CDB3308
Evaluation Board for CS3308
Features
Description
Single-ended Analog Inputs
The CDB3308 evaluation board is an excellent means
for evaluating the CS3308 analog volume control. Evaluation requires an analog signal source and analyzer,
power supplies, and a Windows PC compatible
computer.
Single-ended Analog Outputs
Supports AC and DC-Coupled Analog I/O
Flexible Serial Control I/O Headers
–
–
–
Serial Control Input Header to
Accommodate On-board and External
Serial Controllers
Serial Control Output Headers for
“Chaining” Serial Control Across Multiple
CDB3308 Evaluation Boards
3.3 V Logic Interface Level
Demonstrates Recommended Layout and
Grounding Arrangements
±5 V and Ground
Windows® Compatible Software Interface
–
–
The Windows software provides a GUI to make configuration of the CDB3308 easy. The software
communicates through the PC’s USB or Serial port to
configure the control port registers so that all features of
the CS3308 can be evaluated.
As an alternative to the serial control provided via a PC,
the evaluation board may be configured to accept external control signals for operation in a user application
during system development.
Minimal Power Supply Requirements
–
Standard RCA phono jacks are provided to easily interface external analog signals with the evaluation board.
Each of the CS3308’s inputs and outputs may be independently AC or DC-coupled to their respective I/O
connectors.
Easy and Intuitive Graphical Interface to
Channel and Master Volume Controls
Supports USB and RS-232 PC
Connectivity
To facilitate multi-CS3308 system design efforts, headers are provided for connecting serial control signals
between multiple CDB3308 evaluation boards.
ORDERING INFORMATION
CDB3308
Evaluation Board
CS3308
8-Channel
Passive
Inputs
USB/RS232
PC Interface
http://www.cirrus.com
AC/DC
Coupling
8-Channel
Digitally Controlled
Analog Volume Control
PC or External
Serial Control Input
Copyright © Cirrus Logic, Inc. 2006
(All Rights Reserved)
AC/DC
Coupling
8-Channel
Passive
Outputs
External
Serial Control Output
MAY '06
DS702DB2
CDB3308
TABLE OF CONTENTS
1. SYSTEM OVERVIEW ............................................................................................................................. 3
1.1 Power ............................................................................................................................................... 3
1.2 Grounding and Power Supply Decoupling ........................................................................................ 3
1.3 CS3308 Analog Volume Control ....................................................................................................... 3
1.4 External Control Headers ................................................................................................................. 3
1.5 Analog Inputs .................................................................................................................................... 4
1.6 Analog Outputs ................................................................................................................................. 4
1.7 PC Interfaces .................................................................................................................................... 4
2. PC SOFTWARE CONTROL ................................................................................................................... 5
2.1 CS3308 Controls Tab ....................................................................................................................... 5
2.2 Register Maps Tab ........................................................................................................................... 6
3. PERFORMANCE PLOTS ....................................................................................................................... 7
4. SYSTEM CONNECTIONS & JUMPERS ................................................................................................ 8
5. CDB BLOCK DIAGRAM ........................................................................................................................ 9
6. CDB SCHEMATICS .............................................................................................................................. 10
7. CDB LAYOUT ....................................................................................................................................... 13
8. REVISION HISTORY ............................................................................................................................ 16
LIST OF FIGURES
Figure 1.CS3308 Controls Tab ................................................................................................................... 5
Figure 2.Register Maps Tab ........................................................................................................................ 6
Figure 3.Frequency Response .................................................................................................................... 7
Figure 4.THD+N vs. Amplitude ................................................................................................................... 7
Figure 5.THD+N vs. Frequency .................................................................................................................. 7
Figure 6.Crosstalk ....................................................................................................................................... 7
Figure 7.Block Diagram ............................................................................................................................... 9
Figure 8.CS3308 ....................................................................................................................................... 10
Figure 9.Analog Inputs and Outputs ......................................................................................................... 11
Figure 10.Serial Control / Power ............................................................................................................... 12
Figure 11.Silkscreen Top .......................................................................................................................... 13
Figure 12.Top Side Copper Layer ............................................................................................................. 14
Figure 13.Bottom Side Copper Layer ........................................................................................................ 15
LIST OF TABLES
Table 1. System Connections ..................................................................................................................... 8
Table 2. On-Board Switches ....................................................................................................................... 8
Table 3. System Headers ............................................................................................................................ 8
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CDB3308
1. SYSTEM OVERVIEW
The CDB4265 evaluation board is an excellent means for evaluating the CS3308 digitally controlled analog volume
control. Analog audio signal interfaces are provided, an on-board microcontroller and USB/RS-232 PC interface is
used for easily configuring the CS3308’s internal registers, and a USB cable is included for use with the FlexGUI
Windows configuration software.
