CIRRUS CS4297A

CS4297A
CS4297A
®
CrystalClear
® SoundFusion™ Audio Codec ‘97
CrystalClear
Audio
Codec
CrystalClearSoundFusion™
SoundFusion™ Audio
Codec
’97 ‘97
l AC
’97 2.1 Compatible
l Industry
or Exceeds the Microsoft PC 99
Audio Performance Requirements
l S/PDIF Digital Audio Output
l CrystalClear 3D Stereo Enhancement
l Meets
Features
Leading Mixed Signal Technology
l 20-bit
Stereo Digital-to-Analog Converters
Description
l 18-bit
Stereo Analog-to-Digital Converters
The CS4297A is an AC ’97 2.1 compatible stereo audio
codec designed for PC multimedia systems. Using the
industry leading CrystalClear delta-sigma and mixed
signal technology, the CS4297A enables the design of
PC 99-compliant desktop, portable, and entertainment
PCs.
l Four
Analog Line-level Stereo Inputs for
LINE_IN, CD, VIDEO, and AUX
l Two
Analog Line-level Mono Inputs for
Modem and Internal PC Beep
Coupling the CS4297A with a PCI audio accelerator or
core logic supporting the AC ’97 interface, implements a
cost effective, superior quality, audio solution. The
CS4297A surpasses PC 99 and AC ’97 2.1 audio quality
standards.
l Dual
Stereo Line-level Outputs for
LINE_OUT and ALT_LINE_OUT
l Dual
Microphone Inputs
l High
Quality Pseudo-Differential CD Input
l Extensive
Power Management Support
ORDERING INFO
CS4297A-KQZ lead-free 48-pin TQFP 9x9x1.4 mm
CS4297A-JQZ lead-free 48-pin TQFP 9x9x1.4 mm
AC-LINK AND AC’97
REGISTERS
ANALOG INPUT MUX
AND OUTPUT MIXER
PWR
MGT
SYNC
BIT_CLK
SDATA_OUT
SDATA_IN
RESET#
ACLINK
PCM_DATA
ADC INPUT
18 bits MUX
MIC1
MIC2
GAIN / MUTE CONTROLS
PHONE
PC_BEEP
MIXER / MUX SELECTS
AC’97
REGISTERS
OUTPUT
MIXER
PCM_DATA
S/PDIF
LINE
CD
AUX
VIDEO
DAC
20 bits
Σ
LINE_OUT
ALT_LINE_OUT
MONO_OUT
document contains information for a new product.
Preliminary Product InformationThisThis
Cirrus
Logic reserves
right to modify
product
without notice.
document
containsthe
information
for athis
new
product.
Preliminary Product Information
P.O. Box 17847, Austin, Texas 78760
(512)http://www.cirrus.com
445 7222 FAX: (512) 445 7581
http://www.cirrus.com
Cirrus Logic reserves the right to modify this product without notice.
MAR ‘06
Copyright
 Cirrus
Logic, Inc. 2006
Copyright © Cirrus
Logic,
Inc. 2006
March '06
DS318PP5
(All
Rights
Reserved)
(All Rights Reserved)
DS318PP6
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CS4297A
CS4297A
TABLE OF CONTENTS
1. CHARACTERISTICS AND SPECIFICATIONS .................................................................5
Analog Characteristics ........................................................................................................5
Mixer Characteristics ..........................................................................................................6
Absolute Maximum Ratings ................................................................................................6
Recommended Operating Conditions.................................................................................6
Digital Characteristics .........................................................................................................6
AC ’97 Serial Port Timing....................................................................................................7
2. GENERAL DESCRIPTION ...............................................................................................10
2.1 AC-Link ....................................................................................................................10
2.2 Control registers ......................................................................................................10
2.3 Output Mixer .............................................................................................................11
2.4 Input Mux .................................................................................................................11
2.5 Volume Control ........................................................................................................11
3. AC LINK FRAME DEFINITION .........................................................................................13
3.1 AC-Link Serial Data Output Frame ..........................................................................14
3.1.1 Serial Data Output Slot Tags (Slot 0) ...........................................................14
3.1.2 Command Address Port (Slot 1) ..................................................................15
3.1.3 Command Data Port (Slot 2) ........................................................................15
3.1.4 PCM Playback Data (Slots 3-10) .................................................................15
3.2 AC-Link Audio Input Frame ......................................................................................16
3.2.5 Serial Data Input Slot Tag Bits (Slot 0) .......................................................16
3.2.6 Status Address Port (Slot 1) .........................................................................16
3.2.7 Status Data Port (Slot 2) ..............................................................................17
3.2.8 PCM Capture Data (Slot 3-10) .....................................................................17
3.3 AC-Link Protocol Violation - Loss of SYNC ..............................................................18
4. REGISTER INTERFACE ..................................................................................................19
4.3 Reset Register (Index 00h) ......................................................................................20
4.4 Master Volume Register (Index 02h) .......................................................................20
4.5 Alternate Volume Register (Index 04h) ....................................................................21
4.6 Mono Volume Register (Index 06h) .........................................................................21
4.7 PC_BEEP Volume Register (Index 0Ah) .................................................................22
4.8 Phone Volume Register (Index 0Ch) ........................................................................22
4.9 Microphone Volume Register (Index 0Eh) ................................................................23
Contacting Cirrus Logic Support
For a complete listing of Direct Sales, Distributor, and Sales Representative contacts, visit the Cirrus Logic web site at:
http://www.cirrus.com/corporate/contacts/sales.cfm
Microsoft is a registered trademark of Microsoft Corporation in the United States and/or other countries.
Intel is a registered trademark of Intel Corporation.
Crystal Clear and Sound Fusion are trademarks of Cirrus Logic.
Preliminary product information describes products which are in production, but for which full characterization data is not yet available. Advance product information describes products which are in development and subject to development changes. Cirrus Logic, Inc. has made best efforts to ensure 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). No responsibility is assumed by Cirrus Logic, Inc. for the use of this information, nor for infringements of patents or
other rights of third parties. This document is the property of Cirrus Logic, Inc. and implies no license under patents, copyrights, trademarks, or trade secrets.
No part of this publication may be copied, reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photographic, or otherwise) without the prior written consent of Cirrus Logic, Inc. Items from any Cirrus Logic website or disk may be printed for use by the user.
However, no part of the printout or electronic files may be copied, reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photographic, or otherwise) without the prior written consent of Cirrus Logic, Inc.Furthermore, no part of this publication may be used as a
basis for manufacture or sale of any items without the prior written consent of Cirrus Logic, Inc. The names of products of Cirrus Logic, Inc. or other vendors
and suppliers appearing in this document may be trademarks or service marks of their respective owners which may be registered in some jurisdictions. A list
of Cirrus Logic, Inc. trademarks and service marks can be found at http://www.cirrus.com.
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4.10 Stereo Analog Mixer Input Gain Registers (Index 10h - 18h) ................................. 24
4.11 Input Mux Select Register (Index 1Ah) ................................................................... 25
4.12 Record Gain Register (Index 1Ch) ......................................................................... 25
4.13 General Purpose Register (Index 20h) ................................................................... 26
4.14 3D Control Register (Index 22h) ............................................................................. 26
4.15 Powerdown Control/Status Register (Index 26h) ................................................... 27
4.16 Extended Audio ID Register (Index 28h) ................................................................ 28
4.17 PCM Front DAC Rate Register (Index 2Ch) ........................................................28
4.18 PCM L/R ADC Rate Register (Index 32h) .............................................................. 28
4.19 AC Mode Control Register (Index 5Eh) .................................................................. 29
4.20 Misc. Crystal Control Register (Index 60h) ............................................................. 29
4.21 S/PDIF Control Register (Index 68h) .....................................................................30
4.22 Vendor ID1 Register (Index 7Ch) ........................................................................... 31
4.23 Vendor ID2 Register (Index 7Eh) ........................................................................... 31
5. POWER MANAGEMENT ................................................................................................. 32
5.1 AC ’97 Reset Modes ................................................................................................ 32
5.1.1 Cold AC ‘97 Reset ....................................................................................... 32
5.1.2 Warm AC ’97 Reset ..................................................................................... 32
5.1.3 Register AC ’97 Reset ................................................................................. 32
5.2 Powerdown Controls ................................................................................................ 33
6. ANALOG HARDWARE DESCRIPTION ......................................................................... 35
6.1 Analog Inputs ...........................................................................................................35
6.1.4 Line-Level Inputs ........................................................................................35
6.1.5 CD Input .....................................................................................................35
6.1.6 Microphone Inputs ......................................................................................36
6.1.7 PC Beep Input ............................................................................................36
6.1.8 Phone Input ................................................................................................37
6.2 Analog Outputs ........................................................................................................37
6.2.9 Stereo Outputs ...........................................................................................37
6.2.10 Mono Output .............................................................................................37
6.3 Miscellaneous Analog Signals .................................................................................38
6.4 Power Supplies ........................................................................................................38
6.5 Reference Design ....................................................................................................38
7. SONY/PHILIPS DIGITAL INTERFACE (S/PDIF) ............................................................39
8. GROUNDING AND LAYOUT ..........................................................................................39
9. PIN DESCRIPTIONS
41
10. PARAMETER AND TERM DEFINITIONS ....................................................................46
11. REFERENCE DESIGN .................................................................................................48
12. REFERENCES ..............................................................................................................49
13. PACKAGE DIMENSIONS .............................................................................................50
LIST OF FIGURES
Figure 1. Power Up Timing ....................................................................................................... 8
Figure 2. Codec Ready from Startup or Fault Condition ........................................................... 8
Figure 3. Clocks ........................................................................................................................ 8
Figure 4. Data Setup and Hold.................................................................................................. 9
Figure 5. PR4 Powerdown and Warm Reset ............................................................................ 9
Figure 6. Test Mode .................................................................................................................. 9
Figure 7. AC-link Connections ................................................................................................ 10
Figure 8. Mixer Diagram.......................................................................................................... 12
Figure 9. AC-link Input and Output Framing ........................................................................... 13
Figure 10. Line Input (Replicate for Video and Aux) ...............................................................35
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Figure 11. Differential 2 VRMS CD Input ................................................................................35
Figure 12. Differential 1 VRMS CD Input ................................................................................35
Figure 13. Microphone Input ...................................................................................................36
Figure 14. Microphone Pre-amplifier .......................................................................................36
Figure 15. PC_BEEP Input......................................................................................................36
Figure 16. Modem Connection ................................................................................................37
Figure 17. Alternate Line Output as Headphone Output .........................................................37
Figure 18. Stereo Output.........................................................................................................37
Figure 19. Voltage Regulator ..................................................................................................38
Figure 20. S/PDIF Output........................................................................................................39
Figure 21. Conceptual Layout for the CS4297A......................................................................40
Figure 22. Pin Locations for the CS4297A ..............................................................................41
Figure 23. CS4297A Reference Design ..................................................................................48
LIST OF TABLES
Table 1. Mixer Registers .........................................................................................................19
Table 2. Analog Mixer Output Attenuation ..............................................................................21
Table 3. Microphone Input Gain Values ..................................................................................23
Table 4. Analog Mixer Input Gain Values................................................................................24
Table 5. Stereo Volume Register Index ..................................................................................24
Table 6. Input Mux Selection...................................................................................................25
Table 7. Slot Mapping ............................................................................................................29
Table 8. Device ID with Corresponding Part Number .............................................................31
Table 9. Revision Values.........................................................................................................31
Table 10. Powerdown PR Bit Functions..................................................................................33
Table 11. Powerdown PR Function Matrix ..............................................................................34
Table 12. Power Consumption by Powerdown Mode .............................................................34
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CS4297A
CS4297A
1. CHARACTERISTICS AND SPECIFICATIONS
ANALOG CHARACTERISTICS Standard test conditions unless otherwise noted: Tambient = 25° C,
AVdd = 5.0 V ±5%, DVdd = 3.3 V ±5%; 1 kHz Input Sine wave; Sample Frequency, Fs = 48 kHz; ZAL=100 kΩ/
1000 pF load, CDL = 18 pF load (Note 1); Measurement bandwidth is 20 Hz - 20 kHz, 18-bit linear coding for ADC
functions, 20-bit linear coding for DAC functions; Mixer registers set for unity gain.
CS4297A-KQZ
Parameter
Symbol Path
(Note 2)
(Note 3)
Full Scale Input Voltage
A-D
Line Inputs
A-D
Mic Inputs
A-D
Mic Inputs
(20 dB internal gain)
Full Scale Output Voltage
Line,Alternate Line, and Mono Outputs
D-A
FR
Frequency Response
(Note 4)
A-A
Analog
Ac = ± 0.25 dB
D-A
DAC
Ac = ± 0.25 dB
A-D
ADC
Ac = ± 0.25 dB
DR
Dynamic Range
A-A
Stereo Analog inputs to LINE_OUT
A-A
Mono Analog inputs to LINE_OUT
D-A
DAC Dynamic Range
A-D
ADC Dynamic Range
DAC SNR (-20 dB FS input w/
SNR
CCIR-RMS filter on output)
D-A
THD+N
Total Harmonic Distortion + Noise
(-3 dB FS input signal):
A-A
Line/Alternate Line Output
D-A
DAC
A-D
ADC
(all inputs except phone/mic)
A-D
ADC
(phone/mic)
Power Supply Rejection Ratio
(1 kHz, 0.5 VRMS w/ 5 V DC offset)(Note 4)
Interchannel Isolation
Spurious Tone
Input Impedance
External Load Impedance
Output Impedance
Input Capacitance
Vrefout
(Note 4)
(Note 4)
(Note 4)
(Note 4)
Min
Typ
0.91 1.00
0.91 1.00
0.091 0.10
Max
-
CS4297A-JQZ
Min
Typ
0.91 1.00
0.91 1.00
0.091 0.10
Max
Unit
-
VRMS
VRMS
VRMS
0.91
1.0
1.13
0.91
1.0
1.13
VRMS
20
20
20
-
20,000
20,000
20,000
20
20
20
-
20,000
20,000
20,000
Hz
Hz
Hz
90
85
85
85
95
90
90
90
-
-
90
85
87
85
-
dB FS A
dB FS A
dB FS A
dB FS A
-
70
-
-
-
-
dB
-
-90
-91
-88
-84
-80
-80
-80
-74
-
-
-74
-74
-74
-74
dB FS
dB FS
dB FS
dB FS
40
60
-
-
40
-
dB
70
10
10
2.0
88
-100
730
5
2.28
2.5
10
10
2.0
88
-100
730
5
2.28
2.5
dB
dB FS
kΩ
kΩ
Ω
pF
V
Notes: 1. ZAL refers to the analog output pin loading and CDL refers to the digital output pin loading.
