ETC STAC9721

DATA SHEET
SigmaTel, Inc.
STAC9721/23
Integrating Mixed-Signal Solutions
Stereo AC'97 Codec
With Multi-Codec Option
GENERAL DESCRIPTION:
SigmaTel’s STAC9721/23 is a general-purpose 18-bit stereo, full duplex, audio codec that conforms to
the analog component specification of AC'97 (Audio Codec 97 Component Specification Rev. 2.1). The
STAC9721/23 incorporates SigmaTel’s proprietary Sigma-Delta technology to achieve a DAC SNR in
excess of 95dB. The DACs, ADCs, and mixer are integrated with analog I/Os, which include four analog
line-level stereo inputs, two analog line-level mono inputs, two stereo outputs, and one mono output
channel. Also included are SigmaTel’s 3D stereo enhancement (SS3D), and an extra true line-level out
for headphones or speaker amplifiers. The STAC9721/23 may be used as a secondary codec, with the
STAC9700/04/07/44/45 or a 4-channel STAC9708 as the primary, in multiple codec configurations
conforming to the AC'97 Rev. 2.1 specification. This configuration can provide up to six-channel output,
providing AC-3 playback for DVD applications. The STAC9721/23 communicates via the five-wire ACLink interface with any AC-Link capable controller or advanced core logic chip-set. Packaged in an
AC'97 compliant 48-pin TQFP, the STAC9721/23 can be placed on motherboards, daughter boards, addon cards or AMR/MDC cards.
FEATURES:
•
High performance Σ∆ technology
•
EAPD – External Amplifier Power Down Control
•
Energy saving power down modes
•
Multi-Codec option (Intel AC'97 rev 2.1)
•
18-bit full duplex stereo ADC, DACs
•
Six analog line-level inputs
•
AC-Link protocol compliance
•
48-pin TQFP
•
3.3V Multiple power supply options
•
LINE-to-LINE SNR 102dB
•
Pin compatible with the STAC9700/44/45
•
The STAC9723 is tested at +3.3V
•
SigmaTel Surround (SS3D) Stereo Enhancement
ORDERING INFORMATION:
PART
NUMBER
PACKAGE
TEMPERATURE
RANGE
SUPPLY RANGE
STAC9721T
48-pin TQFP 7mm x7mm x 1.4mm
DVdd = 3.3V or 5V, AVdd = 5V
STAC9723T
48-pin TQFP 7mmx7mm x 1.4mm
0o C to +70o C
0o C to +70o C
DVdd = 3.3V, AVdd = 3.3V
SigmaTel reserves the right to change specifications without notice
1
04/07/00
SigmaTel, Inc.
Data Sheet
Table of Contents
GENERAL DESCRIPTION:.........................1
TABLE OF CONTENTS – FIGURES ..........3
2.
3.
4.
PIN/SIGNAL DESCRIPTIONS .............7
1.1
DIGITAL I/O
7
1.2
ANALOG I/O
8
1.3
FILTER/REFERENCES/GPIO
9
1.4
POWER AND GROUND SIGNALS 9
CLOCKING
10
2.2
RESET
10
AC-LINK SERIAL INTERFACE
3.2
AC-LINK LOW POWER MODE 18
STAC9721/23 MIXER ...........................19
MIXER INPUT
20
4.2
MIXER OUTPUT
20
4.3
PC BEEP IMPLEMENTATION
4.4
PROGRAMMING REGISTERS:
MAXIMUM RATINGS:
38
10.2
RECOMMENDED CONDITIONS 38
10.3
POWER CONSUMPTION
39
10.4
AC-LINK STATIC DIGITAL
41
10.5
STAC9721 ANALOG
41
10.6
STAC9723 ANALOG
43
Table 1. Package Dimensions
4
Table 2. Pin Designation
4
Table 3. Digital Signal List
7
Table 4. Analog Signal List
8
Table 5. Filtering and Voltage References
9
20
Table 7. Programming Registers
21
21
Table 8. Play Master Volume Register
22
Table 9. PC_BEEP Register
22
Table 10. Analog Mixer Input Gain Register
23
Table 11. Record Select Control Registers
23
6.
MULTIPLE CODEC SUPPORT .........31
6.1
PRIMARY/SECONDARY CODEC 31
6.2
SECONDARY CODEC ACCESS
Table 12. Left Record Select Control Registers 23
32
7.
TESTABILITY ......................................32
8.
EXTENDED FUNCTIONALITY ........33
9.
10.1
20
LOW POWER MODES ........................29
ANTI-POP CIRCUITRY
37
Table 6. Mixer Functional Connections
5.