The CDB3308 schematic set is shown in Figure 8 through Figure 10.
1.1
Power
Power (±5 V) must be supplied to the evaluation board through the red VA+ and green VA- binding posts.
An on-board regulator provides a 3.3 V supply to the digital circuitry. All voltage inputs must be referenced
to the single black binding post ground connector (see the System Connections table on page 8).
WARNING: Please refer to the CS3308 data sheet for allowable voltage levels.
1.2
Grounding and Power Supply Decoupling
The CS3308 requires careful attention to power supply and grounding arrangements to optimize performance. Figure 7 on page 9 provides an overview of the connections to the CS3308. Figure 11 on page 13
shows the component placement. Figure 12 on page 14 shows the top layout. Figure 13 on page 15 shows
the bottom layout. The decoupling capacitors are located as close to the CS3308 as possible. Extensive
use of ground plane fill in the evaluation board yields large reductions in radiated noise.
1.3
CS3308 Analog Volume Control
A complete description of the CS3308 is included in the CS3308 product data sheet.
The required configuration settings of the CS3308 are achieved via its control port registers, accessible
through the CS3308 tab of the Cirrus Logic FlexGUI software. A register-level configuration interface is provided on the Register Maps tab. See the “PC Software Control” section on page 5 for more information.
1.4
External Control Headers
The evaluation board has been designed to allow interfacing with external systems via the headers J17,
J88, and J89.
The 15-pin, 3 column header, J17, provides bidirectional access to the CS3308’s SPITM/I²C® and MUTE
digital control signals. The pins located in the column labeled “PC” connect to the on-board PC interface
circuitry, and those in the column labeled “In” connect directly to the CS3308’s digital control I/O pins. By
default, shunts are populated across these rows, connecting the PC interface to the CS3308’s digital control
I/O. To use an external digital control source, simply remove the shunts and connect a ribbon cable to the
“In” position. A single “GND” column for the ribbon cable’s ground connection is provided to maintain signal
integrity. Two unpopulated pull-up resistors are also available should the CDB3308 be required to provide
the pull-up function for the I²C bus.
The 10-pin, 2 column header, J89, provides bidirectional access to the CS3308’s I²C SDA and SCL signals,
as well as unidirectional output access to the CS3308’s AD0, ENOut, and MUTE signals. The SDA and SCL
signals are connected directly to their corresponding pins on the CS3308, as well as those on J17 described
above. The AD0, ENOut, and MUTE signals are re-driven versions of these signals as present directly on
their respective I/O pins on the CS3308. This header may be used to connect the serial control signals between 2 or more CDB3308’s (out of J89 on one and in to J17 on another) for multiple CS3308 I²C serial
control evaluation.
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3
CDB3308
The 10-pin, 2 column header, J88, provides unidirectional output access to the CS3308’s SPI MOSI and
CCLK signals, as well as its AD0, ENOut, and MUTE signals. All of the signals re-driven versions of those
present directly on their respective I/O pins on the CS3308. This header may be used to connect the serial
control signals between 2 or more CDB3308’s (out of J88 on one and in to J17 on another) for multiple
CS3308 SPI serial control evaluation.
1.5
Analog Inputs
RCA connectors supply the CS3308 analog inputs through single-ended passive circuits with no input filtering. Refer to the CS3308 data sheet for the maximum input signal level.
Each analog input may be AC or DC coupled to its respective RCA connector. This selection is made via
the 2-pin headers labeled “DC Couple Input” and placed adjacent to each input connector on the board. To
DC couple an input connector, place a shunt across the respective header. To AC couple an input connector, remove the shunt from the respective header. By default, the input connectors are AC coupled to the
CS3308’s inputs.
1.6
Analog Outputs
The CS3308 analog outputs are routed through single-ended passive circuits with no output filtering and
connected to RCA jacks for easy evaluation.
Each analog output may be AC or DC coupled to its respective RCA connector. This selection is made via
the 2-pin headers labeled “DC Couple Output” and placed adjacent to each output connector on the board.
To DC couple an output connector, place a shunt across the respective header. To AC couple an output
connector, remove the shunt from the respective header. By default, the output connectors are AC coupled
to the CS3308’s outputs.
1.7
PC Interfaces
USB and RS-232 connections are provided to facilitate software control of the CS3308’s internal registers.
A graphical user interface is available for the CDB3308 to allow easy manipulation of the CS3308’s internal
registers. See the CS3308 datasheet for complete internal register descriptions.