2. Parameter definitions are given in the Section 10, Parameter and Term Definitions.
3. Path refers to the signal path used to generate this data. These paths are defined in the Section 10,
Parameter and Term Definitions.
4. This specification is guaranteed by silicon characterization, it is not production tested.
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CS4297A
CS4297A
MIXER CHARACTERISTICS
(for CS4297A-KQZ only)
Parameter
Mixer Gain Range Span
Line In, Aux, CD, Video, Mic1, Mic2, Phone, PC Beep
Mono Out, Alternate Line Out
Line Out
Step Size
All volume controls except PC Beep
PC Beep
Min
Typ
Max
Unit
-
46.5
46.5
94.5
-
dB
dB
dB
-
1.5
3.0
-
dB
dB
Max
6.0
6.0
6.0
1.25
10
15
AVdd+
0.3
DVdd +
0.3
110
150
Unit
V
V
V
W
mA
mA
V
ABSOLUTE MAXIMUM RATINGS (AVss1 = AVss2 = DVss1 = DVss2 = 0 V)
Parameter
Power Supplies
Total Power Dissipation
Input Current per Pin
Output Current per Pin
Analog Input voltage
+3.3 V Digital
+5 V Digital
Analog
(Supplies, Inputs, Outputs)
(Except Supply Pins)
(Except Supply Pins)
Digital Input voltage
Ambient Temperature
Storage Temperature
(Power Applied)
Min
-0.3
-0.3
-0.3
-10
-15
-0.3
Typ
-
-0.3
-
-55
-65
-
V
°C
°C
RECOMMENDED OPERATING CONDITIONS (AVss1 = AVss2 = DVss1 = DVss2 = 0 V)
Parameter
Power Supplies
Symbol
+3.3 V Digital DVdd1, DVdd2
+5 V Digital DVdd1, DVdd2
Analog AVdd1, AVdd2
Min
3.135
4.75
4.75
0
Operating Ambient Temperature
Typ
3.3
5
5
-
Max
3.465
5.25
5.25
70
Unit
V
V
V
°C
DIGITAL CHARACTERISTICS (AVss = DVss = 0 V)
Parameter
Symbol
Low level input voltage
Vil
High level input voltage
Vih
High level output voltage
Voh
Low level output voltage
Vol
Input Leakage Current (AC-link inputs)
Output Leakage Current (Tri-stated AC-link outputs)
Output buffer drive current
BIT_CLK, S/PDIF_OUT
SDATA_IN, EAPD
(Note 4)
6
6
Min
Typ
Max
0.8
0.65 x DVdd
0.90 x DVdd 0.99 x DVdd
0.03
0.10 x DVdd
-10
10
-10
10
-
24
4
-
Unit
V
V
V
V
µA
µA
mA
mA
DS318PP6
CS4297A
CS4297A
AC ’97 SERIAL PORT TIMING Standard test conditions unless otherwise noted: Tambient = 25° C,
AVdd = 5.0 V, DVdd = 3.3 V; CL = 55 pF load.
Parameter
RESET Timing
RESET# active low pulse width
RESET# inactive to BIT_CLK start-up delay
1st SYNC active to CODEC READY set
Vdd stable to Reset inactive
Clocks
BIT_CLK frequency
BIT_CLK period
BIT_CLK output jitter (depends on XTAL_IN source)
BIT_CLK high pulse width
BIT_CLK low pulse width
SYNC frequency
SYNC period
SYNC high pulse width
SYNC low pulse width
Data Setup and Hold
Output Propagation delay from rising edge of BIT_CLK
Input setup time from falling edge of BIT_CLK
Input hold time from falling edge of BIT_CLK
Input Signal rise time
Input Signal fall time
Output Signal rise time
(Note 4)
Output Signal fall time
(Note 4)
Misc. Timing Parameters
End of Slot 2 to BIT_CLK, SDATA_IN low (PR4)
SYNC pulse width (PR4) Warm Reset
SYNC inactive (PR4) to BIT_CLK start-up delay
Setup to trailing edge of RESET# (ATE test mode) (Note 4)
Rising edge of RESET# to Hi-Z delay
(Note 4)
DS318PP6
Symbol
Min
Typ
Max
Unit
Trst_low
Trst2clk
Tsync2crd
Tvdd2rst#
1.0
100
40.0
62.5
-
-
µs
µs
µs
µs
Fclk
36
36
-
12.288
81.4
40.7
40.7
48
20.8
1.3
19.5
750
45
45
-
MHz
ns
ps
ns
ns
kHz
µs
µs
µs
Tisetup
Tihold
Tirise
Tifall
Torise
Tofall
8
10
0
2
2
2
2
10
4
4
12
6
6
6
6
ns
ns
ns
ns
ns
ns
ns
Ts2_pdown
Tsync_pr4
Tsync2clk
Tsetup2rst
Toff
1.0
162.8
15
-
.28
285
-
1.0
25
µs
µs
ns
ns
ns
Tclk_period
Tclk_high
Tclk_low
Fsync
Tsync_period
Tsync_high
Tsync_low
Tco
7
7
CS4297A
CS4297A
BIT_CLK
Trst_low
Trst2clk
RESET#
Tvdd2rst#
Vdd
Figure 1. Power Up Timing
BIT_CLK
SYNC
Tsync2crd
CODEC_READY
Figure 2. Codec Ready from Startup or Fault Condition
BIT_CLK
Torise
Tifall
Tclk_high Tclk_low
Tclk_period
SYNC
Tirise
Tsync_high
Tifall
Tsync_low
Tsync_period
Figure 3. Clocks
8
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DS318PP6
CS4297A
CS4297A
BIT_CLK
SDATA_IN
Tco
SDATA_OUT,
SYNC
Tisetup
Tihold
Figure 4. Data Setup and Hold
BIT_CLK
Slot 1
SDATA_OUT Write to 0x20
Slot 2
Data PR4
Don’t Care
Ts2_pdown
SDATA_IN
SYNC
Tsync_pr4
Tsync2clk
Figure 5. PR4 Powerdown and Warm Reset
RESET#
Tsetup2rst
SDATA_OUT,
SYNC
Toff
SDATA_IN,
BIT_CLK
Hi-Z
Figure 6. Test Mode
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CS4297A
CS4297A
2. GENERAL DESCRIPTION
The CS4297A is a mixed-signal serial audio Codec
compliant to the Intel® Audio Codec ‘97 Specification, revision 2.1 [1]. It is designed to be paired
with a digital controller, typically located on the
PCI bus or integrated within the system core logic
chip set. The controller is responsible for all communications between the CS4297A and the remainder of the system. The CS4297A contains two
distinct functional sections: digital and analog. The
digital section includes the AC-link interface,
S/PDIF interface, serial data port, and power management support. The analog section includes the
analog input multiplexer (mux), stereo output mixer, mono output mixer, stereo Analog-to-Digital
Converters (ADCs), stereo Digital-to-Analog Converters (DACs), and their associated volume controls.
2.1
AC-Link
All communication with the CS4297A is established with a 5-wire digital interface to the controller, as shown in Figure 7. This interface is called
the AC-link. All clocking for the serial communication is synchronous to the BIT_CLK signal.
BIT_CLK is generated by the primary audio codec
and is used to clock the controller and any second-
Digital AC’97
Controller
ary audio codecs. Both input and output AC-link
audio frames are organized as a sequence of 256 serial bits forming 13 groups referred to as ‘slots’.
During each audio frame, data is passed bi-directionally between the CS4297A and the controller.
The input frame is driven from the CS4297A on the
SDATA_IN line. The output frame is driven from
the controller on the SDATA_OUT line. The controller is also responsible for issuing reset commands via the RESET# signal. Following a Cold
Reset, the CS4297A is responsible for notifying the
controller that it is ready for operation after synchronizing its internal functions. The CS4297A
AC-link signals must use the same digital supply
voltage as the controller chip, either +5 V or
+3.3 V. See Section 3, AC Link Frame Definition,
for detailed AC-link information.
2.2
Control registers
The CS4297A contains a set of AC ’97 compliant
control registers and a set of Cirrus Logic defined
control registers. These registers control the basic
functions and features of the CS4297A. Read accesses of the control registers by the AC ’97 controller are accomplished with the requested register
index in Slot 1 of a SDATA_OUT frame. The following SDATA_IN frame will contain the read
SYNC
CODEC
BIT_CLK
SDATA_OUT
SDATA_IN
RESET#
Figure 7. AC-link Connections
10
10
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CS4297A
CS4297A
data in its Slot 2. Write operations are similar, with
the register index in Slot 1 and the write data in Slot
2 of a SDATA_OUT frame. The function of each
input and output frame is detailed in Section 3,
AC Link Frame Definition. Individual register descriptions are found in Section 4, Register Interface.
2.4
The input multiplexer controls which analog input
is sent to the ADCs. The output of the input mux is
converted to stereo 18-bit digital PCM data and
sent to the controller by means of the AC-link
SDATA_IN signal.
2.5
2.3
Output Mixer
The CS4297A has two output mixers, illustrated in
Figure 8. The stereo output mixer sums together
the analog inputs to the CS4297A, including the
PC_BEEP and PHONE signals, according to the
settings in the volume control registers. The stereo
output mix is sent to the LINE_OUT and
ALT_LINE_OUT pins on the CS4297A. The
mono output mixer generates a monophonic sum of
the left and right channels from the stereo input
mixer. The mono output mix is sent to the
MONO_OUT output pin on the CS4297A.
DS318PP6
Input Mux
Volume Control
The CS4297A volume registers control analog input levels to the input mixer and analog output levels, including the master volume level, and the
alternate volume level. The PC_BEEP volume control uses 3 dB steps with a range of 0 dB to -45 dB
attenuation. All other analog volume controls use
1.5 dB steps. The analog inputs have a mixing
range of +12 dB signal gain to -34.5 dB signal attenuation. The analog output volume controls have
from 0 dB to -94.5 dB attenuation for LINE_OUT
and from 0 dB to -46.5 dB attenuation for
ALT_LINE_OUT and MONO_OUT.
11
11
CS4297A
CS4297A
PC BEEP BYPASS
MUTE
VOL
MUTE
VOL
MUTE
VOL
PHONE
VOL
PC_BEEP
MUTE
MAIN D/A
CONVERTERS
PCM_OUT
MIC2
DAC DIRECT
MODE
Σ
Σ
Σ
ANALOG STEREO
OUTPUT MIXER
3D OUTPUT
MIXER
MASTER
VOLUME
LINE OUT
MUTE
OUTPUT
BUFFER
MUTE
OUTPUT
BUFFER
MUTE
OUTPUT
BUFFER
ALT LINE
VOLUME
ALT LINE OUT
VOL
MUTE
3D
VOL
MUTE
VOL
AUX
MUTE
VOL
VIDEO
MUTE
VOL
CD
VOL
LINE
BOOST
BYPASS
BUFFER
ANALOG STEREO
INPUT MIXER
MIC1
DAC
MIC
SELECT
STEREO TO
MONO MIXER
Σ
MONO OUT
SELECT
VOL
STEREO TO
MONO MIXER
MONO
VOLUME
MONO OUT
1/2
Σ
1/2
MAIN A/D
CONVERTERS
MAIN ADC
GAIN
VOL
ADC
INPUT
MUX
MUTE
PCM_IN
ADC
Figure 8. Mixer Diagram
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3. AC LINK FRAME DEFINITION
The AC-link is a bidirectional serial port with data
organized into frames consisting of one 16-bit and
twelve 20-bit time-division multiplexed slots. The
first slot, called the tag slot, contains bits indicating
if the CS4297A is ready to receive data (input
frame) and which, if any, other slots contain valid
data. Slots 1 through 12 contain audio or control/status data. Both the serial data output and input frames are defined from the controller
perspective, not from the CS4297A perspective.
The controller synchronizes the beginning of a
frame with the assertion of the SYNC signal.
Figure 9 shows the position of each bit location
within the frame. The first bit position in a new serial data frame is F0 and the last bit position in the
serial data frame is F255. When SYNC goes active
(high) and is sampled active by the CS4297A (on
the falling edge of BIT_CLK), both devices are
synchronized to a new serial data frame. The data
on the SDATA_OUT pin at this clock edge is the
final bit of the previous frame’s serial data. On the
next rising edge of BIT_CLK, the first bit of Slot 0
is driven by the controller on the SDATA_OUT
pin. On the next falling edge of BIT_CLK, the
CS4297A latches this data in, as the first bit of the
frame.