8.1
ATE TEST MODE
TABLE of Tables
11
4.1
9.7
APPENDIX B ................................................46
DIGITAL INTERFACE........................11
3.1
AC-LINK LOW POWER MODE 36
APPENDIX A ................................................45
AC-LINK ................................................10
2.1
9.6
10. ELECTRICAL SPECIFICATIONS: ...38
TABLE OF CONTENTS................................2
1.
STAC9721
Table 13. Record Gain Registers
24
Table 14. General Purpose Register
24
Table 15. 3D Control Registers
33
Error! Bookmark
not defined.
AC TIMING CHARACTERISTICS .33
Table 16. Powerdown Status Registers
25
9.1
COLD RESET
33
Table 17. Extended Audio ID Functions
26
9.2
WARM RESET
34
Table 19: Analog Current Adjust
27
9.3
CLOCKS
34
Table 16. Multi-Channel Programming
28
9.4
DATA SETUP AND HOLD
35
Table 18. Low Power Modes
29
9.5
SIGNAL RISE AND FALL
35
Table 19. Codec ID Selection
31
Table 20. Secondary Codec Register Access
32
2
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Table 21. Cold Reset
33
Figure 2. STAC9721/23 Block Diagram............... 5
Table 22. Warm Reset
34
Figure 3. AC-Link to its companion controller .. 10
Table 23. Clocks
34
Figure 4. Bi-directional Audio Frame ................. 12
Table 24. Data Setup and Hold
35
Figure 5. AC-Link Audio Output Frame .......... 12
Table 25. Signal Rise and Fall Times
35
Figure 6. Start of an Audio Output Frame ....... 13
Table 26. AC-Link Low Power Mode Timing
36
Figure 7. STAC9721/23 Audio Input Frame ..... 16
Table 27. ATE Test Mode
37
Figure 8. Start of an Audio Input Frame ........... 16
Table 28. Operating Conditions
38
Figure 9. STAC9721/23 Powerdown Timing ..... 18
Table 33: Power Consumption 39
Figure 10. STAC9721/23 Mixer ......................... 19
Table 34: Power Consumption at 3.3V Analog 39
Figure 11. Powerdown/Powerup flow.................. 29
Table 35: Reduced Analog Power Settings
40
Figure 12. Powerdown/Powerup flow ................. 30
Table 30. AC-Link Static Specifications
41
Figure 13. Cold Reset........................................... 33
Table 31. Analog Performance Characteristics 41
Figure 14. Warm Reset ........................................ 34
Table 32. Analog Performance Characteristics 43
Figure 15. Clocks.................................................. 34
Figure 16. Data Setup and Hold.......................... 35
Figure 17. Signal Rise and Fall Times ................ 35
Table of Contents – Figures
Figure 18. AC-Link Low Power Mode Timing.. 36
Figure 19. ATE Test Mode .................................. 37
Figure 1. Package Outline ..................................... 4
3
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Table 1. Package Dimensions
Figure 1. Package Outline
D
Key
TQFP Dimensions
D
D1
E
E1
a (lead
width)
e (pitch)
thickness
9.00 mm
7.00 mm
9.00 mm
7.00 mm
0.20 mm
D1
a
26
38
SigmaTel
E
e
48 pin TQFP
E1
14
2
0.50 mm
1.4 mm
Table 2. Pin Designation
PIN
#
Signal Name
PI
N#
Signal Name
PIN
#
Signal Name
PIN
#
Signal Name
1
2
3
4
5
6
7
8
9
10
11
12
DVdd1
XTL_IN
XTL_OUT
DVss1
SDATA_OUT
BIT_CLK
DVss2
SDATA_IN
DVdd2
SYNC
RESET#
PC_BEEP
13
14
15
16
17
18
19
20
21
22
23
24
PHONE
AUX_L
AUX_R
VIDEO_L
VIDEO_R
CD_L
CD_GND
CD_R
MIC1
MIC2
LINE_IN_L
LINE_IN_R
25
26
27
28
29
30
31
32
33
34
35
36
AVdd1
AVss1
Vref
Vrefout
AFILT1
AFILT2
CAP1
CAP2
CAP3
APOP
LINE_OUT_L
LINE_OUT_R
37
38
39
40
41
42
43
44
45
46
47
48
MONO_OUT
AVdd2
LNLVL_OUT_L
NC
LNLVL_OUT_R
AVss2
NC
NC
CID0
CID1
EAPD
NC
# denotes active low
4
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
2 mono sources
4 stereo
sources
mono
Power
Management
stereo
PCM out DACs
48Kss
AC-link
SYNC
BIT_CLK
SDATA_OUT
SDATA_IN
RESET
Digital
Interface
Registers
64 x 16 bits
LNLVL_OUT
DAC
DAC
PCM in ADCs
ADC
ADC
MIXER
LINE_OUT
MONO_OUT
Analog mixing
and
Gain control
Mic
Boost
0/20 dB
48Kss
M
U
X
MIC1
MIC2
Figure 2. STAC9721/23 Block Diagram
The STAC9721/23 block diagram is illustrated above. It performs fixed 48K sample rate D-A & A-D
conversion, mixing, and analog processing. The digital interface communicates with the AC'97 controller
via the five wire AC-Link and contains the 64 word by 16-bit registers. Two, fixed 48Ks/s DAC’s
support two stereo PCM-out channels. The digital mix of all software sources, including the internal
synthesizer and any other digital sources, is performed in the digital controller. The Mixer block mixes
the PCM_OUT with any analog sources, then outputs to LINE_OUT and LNLVL_OUT. The
MONO_OUT delivers either mic only or a mono mix of sources from the mixer. The two fixed 48Ks/s
ADC’s take any mix of mono or stereo sources and convert it to a stereo PCM-in signal. All ADC's and
DAC's operate at 18-bit resolution.