To enable the CDB3308, simply connect the supplied USB cable from an available USB port on a PC to the
USB connector (J37), or alternatively connect a 9-pin serial cable from an available COM port on a PC to
the RS-232 connector (J42) and launch the Cirrus Logic FlexGUI software.
Refer to “PC Software Control” on page 5 for a description of the Graphical User Interface (GUI).
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CDB3308
2. PC SOFTWARE CONTROL
The CDB3308 is designed for use with the Microsoft Windows based FlexGUI graphical user interface. This interface provides comprehensive control over the CS3308’s internal registers via a PC’s USB or RS-232 port.
The FlexGUI software may be downloaded and installed from www.cirrus.com/msasoftware.
Step-by-step instructions for using the FlexGUI are provided as follows:
1. Download and install the FlexGUI software from www.cirrus.com/msasoftware.
2. Connect the CDB3308 to a host PC using the supplied USB cable or a 9-pin serial cable.
3. Apply positive power, negative power, and ground to the VA+, VA-, and GND binding posts respectively.
4. Launch the FlexGUI software. The GUI will load and be displayed.
5. Un-check the “Power Down CS3308” check box to allow audio to pass through the device.
2.1
CS3308 Controls Tab
The CS3308 Controls tab provides a high-level intuitive interface to many of the configuration options of the
CS3308. Control over the state of the CS3308’s MUTE and RESET input pins is also provided.
Figure 1. CS3308 Controls Tab
The Master X Mask check boxes are used to map each channel to the master controls. These check-boxes
reflect the state of their associated Master X Mask bits; when checked, the channel is un-masked.
The sliders facilitate control over the Ch X Volume registers, providing gain and attenuation in ½ dB steps.
The +¼ dB Gain check boxes are used to add an additional ¼ dB of gain to the volume level displayed for
each channel.
See the CS3308 datasheet for complete internal register descriptions.
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CDB3308
2.2
Register Maps Tab
The Register Maps tab provides an easy register-level interface to the on-board devices. Register values
can be modified on a bit-wise or byte-wise basis. To modify a single bit, first select the register by clicking
its position in the register matrix, then click the appropriate push-button for the desired bit. To modify an
entire register, simply enter the register’s new value directly into the register matrix.
Within the Register Maps tab, the CS3308 tab is used to access the CS3308’s internal registers, and the
GPIO tab is used to access the on-board microcontroller outputs used to control the CS3308’s MUTE input
and default I²C address.
Figure 2. Register Maps Tab
The Comm Mode Select box may be used to change the CS3308’s serial communication protocol between
I²C and SPI. The CS3308 will be automatically reset when the communication protocol is changed.
The software is only capable of addressing the CS3308 at its default address. If the CS3308’s individual
address is changed, the software will loose communication with the device until it is reset, thereby returning
to its default address. See the CS3308 datasheet for more information about the device’s individual address.
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CDB3308
3. PERFORMANCE PLOTS
(TA = +25 ºC, VA+ = +5 V, VA- = -5 V, VD = +3.3 V, RL = 100 kΩ, CL = 20 pF, VIN = 2 VRMS, FIN = 1 kHz,
Gain = 0 dB, Measurement Bandwidth = 20 Hz to 20 kHz, unless otherwise noted.)
+1
1
+0.9
0.5
+0.8
+0.7
0.2
+0.6
+0.5
0.1
+0.4
0.05
+0.3
+0.2
0.02
d
B
r
A
+0.1
%
+0
0.01
-0.1
0.005
-0.2
-0.3
0.002
-0.4
-0.5
0.001
-0.6
0.0005
-0.7
-0.8
0.0002
-0.9
-1
20
50
100
200
500
1k
2k
5k
10k
20k
50k
100k
0.0001
100m
200k
200m
300m
400m
500m
Hz
600m 700m 800m900m 1
2
3
Vrms
Figure 3. Frequency Response
Figure 4. THD+N vs. Amplitude
1
+0
-10
0.5
-20
-30
0.2
-40
0.1
-50
0.05
-60
-70
0.02
%
d
B
r
0.01
A
0.005
-80
-90
-100
-110
-120
0.002
-130
0.001
-140
0.0005
-150
-160
0.0002
-170
0.0001
20
50
100
200
500
1k
2k
5k
Hz
Figure 5. THD+N vs. Frequency
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10k
20k
-180
20
50
100
200
500
1k
2k
5k
10k
20k
Hz
Figure 6. Crosstalk
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CDB3308
4. SYSTEM CONNECTIONS & JUMPERS
Connector
Name
Reference
Designator
Signal
Direction
GND
VA+
VAIn 1
In 2
In 3
In 4
In 5
In 6
In 7
In 8
Out 1
Out 2
Out 3
Out 4
Out 5
Out 6
Out 7
Out 8
USB I/O
RS-232 I/O
I²C/SPI Input
I²C Output
SPI Output
C2
J5
J8
J7
J29
J27
J11
J15
J55
J57
J71
J73
J19
J21
J46
J48
J62
J64
J79
J81
J37
J42
J17
J89
J88
J36
Input
Input
Input
Ground reference.