20.8 µ s
(48 kHz)
Tag Phase
Data Phase
SYNC
12.288 MHz
81.4 ns
BIT_CLK
Bit Frame Position:
SDATA_OUT
F255
0
F0
Valid
Frame
F1
F2
F12
F13
F14
F15
F16
F35
F36
F56
F57
F76
F96
F255
Slot 1
Valid
Slot 2
Valid
Slot 12
Valid
0
Codec
ID1
Codec
ID0
R/W
0
WD15
D19
D18
D19
D19
0
F15
F16
F35
F36
F56
0
0
RD15
D19
Bit Frame Position:
F255
F0
F1
F2
F12
F13
F14
SDATA_IN
GPIO
INT
Codec
Ready
Slot 1
Valid
Slot 2
Valid
Slot 12
Valid
0
0
Slot 0
0
Slot 1
Slot 2
F57
D18
Slot 3
F76
F96
D19
D19
Slot 4
F255
GPIO
INT
Slots 5-12
Figure 9. AC-link Input and Output Framing
DS318PP6
13
13
CS4297A
CS4297A
3.1
AC-Link Serial Data Output Frame
In the serial data output frame, data is passed on the SDATA_OUT pin to the CS4297A from the AC ’97
controller. Figure 9 illustrates the serial port timing.
The PCM playback data being passed to the CS4297A is shifted out MSB first in the most significant bits
of each slot. Any PCM data from the AC ’97 controller that is not 20 bits wide should be left justified in
its corresponding slot and dithered or zero-padded in the unused bit positions.
Bits that are reserved should always be ‘cleared’ by the AC ’97 controller.
3.1.1
Serial Data Output Slot Tags (Slot 0)
Bit 15
14
13
12
11
10
9
8
7
6
5
Valid Slot 1 Slot 2 Slot 3 Slot 4 Slot 5 Slot 6 Slot 7 Slot 8 Slot 9 Slot 10
Frame Valid Valid Valid Valid Valid Valid Valid Valid Valid Valid
4
3
Reserved
2
1
0
Codec Codec
ID1
ID0
Valid Frame
The Valid Frame bit determines if any of the following slots contain either valid playback data
for the CS4297A DACs or data for read/write operations. When ‘set’, at least one of the other
AC-link slots contain valid data. If this bit is ‘clear’, the remainder of the frame is ignored.
Slot [1:2] Valid
The Slot [1:2] Valid bits indicate the validity of data in their corresponding serial data output
slots. If a bit is ‘set’, the corresponding output slot contains valid data. If a bit is ‘cleared’, the
corresponding slot will be ignored.
Slot [3:10] Valid
The Slot [3:10] Valid bits indicate Slot [3:10] contains valid playback data for the CS4297A. If a
Slot Valid bit is ‘set’, the named slot contains valid audio data. If the bit is ‘clear’, the slot will be
ignored. The CS4297A supports alternate slot mapping as defined in the AC ’97 2.1 specification. For more information, see the AC Mode Control Register (Index 5Eh).
Codec ID[1:0]
The Codec ID[1:0] bits display the Codec ID of the audio codec being accessed during the current AC-link frame. Codec ID[1:0] = 00 indicates the primary codec is being accessed. Codec
ID[1:0] = 01, 10, or 11 indicates one of three possible secondary codecs is being accessed. A
non-zero value of one or more of the Codec ID bits indicates a valid Read or Write Address in
Slot 1, and the Slot 1 R/W bit indicates presence or absence of valid Data in Slot 2.
14
14
DS318PP6
CS4297A
CS4297A
3.1.2
Command Address Port (Slot 1)
Bit 19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R/W
RI6
RI5
RI4
RI3
RI2
RI1
RI0
0
0
0
0
0
0
0
0
0
0
0
0
R/W
Read/Write. When this bit is ‘set’, a read of the AC ’97 register specified by the register index
bits will occur in the AC ’97 2.1 audio codec. When the bit is ‘cleared’, a write will occur. For any
read or write access to occur, the Frame Valid bit (F0) must be ‘set’ and the Codec ID[1:0] bits
(F[14:15]) must match the Codec ID of the AC ’97 2.1 audio codec being accessed. Additionally,
for a primary codec, the Slot 1 Valid bit (F1) must be ‘set’ for a read access and both the Slot 1
Valid bit (F1) and the Slot 2 Valid bit (F2) must be ‘set’ for a write access. For a secondary codec, both the Slot 1 Valid bit (F1) and the Slot 2 Valid bit (F2) must be ‘cleared’ for read and
write accesses. See Figure 9 for bit frame positions.
RI[6:0]
Register Index. The RI[6:0] bits contain the 7-bit register index to the AC ’97 registers in the
CS4297A. All registers are defined at word addressable boundaries. The RI0 bit must be ‘clear’
to access CS4297A registers.
3.1.3
Bit 19
Command Data Port (Slot 2)
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
WD15 WD14 WD13 WD12 WD11 WD10 WD9 WD8 WD7 WD6 WD5 WD4 WD3 WD2 WD1 WD0
2
1
0
Reserved
WD[15:0]
Write Data. The WD[15:0] bits contain the 16-bit value to be written to the register. If an access
is a read, this slot is ignored.
NOTE:
For any write to an AC ’97 register, the write is defined to be an ‘atomic’ access. This means
that when the Slot 1 Valid bit in output Slot 0 is ‘set’, the Slot 2 Valid bit in output slot 0 should
always be ‘set’ during the same audio frame. No write access may be split across 2 frames.
3.1.4 PCM Playback Data (Slots 3-10)
Bit 19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PD19 PD18 PD17 PD16 PD15 PD14 PD13 PD12 PD11 PD10 PD9 PD8 PD7 PD6 PD5 PD4 PD3 PD2 PD1 PD0
PD[19:0]
DS318PP6
Playback Data. The PD[19:0] bits contain the 20-bit PCM playback (2’s complement) data for
the left and right DACs and/or the S/PDIF transmitter. Table 7 on page 29 lists a cross reference
for each function and its respective slot. The mapping of a given slot to a DAC is determined by
the state of the ID[1:0] bits in the Extended Audio ID Register (Index 28h) and by the SM[1:0]
and AMAP bits in the AC Mode Control Register (Index 5Eh).
15
15
CS4297A
CS4297A
3.2
AC-Link Audio Input Frame
In the serial data input frame, data is passed on the SDATA_IN pin from the CS4297A to the AC ’97 controller. The data format for the input frame is very similar to the output frame. Figure 9 on page 13 illustrates the serial port timing.
The PCM capture data from the CS4297A is shifted out MSB first in the most significant 18 bits of each
slot. The least significant 2 bits in each slot will be ‘cleared’. If the host requests PCM data from the
AC ’97 Controller that is less than 18 bits wide, the controller should dither and round or just round (but
not truncate) to the desired bit depth.
Bits that are reserved or not implemented in the CS4297A will always be returned ‘cleared’.
3.2.1
Serial Data Input Slot Tag Bits (Slot 0)
Bit 15
14
13
12
11
10
9
8
7
6
5
Codec Slot 1 Slot 2 Slot 3 Slot 4 Slot 5 Slot 6 Slot 7 Slot 8 Slot 9 Slot 10
Ready Valid Valid Valid Valid Valid Valid Valid Valid Valid Valid
4
3
2
1
0
0
0
0
0
0
Codec Ready
The Codec Ready bit indicates the readiness of the CS4297A AC-link. Immediately after a
Cold Reset this bit will be ‘clear’. Once the CS4297A clocks and voltages are stable, this bit
will be ‘set’. Until the Codec Ready bit is ‘set’, no AC-link transactions should be attempted
by the controller. The Codec Ready bit does not indicate readiness of the DACs, ADCs, Vref,
or any other analog function. Those must be checked in the Powerdown Control/Status Register (Index 26h) by the controller before any access is made to the mixer registers. Any accesses to the CS4297A while Codec Ready is ‘clear’ are ignored.
Slot 1 Valid
When ‘set’, the Slot 1 Valid bit indicates Slot 1 contains a valid read back address.
Slot 2 Valid
When ‘set’, the Slot 2 Valid bit indicates Slot 2 contains valid register read data.
Slot [3:10] Valid
When ‘set’, the Slot [3:10] Valid bits indicate Slot [3:10] contains valid capture data from the
CS4297A ADCs. Only if a Slot [3:10] Valid bit is ‘set’ will the corresponding input slot contain
valid data.
3.2.2
Status Address Port (Slot 1)
Bit 19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
0
RI6
RI5
RI4
RI3
RI2
RI1
RI0
0
0
0
0
0
0
0
0
0
RI[6:0]
16
16
2
1
0
Reserved
Register Index. The RI[6:0] bits echo the AC ’97 register address when a register read has
been requested in the previous frame. The CS4297A will only echo the register index for a
read access. Write accesses will not return valid data in Slot 1.
DS318PP6
CS4297A
CS4297A
3.2.3
Bit 19
Status Data Port (Slot 2)
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
RD15 RD14 RD13 RD12 RD11 RD10 RD9 RD8 RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0
RD[15:0]
2
1
0
Reserved
Read Data. The RD[15:0] bits contain the register data requested by the controller from the
previous read request. All read requests will return the read address in the input Slot 1 and
the register data in the input Slot 2 on the following serial data frame.
3.2.4 PCM Capture Data (Slot 3-10)
Bit 19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
CD17 CD16 CD15 CD14 CD13 CD12 CD11 CD10 CD9 CD8 CD7 CD6 CD5 CD4 CD3 CD2 CD1 CD0
CD[17:0]
DS318PP6
1
0
0
0
Capture Data. The D[17:0] bits contain 18-bit PCM (2’s complement) capture data. The mapping of a given slot to an ADC is determined by the state of the ID[1:0] bits in the Extended
Audio ID Register (Index 28h) and the SM[1:0] and AMAP bits in the AC Mode Control Register (Index 5Eh). The definition of each slot can be found in Table 7 on page 29.
17
17
CS4297A
CS4297A
3.3
AC-Link Protocol Violation - Loss of
SYNC
The CS4297A is designed to handle SYNC protocol violations. The following are situations where
the SYNC protocol has been violated:
•
The SYNC signal is not sampled high for exactly 16 BIT_CLK clock cycles at the start of an
audio frame.
•
The SYNC signal is not sampled high on the
256th BIT_CLK clock period after the previous
SYNC assertion.
•
The SYNC signal goes active high before the
256th BIT_CLK clock period after the previous
SYNC assertion.
18
18
Upon loss of synchronization with the controller,
the CS4297A will ‘clear’ the Codec Ready bit in
the serial data input frame until two valid frames
are detected. During this detection period, the
CS4297A will ignore all register reads and writes
and will discontinue the transmission of PCM capture data. In addition, if the LOSM bit in the Misc.
Crystal Control Register (Index 60h) is ‘set’ (default), the CS4297A will mute all analog outputs. If
the LOSM bit is ‘clear’, the analog outputs will not
be muted.
DS318PP6
CS4297A
CS4297A
4. REGISTER INTERFACE
Reg
Register Name
00h Reset
D15 D14 D13 D12 D11 D10 D9
0
02h Master Volume
Mute
SE4 SE3 SE2 SE1 SE0
0
D8
D7
D6
D5
D4
D3
D2
D1
ID8
ID7
0
0
ID4
0
0
0
0
0
0
ML5 ML4 ML3 ML2 ML1 ML0
ML5 ML4 ML3 ML2 ML1 ML0
D0 Default
0
1990h
MR5 MR4 MR3 MR2
MR1 MR0
8000h
MR1 MR0
8000h
04h Alternate Volume
Mute
0
0
0
MR5 MR4 MR3 MR2
06h Mono Volume
Mute
0
0
0
0
0
0
0
0
0
MM5 MM4 MM3 MM2 MM1 MM0
0Ah PC_BEEP Volume
Mute
0
0
0
0
0
0
0
0
0
0
PV3 PV2
PV1
PV0
0
8000h
0000h
0Ch Phone Volume
Mute
0
0
0
0
0
0
0
0
0
0
GN4 GN3 GN2
GN1
GN0
8008h
0Eh Mic Volume
Mute
0
0
0
0
0
0
0
0
20dB
0
GN4 GN3 GN2
GN1
GN0
8008h
10h Line In Volume
Mute
0
0
GL4 GL3 GL2 GL1 GL0
0
0
0
GR4 GR3 GR2
GR1
GR0
8808h
12h CD Volume
Mute
0
0
GL4 GL3 GL2 GL1 GL0
0
0
0
GR4 GR3 GR2
GR1
GR0
8808h
14h Video Volume
Mute
0
0
GL4 GL3 GL2 GL1 GL0
0
0
0
GR4 GR3 GR2
GR1
GR0
8808h
16h Aux Volume
Mute
0
0
GL4 GL3 GL2 GL1 GL0
0
0
0
GR4 GR3 GR2
GR1
GR0
8808h
18h PCM Out Volume
Mute
0
0
GL4 GL3 GL2 GL1 GL0
0
0
0
GR4 GR3 GR2
GR1
GR0
8808h
0
0
0
0
SL0
0
0
0
0
Mute
0
0
0
GL3 GL2 GL1 GL0
0
0
0
0
1Ah Record Select
1Ch Record Gain
0
SL2
SL1
20h General Purpose
0
0
3D
0
0
0
MIX
22h 3D Control
0
0
0
0
0
0
0
26h Powerdown Ctrl/Stat
28h Extended Audio ID
EAPD PR6 PR5 PR4 PR3 PR2
ID1
ID0
0
0
0
0
PR1 PR0
AMAP
0
0
SR1
SR0
0000h
GR1
GR0
8000h
0
0
0
0
0
0
0
0000h
0
0
0
0
S3
S2
S1
S0
0000h
0
0
0
0
REF
ANL
0
0
0
0
0
0
0
VRA
0201h
MS LPBK
0
SR2
GR3 GR2
DAC ADC
000Fh
2Ch PCM Front DAC Rate
SR15 SR14 SR13 SR12 SR11 SR10 SR9
SR8 SR7 SR6 SR5 SR4 SR3
SR2
SR1
SR0
BB80h
32h PCM L/R ADC Rate
SR15 SR14 SR13 SR12 SR11 SR10 SR9
SR8 SR7 SR6 SR5 SR4 SR3
SR2
SR1
SR0
BB80h
0
Cirrus Logic Defined Registers:
5E
AC Mode Control
0
0
0
0
60
Misc. Crystal Control
0
0
0
0
68
S/PDIF Control
0
0
0
DDM AMAP
Reserved
0
SPEN
Val
0
Fs
L
7Ch Vendor ID1(CR)
F7
F6
F5
F4
F3
F4
F1
F0
S7
7Eh Vendor ID2(Y-)
T7
T6
T5
T4
T3
T2
T1
T0
0
0
SM1 SM0
0
0
0
Reserved
0
Reserved
CC6 CC5 CC4 CC3 CC2 CC1 CC0 Emph Copy /Audio
S6
S5
S4
DID2 DID1 DID0
S3
0
S2
S1
0
0080h
LOSM
0023h
Pro
0000h
S0
4352h
REV2 REV1 REV0
5931h
Table 1. Mixer Registers
DS318PP6
19
19
CS4297A
CS4297A
4.1
D15
0
Reset Register (Index 00h)
D14
SE4
D13
SE3
D12
SE2
D11
SE1
D10
SE0
D9
0
D8
ID8
D7
ID7
D6
0
D5
0
D4
ID4
D3
0
D2
0
D1
0
SE[4:0]
Crystal 3D Stereo Enhancement. SE[4:0] = 00110, indicating this feature is present.