The STAC9721/23 is designed primarily to support stereo, 2-speaker audio. However, true AC-3
playback can be achieved for 6-speaker applications by taking advantage of the multi-codec option in the
STAC9721/23. Using this option with a STAC9704/07/21/23 or the 4-channel STAC9708 as the primary
codec, and the STAC9721/23 as the secondary codec, 6-channel output can be achieved in an AC'97
architecture. Also, the STAC9721/23 provides for a stereo enhancement feature, SigmaTel Surround 3D
or SS3D. SS3D provides the listener with several options to expand the soundstage beyond the normal 2speaker arrangement.
Together, with the logic component (controller or advanced core logic chip-set) of AC'97, the
STAC9721/23 can be SoundBlaster and Windows Sound System compatible. SoundBlaster is a
registered trademark of Creative Labs. Windows is a registered trademark of Microsoft Corporation.
5
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Figure 3. Connection Diagram –
See Appendix A for an alternative connection diagram when using separate supplies.
See Appendix B for specific connection requirements prior to operation.
2 ohm *
0.1uF
Ferrite Bead *
* Suggested
10uF
0.1uF
1uF
25
AVdd1
3.3V or 5V ± 5%
0.1uF
0.1uF
38
1
AVdd2
DVdd1
9
2
DVdd2
27pF
XTL_IN
12
13
14
15
16
17
18
19
20
21
22
23
24.576MHz
_
PC BEEP
XTL_OUT
3
SDATA_OUT
5
27pF
PHONE
AUX_L
AUX_R
SigmaTel
VIDEO_L
32
46
CID1
CD_GND
27
Vref
CD_R
0.1uF
MIC1
Vrefout
MIC2
Optional Anti-Pop Circuit
31
CAP1
LINE_IN_L
33
LINE_IN_R
10uF
100uF
APOP
34
CAP2
EAPD
29
1uF
28
LINE_OUT_L
820pF
27pF
45
CID0
CD_L
EMI
Filter
11
RESET
1uF
0.1uF
10
SYNC
CAP3
24
8
SDATA_IN
STAC9721/23
VIDEO_R
22 ohms
6
BIT_CLK
LINE_OUT_R
47
35
36
AFILT1
37
820pF
30
MONO_OUT
AFILT2
AVss1
26
AVss2
42
DVss1
4
DVss2
7
NOTE: Pins 31, 33, 34, 40
LNLVL_OUT_L
39
LNLVL_OUT_R
41
** Teminate ground
plane as close to power
supply as possible
43, 44, and 48 are No Connects
Analog Gnd
6
04/07/00
Digital Gnd
04/07/00
SigmaTel, Inc.
1.
Data Sheet
STAC9721
PIN/SIGNAL DESCRIPTIONS
1.1 Digital I/O
These signals connect the STAC9721/23 to its AC'97 controller counterpart, an external crystal, multicodec selection and external audio amplifier.
Table 3. Digital Signal List
Signal Name
Type
Description
RESET #
I
AC'97 Master H/W Reset
XTL_IN
I
24.576 MHz Crystal
XTL_OUT
O
24.576 MHz Crystal
SYNC
I
48 kHz fixed rate sample sync
BIT_CLK
O
12.288 MHz serial data clock
SDATA_OUT
I
Serial, time division multiplexed, AC'97 input stream
SDATA__IN
O
Serial, time division multiplexed, AC'97 output stream
CID0
I
Multi-Codec ID select – bit 0
CID1
I
Multi-Codec ID select – bit 1
EAPD
O
External Amplifier Power Down
# denotes active low
7
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
1.2 Analog I/O
These signals connect the STAC9721/23 to analog sources and sinks, including microphones and
speakers.
