Module

1 Introduction

The original design of Mozart II includes everything an audio system designer needs in terms of digital
to analog conversion and analog signal management ready to feed to analog amplifiers or outputs.
Basically, ADC,DAC, FM tuner and all volume control and equalization are built-in.

Some applications do not make use of analog output (for instance, connecting the module to some
digital audio processor does not require analog) or will make use of their own converters for feature or
cost reasons. Therefore, Mozart II can be delivered as “digital only”, which means only the digital
stream is provided to the outside world.

The general considerations on Mozart II use can be found in the master documentation for the full­fledged module. This document only describes the changes between the two versions. It is therefore
recommended to read the full-fledged version documentation before this one.

A reference schematic for Mozart II Digital implementation is provided.

2 Clocking

As in any digital audio system, clocking is an important point. Mozart II is using I2S 3-Wire protocol by
default and needs a Master Clock frequency to be provided on I2S_REF pin and equal to 11.2896MHz
or 12.288MHz. The internal module dividers provide the according I2S_LRCK, I2S_BCLK and the
I2S_DATA is latched conforming to I2S 16 bits per channel standard. Awox may carry on particular
studies upon customer request for specific unsupported sound peripherals.

3 DACs and amplifiers

3.1 SUPPORTED DACS

The reference DAC for use with Mozart II Digital is Wolfson Micro WM8711. This low-cost DAC allows
simple and easy construction of analog products using Mozart II Digital. It is the one that is used on
the Analog variant of the module and is therefore not part of the reference schematic for sake of
explanation; Mozart II Digital makes little sense versus the analog variant if the same peripherals are
used; the goal is to be able to use feature-rich peripherals for mid to high-end devices. Please contact
AwoX for more information.

3.2 AMPLIFIERS

The reference digital amplifier, Class-D, for use with Mozart II Digital is the Cirrus Logic CS4525. It
has provision for analog parts without adding external circuitry while still giving the benefit of the low­cost and simplicity of Mozart II Digital.

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4 Other Peripherals

4.1 S/PDIF

The optical and coaxial outputs for S/PDIF are driven by a Cirrus Logic CS8406 S/PDIF encoder.
Software re-sampling is used for non-native frequencies. The Quartet II reference schematic includes
this part configured to drive an optical transmitter. To support coaxial SPDIF output, please contact
AwoX for more information.

4.2 FM TUNER

The reference tuner for use with Mozart II Digital is the Silicon Labs Si4704. The tuner has analog
outputs, which means that its use on a daughterboard requires proper analog signal handling. The
part is the same that is used on the analog variant of Mozart.

5 Daughterboard Schematic Description

Front Panel, iPod , and Rear Panel Interface are identical to the digital version (with the exception of
the Line Out replaced by Line In for demonstration purposes, but this input is directly managed by the
amplifier used).

Therefore, the description only highlights the Main Board which is quite simple.

5.1 AUDIO AMP SECTION (PAGE 1)

The amplifier U4 and the module use external I2S clocking, providing the main frequency from crystal
Y2.

5.2 FM TUNER & INTERCONNECT (PAGE 2)

The FM tuner requires the use of a band-pass filter for proper FM reception. It uses its own external
clock (Y3). Note that the interrupt line to the processor is shared and therefore open-drain, J20 is the
connection to interface board.

5.3 5.3 POWER & CONNECTORS (PAGE 3)

Strictly identical to analog version.

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AWOX, S.A.
93 Place Pierre Duhem
34000 MONTPELLIER, France
Tel: [phone], Fax: [phone]

www.awox.com [e-mail]

Technical Note

Using Mozart II

1 Introduction to Mozart II Module

HARDWARE FEATURES

• RaLink RT3050/RT3052 system-on-chip

• Memory

- 32 MB 133 MHZ SDRAM (64 MB optional)

- 32 MB NAND flash memory for system

• FM Tuner

• Audio

- Stereo output (L/R RCA, daughterboard*) w/
headphones and line level

- Stereo input (L/R RCA, daughterboard*)

- I2S output, 16bits stereo

- SPDIF output (Optical/RCA, daughterboard*)

• Storage

- USB 2.0 host (daughterboard*)

• Network

- 10/100Mb Ethernet MAC & PHY

- Onboard Wireless LAN 802.11b/g/n

- Encryption support: 40- and 128- bit WEP, WPA,

CCX, TKIP & AES

- WPS 2.0 security

• Interface

- Control LCD screen via SPI; supports monochrome
and color TFT

- Support for keyboard, up to 16 keys and one rotary
encoder

- Infrared decoder function for RC5 & NEC

- Adjustable analog output within 0 ~ 3,3V range

- External FM antenna (mini jack, daughterboard*)

