Nuvoton CODEC 8812 series User manual

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CODEC Motherboard
Nuvoton Audio Codec
Motherboard
Evaluation Board User’s Guide
(For Nuvoton CODEC series: 8812, 8814, 8810, 88C10, 8811, 8820,
8822, 8822L, 88C22, 8401, 8402, 8501, and 8502.)

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Introduction
This system is a combination of hardware and software that enables fast and detailed evaluation
of Nuvoton audio products. The hardware consists of a base evaluation board and a daughter
card which contains the specific audio product to be evaluated. The daughter card system
enables the use of the same base motherboard hardware and software to evaluate many different
Nuvoton audio products. The software must be installed on a Windows based PC, and is
compatible with most PC products and versions of the Windows operating system.
Summary Hardware Description
The motherboard includes a wide range of audio, power, and data input/output connectors that
enable testing a very wide range of features and audio products. The motherboard kit includes a
USB cable and the specific daughter card that was ordered with the system.
In most applications, the motherboard can be entirely powered via the included USB cable, and
most testing can be done using only this cable as the power source. This system uses a large
amount of USB power, and should NOT be used with longer or unknown quality USB cables.
These can cause unreliable operation.
If additional daughter cards have been ordered with this system, it is strongly recommended to
first install the software and test the system using the pre-installed daughter card. The
motherboard and pre-installed daughter card have been carefully tested together, and it is best to
fully verify the hardware/software system is working before changing to a different daughter card.
Summary Software Description
The supporting software includes many features that enable quick and thorough evaluation of the
various supported Nuvoton audio products. The software includes easy-to-use predefined
configurations, an intuitive GUI user interface, and also detailed register and bit manipulation
controls to facilitate every technical level of device operation and evaluation.
Depending on how this system was ordered and delivered, software may either be provided on
an included CD-ROM, or may be separately downloaded via the Internet. The software must be
installed on a Windows based PC system. Downloaded versions of the software will require a
Username and Password in order to start the installation process. Normally, this login information
will have been provided in advance by a Nuvoton sales representative.

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TABLE OF CONTENTS
1. Hardware Overview.................................................................................................6
2. Software Installation and Set-Up .............................................................................7
3. PC Configuration.....................................................................................................8
4. Running the GUI Application ...................................................................................9
5. Getting Started Using the GUI Application.............................................................10
5.1. DEMO Panel Status Indicators ......................................................................10
5.1.1. Device Attached/Detached Indicator ......................................................10
5.1.2. Power Up Indicator.................................................................................11
5.1.3. Busy Indicator........................................................................................11
5.2. Introduction to Main Menu Bar.......................................................................11
5.2.1. Device....................................................................................................11
5.2.2. Mode......................................................................................................11
5.2.3. Config ....................................................................................................11
6. The Control Tabs...................................................................................................12
6.1. Demo Panel...................................................................................................12
6.1.1. Step 1: Configure...................................................................................13
6.1.2. Step 2: Load Settings.............................................................................13
6.1.3. Step 3: Evaluate.....................................................................................13
6.1.4. Demo Example for NAU8822.................................................................14
6.2. Path View Control Panel................................................................................14
6.2.1. Description of Special Icons in Path View...............................................15
6.2.2. Path View Navigation Shortcuts.............................................................15
6.3. Device Control Panel.....................................................................................16
6.3.1. Device Settings......................................................................................17
6.3.2. Board Settings .......................................................................................18
6.3.2.1. Command Interface............................................................................18
6.3.2.1.1. External Control...........................................................................19
6.3.2.2. I2S Signal Connection........................................................................19
6.3.2.2.1. Digital Audio Reset ......................................................................19
6.3.2.2.2. I2S Master ...................................................................................19
6.3.2.2.2.1. On-Board USB......................................................................19
6.3.2.2.2.2. Audio Precision I2S Master...................................................19
6.3.2.2.2.3. Digital Audio Master..............................................................20
6.3.2.2.3. I2S Slave.....................................................................................21
6.3.2.2.3.1. Audio Precision Slave Mode .................................................21
6.3.2.2.3.2. Digital Audio Slave................................................................21
6.3.2.2.4. Direct Digital Audio Interface Header Enable...............................21
6.3.3. Power Management...............................................................................22
6.4. Input Path Control Panel................................................................................23
6.4.1. Microphone Bias ....................................................................................23
6.5. ADC/Filtering Control Panel...........................................................................24
6.6. Equalizer Control Panel.................................................................................25
6.7. Input Limiter and ALC Control Panel..............................................................26
6.8. DAC/PLL/Digital Audio Control Panel ............................................................27
6.8.1. DAC Control...........................................................................................28
6.8.1.1. Oversampling.....................................................................................28
6.8.2. PLL Control............................................................................................29