Table 4. Analog Signal List
Signal Name
Type
Description
PC-BEEP
I
PC Speaker beep pass-through
PHONE
I
From telephony subsystem speakerphone (or DLP - Down
Line Phone)
MIC1
I
Desktop Microphone Input
MIC2
I
Second Microphone Input
LINE-IN-L
I
Line In Left Channel
LINE-IN-R
I
Line In Right Channel
CD-L
I
CD Audio Left Channel
CD-GND
I
CD Audio analog ground
CD-R
I
CD Audio Right Channel
VIDEO-L
I
Video Audio Left Channel
VIDEO-R
I
Video Audio Right Channel
AUX-L
I
Aux Left Channel
AUX-R
I
Aux Right Channel
LINE-OUT-L
O
Line Out Left Channel
LINE-OUT-R
O
Line Out Right Channel
MONO-OUT
O
To telephony subsystem speakerphone (or DLP – Down
Line Phone)
LNLVL_OUT_
L
O
True Line Level Out Left Channel
LNLVL_OUT_
R
O
True Line Level Out Right Channel
* Note: any unused input pins should be tied together and connected to ground with a capacitor (0.1 uF
suggested), except the MIC1 and MIC2 inputs which require their own 0.1 uF capacitors to ground if not
used.
8
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
1.3 Filter/References/GPIO
These signals are connected to resistors, capacitors, specific voltages, or provide general purpose I/O.
Table 5. Filtering and Voltage References
Signal Name
Type
Description
Vref
O
Reference Voltage
Vrefout
O
Reference Voltage out 5mA drive (intended for mic
bias)
AFILT1
O
Anti-Aliasing Filter Cap - ADC channel
AFILT2
O
Anti-Aliasing Filter Cap - ADC channel
CAP1
O
Analog Output Hold-Off Delay
CAP2
O
ADC reference Cap
CAP3
O
Anti-Pop Power Sustain Delay
APOP
O
Anti-Pop Output Ground Shunt Control
EAPD
O
External Amplifier Power Down Control
1.4 Power and Ground Signals
Table 6. Power Signal List STAC9721/23
Signal Name
Type
STAC9721
STAC9723
AVdd1
I
Analog Vdd = 5.0V
Analog Vdd = 3.3V
AVdd2
I
Analog Vdd = 5.0V
Analog Vdd = 3.3V
AVss1
I
Analog Gnd
Analog Gnd
AVss2
I
Analog Gnd
Analog Gnd
DVdd1
I
Digital Vdd = 5.0V or 3.3V
Digital Vdd = 3.3V
DVdd2
I
Digital Vdd = 5.0V or 3.3V
Digital Vdd = 3.3V
DVss1
I
Digital Gnd
Digital Gnd
DVss2
I
Digital Gnd
Digital Gnd
9
04/07/00
04/07/00
SigmaTel, Inc.
2.
Data Sheet
STAC9721
AC-LINK
Below is the figure of the AC-Link point to point serial interconnect between the STAC9721/23 and its
companion controller. All digital audio streams and command/status information are communicated over
this AC-Link. Please refer to the “Digital Interface” section 3 for details.
Figure 3. STAC9721/23’s AC-Link to its companion controller
XTAL_IN
SYNC
Digital
DC’97
Controller
BIT CLK
SigmaTel
SDATA_OUT
AC’97 Codec
SDATA_IN
XTAL_OUT
RESET
2.1 Clocking
STAC9721/23 derives its clock internally from an externally connected 24.576 MHz crystal or an
oscillator through the XTAL_IN pin. Synchronization with the AC'97 controller is achieved through the
BIT_CLK pin at 12.288 MHz (half of crystal frequency).
The beginning of all audio sample packets, or “Audio Frames”, transferred over AC-Link is synchronized
to the rising edge of the “SYNC” signal driven by the AC'97 controller. Data is transitioned on AC-Link
on every rising edge of BIT_CLK, and subsequently sampled by the receiving side on each immediately
following falling edge of BIT_CLK.
2.2 Reset
There are 3 types of resets as detailed under “Timing Characteristics”.
•
•
•
“cold” reset where all STAC9721/23 logic and registers are initialized to their default state
“warm” reset where the contents of the STAC9721/23 register set are left unaltered
“register” reset which only initializes the STAC9721/23 registers to their default states
After signaling a reset to the STAC9721/23, the AC'97 controller should not attempt to play or capture
audio data until it has sampled a “Codec Ready” indication via register 26h from the STAC9721/23. For
proper reset operation SDATA_OUT should be “0” during “cold” reset. See “Testability” section for
more information.
10
04/07/00
04/07/00
SigmaTel, Inc.
3.