ID8
18-bit ADC Resolution. The ID8 bit is ‘set’, indicating this feature is present.
ID7
20-bit DAC resolution. The ID7 bit is ‘set’, indicating this feature is present.
ID4
Headphone Output (Alt Line Out). The ID4 bit is ‘set’, indicating this feature is present.
Default
1990h. The data in this register is read-only data.
D0
0
Any write to this register causes a Register Reset to the default state of the audio (Index 00h - 38h) and vendor specific (Index 5Ah - 7Ah) registers. A read from this register returns configuration information about the CS4297A.
4.2
D15
Mute
Master Volume Register (Index 02h)
D14
0
D13
ML5
D12
ML4
D11
ML3
D10
ML2
D9
ML1
D8
ML0
D7
0
D6
0
D5
MR5
D4
MR4
D3
MR3
D2
MR2
D1
MR1
D0
MR0
Mute
Master Mute. Setting this bit mutes the LINE_OUT_L/R output signals.
ML[5:0]
Master Volume Left. These bits control the left master output volume. Each step corresponds
to 1.5 dB gain adjustment, with 00000 = 0 dB. The total range is 0 dB to -94.5 dB attenuation.
MR[5:0]
Master Volume Right. These bits control the right master output volume. Each step corresponds
to 1.5 dB gain adjustment, with 00000 = 0 dB. The total range is 0 dB to -94.5 dB attenuation.
Default
8000h. This value corresponds to 0 dB attenuation and Mute ‘set’.
20
20
DS318PP6
CS4297A
CS4297A
4.3
D15
Mute
Alternate Volume Register (Index 04h)
D14
0
D13
ML5
D12
ML4
D11
ML3
D10
ML2
D9
ML1
D8
ML0
D7
0
D6
0
D5
MR5
D4
MR4
D3
MR3
D2
MR2
D1
MR1
D0
MR0
Mute
Alternate Mute. Setting this bit mutes the ALT_LINE_OUT_L/R output signals.
ML[4:0]
Alternate Volume Left. These bits control the left alternate output volume. Each step corresponds to 1.5 dB gain adjustment, with 00000 = 0 dB. The total range is 0 dB to -46.5 dB attenuation. See Table 2 for further attenuation levels.
ML5
Alternate Volume Left Max Attenuation. Setting ML5 sets the left channel attenuation to
-46.5 dB by forcing ML[4:0] to a ‘1’ state. ML[5:0] will read back 011111 when ML5 has been
‘set’. Table 2 summarizes this behavior.
MR[4:0]
Alternate Volume Right. These bits control the right alternate output volume. Each step corresponds to 1.5 dB gain adjustment, with 00000 = 0 dB. The total range is 0 dB to -46.5 dB attenuation. See Table 2 for further attenuation levels.
MR5
Alternate Volume Right Max Attenuation. Setting MR5 sets the right channel attenuation to
-46.5 dB by forcing MR[4:0] to a ‘1’ state. MR[5:0] will read back 011111 when MR5 has been
‘set’. Table 2 summarizes this behavior.
Default
8000h. This value corresponds to 0 dB attenuation and Mute ‘set’.
Mx[5:0]
Write
Mx[5:0]
Read
Gain
Level
000000
000000
0 dB
000001
000001
-1.5 dB
…
…
...
011111
011111
-46.5 dB
100000
011111
-46.5 dB
...
...
...
111111
011111
-46.5 dB
Table 2. Analog Mixer Output Attenuation
4.4
D15
Mute
Mono Volume Register (Index 06h)
D14
0
D13
0
D12
0
D11
0
D10
0
D9
0
D8
0
D7
0
D6
0
D5
MM5
D4
MM4
D3
MM3
D2
MM2
D1
MM1
D0
MM0
Mute
Mono Mute. Setting this bit mutes the MONO_OUT signal.
MM[5:0]
Mono Volume. These bits control the mono output volume. Each step corresponds to 1.5 dB
gain adjustment, with a total available range from 0 dB to -46.5 dB attenuation. See Table 2 for
further attenuation levels.
MM5
Mono Volume Max Attenuation. Setting the MM5 bit sets the mono attenuation to -46.5 dB by
forcing MM[4:0] to a ‘1’ state. MM[5:0] will read back 011111 when MM5 has been ‘set’. Table 2
summarizes this behavior.
Default
8000h. This value corresponds to 0 dB attenuation and Mute ‘set’.
DS318PP6
21
21
CS4297A
CS4297A
4.5
D15
Mute
PC_BEEP Volume Register (Index 0Ah)
D14
0
D13
0
D12
0
D11
0
D10
0
D9
0
D8
0
D7
0
D6
0
D5
0
D4
PV3
D3
PV2
D2
PV1
D1
PV0
D0
0
Mute
PC_BEEP Mute. Setting this bit mutes the PC_BEEP input signal.
PV[3:0]
PC_BEEP Volume Control. The PV[3:0] bits are used to control the gain levels of the PC_BEEP
input source to the Input Mixer. Each step corresponds to 3 dB gain adjustment, with
0000 = 0 dB. The total range is 0 dB to -45 dB attenuation.
Default
0000h. This value corresponds to 0 dB attenuation and Mute ‘clear’.
This register has no effect on the PC_BEEP volume during RESET#.
4.6
D15
Mute
Phone Volume Register (Index 0Ch)
D14
0
D13
0
D12
0
D11
0
D10
0
D9
0
D8
0
D7
0
D6
0
D5
0
D4
GN4
D3
GN3
D2
GN2
D1
GN1
D0
GN0
Mute
Phone Mute. Setting this bit mutes the Phone input signal.
GN[4:0]
Phone Volume Control. The GN[4:0] bits are used to control the gain levels of the Phone input
source to the Input Mixer. Each step corresponds to 1.5 dB gain adjustment, with 01000 = 0 dB.
The total range is +12 dB to -34.5 dB gain. See Table 4 on page 24 for further details.
Default
8008h. This value corresponds to 0 dB gain and Mute ‘set’.
22
22
DS318PP6
CS4297A
CS4297A
4.7
D15
Mute
Microphone Volume Register (Index 0Eh)
D14
0
D13
0
D12
0
D11
0
D10
0
D9
0
D8
0
D7
0
D6
20dB
D5
0
D4
GN4
D3
GN3
D2
GN2
D1
GN1
D0
GN0
Mute
Microphone Mute. Setting this bit mutes the MIC1 or MIC2 signal. The selection of the MIC1 or
MIC2 input pin is controlled by the MS bit in the General Purpose Register (Index 20h).
GN[4:0]
Microphone Volume Control. The GN[4:0] bits are used to control the gain level of the Microphone input source to the Input Mixer. Each step corresponds to 1.5 dB gain adjustment, with
01000 = 0 dB. The total range is +12 dB to -34.5 dB gain. See Table 3 for further details.
20dB
Microphone 20 dB Boost. When ‘set’, the 20dB bit enables the +20 dB microphone boost block.
This bit allows for variable boost of 0 dB or +20 dB. Table 3 summarizes this behavior.
Default
8008h. This value corresponds to 0 dB gain and Mute ‘set’.
GN[4:0]
Gain Level
20dB = 0
20dB = 1
00000
+12.0 dB
+32.0 dB
00001
+10.5 dB
+30.5 dB
…
…
...
00111
+1.5 dB
+21.5 dB
01000
0.0 dB
+20.0 dB
01001
-1.5 dB
+18.5 dB
…
…
...
11111
-34.5 dB
-14.5 dB
Table 3. Microphone Input Gain Values
DS318PP6
23
23
CS4297A
CS4297A
4.8
D15
Mute
Stereo Analog Mixer Input Gain Registers (Index 10h - 18h)
D14
0
D13
0
D12
GL4
D11
GL3
D10
GL2
D9
GL1
D8
GL0
D7
0
D6
0
D5
0
D4
GR4
D3
GR3
D2
GR2
D1
GR1
D0
GR0
Mute
Stereo Input Mute. Setting this bit mutes the respective input signal, both right and left inputs.
GL[4:0]
Left Volume Control. The GL[4:0] bits are used to control the gain level of the left analog input
source to the Input Mixer. Each step corresponds to 1.5 dB gain adjustment, with 01000 = 0 dB.
The total range is +12 dB to -34.5 dB gain. See Table 4 for further details.
GR[4:0]
Right Volume Control. The GR[4:0] bits are used to control the gain level of the right analog input source to the Input Mixer. Each step corresponds to 1.5 dB gain adjustment, with 01000 =
0 dB. The total range is +12 dB to -34.5 dB gain. See Table 4 for further details.
Default
8808h. This value corresponds to 0 dB gain and Mute ‘set’.
The Stereo Analog Mixer Input Gain Registers are listed in Table 5.
Gx[4:0]
Gain Level
00000
+12.0 dB
00001
+10.5 dB
…
…
00111
+1.5 dB
01000
0.0 dB
01001
-1.5 dB
…
…
11111
-34.5 dB
Table 4. Analog Mixer Input Gain Values
Register Index
Function
10h
Line In Volume
12h
CD Volume
14h
Video Volume
16h
Aux Volume
18h
PCM Out Volume
Table 5. Stereo Volume Register Index
24
24
DS318PP6
CS4297A
CS4297A
4.9
D15
0
Input Mux Select Register (Index 1Ah)
D14
0
D13
0
D12
0
D11
0
D10
SL2
D9
SL1
D8
SL0
D7
0
D6
0
D5
0
D4
0
D3
0
D2
SR2
D1
SR1
D0
SR0
SL[2:0]
Left Channel Source. The SL[2:0] bits select the left channel source to pass to the ADCs for
recording. See Table 6 for possible values.
SR[2:0]
Right Channel Source. The SR[2:0] bits select the right channel source to pass to the ADCs for
recording. See Table 6 for possible values.
Default
0000h. This value selects the Mic input for both channels.
Sx[2:0]
Record Source
000
Mic
001
CD Input
010
Video Input
011
Aux Input
100
Line Input
101
Stereo Mix
110
Mono Mix
111
Phone Input
Table 6. Input Mux Selection
4.10
D15
Mute
Record Gain Register (Index 1Ch)
D14
0
D13
0
D12
0
D11
GL3
D10
GL2
D9
GL1
D8
GL0
D7
0
D6
0
D5
0
D4
0
D3
GR3
D2
GR2
D1
GR1
D0
GR0
Mute
Record Gain Mute. Setting this bit mutes the input to the L/R ADCs.
GL[3:0]
Left ADC Gain. The GL[3:0] bits control the input gain on the left channel of the analog source,
applied after the input mux and before the ADCs. Each step corresponds to 1.5 dB gain adjustment, with 0000 = 0 dB. The total range is 0 dB to +22.5 dB gain.
GR[3:0]
Right ADC Gain. The GR[3:0] bits control the input gain on the right channel of the analog
source, applied after the input mux and before the ADCs. Each step corresponds to 1.5 dB gain
adjustment, with 0000 = 0 dB. The total range is 0 dB to +22.5 dB gain.
Default
8000h. This value corresponds to 0 dB gain and Mute ‘set’.
DS318PP6
25
25
CS4297A
CS4297A
4.11
D15
0
General Purpose Register (Index 20h)
D14
0
D13
3D
D12
0
D11
0
D10
0
D9
MIX
D8
MS
D7
LPBK
D6
0
D5
0
D4
0
D3
0
D2
0
D1
0
D0
0
3D
3D Enable. When ‘set’, the 3D bit enables the CrystalClearTM 3D stereo enhancement. This
function is not available in DAC Direct Mode (DDM).
MIX
Mono Output Select. The MIX bit selects the source for the Mono Out output. When ‘set’, the
microphone input is selected. When ‘clear’, the stereo-to-mono mixer is selected.
MS
Microphone Select. The MS bit determines which of the two Mic inputs are passed to the mixer.
When ‘set’, the MIC2 input is selected. When ‘clear’, the MIC1 input is selected.
LPBK
Loopback Enable. When ‘set’, the LPBK bit enables the ADC/DAC Loopback Mode. This bit
routes the output of the ADCs to the input of the DACs without involving the AC-link.
Default
0000h
4.12
D15
0
3D Control Register (Index 22h)
D14
0
D13
0
D12
0
D11
0
D10
0
D9
0
D8
0
D7
0
D6
0
D5
0
D4
0
D3
S3
D2
S2
D1
S1
D0
S0
S[3:0]
Spacial Enhancement Depth. These bits control the amount of “space” added to the output stereo signal. When S[3:0] = 0000, the minimum amount of spatial enhancement is added. When
S[3:0] = 1111, the maximum amount of spatial enhancement is added. The 3D function is enabled and disabled by the 3D bit in the General Purpose Register (Index 20h).