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6.8.2.1. REFIMP .............................................................................................29
6.8.2.2. FS (Frame Sync)................................................................................30
6.8.2.3. Clock Prescalers ................................................................................30
6.8.2.4. Config PLL .........................................................................................30
6.8.3. Digital Audio Control ..............................................................................31
6.8.3.1. Clock Generation Control...................................................................31
6.8.3.1.1. CLKIOEN Master Mode ...............................................................31
6.8.3.1.2. CLKM Master Clock.....................................................................32
6.8.3.1.3. BCLKSEL ....................................................................................32
6.8.3.1.4. SMPLR Sample Rate...................................................................32
6.8.3.2. Companding Control ..........................................................................32
6.8.3.2.1. PASSTHRU.................................................................................32
6.8.3.3. Audio Interface Control.......................................................................32
6.8.3.4. Jack Detect Bus Switching.................................................................32
6.9. Output Path Control Panel.............................................................................33
6.10. Register Map Control Panel...........................................................................34
6.10.1. Register Map Bit Control........................................................................35
6.10.1.1. Register Map Update Bits (write-only bits)......................................35
6.10.2. Audio Codec Register Control................................................................35
6.11. Script Control Panel.......................................................................................36
6.11.1. Script Panel Structure ............................................................................36
6.11.2. Script Panel Syntax................................................................................36
7. Daughter Card System..........................................................................................38
7.1. Changing Daughter Cards .............................................................................38
7.2. NAU8822 Daughter Card...............................................................................38
8. Jumpers and Connectors.......................................................................................40
8.1. Power Related Connectors and Options........................................................40
8.1.1. Summary of Power Options and Limits ..................................................41
8.1.2. Main 5Vdc Power...................................................................................41
8.1.3. Power LINK Jumpers .............................................................................42
8.2. Analog Inputs for NAU8822 ...........................................................................43
8.3. Analog Outputs for NAU8822.........................................................................44
8.3.1. Analog Output Options for NAU8822......................................................45
8.3.1.1. Headphone Detect .............................................................................46
8.3.1.2. Headphone Virtual Ground.................................................................46
8.3.1.3. DC Coupled Headphone Outputs.......................................................46
8.3.1.4. Ear Speaker Mode .............................................................................46

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8.4. Digital Audio Using the NAU8822 ..................................................................47
8.4.1. NAU8822 Master Clock Requirement.....................................................47
8.4.2. Master Clock Selection...........................................................................47
8.4.3. Frame Sync (Sample Rate Clock)..........................................................47
8.4.4. Bit Clock (BLCK)....................................................................................47
8.5. Digital Audio Input..........................................................................................48
8.5.1. Formatted Digital Audio..........................................................................49
8.5.2. USB Audio .............................................................................................49
8.5.3. Unformatted Audio.................................................................................49
8.6. Digital Audio Output.......................................................................................50
8.6.1. Formatted Digital Audio..........................................................................50
8.6.2. USB Audio .............................................................................................50
8.6.3. Unformatted Audio.................................................................................50
8.7. Digital Audio Related Connector Options.......................................................51
8.8. USB and External Control CONNECTIONS...................................................52
8.8.1. Special Connectors................................................................................52
8.9. Jumpers.........................................................................................................53
8.10. Table of Jumper Options................................................................................54
8.11. Test Points.....................................................................................................55
8.12. Table of Test Points.......................................................................................56
9. NAU8822-EVB Schematics (High Resolution Images)...........................................57
10. LIST OF FIGURES............................................................................................65
11. LIST OF TABLES ..............................................................................................65
12. VERSION HISTORY..........................................................................................65

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1 Hardware Overview
All instructions in this guide require some familiarity with the physical layout of the motherboard
and daughter cards. This information is introduced as needed, so it is not necessary at first to
memorize or understand the complete layout and functions of the hardware.
There are various daughter card can be used for the same motherboard. They are NAU8812,
NAU8814, NAU8810, NAU88C10, NAU8811, NAU8820, WAU8822, NAU8822L, NAU88C22,
NAU8401, NAU8402, NAU8501, and NAU8502.
However, to get started, a few basic inputs and outputs must be noted. The USB connector and
external audio inputs/outputs are highlighted in this section.
Control and power are supplied via the USB connector. When first learning how to use this
system, it is recommended to choose a simple audio input and output combination. One example
would be to input audio from a line level source such as a CD-audio player into the Aux inputs,
and to listen to the output on the headphone connector.
Figure 1: CODEC Motherboard SYSTEM