Positive analog power. +5 V.
Negative analog power. -5 V.
Input
Analog input to CS3308.
Output
Input/Output
Input/Output
Input/Output
Output
Output
Input/Output
Connector Function
Analog output from CS3308.
USB connection to PC for software control.
Serial RS-232 connection to PC for software control.
Connection for internal/external I²C/SPI control signals.
Output connection for on-board I²C control signals.
Output connection for on-board SPI control signals.
Connection for programming the on-board microcontroller (U46).
Table 1. System Connections
Switch Name
Reference Designator
uC Reset
J5
Switch Function
Resets the on-board microcontroller (U46).
Table 2. On-Board Switches
Connector Name
Reference
Designator
DC Couple Input 1
DC Couple Input 2
DC Couple Input 3
DC Couple Input 4
DC Couple Input 5
DC Couple Input 6
DC Couple Input 7
DC Couple Input 8
DC Couple Output 1
DC Couple Output 2
DC Couple Output 3
DC Couple Output 4
DC Couple Output 5
DC Couple Output 6
DC Couple Output 7
DC Couple Output 8
J2
J3
J16
J18
J58
J59
J74
J75
J32
J33
J51
J52
J67
J68
J84
J85
Header Function
When a shunt is present across its pins, each header DC couples its respective input connector to the associated input of the CS3308.
When no shunt is present across the header’s pins, its respective input connector will be AC coupled to the associated input of the CS3308.
When a shunt is present across its pins, each header DC couples its respective output connector to the associated output of the CS3308.
When no shunt is present across the header’s pins, its respective output
connector will be AC coupled to the associated output of the CS3308.
Table 3. System Headers
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DS702DB2
USB/RS232
PC Interface
8-Channel
Passive
Inputs
AC/DC
Coupling
Figure 7. Block Diagram
PC or External
Serial Control Input
8-Channel
Digitally Controlled
Analog Volume Control
CS3308
8-Channel
Passive
Outputs
External
Serial Control Output
AC/DC
Coupling
CDB3308
5. CDB BLOCK DIAGRAM
9
CDB3308
10
Schematic Page 1
Figure 8. CS3308
6. CDB SCHEMATICS
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DS702DB2
Schematic Page 2
Figure 9. Analog Inputs and Outputs
CDB3308
11
12
Schematic Page 3
Figure 10. Serial Control / Power
CDB3308
DS702DB2
CDB3308
Figure 11. Silkscreen Top
±5V
CDB3308
7. CDB LAYOUT
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13
Figure 12. Top Side Copper Layer
CDB3308
14
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Figure 13. Bottom Side Copper Layer
CDB3308
DS702DB2
15
CDB3308
8. REVISION HISTORY
Release
DB1
DB2
Changes
Initial Release
Updated performance plots shown in Figures 3 - 6 on page 7.
Contacting Cirrus Logic Support
For all product questions and inquiries, contact a Cirrus Logic Sales Representative.
To find the one nearest to you, go to www.cirrus.com.
IMPORTANT NOTICE
Cirrus Logic, Inc. and its subsidiaries ("Cirrus") believe that the information contained in this document is accurate and reliable. However, the information is subject
to change without notice and is provided "AS IS" without warranty of any kind (express or implied). Customers are advised to obtain the latest version of relevant
information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale
supplied at the time of order acknowledgment, including those pertaining to warranty, indemnification, and limitation of liability. No responsibility is assumed by Cirrus
for the use of this information, including use of this information as the basis for manufacture or sale of any items, or for infringement of patents or other rights of third
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does not extend to other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). CIRRUS PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED FOR USE
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WITH THESE USES.
Cirrus Logic, Cirrus, and the Cirrus Logic logo designs are trademarks of Cirrus Logic, Inc. All other brand and product names in this document may be trademarks
or service marks of their respective owners.
SPI is a trademark of Motorola, Inc.
I²C is a registered trademark of Philips Semiconductor.
Windows is a registered trademark of Microsoft Corporation.
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DS702DB2