Default
0000h. This value corresponds to minimum spatial enhancement added to the output signal.
26
26
DS318PP6
CS4297A
CS4297A
4.13
D15
EAPD
Powerdown Control/Status Register (Index 26h)
D14
PR6
D13
PR5
D12
PR4
D11
PR3
D10
PR2
D9
PR1
D8
PR0
D7
0
D6
0
D5
0
D4
0
D3
REF
D2
ANL
D1
DAC
D0
ADC
EAPD
External Amplifier Power Down. The EAPD pin follows this bit and is generally used to power
down external amplifiers.
PR6
Alternate Line Out Powerdown. When ‘set’, the alternate line out buffer is powered down.
PR5
Internal Clock Disable. When ‘set’, this bit completely powers down both the analog and digital
sections of the CS4297A. The only way to recover from setting this bit is through a Cold Reset
(driving the RESET# signal active).
PR4
AC-link Powerdown. When ‘set’, the AC link is powered down (BIT_CLK off). The AC-link can
be restarted through a Warm Reset using the SYNC signal, or a Cold Reset using the RESET#
signal (primary audio codec only).
PR3
Analog Mixer Powerdown (Vref off). When ‘set’, the analog mixer and voltage reference are
powered down. When clearing this bit, the ANL, ADC, and DAC bits should be checked before
writing any mixer registers.
PR2
Analog Mixer Powerdown (Vref on). When ‘set’, the analog mixer is powered down (the voltage
reference is still active). When clearing this bit, the ANL bit should be checked before writing
any mixer registers.
PR1
Front DACs Powerdown. When ‘set’, the DACs are powered down. When clearing this bit, the
DAC bit should be checked before sending any data to the DACs.
PR0
L/R ADCs and Input Mux Powerdown. When ‘set’, the ADCs and the ADC input muxes are powered down. When clearing this bit, no valid data will be sent down the AC link until the ADC bit
goes high.
REF
Voltage Reference Ready Status. When ‘set’, indicates the voltage reference is at a nominal
level.
ANL
Analog Ready Status. When ‘set’, the analog output mixer, input multiplexer, and volume controls are ready. When clear, no volume control registers should be written.
DAC
Front DAC Ready Status. When ‘set’, the DACs are ready to receive data across the AC link.
When clear, the DACs will not accept any valid data.
ADC
L/R ADC Ready Status. When ‘set’, the ADCs are ready to send data across the AC link. When
clear, no data will be sent to the Controller.
Default
0000h. This value indicates all blocks are powered on. The lower four bits will change as the
CS4297A finishes an initialization and calibration sequence.
The PR[6:0] and the EAPD bits are powerdown control for different sections of the CS4297A as well as external
amplifiers. The REF, ANL, DAC, and ADC bits are read-only status bits which, when ‘set’, indicate that a particular
section of the CS4297A is ready. After the controller receives the Codec Ready bit in input Slot 0, these status bits
must be checked before writing to any mixer registers. See Section 5, Power Management, for more information on
the powerdown functions.
DS318PP6
27
27
CS4297A
CS4297A
4.14
Extended Audio ID Register (Index 28h)
D15
ID1
D14
ID0
D13
0
D12
0
D11
0
D10
0
D9
AMAP
D8
0
D7
0
D6
0
D5
0
D4
0
D3
0
D2
0
D1
0
D0
VRA
ID[1:0]
Codec Configuration ID. When ID[1:0] = 00, the CS4297A is the primary audio codec. When
ID[1:0] = 01, 10, or 11, the CS4297A is a secondary audio codec. The state of the ID[1:0] bits
is determined at power-up from the ID[1:0]# pins.
AMAP
Audio Slot Mapping. The AMAP bit indicates whether the optional AC ’97 2.1 compliant AC-link
slot to audio DAC mapping is supported. This bit is a shadow of the AMAP bit in the AC Mode
Control Register (Index 5Eh). The PCM playback and capture slots are mapped according to
Table 7 on page 29.
VRA
Variable Rate PCM Audio. The VRA bit indicates whether variable rate PCM audio is supported.
This bit always returns ‘0’, indicating that variable rate PCM audio is not available.
Default
x200h. Where x is determined by the state of ID[1:0]# input pins. The Extended Audio ID Register (Index 28h) is a read only register.
4.15
PCM Front DAC Rate Register (Index 2Ch)
D15
D14
SR15 SR14
D13
D12
SR13 SR12
D11
SR11
D10
SR10
D9
SR9
D8
SR8
D7
SR7
D6
SR6
D5
SR5
D4
SR4
D3
SR3
D2
SR2
D1
SR1
D0
SR0
SR[15:0]
Front DAC Sample Rate. The SR[15:0] bits are read-only bits, and always read BB80h indicating 48 kHz sample rate.
Default
BB80h. This value corresponds to 48 kHz sample rate.
4.16
PCM L/R ADC Rate Register (Index 32h)
D15
D14
SR15 SR14
D13
D12
SR13 SR12
D11
SR11
D10
SR10
D9
SR9
D8
SR8
D7
SR7
D6
SR6
D5
SR5
D4
SR4
D3
SR3
D2
SR2
D1
SR1
D0
SR0
SR[15:0]
Left/Right ADC Sample Rate. The SR[15:0] bits are read-only bits, and always read BB80h indicating 48 kHz sample rate.
Default
BB80h. This value corresponds to 48 kHz sample rate.
28
28
DS318PP6
CS4297A
CS4297A
4.17
D15
0
AC Mode Control Register (Index 5Eh)
D14
0
D13
0
D12
0
D11
0
D10
0
D9
0
D8
D7
DDM AMAP
D6
0
D5
SM1
D4
SM0
D3
0
D2
0
D1
0
D0
0
DDM
DAC Direct Mode. This bit controls the source to the line and alternate line output drivers. When
‘set’, the L/R DACs directly drive the line and alternate line outputs by bypassing the audio mixer. When ‘clear’, the audio mixer is the source for the line and alternate line outputs.
AMAP
Audio Slot Mapping. This read/write bit controls whether the CS4297A responds to the Codec
ID based slot mapping as outlined in the AC ’97 2.1 specification. The bit is shadowed in the
Extended Audio ID Register (Index 28h). Refer to Table 7 for the slot mapping configurations.
SM[1:0]
Slot Map. The SM[1:0] bits define the Slot Mapping for the CS4297A when the AMAP bit is
‘cleared’. Refer to Table 7 for the slot mapping configurations.
Default
0080h
Codec ID
Slot
Assignment
Mode
Slot Map
ID1 ID0 SM1 SM0
Slot Assignments
AMAP
DAC,
SPDIF
ADC
L
R
L
R
AMAP Mode 0
0
0
X
X
1
3
4
3
4
AMAP Mode 1
0
1
X
X
1
3
4
3
4
AMAP Mode 2
1
0
X
X
1
7
8
7
8
AMAP Mode 3
1
1
X
X
1
6
9
6
9
Slot Map Mode 0
X
X
0
0
0
3
4
3
4
Slot Map Mode 1
X
X
0
1
0
5
6
5
6
Slot Map Mode 2
X
X
1
0
0
7
8
7
8
Slot Map Mode 3
X
X
1
1
0
9
10
9
10
Table 7. Slot Mapping
4.18
D15
0
Misc. Crystal Control Register (Index 60h)
D14
0
D13
0
D12
0
D11
D10
D9
Reserved
D8
D7
0
D6
0
D5
D4
Reserved
D3
0
D2
D1
Reserved
D0
LOSM
LOSM
Loss of SYNC Mute Enable. The LOSM bit controls the loss of SYNC mute function. If this bit
is ‘set’, the CS4297A will mute all analog outputs for the duration of loss of SYNC. If this bit
is ‘cleared’, the mixer will continue to function normally during loss of SYNC. The CS4297A
expects to sample SYNC ‘high’ for 16 consecutive BIT_CLK periods and then ‘low’ for 240
consecutive BIT_CLK periods, otherwise loss of SYNC becomes true.
Default
0023h
DS318PP6
29
29
CS4297A
CS4297A
4.19
D15
SPEN
S/PDIF Control Register (Index 68h)
D14
Val
D13
0
D12
Fs
D11
L
D10
CC6
D9
CC5
D8
CC4
D7
CC3
D6
CC2
D5
CC1
D4
CC0
D3
Emph
D2
D1
Copy /Audio
D0
Pro
SPEN
S/PDIF Enable. The SPEN bit enables S/PDIF data transmission on the S/PDIF_OUT pin.
The SPEN bit routes the left and right channel data from the AC ’97 controller, the digital mixer, or the digital effects engine to the S/PDIF transmitter block. The actual data routed to the
S/PDIF block is controlled through the AMAP/SM[1:0] configuration in the AC Mode Control
Register (Index 5Eh).
Val
Validity. The V bit is mapped to the V bit (bit 28) of every sub-frame. If this bit is ‘0’, the signal
is suitable for conversion or processing.
Fs
Sample Rate. The Fs bit indicates the sampling rate for the S/PDIF data. The inverse of this
bit is mapped to bit 25 of the channel status block. When the Fs bit is ‘clear’, the sampling
frequency is 48 kHz. When ‘set’, the sampling frequency is 44.1 kHz. The actual rate at which
S/PDIF data are being transmitted solely depends on the master clock frequency of the
CS4297A. The Fs bit is merely an indicator to the S/PDIF receiver.
L
Generation Status. The L bit is mapped to bit 15 of the channel status block. For category
codes 001xxxx, 0111xxx and 100xxxx, a value of ‘0’ indicates original material and a value of
‘1’ indicates a copy of original material. For all other category codes the definition of the L bit
is reversed.
CC[6:0]
Category Code. The CC[6:0] bits are mapped to bits 8-14 of the channel status block.
Emph
Data Emphasis. The Emph bit is mapped to bit 3 of the channel status block. If the Emph bit
is ‘1’, 50/15us filter pre-emphasis is indicated. If the bit is ‘0’, no pre-emphasis is indicated.
Copy
Copyright. The Copy bit is mapped to bit 3 of the channel status block. If the Copy bit is ‘1’
copyright is not asserted and copying is permitted.
/Audio
Audio / Non-Audio. The /Audio bit is mapped to bit 1 of the channel status block. If the /Audio
bit is ‘0’, the data transmitted over S/PDIF is assumed to be digital audio. If the /Audio bit is
‘1’, non-audio data is assumed.
Pro
Professional/Consumer. The Pro bit is mapped to bit 0 of the channel status block. If the Pro
bit is ‘0’, consumer use of the audio control block is indicated. If the bit is ‘1’, professional use
is indicated.
Default
0000h
For a further discussion of the proper use of the channel status bits see application note AN22: Overview of Digital
Audio Interface Data Structures [3].
30
30
DS318PP6
CS4297A
CS4297A
4.20
Vendor ID1 Register (Index 7Ch)
D15
F7
D14
F6
D13
F5
D12
F4
D11
F3
D10
F2
D9
F1
D8
F0
D7
S7
D6
S6
D5
S5
D4
S4
D3
S3
D2
S2
D1
S1
D0
S0
F[7:0]
First Character of Vendor ID. With a value of F[7:0] = 43h, these bits define the ASCII ‘C’
character.
S[7:0]
Second Character of Vendor ID. With a value of S[7:0] = 52h, these bits define the ASCII ‘R’
character.
Default
4352h. This register contains read-only data.
4.21
Vendor ID2 Register (Index 7Eh)
D15
T7
D14
T6
D13
T5
D12
T4
D11
T3
D10
T2
D9
T1
D8
T0
D7
0
D6
DID2
D5
DID1
D4
DID0
D3
0
D2
D1
D0
REV2 REV1 REV0
T[7:0]
Third Character of Vendor ID. With a value of T[7:0] = 59h, these bits define the ASCII ‘Y’
character.
DID[2:0]
Device ID. With a value of DID[2:0] = 001, these bits specify the audio codec is a CS4297A.
REV[2:0]
Revision. With a value of REV[2:0] = 001, these bits specify the audio codec revision is ‘A’.
Default
591xh. This register contains read-only data.
The two Vendor ID registers provide a means to determine the manufacturer of the AC ’97 audio codec. The first
three bytes of the Vendor ID registers contain the ASCII code for the first three letters of Crystal (CRY). The final
byte of the Vendor ID registers is divided into a Device ID field and a Revision field. Table 8 lists the currently defined
Device ID’s. Table 9 lists the current revisions of the CS4297A.
DID[2:0]
Part Name
000
CS4297
001
CS4297A
010
CS4294/CS4298
011
CS4299
100
CS4201
101
CS4205
Table 8. Device ID with Corresponding Part Number
REV[2:0]
Revision
001
A
010
B
011
C
100
D, E, F, G, H
101
K
110
L
Table 9. Revision Values
DS318PP6
31
31
CS4297A
CS4297A
5. POWER MANAGEMENT
5.1.2
5.1
A Warm Reset allows the AC-link to be reactivated
without losing information in the CS4297A registers. A Warm Reset is required to resume from a
D3hot state, where the AC-link had been halted yet
full power had been maintained. A primary codec
Warm Reset is initiated when the SYNC signal is
driven high for at least 1 µs and then driven low in
the absence of the BIT_CLK clock signal. The
BIT_CLK clock will not restart until at least 2 normal BIT_CLK clock periods (162.8 ns) after the
SYNC signal is deasserted. A Warm Reset of the
secondary codec is recognized when the primary
codec on the AC-link resumes BIT_CLK generation. The CS4297A will wait for BIT_CLK to be
stable to restore SDATA_IN activity and/or
S/PDIF transmission on the following frame.
AC ’97 Reset Modes
The CS4297A supports three reset methods, as defined in the AC ’97 Specification: Cold AC ’97 Reset, Warm AC ’97 Reset, Register AC ’97 Reset. A
Cold Reset results in all AC ’97 logic (registers included) initialized to its default state. A Warm Reset leaves the contents of the AC ’97 register set
unaltered. A Register Reset initializes only the
AC ’97 registers to their default states.