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2 Software Installation and Set-Up
The software is installed using a standard PC installation software program that has been
downloaded or supplied on a CD-ROM. The software installer is not an auto-start program, so it
is necessary to locate the single executable (type .exe) file and run this program manually.
If the installation software has been downloaded, the installer program will request a Username
and Password to complete the installation procedure. Normally, these will have been provided in
advance by a Nuvoton sales representative. Using a downloaded version of the software will
insure having the most recently released version of the program.
1. If no version of this GUI Application has been previously installed on the PC, components
will be added that enable the PC to recognize the Nuvoton USB audio hardware.
Depending on the operating system and configuration, it may be necessary to reboot the
PC after the first-time installation. If the installation program recommends rebooting the
PC, it is best to do so. However, a requested reboot can usually be ignored, and all
components will operate correctly.
The software installation procedure does not overwrite or replace older versions of the GUI
Application software. In some cases, it may be desirable to keep older versions of the application
available while learning to use a newer version.
If it is preferred to remove older versions of the application, the software should be removed
BEFORE installing the new software. The reason is that the un-install process may remove
common shared library components needed by the newer version of the application. An
undesired version application can be removed (before installing a newer version) using the
standard un-install feature included in Windows PC "Add or Remove Programs" control panel.

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3 PC Configuration
IMPORTANT INFORMATION: The GUI Application software installation and configuration is
entirely automatic. However, because the EVB is registered with the PC as an "Audio Device,"
sound from inside the PC may automatically be routed to the Nuvoton EVB. The EVB is
registered as a USB audio device, because it has the capability to receive an audio stream over
the USB bus.
Thus, after plugging the EVB into a PC, audio inside the PC may appear to stop working or be
changed in ways that are surprising. Managing the PC audio routing will be especially important
if it is desired to use the PC as an audio source as part of the EVB evaluation process.
Therefore, it is important to understand how to manage and control the PC built-in software and
hardware audio features. What happens automatically, and the details of how to manage audio
inside the PC will vary depending on the Windows version and specific PC hardware. Further
details may be different if other audio hardware and or software has been installed on the PC.
In all Windows systems, the management of audio is similar. This is typically done using the
"Control Panel" option in the Start Menu, and then selecting the appropriate audio control icon or
menu item. It may also be possible to access the PC audio control panel by clicking or right-
clicking on the speaker icon in the Task Bar, normally at the bottom of the PC screen.
After activating the audio control panel, there will be various options. There will be an option for
routing sound to and from the PC, and in this option there will be a list of possible audio devices.
The Nuvoton EVB is registered as an "Audio Device." It is possible other audio devices attached
to the PC may have the same or similar name. The Nuvoton EVB can be identified in this case
by unplugging/replugging into the PC to see which item is changed in the list of audio devices.
Again depending on the Windows system and configuration, any selection made in the control
panel may later be automatically changed by the PC system. Also, media player software may
not immediately recognize that the PC audio path has been changed. It is best to quit and then
restart any media player application after making a change to the audio routing using the PC
control panel.

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4 Running the GUI Application
After installation, and depending on the Windows operating system and installation options, an
icon to start the application may have been added to either or both the Desktop and Start Menu
locations. The program will always be available under the Run option in the Start Menu. The
application name will always start with the word "Nuvoton.”
The application may be started with or without the motherboard USB hardware attached. If the
motherboard is not attached, the application will run in a "software demo" mode that enables
becoming more familiar with the software.
After starting, the following start-up screen will be displayed.
The normal use of the application at this time is to click on the icon that matches the actual device
that is on the installed hardware daughter card. Clicking on this icon will then configure the
software to match the attached hardware, and after this, evaluation can begin immediately. The
next window that opens will be the DEMO page that is explained below.
Figure 2: GUI APPLICATION START-UP SCREEN

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5 Getting Started Using the GUI Application
After making the selection on the start-up screen to select the audio device to be evaluated, the
GUI Application will open to the Demo Panel screen. All panels are structured similarly and
include the Main Menu Bar, Control Tabs, and Status Indicators.
5.1 DEMO Panel Status Indicators
The Status Indicators are located in the lower left hand corner of every Control Tab screen.
These indicators are especially important, as they provide the highest level of system status.
Figure 3: DEMO PANEL OVERVIEW
5.1.1 Device Attached/Detached Indicator
The Status Indicator on the far left is the most important. This indicator will be Green when the
motherboard hardware is attached to the PC, and signals that the PC has recognized the
hardware and established communication with the hardware. If the indicator is white, then no
interaction with the motherboard or daughter card is possible.