• Clock

- Alarm, wake-up, snooze and sleep features

• Power Supply required

- 3.3V for main activity

• Dimensions

- 80 x 60 x 17 mm

S

OFTWARE FEATURES

tored in NAND flash memory, fully upgradable via the

• S

Internet

• Audio decoders

- MP3

- WMA

- WAV

- AAC-LC

- Real

• AwoX streaming engine

- HTTP

- MMS

• I

nternet Radio Directory

- vTuner Internet

- baracoda

• Digital Media Player (compliant with DLNA 1.5

guidelines)

• Digital Media Renderer (compliant with DLNA 1.5

guidelines)

• Linux Kernel 2.6.21

• Linux Drivers

- Monochrome 128x64 LCD and QVGA TFT

- Keyboard/keypad input

- Wi-Fi Interface

- FM tuner with optional RDS

- Full-speed USB 2.0 host

- Ethernet

- SPDIF transmitter

- Wi-Fi STA and AP

2 Introduction to Mozart II Module

AwoX S.A. has developed and is manufacturing an electronic module, codenamed “Mozart II”, that
allows building many types of connected audio platforms at the cost of simple expansion boards for
power supply, network connection, audio outputs and man-machine interface. All the standard
peripherals of such a device can be connected to the module which will be able to drive them with few
or no additional glue.

The module requires +3.3v, 1.2 A power supply.

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The module is delivered with operating system and applications. There is a standard peripheral /
function support set that can be customized upon request. The module has built-in features but is also
able to support external peripherals. Customer support for additional peripherals can be integrated
after feasibility study.

Additionally, the module comes with a set of preprogrammed pins for standard uses, but most of them
have multiplexing capabilities allowing for different usage patterns. Please contact your local sales
representative for customization information or feasibility questions.

Overall, the Mozart II module allows for easy design of equipment with standard features as well as
room for customization and evolution. Custom design services (for both hardware and software) are
available.

3 Module Block Diagram

4 Standard Features and Peripherals

4.1 MODULE INTERNALS

On the module itself, the “smart” peripherals available are a stereo PLL FM tuner, an audio codec with
line in, line out and amplified headphones output, and a built-in Ethernet PHY for 100baseT networks.
The module has an internal Wi-Fi interface. The FM tuner audio output is available on the main
connector as well as the Codec Line In. The module features 32MB of fully reprogrammable NAND
flash and RAM. FM Tuner and Audio Codec are internally linked to the I2C bus, which might be
shared with external peripherals.

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All the internal peripherals are supported by the software distribution, as well as some external
peripherals. The module has its own reset circuitry, which generates an externally available signal for
resetting external devices. This reset line will be asserted at power on, when a power supply failure is
detected, or when the software reboots the module (this can happen after firmware upgrade for
instance). If the reset line is not used by an external device, care must be taken to reset the device at
least under power on and power failure conditions by additional means.

4.2 EXTERNAL CONTROLS & INPUTS

The module features a number of pins that allow sensing data from the outside world as well as
control information. Several digital I/O pins are available. All digital inputs are interrupt-capable in
order to trigger predetermined software behaviors upon given external conditions. Digital outputs are

3.3v CMOS outputs; their maximum output current is 10 mA.

4.3 EXTERNAL BUSES

4.3.1 I2C

The module acts as an I2C compatible master controller. The default bus speed is 100KHz. The bus
level is 3.3v; the module already has 4k7 pull-up resistors on both SCL and SDA lines. The external
lines, if used without repeater, should be kept as short as possible.

4.3.2 USB

Signals for an USB host interface are available. The
standard. The powering of external USB devices is left to the integrator and must comply with USB
constraints (coil decoupling of powering and appropriate impedance matching and adaptation of lines).

Most often, the host interface will be used for USB keys or mass storage devices. Should more USB
ports be needed, an external hub can be added on the module port.

VCC5V

C1

100n 16V

R1

4k7

R2

DNP

U2 LM3525M-L

7

IN

OUT1
OUT2

2

FLG

NC1

1

EN

NC2

GND

3

DGNDDGND DGNDDGND

6
8

4
5

L1 120R 100MHz

+

C2
47u 16V

USB Mass Storage Support is part of the standard software delivery. Note that USB device or OTG
can be supported but is not part of the standard implementation

interface is fully compliant with USB 2.0 fullspeed

DGND

DGND

HDM
HDP

USB

C3

47p 50VC447p 50V

USB_5V
HDM
HDP
USB_GND

L2
120R 100MHz

ESD7 ESD8

ESD5 ESD6

DGNDDGND

1
2
3
4

6

J2

USB_5V
HOST_D­HOST_D+
DGND

FGND

FGND

Conn USB type A horiz

5

DGNDDGNDDGND

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4.4 AUDIO SECTION

4.4.1 LINE OUT

The module has a Line Out stereo connection. The lines are DC coupled with a 1.35V offset and a

0.7Vpp modulation range. Depending on the software configuration, the modulation level can be fixed
or may follow user volume settings.