Data Sheet
STAC9721
DIGITAL INTERFACE
3.1 AC-Link Digital Serial Interface Protocol
The STAC9721/23 communicates to the AC'97 controller via a 5-pin digital serial AC-Link interface,
which is a bi-directional, fixed rate, serial PCM digital stream. All digital audio streams, commands and
status information are communicated over this point-to-point serial interconnect. The AC-Link handles
multiple inputs, and output audio streams, as well as control register accesses using a time division
multiplexed (TDM) scheme. The AC'97 controller synchronizes all AC-Link data transaction. The
following data streams are available on the STAC9721/23:
PCM Playback
4 output slots
4 Channel composite PCM output stream
PCM Record data
2 input slots
2 Channel composite PCM input stream
Control
2 output slots
Control register write port
Status
2 input slots
Control register read port
Synchronization of all AC-Link data transactions is handled by the AC'97 controller. The STAC9721/23
drives the serial bit clock onto AC-Link. The AC'97 controller then qualifies with a synchronization
signal to construct audio frames.
SYNC, fixed at 48 kHz, is derived by dividing down the serial bit clock (BIT_CLK). BIT_CLK, fixed at
12.288 MHz, provides the necessary clocking granularity to support 12, 20-bit outgoing and incoming
time slots. AC-Link serial data is transitioned on each rising edge of BIT_CLK. The receiver of ACLink data, STAC9721/23 for outgoing data and AC'97 controller for incoming data, samples each serial
bit on the falling edges of BIT_CLK.
The AC-Link protocol provides for a special 16-bit (13-bits defined, with 3 reserved trailing bit positions)
time slot (Slot 0) wherein each bit conveys a valid tag for its corresponding time slot within the current
audio frame. A “1” in a given bit position of slot 0 indicates that the corresponding time slot within the
current audio frame has been assigned to a data stream, and contains valid data. If a slot is “tagged”
invalid, it is the responsibility of the source of the data (STAC9721/23 for the input stream, AC'97
controller for the output stream) to stuff all bit positions with 0’s during that slot’s active time.
SYNC remains high for a total duration of 16 BIT_CLKs at the beginning of each audio frame. The
portion of the audio frame where SYNC is high is defined as the “Tag Phase”. The remainder of the
audio frame where SYNC is low is defined as the “Data Phase”.
Additionally, for power savings, all clock, sync, and data signals can be halted.
11
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
SYNC
TAG
OUTGOING STREAMS
CMD
DATA
PCM
LEFT
PCM
RT
NA
PCM
CTR
PCM
LSURR
PCM
RSURR
STATUS
PCM
LEFT
PCM
RT
NA
NA
RSVD
RSVD
CMD
ADR
INCOMING STREAMS
TAG
STATUS
ADR
DATA
TAG PHASE
PCM
LFE
PCM
LALT
PCM
RALT
RSVD
RSVD
RSVD
RSVD
RSVD
DATA PHASE
Figure 4. AC'97 Standard Bi-directional Audio Frame
3.1.1
AC-Link Audio Output Frame (SDATA_OUT)
The audio output frame data streams correspond to the multiplexed bundles of all digital
output data targeting the STAC9721/23 DAC inputs, and control registers. Each audio
output frame supports up to 12 20-bit outgoing data time slots. Slot 0 is a special
reserved time slot containing 16 bits that are used for AC-Link protocol infrastructure.
Within slot 0, the first bit is a global bit (SDATA_OUT slot 0, bit 15) which flags the
validity for the entire audio frame. If the “Valid Frame” bit is a 1, this indicates that the
current audio frame contains at least one slot time of valid data. The next 12 bit positions
sampled by the STAC9721/23 indicate which of the corresponding 12 times slots contain
valid data. In this way data streams of differing sample rates can be transmitted across
AC-Link at its fixed 48kHz audio frame rate. The following diagram illustrates the time
slot based AC-Link protocol.
Figure 5. AC-Link Audio Output Frame
Data Phase
Tag Phase
SYNC
20.8 uS (48 kHZ)
12.288 MHz
BIT_CLK
SDATA_OUT
valid
Frame
slot1
slot2
slot(12) "0"
CID1 CID0
19
"0"
19
"0"
19
"0"
19
"0"
End of previous audio frame
Time Slot "Valid" Bits
("1" = time slot contains valid PCM data)
Slot 1
Slot 2
Slot 3
Slot 12
e
A new audio output frame begins with a low to high transition of SYNC. SYNC is
synchronous to the rising edge of BIT_CLK. On the immediately following falling edge
of BIT_CLK, the STAC9721/23 samples the assertion of SYNC. This following edge
marks the time when both sides of AC-Link are aware of the start of a new audio frame.
On the next rising edge of BIT_CLK, the AC'97 controller transitions SDATA_OUT into
the first bit position of slot 0 (Valid Frame bit). Each new bit position is presented to
AC-Link on a rising edge of BIT_CLK, and subsequently sampled by the STAC9721/23
on the following falling edge of BIT_CLK. This sequence ensures that data transitions,
and subsequent sample points for both incoming and outgoing data streams are time
aligned.