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5.1.2 Power Up Indicator
The middle status indicator is the Power Up Indicator. This will be Green after the software has
powered up all elements on the motherboard necessary to interoperate with the daughter card. If
the indicator is white, then the motherboard and communications between the motherboard and
daughter card have not been set up, and no interaction with the daughter card is possible.
5.1.3 Busy Indicator
The status indicator on the right-hand side indicates when the GUI Application is making changes
to the motherboard and/or the daughter card. This will be Green when all changes are completed
and the hardware is configured for operation. This indicator will be white when the GUI
Application is busy making changes to the motherboard and/or the daughter card.
5.2 Introduction to Main Menu Bar
The Main Menu Bar is included on the Demo Panel, the start-up screen, and all other views. This
enables direct and quick access to some features common to all devices. Many of these features
are for more experienced users, and this section can be studied as needed at a future time.
5.2.1 Device
The Device menu allows changing the selected daughter card device without restarting the
application. This can be useful if the wrong device was accidentally selected, or it can be used to
switch daughter cards without restarting or powering down the hardware. However it is preferred
to power-down the hardware and restart the application to change daughter cards This more
conservative procedure will insure the greatest reliability for both the hardware and software.
5.2.2 Mode
The Mode selection is normally automatic and the user should NOT change this. This menu item
enables changing the hardware control bus protocol between the motherboard and the audio
device being tested.
The Mode feature is included for instances when the motherboard or daughter card hardware has
been custom modified to be hard-wired into a particular control bus configuration. Then, it is
important to have a top-level menu control to change this selection. The control bus modes are
explained in more detail in the section describing the Device Control menu tab functionality.
5.2.3 Config
The Config menu enables Exporting or Importing settings from a standard file stored on the PC
system. This feature saves only the settings for the audio device being tested, and not the
configuration of the motherboard itself. So, the motherboard must already be initialized and set
up in the desired mode before executing the Import function.
Export/Import is useful for saving configurations for future use, or for sharing configurations with
other users. It is also a convenient way to copy/paste a set of desired register settings from the
EVB environment directly into software used to control the device in the actual end product.

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6 The Control Tabs
All of the main features and many options are selected by choosing one of the Control Tabs. This
is the horizontal menu list immediately below the Main Menu. After the user selects the device,
the application automatically opens into the Control Tab for the Demo Panel. It is best to first
work with the Demo Panel to begin learning how to use this application and the other Control
Tabs. The following sections describe the functions of each Control Tab in more detail.
6.1 Demo Panel
The Demo Panel is important, because it enables complete, proven, and working examples of
how to configure the device on the daughter card. This panel also will automatically initialize the
EVB (if necessary) and do other initialization as may be needed to start up the device on the
daughter card. The idea of this panel is to be able to use the EVB with almost no understanding
of any other function of the EVB and its many options.
The Demo Panel breaks down operation of the EVB into three simple steps. These are grouped
together visually on the PC screen, and each group is labeled as a numbered Step.
Figure 4: DEMO CONTROL PANEL

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6.1.1 Step 1: Choose Settings
The Choose Settings selection enables selection of the input, as well as the entire path for audio
from the selected input, through all of the device options, and then to the output. The path
descriptions are listed in an abbreviated form to fit within the GUI display.
The Choose Settings selection also enables choosing various possible outputs and output
combinations that will work with the selected input. These selections may be scrolled one-at-a-
time using the up/down arrows in the output selection area. They may also be selected directly
by clicking on the text of the output path that is shown. This will open a pop up a window showing
all of the possible output selections, and then the desired selection can be made directly.
6.1.2 Step 2: Load Settings
Clicking on this button will cause all of the desired settings to be loaded into the audio device
being tested. Additionally, any necessary changes to the EVB initialization or configuration will be
performed automatically at this time.
While the settings are being loaded, the Status Indicators at the bottom left of the screen may
change from Green to White. IMPORTANT: If the configuration was successfully completed, all
three Status Indicators will be Green, and the configuration is now ready for evaluation.
6.1.3 Step 3: Evaluate Sound
The bottom portion of the screen includes a few controls that enable experimentation with some
of the settings that can be changed on the audio device being tested. These can be changed
using the GUI, and the effect on the device will be immediate. Do NOT push the "Load Settings"
button again while using this feature. This will cause all of the settings to revert to the original
selected Demo configuration.
At this time, it may be useful to select any of the other Control Tabs. These make available many
more controls and features that can be changed after the Demo selection has been loaded.