5.1.1
Cold AC ‘97 Reset
A Cold Reset is achieved by asserting RESET# for
a minimum of 1 µs after the power supply rails
have stabilized. This is done in accordance with the
minimum timing specifications in the AC ’97 Serial Port Timing section on page 7. Once deasserted,
all of the CS4297A registers will be reset to their
default power-on states and the BIT_CLK and
SDATA_IN signals will be reactivated.
32
32
5.1.3
Warm AC ’97 Reset
Register AC ’97 Reset
The third reset mode provides a Register Reset to
the CS4297A. This is available only when the
CS4297A AC-link is active and the Codec Ready
bit is ‘set’. The audio (including extended audio)
registers (Index 00h - 38h) and the vendor specific
registers (Index 5Ah - 7Ah) are reset to their default
states by a write of any value to the Reset Register
(Index 00h).
DS318PP6
CS4297A
CS4297A
5.2
Powerdown Controls
The
Powerdown
Control/Status
Register
(Index 26h) controls the power management functions. The PR[6:0] bits in this register control the
internal powerdown states of the CS4297A. Powerdown control is available for individual subsections
of the CS4297A by asserting any PRx bit or any
combination of PRx bits. Most powerdown states
can be resumed by clearing the corresponding PRx
bit. Table 10 shows the mapping of the power control bits to the functions they manage.
When PR0 is ‘set’, the L/R ADCs and the Input
Mux are shut down and the ADC bit in the Powerdown Control/Status Register (Index 26h) is
‘cleared’ indicating the ADCs are no longer in a
ready state. The same is true for the DACs, the analog mixers, and the reference voltage (Vrefout).
When the PR2 or PR3 bit of the mixer is ‘cleared’,
the mixer section will begin a power-on process,
and the corresponding powerdown status bit will be
‘set’ when the hardware is ready.
Shutting down the AC-link by ‘setting’ PR4 causes
the primary Codec to turn off the BIT_CLK and
drive SDATA_IN low. It also ignores SYNC and
SDATA_OUT in their normal capacities. Either a
Cold Reset or a Warm Reset is required to restore
operation to the CS4297A. A Cold Reset will restore all mixer registers to their power-on default
values. A Warm Reset will not alter the values of
any mixer register, except clearing the PR4 bit in
Powerdown Control/Status Register (Index 26h).
The PR5 bit powers down all analog and digital
subsections of the device. A Cold Reset is the only
way to restore operation to the CS4297A after a
PR5 global powerdown.
The CS4297A does not automatically mute any input or output when the powerdown bits are ‘set’.
The software driver controlling the AC ’97 device
must manage muting the input and output analog
signals before putting the part into any power management state. The definition of each PRx bit may
affect a single subsection or a combination of subsections within the CS4297A. Table 11 on page 34
contains the matrix of subsections affected by the
respective PRx function. Table 12 on page 34
shows the different operating power consumptions
levels for different powerdown functions.
PR Bit
Function
PR0
L/R ADCs and Input Mux Powerdown
PR1
Front DACs Powerdown
PR2
Analog Mixer Powerdown (Vref on)
PR3
Analog Mixer Powerdown (Vref off)
PR4
AC-link Powerdown (BIT_CLK off)*
PR5
Internal Clock Disable
PR6
Alternate Line Out Powerdown
* Applies only to primary codec
Table 10. Powerdown PR Bit Functions
DS318PP6
33
33
CS4297A
CS4297A
PR Bit
ADCs
PR0
•
DACs
Mixer
Alternate
Line Out
Analog
Reference
•
•
•
•
•
•
•
•
PR1
PR2
PR3
•
AC
Link
Internal
Clock Off
•
•
•
PR4
PR5
•
•
•
•
•
PR6
•
Table 11. Powerdown PR Function Matrix
Power State
IDVdd (mA)
[DVdd=3.3 V]
IDVdd (mA)
[DVdd=5 V]
IAVdd (mA)
Full Power + S/PDIF 1
30.1
49.4
37.9
Full Power
24.5
43.4
37.9
ADCs off (PR0)
21.0
38.1
29.0
DACs off (PR1)
22.1
39.6
31.3
Audio off (PR2)
22.1
39.9
10.7
Vref off (PR3)
18.9
34.8
45 µA
AC-Link off (PR4)
19.3
35.5
37.9
Internal Clocks off (PR5)
11 µA
27 µA
45 µA
Alt line out off (PR6)
24.5
43.4
36.2
RESET
11 µA
27 µA
450 µA
Table 12. Power Consumption by Powerdown Mode
1
34
34
Assuming standard resistive load for transformer coupled coaxial S/PDIF output
(Rload = 292 Ohm, DVdd = 3.3 V) (Rload = 415 Ohm, DVdd = 5 V).
General: IDVdd S/PDIF = IDVdd + DVdd/Rload/2
DS318PP6
CS4297A
CS4297A
6. ANALOG HARDWARE
DESCRIPTION
The analog line-level input hardware consists of
four stereo inputs (LINE_IN_L/R, CD_L/GND/R,
VIDEO_L/R, and AUX_L/R), two selectable
mono microphone inputs (MIC1 and MIC2), and
two mono inputs (PC_BEEP and PHONE). The analog line-level output hardware consists of a mono
output (MONO_OUT), and dual stereo line outputs
(LINE_OUT_L/R and ALT_LINE_OUT_L/R).
This section describes the analog hardware needed
to interface with these pins. The designs presented
in this section comply with specifications detailed
in Chapter 17 of the Microsoft PC Design Guidelines [7] (referred to as PC 99). For EMI reduction
techniques refer to the application note N165:
CS4297A/CS4299 EMI Reduction Techniques [5].
6.1
R
1.0 µF
6.8 kΩ
6.8 kΩ
CD_R
CD_L
CD Input
The CD line-level input has an extra pin,
CD_GND, providing a pseudo-differential input
for both CD_L and CD_R. This pin takes the
common-mode noise out of the CD inputs when
DS318PP6
6.8 kΩ
1.0 µ F
6.8 kΩ
1.0 µ F
6.8 kΩ
2.2 µF
3.4 kΩ
CD_COM
CD_R
CD_L
CD_GND
6.8 kΩ
6.8 kΩ
3.4 kΩ
(All resistors 1%)
AGND
Figure 11. Differential 2 VRMS CD Input
CD_R
CD_L
CD_COM
6.1.2
L
Figure 10. Line Input (Replicate for Video and Aux)
Line-Level Inputs
Figure 10 shows circuitry for a line-level stereo input. Replicate this circuit for the Line, Video and
Aux inputs. This design attenuates the input by
6 dB, bringing the signal from the PC 99 specified
2 VRMS, to the CS4297A maximum allowed
1 VRMS.
1.0 µF
6.8 kΩ
Analog Inputs
All analog inputs to the CS4297A, including
CD_GND, should be capacitively coupled to the
input pins. Unused analog inputs should be tied together and connected through a capacitor to analog
ground or tied to the Vrefout pin directly. The maximum allowed voltage for analog inputs, except the
microphone input, is 1 VRMS. For the microphone
input the maximum allowed voltage depends on the
selected boost setting.
6.1.1
connected to the CD analog source ground. Following the reference designs in Figure 11 and
Figure 12 provides extra attenuation of common
mode noise coming from the CD-ROM drive,
thereby producing a higher quality signal. One percent resistors are recommended since closely
matched resistor values provide better common-mode attenuation of unwanted signals. The
circuit shown in Figure 11 can be used to attenuate
a 2 VRMS CD input signal by 6 dB. The circuit
shown in Figure 12 can be used for a 1 VRMS CD input signal.
1.0 µF
100 Ω
1.0 µ F
100 Ω
2.2 µF
100 Ω
47 kΩ
CD_R
CD_L
CD_GND
47 kΩ
47 kΩ
AGND
Figure 12. Differential 1 VRMS CD Input
35
35
CS4297A
CS4297A
6.1.3
Microphone Inputs
6.1.4
Figure 13 illustrates an input circuit suitable for dynamic and electret microphones. Electret, or phantom-powered, microphones use the right channel
(ring) of the jack for power. The design also supports the recommended advanced frequency response for voice recognition as specified in PC 99.
Note the microphone input to the CS4297A has an
integrated pre-amplifier. Using the 20dB bit in the
Microphone Volume Register (Index 0Eh) the
pre-amplifier gain can be set to 0 dB or 20 dB.
Figure 14 shows an external pre-amplifier circuit
for an additional 18 dB gain.
The PC_BEEP input is useful for mixing the output
of the “beeper” (timer chip), provided in most PCs,
with the other audio signals. When the CS4297A is
held in reset, PC_BEEP is passed directly to the
line output. This allows the system sounds or
“beeps” to be available before the AC ’97 interface
has been activated. Figure 15 illustrates a typical
input circuit for the PC_BEEP input. If PC_BEEP
is driven from a CMOS gate, the 4.7 kΩ resistor
should be tied to analog ground instead of +5VA.
Although this input is described for a low-quality
“beeper”, it is of the same high-quality as all other
analog inputs and may be used for other purposes.
2 kΩ
1 µF
47 kΩ
0.33 µF
MC33078 or
MC33178
47 Ω
100 pF
NPO
+
0.1 µF
Vrefout
+5VA (Low Noise) or
AGND if CMOS Source
0.33 µF
X7R
MIC1
or
MIC2
47 kΩ
6.8 K Ω
+
PC Beep Input
4.7 kΩ
47 kΩ
PC_BEEP
PC-BEEP-BUS
220 pF
NPO
0.1 µF
2.7 nF
X7R
X7R
3.3 µF
AGND
Figure 13. Microphone Input
Figure 15. PC_BEEP Input
+5 VA
+5 VA
8
1
U1A
MC33078D
3
+
2
-
4
47 kΩ
+
10 µF
68 kΩ
47 kΩ
AGND
AGND
AGND
100 kΩ
47 kΩ
2.7 kΩ
4
3
5
2
1
AGND
0.068 µF
X7R
220 pF
220 pF
+
AGND
6.8 kΩ
+5 VA U1B
8 MC33078D
5+
1 µF
7
6
MIC1/MIC2
X7R
4
10 µF
AGND
CGND
220 pF
AGND
47 kΩ
Figure 14. Microphone Pre-amplifier
36
36
DS318PP6
CS4297A
CS4297A
6.1.5
Phone Input
MONO_OUT pins require 680 pF to 1000 pF NPO
capacitors between the corresponding pin and analog ground. Each analog output is DC-biased up to
the Vrefout signal reference, nominally 2.3 V. This
requires the outputs be AC-coupled to external circuitry (AC load must be greater than 10 kΩ) or DC
coupled to a buffer op-amp biased at Vrefout.
One application of the PHONE input is to interface
to the output of a modem analog front end (AFE)
device so that modem dialing signals and protocol
negotiations may be monitored through the audio
system. Figure 16 shows a design for a modem
connection where the output is fed from the
CS4297A MONO_OUT pin through a divider. The
divider ratio shown does not attenuate the signal,
providing an output voltage of 1 VRMS. If a lower
output voltage is desired, the resistors can be replaced with appropriate values, as long as the total
load on the output is kept greater than 10 kΩ. The
PHONE input is divided by 6 dB to accommodate
a line-level source of 2 VRMS.
6.2
6.2.1
See Figure 18 for a line-level stereo output reference design. See Figure 17 for a recommended
headphone stereo output reference design.
6.2.2
Mono Output
The mono output, MONO_OUT, can be either a
sum of the left and right output channels, attenuated by 6 dB to prevent clipping at full scale, or the
selected Mic signal. The mono out channel can
drive the PC internal mono speaker using an appropriate buffer circuit
Analog Outputs
The analog line-level output section provides two
stereo outputs and a mono output. The
LINE_OUT_L/R, ALT_LINE_OUT_L/R, and
1.0 µ F
6.8 kΩ
PHONE
MONO_OUT
Stereo Outputs
+
ALT_LINE_OUT_R
ALT_LINE_OUT_L
1
4
1
4
2
3
2
3
47 kΩ
ELEC
1000 pF
NPO
HP_OUT_R
+
1/4 WATT
10 Ω
220 µF
39 kΩ
27 kΩ
1000 pF
NPO
10 Ω
220 µF
22 pF
NPO
MONO_OUT
6.8 kΩ
1
PHONE
1.0 µ F
0Ω
TDA1308
2
3
ELEC
22 pF
NPO
HP_OUT_L
+
1/4 WATT
4
1000 pF
AGND
VREFOUT
6
-
5
+
3
47 kΩ
7
1
2
TDA1308
0.1 µF
Y5V
AGND
1 µF
AGND
AGND
AGND
Figure 16. Modem Connection
Figure 18. Stereo Output
39 kΩ
22 pF
NPO
2
ALT_LINE_OUT_R
27 kΩ
Vrefout
-
3
1
+
220 µ F
ELEC
10 Ω
1/4 Watt
+
220 µ F
ELEC
10 Ω
1/4 Watt
+
TDA1308
5
6
ALT_LINE_OUT_L
+
7
-
27 kΩ
1000 pF 1000 pF
NPO
NPO
AGND
Headphone
Out
22 pF
NPO
39 kΩ
47 kΩ
47 kΩ
AGND
Figure 17. Alternate Line Output as Headphone Output
DS318PP6
37
37
CS4297A
CS4297A
6.3
Miscellaneous Analog Signals
6.4
Power Supplies
The power supplies providing analog power should
be as clean as possible to minimize coupling into
the analog section which could degrade analog performance. The analog power pins, AVdd1 and
AVdd2, supply power to all the analog circuitry on
the CS4297A. The +5 V analog supply should be
generated from a linear voltage regulator (7805
type) connected to a +12 V supply. This helps isolate the analog circuitry from noise typically found
on +5 V digital supplies. A typical voltage regulator circuit for analog power using a
MC78M05CDT +5 V regulator is shown in
Figure 19. The digital power pins, DVdd1 and
DVdd2, should be connected to the same digital
supply as the controller AC-link interface. The digital interface on the CS4297A may operate at either
+3.3 V or +5 V and proper connection of these pins
will depend on the digital power supply of the controller.