12
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Figure 6. Start of an Audio Output Frame
SYNC assertion here
SYNC
first SDATA_OUT bit of frame here
BIT_CLK
valid
Frame
SDATA_OUT
slot1
slot2
End of previous audio frame
SDATA_OUT’s composite stream is MSB justified (MSB first) with all non-valid slots’
bit positions stuffed with 0’s by the AC'97 controller.
.
When mono audio sample streams are sent from the AC'97 controller it is necessary that
BOTH left and right sample stream time slots be filled with the same data.
3.1.1.1 Slot 1: Command Address Port
The command port is used to control features, and monitor status (see Audio Input Frame
Slots 1 and 2) of the STAC9721/23 functions including, but not limited to, mixer
settings, and power management (refer to the control register section of this
specification).
The control interface architecture supports up to 64 16-bit read/write registers,
addressable on even byte boundaries. Only the even registers (00h, 02h, etc.) are valid.
Audio output frame slot 1 communicates control register address, and write/read
command information to the STAC9721/23.
Command Address Port bit assignments:
Bit (19) Read/Write command (1= read, 0=write)
Bit (18:12) Control Register Index (64 16-bit locations, addressed on even byte
boundaries)
Bit (11:0) Reserved (Stuffed with 0's)
The first bit (MSB) sampled by STAC9721/23 indicates whether the current control
transaction is a read or a write operation. The following 7 bit positions communicate the
targeted control register address. The trailing 12 bit positions within the slot are reserved
and must he stuffed with 0's by the AC'97 controller.
3.1.1.2 Slot 2: Command Data Port
The command data port is used to deliver 16-bit control register write data in the event
that the current command port operation is a write cycle. (as indicated by Slot 1, bit 19)
Bit (19:4)
read)
Bit (3 :0)
Control Register Write Data
Reserved
(Stuffed with 0's)
13
04/07/00
(Stuffed with 0's if current operation is a
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
If the current command port operation is a read then the entire slot time must be stuffed
with 0's by the AC'97 controller.
3.1.1.3 Slot 3: PCM Playback Left Channel
Audio output frame slot 3 is the composite digital audio left playback stream. In a typical
“Games Compatible" PC this slot is composed of standard PCM (.wav) output samples
digitally mixed (by the AC'97 controller or host processor) with music synthesis output
samples. If a sample stream of resolution less than 20-bits is transferred, the AC'97
controller must stuff all trailing non-valid bit positions within this time slot with 0's.
Please refer to the register programming section for details on the multi-channel
programming options.
3.1.1.4 Slot 4: PCM Playback Right Channel
Audio output frame slot 4 is the composite digital audio right playback stream. In a
typical “Games Compatible" PC this slot is composed of standard PCM (.wav) output
samples digitally mixed (by the AC'97 controller or host processor) with music synthesis
output samples. If a sample stream of resolution less than 20-bits is transferred, the
AC'97 controller must stuff all trailing non-valid bit positions within this time slot with
0's. Please refer to the register programming section for details on the multi-channel
programming options.
3.1.1.5 Slot 5: Reserved
Audio output frame slot 5 is reserved for modem operation and is not used by the
STAC9721/23.
3.1.1.6 Slot 6: PCM Center Channel
Audio output frame slot 6 is the composite digital audio center stream used in a multichannel application where the STAC9721/23 has been programmed to accept the DAC
PCM data from slots 6 and 9. Please refer to the register programming section for details
on the multi-channel programming options.
3.1.1.7 Slot 7: PCM Left Surround Channel
Audio output frame slot 7 is the composite digital audio left surround stream used in a
multi-channel application where the STAC9721/23 has been programmed to accept the
DAC PCM data from slots 7 and 8. Please refer to the register programming section for
details on the multi-channel programming options.
3.1.1.8 Slot 8: PCM Right Surround Channel
Audio output frame slot 8 is the composite digital audio right surround stream used in a
multi-channel application where the STAC9721/23 has been programmed to accept the
DAC PCM data from slots 7 and 8. Please refer to the register programming section for
details on the multi-channel programming options.
14
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
3.1.1.9 Slot 9: PCM Low Frequency Channel
Audio output frame slot 9 is the composite digital audio low frequency stream used in a
multi-channel application where the STAC9721/23 has been programmed to accept the
DAC DAC PCM data from slots 6 and 9. Please refer to the register programming
section for details on the multi-channel programming options.
3.1.1.10 Slot 10: PCM Alternate Left
Audio output frame slot 10 is the composite digital audio alternate left stream used in a
multi-channel application where the STAC9721/23 has been programmed to accept the
DAC PCM data from slots 10 and 11. Please refer to the register programming section
for details on the multi channel programming options.