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7 Demo Example for NAU8822
In this example, the goal is to pass audio from the left and right auxiliary inputs, into the ADC,
from the ADC into the DAC, and then output to the headphones. This is accomplished by the
following three steps:
Choose: "L/R AUXIN => L/R AuxBstGain => L/RADC => L/RDAC => M Mixer =>
Select for the output: Headphone
Push the "Load Settings" button and verify all three Status Indicators change to Green
At this point, any line level audio input attached to the Aux inputs should be audible in a
headphone attached to the headphone jack. A suitable line level audio source would be the
output from a CD-audio player or other media player device.
7.1 Path View Control Panel
This panel shows in a graphical form the internal structure of the device being tested as it related
to the available input, output, and control pins on the device. This is a highly interactive panel,
and most of the features and controls are "clickable." This means that on the GUI screen you can
simply click on a functional block or path and change its settings. You can also use this panel to
see some of the settings that are currently in use.
Figure 5: PATH VIEW

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This panel is intended to be used after a full set of settings has already been loaded into the
device. This panel is difficult or impossible to use without having done this first. The main reason
for this is that power control features are in the "off" condition, and these are not all directly
available on the Path View.
To simplify use of the Path View, the Demo settings have been set up with all of the power control
features in the "on" condition. This makes the Path View simpler to use, because it may not be at
all obvious that a particular path is not working because one of the elements in the path does not
have power.
7.1.1 Description of Special Icons in Path View
Here is a summary of the "language" that can be used in this graphical environment:
The active path over which audio is enabled, is indicated by red colored
lines in the GUI. In some cases, the lines are clickable and the path can
be enabled/disabled simply by clicking on the line. This includes on/off
switches which are also clickable with the active path indicated in red.
A speaker icon indicates that an output or input block is enabled. The
disabled state will show the speaker icon with the international red
"crossed out" overlay.
Items for which a drop-down or pop-up menu will appear are marked with
a small down-arrow icon. This can be used to either view the current
setting or to change a setting.
On NAU8822 devices, some of the outputs can be in a "boost" or
"non-boost" gain configuration. This status is indicated near the output
icon with a red up-arrow symbol to indicate the Boost state, or a red
horizontal line symbol indicating the "Non-Boost" state.
Additionally, if a block is does not have power, this will be indicated by a
right-angle down-arrow icon. To reduce visual clutter on the display, the
"power-on" status is not shown. Because the Demo selections enable all
power to all blocks, no power-down icons will normally be seen. However,
if power is turned off using other Control Tabs, or the Path View is selected
before loading any settings into the device, then the power-down icons will
be visible.
7.1.2 Path View Navigation Shortcuts
Clicking on blocks in the GUI view that have many functions will in some cases cause the display
to switch to the Control Tab view appropriate for that block. This is a quick, powerful, and
convenient way to change features in a block too complex to show in this Path View.
After clicking on a block that switches to a different Control Tab view, changes can be made in
that view. When the changes are complete, simply right-click on the current Control Tab view,
and the display will automatically switch back to the Path View. The Path View will automatically
be updated to show any changes that were made in any of the other Control Tab panels.

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7.2 Device Control Panel
This panel modifies the basic configuration of both the motherboard and the audio device under
test. In general, these features are for advanced users. Except for the "Initialize Board,"
"Initialize Device," and "Device Control" radio buttons, other settings in this panel should not be
changed without a good understanding of the underlying functions.
The panel manages four basic groups of functions:
1) Radio button controls for motherboard and device management
2) Board Settings to select various motherboard hardware configuration options
3) Device Settings to select power options for high voltage NAU8822 outputs
4) Power Management features for the NAU8822 device
For less experienced users, the only Device Control radio buttons that should be used are the
"Initialize Board" and "Initialize Device" buttons. These set up the motherboard and device,
respectively, to basic starting conditions. These buttons may be most useful after having made
many changes, and the state of the motherboard or device is unclear.
Figure 6: DEVICE CONTROL OVERVIEW