The AFLT1 and AFLT2 pins must have a 1000 pF
NPO capacitor to analog ground. These capacitors
provide a single-pole low-pass filter at the inputs to
the ADCs. This makes low-pass filters at each analog input pin unnecessary.
The REFFLT pin must have a 1 µF and a 0.1 µF capacitor connected to analog ground with a short,
wide trace to this pin (see Figure 21 in Section 8,
Grounding and Layout, for an example). The 1 µF
capacitor must not be replaced with any value higher than 1 µF. No other connection should be made,
as any coupling onto this pin will degrade the analog performance of the CS4297A. Likewise, digital
signals should be kept away from REFFLT for similar reasons.
The Vrefout pin is typically 2.3 V and provides a
common mode signal for single-supply external
circuits. Vrefout only supports light DC loads and
should be buffered if AC loading is needed. For
typical use the Vrefout pin should have a 1 µF and
a 0.1 µF capacitor connected to analog ground.
6.5
Reference Design
See Section 11 for a CS4297A reference design.
+12VD
+5VA
MC78M05CDT
1
Y5V
0.1µF
+ ELEC
10µF
IN
OUT
3
+ ELEC
GND
2
Y5V
0.1µF
DGND
10µF
AGND
Figure 19. Voltage Regulator
38
38
DS318PP6
CS4297A
CS4297A
7. SONY/PHILIPS DIGITAL
INTERFACE (S/PDIF)
The S/PDIF digital output is used to interface the
CS4297A to consumer audio equipment external to
the PC. This output provides an interface for storing digital audio data or playing digital audio data
to digital speakers. Figure 20 illustrates the circuits
necessary for implementing the IEC-958 optical or
consumer interface. For further information on
S/PDIF operation see application note AN22: Overview of Digital Audio Interface Data Structures [3].
For further information on S/PDIF recommended
transformers see application note AN134: AES and
S/PDIF Recommended Transformers [4].
8. GROUNDING AND LAYOUT
Figure 21 on page 40 shows the conceptual layout
for the CS4297A. The decoupling capacitors
should be located physically as close to the pins as
possible. Also note the connection of the REFFLT
decoupling capacitors to the ground return trace
connected directly to the ground return pin, AVss1.
cuitry. All analog components and traces should be
located over the analog ground plane and all digital
components and traces should be located over the
digital ground plane.
The common connection point between the two
ground planes (required to maintain a common
ground voltage potential) should be located under
the CS4297A. The AC-link digital interface connection traces should be routed such that the digital
ground plane lies underneath these signals (on the
internal ground layer). This applies along the entire
length of these traces from the AC ’97 controller to
the CS4297A.
Refer to the Application Note AN18: Layout and
Design Rules for Data Converters and Other
Mixed Signal Devices [2] for more information on
layout and design rules.
It is strongly recommended that separate analog
and digital ground planes be used. Separate ground
planes keep digital noise and return currents from
modulating the CS4297A ground potential and degrading performance. The digital ground pins
should be connected to the digital ground plane and
kept separate from the analog ground connections
of the CS4297A and any other external analog cir-
SPDO/SDO2
S/PDIF_OUT
5
J1
R1
+5V_PCI
R2
T1
0.1 µ F
SPDO/SDO2 4
3
8.2 kΩ 2
1
DVdd 3.3V
5V
R1 247.5 Ω 375 Ω
R2 107.6 Ω 93.75 Ω
DGND
DGND
DGND
6
TOTX-173
DGND
Figure 20. S/PDIF Output
DS318PP6
39
39
CS4297A
CS4297A
Vrefout
1000 pF to via
NPO
Via to +5VA
1 µF
0.1 µF
Y5V
Via to +5VA
AFLT2
AFLT1
AVss1
REFFLT
0.1 µF
Y5V
AVdd1
Via to Analog
Ground
AVdd2
Analog
Ground
Via to Analog
Ground
AVss2
Digital
Ground
Via to Digital Ground
Pin 1
DVdd1
0.1 µF
Y5V
DVss1
DVss2
0.1 µF
Y5V
DVdd2
Via to +5VD or +3.3VD
Via to +5VD or +3.3VD
Figure 21. Conceptual Layout for the CS4297A
40
40
DS318PP6
CS4297A
CS4297A
S/PDIF_OUT
EAPD
ID1#
ID0#
NC
NC
AVss2
ALT_LINE_OUT_R
NC
ALT_LINE_OUT_L
AVdd2
MONO_OUT
9. PIN DESCRIPTIONS
48 47 46 45 44 43 42 41 40 39 38 37
CS4297A-xQ
DVss2
SDATA_IN
DVdd2
SYNC
RESET#
PC_BEEP
1
2
3
4
5
6
7
8
9
10
11
12
(48-Pin LQFP)
DVdd1
XTL_IN
XTL_OUT
DVss1
SDATA_OUT
BIT_CLK
36
35
34
33
32
31
30
29
28
27
26
25
LINE_OUT_R
LINE_OUT_L
FLTO
FLTI
FLT3D
BPCFG
AFLT2
AFLT1
Vrefout
REFFLT
AVss1
AVdd1
PHONE
AUX_L
AUX_R
VIDEO_L
VIDEO_R
CD_L
CD_GND
CD_R
MIC1
MIC2
LINE_IN_L
LINE_IN_R
13 14 15 16 17 18 19 20 21 22 23 24
Figure 22. Pin Locations for the CS4297A
DS318PP6
41
41
CS4297A
CS4297A
Audio I/O
PC_BEEP - Analog Mono Source, Input, Pin 12
The PC_BEEP input is intended to allow the PC system POST (Power On Self-Test) tones to pass
through to the audio subsystem. The PC_BEEP input has two connections: the first connection is to the
analog output mixer, the second connection is directly to the LINE_OUT stereo outputs. While the
RESET# pin is actively being asserted and the BCFG pin is left floating, the PC_BEEP bypass path to
the LINE_OUT outputs is enabled. While the CS4297A is in normal operation mode, with RESET#
deasserted or BCFG grounded, PC_BEEP is a monophonic source to the analog output mixer. The
maximum allowable input is 1 VRMS (sinusoidal). This input is internally biased at the Vrefout voltage
reference and requires AC-coupling to external circuitry. If this input is not used, it should be connected
to the Vrefout pin or AC-coupled to analog ground.
PHONE - Analog Mono Source, Input, Pin 13
This analog input is a monophonic source to the analog output mixer. It is intended to be used as a
modem subsystem input to the audio subsystem. The maximum allowable input is 1 VRMS (sinusoidal).
This input is internally biased at the Vrefout voltage reference and requires AC-coupling to external
circuitry. If this input is not used, it should be connected to the Vrefout pin or AC-coupled to analog
ground.
MIC1 - Analog Mono Source, Input, Pin 21
This analog input is a monophonic source to the analog output mixer. It is intended to be used as a
desktop microphone connection to the audio subsystem. The CS4297A internal mixer’s microphone
input is MUX selectable with either MIC1 or MIC2 as the input. The maximum allowable input is 1 VRMS
(sinusoidal). This input is internally biased at the Vrefout voltage reference and requires AC-coupling to
external circuitry. If this input is not used, it should be connected to the Vrefout pin or AC-coupled to
analog ground.
MIC2 - Analog Mono Source, Input, Pin 22
This analog input is a monophonic source to the analog output mixer. It is intended to be used as an
alternate microphone connection to the audio subsystem. The CS4297A internal mixer’s microphone
input is MUX selectable with either MIC1 or MIC2 as the input. The maximum allowable input is 1 VRMS
(sinusoidal). This input is internally biased at the Vrefout voltage reference and requires AC-coupling to
external circuitry. If this input is not used, it should be connected to the Vrefout pin or AC-coupled to
analog ground.
LINE_IN_L, LINE_IN_R - Analog Line Source, Inputs, Pins 23 and 24
These inputs form a stereo input pair to the CS4297A. The maximum allowable input is 1 VRMS
(sinusoidal). These inputs are internally biased at the Vrefout voltage reference and require AC-coupling
to external circuitry. If these inputs are not used, they should both be connected to the Vrefout pin or
both AC-coupled, with separate AC-coupling caps, to analog ground.
CD_L, CD_R - Analog CD Source, Inputs, Pins 18 and 20
These inputs form a stereo input pair to the CS4297A. It is intended to be used for the Red Book CD
audio connection to the audio subsystem. The maximum allowable input is 1 VRMS (sinusoidal). These
inputs are internally biased at the Vrefout voltage reference and require AC-coupling to external circuitry.
If these inputs are not used, they should both be connected to the Vrefout pin or both AC-coupled, with
separate AC-coupling caps, to analog ground.
CD_GND - Analog CD Common Source, Input, Pin 19
This analog input is used to remove common mode noise from Red Book CD audio signals. The
impedance on the input signal path should be one half the impedance on the CD_L and CD_R input
paths. This pin requires AC-coupling to external circuitry. If this input is not used, it should be connected
to the Vrefout pin or AC-coupled to analog ground.
42
42
DS318PP6
CS4297A
CS4297A
VIDEO_L, VIDEO_R - Analog Video Audio Source, Inputs, Pins 16 and 17
These inputs form a stereo input pair to the CS4297A. It is intended to be used for the audio signal
output of a video device. The maximum allowable input is 1 VRMS (sinusoidal). These inputs are
internally biased at the Vrefout voltage reference and require AC-coupling to external circuitry. If these
inputs are not used, they should both be connected to the Vrefout pin or both AC-coupled, with separate
AC-coupling caps, to analog ground.
AUX_L, AUX_R - Analog Auxiliary Source, Inputs, Pins 14 and 15
These inputs form a stereo input pair to the CS4297A. The maximum allowable input is 1 VRMS
(sinusoidal). These inputs are internally biased at the Vrefout voltage reference and require AC-coupling
to external circuitry. If these inputs are not used, they should both be connected to the Vrefout pin or
both AC-coupled, with separate AC-coupling caps, to analog ground.
LINE_OUT_L, LINE_OUT_R - Analog Line-Level, Outputs, Pins 35 and 36
These signals are analog outputs from the stereo output mixer. The full-scale output voltage for each
output is nominally 1 VRMS (sinusoidal). These outputs are internally biased at the Vrefout voltage
reference and require either AC-coupling to external circuitry or DC-coupling to a buffer op-amp biased
at the Vrefout voltage. These pins need a 680-1000 pF NPO capacitor attached to analog ground.
ALT_LINE_OUT_L, ALT _LINE_OUT_R - Analog Alternate Line-Level, Outputs, Pins 39 and 41
These signals are analog outputs from the stereo output mixer. The full-scale output voltage for each
output is nominally 1 VRMS (sinusoidal). These outputs are internally biased at the Vrefout voltage
reference and require either AC-coupling to external circuitry or DC-coupling to a buffer op-amp biased
at the Vrefout voltage. These pins need a 680-1000 pF NPO capacitor attached to analog ground.
MONO_OUT - Analog Mono Line-Level, Output, Pin 37
This signal is an analog output from the stereo-to-mono mixer or MIC1/2. The full-scale output voltage
for this output is nominally 1 VRMS (sinusoidal). This output is internally biased at the Vrefout voltage
reference and requires either AC-coupling to external circuitry or DC-coupling to a buffer op-amp biased
at the Vrefout voltage. This pin needs a 680-1000 pF NPO capacitor attached to analog ground.
Clock and Configuration
XTL_IN - Crystal Input/Clock Input, Pin 2
In primary mode this pin requires either a 24.576 MHz crystal, with the other pin attached to XTL_OUT,
or an external CMOS clock. The crystal frequency must be 24.576 MHz and designed for fundamental
mode, parallel resonance operation. If an external CMOS clock is used to drive this pin, it must run at
24.576 MHz. In secondary mode all timing is derived from the BIT_CLK input signal and this pin should
be left floating.
XTL_OUT - Crystal Output, Pin 3
This pin is used when a crystal is placed between XTL_OUT and XLT_IN. If an external 24.576 MHz
clock is used on XTL_IN, this pin must be left floating with no traces or components connected to it. In
secondary mode this pin should be left floating.
ID1#, ID0# - Codec ID, Inputs, Pins 45 and 46
These pins select the Codec ID and mode of operation for the CS4297A. They are only sampled after
the rising edge of RESET#. These pins are internally pulled up to the digital supply voltage and should
be left floating for logic ‘0’ or tied to digital ground for logic ‘1’. When both pins are left floating the
CS4297A is the primary codec. If either or both pins are tied to ground the CS4297A is a secondary
codec.
DS318PP6
43
43
CS4297A
CS4297A
Analog Reference, Filters, and Configuration
REFFLT - Internal Reference Voltage, Input, Pin 27
This signal is the voltage reference used internal to the CS4297A. A 0.1 µF and a 1.0 µF (must not be
larger than 1 µF) capacitor with short, wide traces must be connected to this pin. No other connections
should be made to this pin.
Vrefout - Voltage Reference, Output, Pin 28
All analog inputs and outputs are centered around Vrefout, nominally 2.3 Volts. This pin may be used to
level shift external circuitry. This pin cannot drive any DC loads, thus any external loading must be
buffered.
AFLT1 - Left ADC Channel Antialiasing Filter, Input, Pin 29
This pin needs a 1000 pF NPO capacitor connected to analog ground.
AFLT2 - Right ADC Channel Antialiasing Filter, Input, Pin 30
This pin needs a 1000 pF NPO capacitor connected to analog ground.