3.1.1.11 Slot 11: PCM Alternate Right
Audio output frame slot 11 is the composite digital audio alternate right stream used in a
multi-channel application where the STAC9721/23 has been programmed to accept the
DAC PCM data from slots 10 and 11. Please refer to the register programming section
for details on the multi channel programming options.
3.1.1.12 Slot 12: Reserved
Audio output frame slot 12 is reserved for modem operations and is not used by the
STAC9721/23.
3.1.2
AC-Link Audio Input Frame (SDATA_IN)
The audio input frame data streams correspond to the multiplexed bundles of all digital
input data targeting the AC'97 controller. As is the case for audio output frame, each ACLink audio input frame consists of 12, 20-bit time slots. Slot 0 is a special reserved time
slot containing 16 bits that are used for AC-Link protocol infrastructure.
Within slot 0 the first bit is a global bit (SDATA_IN slot 0, bit 15) which flags whether
the STAC9721/23 is in the "Codec Ready" state or not. If the “Codec Ready” bit is a 0,
this indicates that STAC9721/23 is not ready for normal operation. This condition is
normal following the de-assertion of power on reset, for example, while STAC9721/23’s
voltage references settle. When the AC-Link "Codec Ready" indicator bit is a 1, it
indicates that the AC-Link and STAC9721/23 control/status registers are in a fully
operational state. The AC'97 controller must further probe the Powerdown Control Status
Register index 26h (refer to Mixer Register section) to determine exactly which
subsections, if any, are ready.
Prior to any attempts at putting STAC9721/23 into operation the AC'97 controller should
poll the first bit in the audio input frame (SDATA_IN slot 0, bit 15) for an indication that
STAC9721/23 has become "Codec Ready". Once the STAC9721/23 is sampled "Codec
Ready", the next 12 bit positions sampled by the AC'97 controller indicate which of the
15
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
corresponding 12 time slots are assigned to input data streams, and that they contain valid
data. The following diagram illustrates the time slot based AC-Link protocol.
Figure 7. STAC9721/23 Audio Input Frame
Data Phase
Tag Phase
SYNC
20.8 uS (48 kHZ)
12.288 MHz
BIT_CLK
SDATA_IN
valid
Frame
slot1
slot2
slot(12) "0"
"0"
"0"
19
"0"
19
"0"
19
"0"
19
"0"
End of previous audio frame
Time Slot "Valid" Bits
("1" = time slot contains valid PCM data)
Slot 1
Slot 2
Slot 3
Slot 12
A new audio input frame begins with a low to high transition of SYNC. SYNC is synchronous to the rising edge of
BIT_CLK. On the immediately following falling edge of BIT_CLK, STAC9721/23 samples the assertion of SYNC.
This falling edge marks the time when both sides of AC-Link are aware of the start of a new audio frame. On the next
rising of BIT_CLK, the STAC9721/23 transitions SDATA_IN into the first bit position of slot 0 ("Codec Ready" bit).
Each new bit position is presented to AC-Link on a rising edge of BIT_CLK and subsequently sampled by the AC'97
controller on the following falling edge of BIT_CLK. This sequence ensures that data transitions, and subsequent
sample points for both incoming and outgoing data streams are time aligned.
Figure 8. Start of an Audio Input Frame
SYNC assertion here
SYNC
first SDATA_OUT bit of frame here
BIT_CLK
SDATA_IN
Codec
Ready
slot1
slot2
End of previous audio frame
SDATA_IN's composite stream is MSB justified (MSB first) with all non-valid bit positions (for assigned and/or
unassigned time slots) stuffed with 0's by STAC9721/23. SDATA_IN data is sampled on the falling edges of
BIT_CLK.
3.1.2.1 Slot 1: Status Address Port
The status port is used to monitor status for STAC9721/23 functions including, but not
limited to, mixer settings, and power management.
16
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Audio input frame slot 1’s stream echoes the control register index, for historical
reference, for the data to be returned in slot 2. (Assuming that slots 1 and 2 had been
tagged “valid” by STAC9721/23 during slot 0)
Status Address Port hit assignments:
Bit (19)
Bit (18;12)
returned)
Bit (11:0)
RESERVED Stuffed with 0)
Control Register Index (Echo of register index for which data is being
RESERVED
(Stuffed with 0's)
The first bit (MSB) generated by STAC9721/23 is always stuffed with a 0. The following
7 bit positions communicate the associated control register address, and the trailing 12 bit
positions are stuffed with 0's by STAC9721/23.
3.1.2.2 Slot 2: Status Data Port
The status data port delivers 16-bit control register read data.