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7.2.1 Device Settings
This changes the 5-volt or 3-volt settings of the NAU8822 outputs to match the actual voltage
supplied on the VDDSPK pin. Management of the power options is explained in other sections of
this document.
IMPORTANT: These settings should NOT be changed unless work is being done to change the
internal or external VDDSPK voltage. For reliable operation, it is very important that these
settings match the actual voltage on VDDSPK. The motherboard is set up by default to the 5-volt
settings for VDDSPK, and this default software selection matches this default configuration.
The other Device Control radio buttons change various features as indicated by the text in the
button. These change many different register values, and in many cases require a detailed
understanding of information in the device data sheet and/or design guide.
Reset: Writes to Register 0x00 of an NAU8822 device for its Reset condition
PowerUp: Turns on basic registers to put an NAU8822 device into an "on" condition
PowerDown: Sets an NAU8822 device into a low power "sleep" condition
MuteAllOutputs: Enables only the Mute function on NAU8822 outputs
EnableAllOutputs: Turns on power control bits for all outputs
DisableAllOutputs: Turns off power control bits for all outputs
LoadDefaultUpdateBits: Write to update bits to cause update feature to take place
Figure 7: DEVICE CONTROL PANEL - DEVICE SETTINGS

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7.2.2 Board Settings
These settings change the basic configuration of the motherboard communications with the
device on the daughter card. These can affect the control bus mode, the I2S audio data stream,
and also select external connectors as alternative sources and sinks for these signals.
IMPORTANT: Changes to this portion of the panel do NOT become effective until pushing the
"Config Board" radio button. This button is located at the bottom of this grouping of controls.
Figure 8: DEVICE CONTROL PANEL –BOARD SETTINGS
7.3 Command Interface
This selects options for the control bus to the daughter card device. Normally, this selection is
automatic and these settings should not be changed unless there is a specific goal to work with
the command interface.
The listed options set up the motherboard and device on the daughter card to work together in
the indicated mode. Additionally, the speed of the I2C clock can be altered.

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7.4 External Control
In addition to the built-in interfaces, an external command interface control can be selected. In
this case, control to and from the daughter card is via the CONT. PORT, Connector J24. Bi-
directional level shifters are used to connect the daughter card to this port instead of to the
internal port provided on the motherboard.
Coupled with the External Control is the ability to set the MODE pin on the NAU8822 device to
high or low. This feature is needed to set the control mode in the NAU8822 device as described
in the NAU8822 device design guide.
When using the CONT. PORT interface, an additional option exists to set the voltage used by the
level shifter. This is changed by the jumper on Connector J23. Pin #1 of this connector is
indicated by a square symbol on the PCB silkscreen.
7.5 I2S Signal Connection
The I2S path is the serial data path for audio the digital audio signal to and from the device on the
daughter card. This feature is automatically handled, and should be changed only when specific
work is being done with the I2S bus.
7.5.1 Digital Audio Reset
A SPDIF controller chip is included on the motherboard for coupling audio to and from the device
on the daughter card using I2S serial data. Selecting this option will reset the SPDIF controller.
7.5.2 I2S Master
The motherboard can be configured as the I2S Master or I2S Slave, but not both at the same
time. In most applications, the motherboard will be the I2S Master. There are several options for
the signal source in I2S Master Mode.
7.5.3 On-Board USB
When audio is streamed from the USB host (typically a PC computer), the USB controller device
on the motherboard is configured by this selection to be the I2S Master. When selecting USB
audio in the Demo Panel, this selection is made automatically.
It should be noted that the built-in USB controller supports only a monophonic data stream. In the
Demo Panel configuration, this same audio stream is output to both the left and right channels.
Also, the USB mode does NOT support streaming of audio from the daughter card to the PC.
7.5.4 Audio Precision I2S Master
This control is for when I2S audio is streamed from an external master source connected to the
I2S_PORT, Connector J15. Bi-directional level shifters are selected by this option to connect the
daughter card to this port instead of to the internal port provided on the motherboard. External
equipment, such as an Audio Precision analyzer must be configured to be the I2S master.

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CODEC Motherboard
7.5.5 Digital Audio Master
This control is for when I2S audio is streamed from the SPDIF controller included on the
motherboard. Bi-directional level shifters are selected by this option to connect the daughter card
to the SPDIF controller, instead of to the USB I2S port also provided on the motherboard. When
selecting SPDIF audio in the Demo Panel, this selection is made automatically.