FLTI, FLTO - 3D Filter, Input, Pin 33 and 34
A 1000 pF capacitor must be connected between FLTI and FLTO if the 3D function is used.
FLT3D - 3D Filter, Input, Pin 32
A 0.01 µF capacitor must be connected from this pin to AGND if the 3D function is used.
BCFG - Beep Configuration, Input, Pin 31
This pin is the configuration control for the PC_BEEP bypass path. If this pin is grounded, the bypass
path is disabled. If this pin is left floating, the PC_BEEP bypass path is enabled.
Misc. Digital Interfaces
S/PDIF_OUT - Sony/Philips Digital Interface, Output, Pin 48
This pin generates the S/PDIF digital output from the CS4297A when the SPEN bit in the S/PDIF
Control Register (Index 68h) is ‘set’. This output may be used to directly drive a resistive divider and
coupling transformer to an RCA-type connector for use with consumer audio equipment.
EAPD - External Amplifier Powerdown, Output, Pin 47
This pin is used to control the powerdown state of an audio amplifier external to the CS4297A. The
output is controlled by the EAPD bit in the Powerdown Ctrl/Stat Register (Index 26h). It is driven as a
normal CMOS output and defaults low (‘0’) upon power-up.
44
44
DS318PP6
CS4297A
CS4297A
AC-Link
RESET# - AC ’97 Chip Reset, Input, Pin 11
This active low signal is the asynchronous Cold Reset input to the CS4297A. The CS4297A must be
reset before it can enter normal operating mode.
SYNC - AC-Link Serial Port Sync pulse, Input, Pin 10
This signal is the serial port timing signal for the AC-link. Its period is the reciprocal of the maximum
sample rate, 48 kHz. The signal is generated by the controller, synchronous to BIT_CLK. SYNC is an
asynchronous input when the CS4297A is configured as a primary audio codec and is in a PR4
powerdown state. A series terminating resistor of 47 Ω should be connected on the signal near the
SYNC source.
BIT_CLK - AC-Link Serial Port Master Clock, Input/Output, Pin 6
This input/output signal controls the master clock timing for the AC-link. In primary mode, this signal is a
12.288 MHz output clock derived from a 24.576 MHz crystal on the XTL_IN input clock. When the
CS4297A is in secondary mode, this signal is an input which controls the AC-link serial interface and
generates all internal clocking including the AC-link serial interface timing and the analog sampling
clocks. A series terminating resistor of 47 Ω should be connected on this signal close to the CS4297A in
primary mode or close to the BIT_CLK source in secondary mode.
SDATA_OUT - AC-Link Serial Data Input Stream to AC ’97, Input, Pin 5
This input signal receives the control information and digital audio output streams. The data is clocked
into the CS4297A on the falling edge of BIT_CLK. A series terminating resistor of 47 Ω should be
connected on this signal near the controller.
SDATA_IN - AC-Link Serial Data Output Stream from AC ’97, Output, Pin 8
This output signal transmits the status information and digital audio input streams from the ADCs. The
data is clocked out of the CS4297A on the rising edge of BIT_CLK. A series terminating resistor of 47 Ω
should be connected on this signal as close to the CS4297A as possible.
Power Supplies
DVdd1, DVdd2 - Digital Supply Voltage, Pins 1 and 9
Digital supply voltage for the AC-link section of the CS4297A. These pins can be tied to +5 V digital or
to +3.3 V digital. The CS4297A and controller AC-link should share a common digital supply
DVss1, DVss2 - Digital Ground, Pins 4 and 7
Digital ground connection for the AC-link section of the CS4297A. These pins should be isolated from
analog ground currents.
AVdd1, AVdd2 - Analog Supply Voltage, Pins 25 and 38
Analog supply voltage for the analog and mixed signal sections of the CS4297A. These pins must be
tied to the analog +5 V power supply. It is strongly recommended that +5 V be generated from a voltage
regulator to ensure proper supply currents and noise immunity from the rest of the system.
AVss1, AVss2 - Analog Ground, Pins 26 and 42
Ground connection for the analog, mixed signal, and substrate sections of the CS4297A. These pins
should be isolated from digital ground currents.
DS318PP6
45
45
CS4297A
CS4297A
10. PARAMETER AND TERM DEFINITIONS
AC ’97 Specification
Refers to the Audio Codec ’97 Component Specification Ver 2.1 published by the Intel® Corporation [6].
AC ’97 Controller or Controller
Refers to the control chip which interfaces to the audio codec AC-link. This has been also called DC ’97
for Digital Controller ’97 [6].
AC ’97 Registers or Codec Registers
Refers to the 64-field register map defined in the AC ’97 Specification.
ADC
Refers to a single Analog-to-Digital converter in the CS4297A. “ADCs” refers to the stereo pair of
Analog-to-Digital converters. The CS4297A ADCs have 18-bit resolution.
Codec
Refers to the chip containing the ADCs, DACs, and analog mixer. In this data sheet, the codec is the
CS4297A.
DAC
Refers to a single Digital-to-Analog converter in the CS4297A. “DACs” refers to the stereo pair of
Digital-to-Analog converters. The CS4297A DACs have 20-bit resolution.
dB FS A
dB FS is defined as dB relative to full-scale. The “A” indicates an A weighting filter was used.
Differential Nonlinearity
The worst case deviation from the ideal code width. Units in LSB.
Dynamic Range (DR)
DR is the ratio of the RMS full-scale signal level divided by the RMS sum of the noise floor, in the
presence of a signal, available at any instant in time (no change in gain settings between
measurements). Measured over a 20 Hz to 20 kHz bandwidth with units in dB FS A.
FFT
Fast Fourier Transform.
Frequency Response (FR)
FR is the deviation in signal level verses frequency. The 0 dB reference point is 1 kHz. The amplitude
corner, Ac, lists the maximum deviation in amplitude above and below the 1 kHz reference point. The
listed minimum and maximum frequencies are guaranteed to be within the Ac from minimum frequency
to maximum frequency inclusive.
Fs
Sampling Frequency.
Interchannel Gain Mismatch
For the ADCs, the difference in input voltage to get an equal code on both channels. For the DACs, the
difference in output voltages for each channel when both channels are fed the same code. Units are in
dB.
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CS4297A
CS4297A
Interchannel Isolation
The amount of 1 kHz signal present on the output of the grounded AC-coupled line input channel with 1
kHz, 0 dB, signal present on the other line input channel. Units are in dB.
Line-level
Refers to a consumer equipment compatible, voltage driven interface. The term implies a low driver
impedance and a minimum 10 kΩ load impedance.
Paths
A-D: Analog in, through the ADCs, onto the serial link.
D-A: Serial interface inputs through the DACs to the analog output.
A-A: Analog in to Analog out (analog mixer).
PC 99
Refers to the PC 99 System Design Guide published by the Microsoft® Corporation [7].
PLL
Phase Lock Loop. Circuitry for generating a desired clock from an external clock source.
Resolution
The number of bits in the output words to the DACs, and in the input words to the ADCs.
Signal to Noise Ratio (SNR)
SNR, similar to DR, is the ratio of an arbitrary sinusoidal input signal to the RMS sum of the noise floor,
in the presence of a signal. It is measured over a 20 Hz to 20 kHz bandwidth with units in dB.
S/PDIF
Sony/Phillips Digital Interface. This interface was established as a means of digitally interconnecting
consumer audio equipment. The documentation for S/PDIF has been superseded by the IEC-958
consumer digital interface document.
SRC
Sample Rate Converter. Converts data derived at one sample rate to a differing sample rate. The
CS4297A operates at a fixed sample frequency of 48 kHz. The internal sample rate converters are used
to convert digital audio streams playing back at other frequencies to 48 kHz.
Total Harmonic Distortion plus Noise (THD+N)
THD+N is the ratio of the RMS sum of all non-fundamental frequency components, divided by the RMS
full-scale signal level. It is tested using a -3 dB FS input signal and is measured over a 20 Hz to 20 kHz
bandwidth with units in dB FS.
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47
2
1
PHONO-1/8
J7
4
2.2K
+5VA
1uF
Y5V
AGND
AGND
Y5V
C25
AGND
28
1uF
+
C30
DGND
AGND
X7R
0.1uF
C27
1000pF
NPO
C26
1000pF
NPO
AGND
X7R
0.01uF
Y1
NPO
1000pF
C29
CS4297A
C6
ELEC
10uF
C34
+5VD
S/PDIF_OUT
nc7
nc6
nc5
ID1#
ID0#
EAPD
BCFG
MONO_OUT
ALT_LINE_OUT_L
ALT_LINE_OUT_R
LINE_OUT_L
LINE_OUT_R
RESET#
SYNC
SDATA_IN
SDATA_OUT
BIT_CLK
R7
1
2
5
AGND
24.576 MHz
(50 PPM)
DGND
NPO
22pF
Figure 23. CS4297A Reference Design
DGND
22pF
AGND
NPO
ELEC
under the codec
Tie at one point only
10uF
Y5V
GND_TIE
C33
100
C32
R20
C17
C15
ELEC
10uF
ELEC
10uF
48
44
43
40
46
45
R21
AGND
DGND
4
DGND
X7R
0.1uF
6
5
1
TOTX-173
J6
S/PDIF OUT
AGND
NPO
C18
1000pF
NPO
C19
1000pF
AGND
220K
ARST#
ASYNC
ASDIN
ASDOUT
ABITCLK
or ICH Controller
R12
47
47
PCI Audio Controller
AC LINK
47
C31
R8
X7R
X7R
+
31
37
39
41
35
36
11
10
8
5
6
0.1uF
0.1uF
AGND
C11
C10
3
1uF
Y5V
X7R
Y5V
60 mil trace
1uF
0.1uF
1uF
FLT3D
AFLT2
AFLT1
REFFLT
Vrefout
PHONE
VIDEO_L
VIDEO_R
MIC2
MIC1
LINE_IN_L
LINE_IN_R
CD_L
CD_GND
CD_R
AUX_L
AUX_R
PC_BEEP
DVss2
+
2
1.5K
C24
C23
C22
U3
X7R
+3.3VD
X7R
0.1uF
C5
3
R19
6.8K
3
0.1uF
C9
DVss1
AGND
OUT
+5VA
4
R18
R17
Y5V
32
6.8K
1
R16
30
2
C21
29
Y5V
1uF
27
C20
13
16
17
22
21
23
24
18
19
5
6.8K
6.8K
100K
Y5V
1uF
3
R15
R14
R11
C16
20
1
C28
12
15
14
DGND
4
7
2
Y5V
C14
C13
1uF
1uF
100K
100K
6.8K
3
R10
R9
R6
Y5V
4
1
MIC IN
PHONO-1/8
J5
AGND
1uF
X7R
C12
C7
0.1uF
6.8K
6.8K
6.8K
X7R
C8
R5
AGND
C4
0.1uF
IN
2
R4
R3
AGND
ELEC
X7R
C3
10uF
2700pF
6.8K
+
C2
R2
1
3
AGND
DGND
X7R
4
LINE IN
4X1HDR-AU
J3
CD IN
4X1HDR-AU
J2
AUX IN
2X1HDR-SN/PB
J1
MC78M05ACDT
GND
2
U1
DVdd1
+12V
26
AVss1
0.1uF
AVss2
C1
25
AVdd1
47K
1
9
FLTI
33
DVdd2
FLTO
34
42
XTL_OUT
3
R1
XTL_IN
2
38
AVdd2
48
48
+
PC SPEAKER
IN
AGND
220K
R13
AGND
1
2
5
3
4
PHONO-1/8
LINE OUT
J4
CS4297A
CS4297A
11. REFERENCE DESIGN
DS318PP6
CS4297A
CS4297A
12. REFERENCES
1) Cirrus Logic, Audio Quality Measurement Specification, Version 1.0, 1997
http://www.cirrus.com/products/papers/meas/meas.html
2) Cirrus Logic, AN18: Layout and Design Rules for Data Converters and Other Mixed Signal Devices,
Version 6.0, February 1998
3) Cirrus Logic, AN22: Overview of Digital Audio Interface Data Structures, Version 2.0, February 1998
4) Cirrus Logic, AN134: AES and S/PDIF Recommended Transformers, Version 2, April 1999
5) Cirrus Logic, AN165: CS4297A/CS4299 EMI Reduction Techniques, Version 1.0, September 1999
6) Intel®, Audio Codec ’97 Component Specification, Revision 2.1, May 1998
http://developer.intel.com/ial/scalableplatforms/audio/index.htm
7) Microsoft®, PC 99 System Design Guide, Version 1.0, July 1999
http://www.microsoft.com/hwdev/desguid/
8) Intel® 82801AA (ICH) and 82801AB (ICH0) I/O Controller Hub, June 1999
http://developer.intel.com/design/chipsets/datashts/290655.htm
DS318PP6
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CS4297A
CS4297A
13. PACKAGE DIMENSIONS
48L LQFP PACKAGE DRAWING
E
E1
D D1
1
e
B
∝
A
A1
L
DIM
A
A1
B
D
D1
E
E1
e*
L
MIN
--0.002
0.007
0.343
0.272
0.343
0.272
0.016
0.018
0.000°
∝
* Nominal pin pitch is 0.50 mm
INCHES
NOM
0.055
0.004
0.009
0.354
0.28
0.354
0.28
0.020
0.24
4°
MAX
0.063
0.006
0.011
0.366
0.280
0.366
0.280
0.024
0.030
7.000°
MIN
--0.05
0.17
8.70
6.90
8.70
6.90
0.40
0.45
0.00°
MILLIMETERS
NOM
1.40
0.10
0.22
9.0 BSC
7.0 BSC
9.0 BSC
7.0 BSC
0.50 BSC
0.60
4°
MAX
1.60
0.15
0.27
9.30
7.10
9.30
7.10
0.60
0.75
7.00°
Controlling dimension is mm.
JEDEC Designation: MS022
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• Notes •
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52
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