4.4.2 FM OUT

The analog outputs of the FM tuner are available to provide flexibility for out-of-module analog paths.
The normal way to use them is to link to Line_In pins; if an external multiplexer has to be used, then
the SELECT signal can be used to distinguish between FM and external source.

4.4.3 LINE IN

The module has a Line In stereo connection. The line
modulation range. Depending on the software configuration, the input level can be fixed or may follow
user settings. Input impedance is 47kOhms.

s are DC coupled and will accept a 0.7Vpp

4.4.4 HP OUT

The module has a Headphones amplified stereo connection. The lines are DC coupled with a 1.35V
offset and will drive 16 Ohm headphones at up to 30 mW and 32 Ohm headphones at up to 15 mW.

4.5 VOLUME CONTROL STRATEGIES

The module features two audio outputs; one is a line-level output and one is a headphones output.
Both can be controlled by software independently, however the way to use them depends on the
global design of the target product and the envisioned use cases.

The headphones output is capable of driving standard 32 Ohm headphones at up to 15 mW output
power. It is up to the customer to decide whether this is enough or not; if not external amplification
must be used.

If headphones plug need to be added, there are two solutions:

• Use the module headphones output. In this case, if internal speaker cut-off is required, it must
be implemented in relationship with the amplifier.

• Use the amplifier output to drive the headphones.

When simultaneous speakers and line out is required, in most cases the volume of the line outputs will
not vary. In this case, the only solution is to use the headphones output to feed the internal amplifier
(with jack before or after amplifier), and to connect the line outputs directly to the line out connector.

The module has a STANDBY and a MUTE signal. The MUTE signal will be active as soon as the
module is not producing audio signals. The STANDBY signal needs to control powering of the
amplifier, while the MUTE signal can be used to make sure audio outputs from the module will be
turned down. It is important to note that at initialization time, the audio output of the module can
produce spurious sounds – this is why the external logic must take care of not amplifying them.

In case of required mono internal speaker, the internal amplifier will be monophonic as well and will be
fed with a mix of the left and right signals. In this case, it will not be possible to have a design on which
the heapdhones jack will be connected to the internal amplifier – the only way to have stereo output is
to use the amplified outputs of the module.

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It is important to note that the integrity of the audio outputs cannot be guaranteed while the module
initializes. The module has a MUTE signal that must be used to physically remove the signal at places
where it would be audible (namely, the audio amplifier). The MUTE signal is raised as soon as the
module is not outputting any sound on its audio outputs in standard software deliveries. It is highly
recommended to design the external circuitry with an amplifier that supports built-in muting instead of
using additional circuitry.

The following drawings illustrate how to use outputs from the module in various cases. The simplest
possible equipment has only internal speaker; if the device is monophonic then left and right channels
must be mixed before use – the output from the module will always be stereo; using only one channel
will not be sufficient.

Adding headphones output is only at cost of the connector (the internal amplifier can be mono or
stereo of course). However, this configuration does not allow automatic cutoff when headphones are
plugged in:

If cutoff is required, it must be either managed outside of the module, or the following scheme can be
used. In this case, impedance match at amplifier input is different from the LineOut feed:

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For complete equipment, Line Outputs can be used as well. In this kind of structure, the Line Outputs
will often be fixed-volume:

Finally, “accessory” devices will not have internal speakers (but they can still use headphones !).
Internal amplification is removed in this case and the amplifier feed is connected directly to output
jacks.

4.6 USING LINE INPUT

The Line In terminals can be used to grab audio from an external source, such as an MP3 player, CD
player, cassette deck, iPod, etc. The audio analog is routed through the internal DAC therefore sound
control for it is available. The Line Input and the FM tuner mode are exclusive.

If no Line In is requested, then the FM Out should be tied directly to Line In.

4.7 POWERING CONSIDERATIONS

The module requires 3.3v power rail. The 3.3v is the main power supply and, as all digital power
supplies, is highly subject to digital commutation bursts and high current flows. It is therefore important
that this line presents low impedance, is well decoupled, and not too long from the power supply
location.

There is no recommended scheme for powering – it really depends on the kind of peripherals used in
the rest of the device. If the main PSU is +5V (this will be the case if the device does not have
amplification, such as a Hi-Fi accessory) then it makes sense to use linear regulation, while DC/DC
scheme could be preferred if the main PSU is +12V. In case of DC/DC use, EMC concerns arise.

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