Bit (19:4) Control Register Read Data (Stuffed with 0's if tagged "invalid")
Bit (3 :0) RESERVED
(Stuffed with 0's)
If Slot 2 is tagged "invalid" by STAC9721/23, then the entire slot will be stuffed with 0's.
Slot 3: PCM Record Left Channel
Audio input frame slot 3 is the left channel output of STAC9721/23 input MUX, postADC.
STAC9721/23 ADCs are implemented to support 18-bit resolution.
STAC9721/23 outputs its ADC data (MSB first), and stuffs any trailing non-valid bit
positions with 0's to fill out its 20-bit time slot.
3.1.2.3 Slot 4: PCM Record Right Channel
Audio input frame slot 4 is the right channel output of STAC9721/23 input MUX, postADC.
STAC9721/23 outputs its ADC data (MSB first), and stuffs any trailing non-valid bit
positions with 0's to fill out its 20-bit time slot.
3.1.2.4 Slots 5-12: Reserved
Audio input frame slots 5-12 are not used by the STAC97908/11 and are always stuffed
with 0's.
17
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
3.2 AC-Link Low Power Mode
The STAC9721/23 AC-Link can be placed in the low power mode by programming register 26h to the
appropriate value. Both BIT_CLK and SDATA_IN will be brought to, and held at a logic low voltage
level. The AC'97 controller can wake up the STAC9721/23 by providing the appropriate reset signals.
Figure 9. STAC9721/23 Powerdown Timing
SYNC
BIT_CLK
SDATA_OUT
SDATA_IN
slot2
per frame
TAG
slot2
per frame
TAG
Write to
0x20
Data
PR4
Note: BIT_CLK not to scale
BIT_CLK and SDATA_IN are transitioned low immediately (within the maximum specified time)
following the decode of the write to the Powerdown Register (26h) with PR4. When the AC'97 controller
driver is at the point where it is ready to program the AC-Link into its low power mode, slots (1 and 2)
are assumed to be the only valid stream in the audio output frame (all sources of audio input have been
neutralized).
The AC'97 controller should also drive SYNC and SDATA_OUT low after programming the
STAC9721/23 to this low power mode.
3.2.1
Waking up the AC-Link
Once the STAC9721/23 has halted BIT_CLK, there are only two ways to “wake up” the
AC-Link. Both methods must be activated by the AC'97 controller.
The AC-Link protocol provides for a “Cold AC'97 Reset”, and a “Warm AC'97 Reset”.
The current power down state would ultimately dictate which form of reset is appropriate.
Unless a “cold” or “register” reset (a write to the Reset register) is performed, wherein
the AC'97 registers are initialized to their default values, registers are required to keep
state during all power down modes. Once powered down, re-activation of the AC-Link
via re-assertion of the SYNC signal must not occur for a minimum of 4 audio frame times
following the frame in which the power down was triggered. When AC-Link powers up
it indicates readiness via the Codec Ready bit (input slot 0, bit 15).
Cold Reset - a cold reset is achieved by asserting RESET# for the minimum specified
time. By driving RESET# low, BIT_CLK, and SDATA_IN will be activated, or reactivated as the case may be, and all STAC9721/23 control registers will be initialized to
their default power on reset values.
Note: RESET# is an asynchronous input.
18
04/07/00
# denotes active low
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Warm Reset - a warm reset will re-activate the AC-Link without altering the current
STAC9721/23 register values. A warm reset is signaled by driving SYNC high for a
minimum of 1us in the absence of BIT_CLK.
Note: Within normal audio frames, SYNC is a synchronous input. However, in the
absence of BIT_CLK, SYNC is treated as an asynchronous input used in the generation
of a warm reset to the STAC9721/23.
4.
STAC9721/23 MIXER
The STAC9721/23 mixer is designed to the AC'97 specification to manage the playback and record of all
digital and analog audio sources in the PC environment. These include:
•
•
•
•
•
•
System Audio: digital PCM input and output for business, games and multimedia
CD/DVD: analog CD/DVD-ROM Redbook audio with internal connections to Codec mixer
Mono microphone: choice of desktop mic, with programmable boost and gain
Speakerphone: use of system mic and speakers for telephone, DSVD, and video conferencing
Video: TV tuner or video capture card with internal connections to Codec mixer
AUX/synth: analog FM or wavetable synthesizer, or other internal source
PCM out
mute
mute
mute
Analog Audio
Sources
vol
mute
LINE IN
CD
vol
vol
mute
mute
Video
AUX
vol
vol
mute
mute
KEY
20dB
Σ
-6dB
Stereo Analog
Digital
Σ
LNLVL
Volume
LNLVL_OUT
-6dB
Master
Volume
LINE_OUT
Mono
Volume
MONO_OUT
3D
Σ
MUX
Mono Analog
MIC1
MIC2
3D
MUX
vol
vol
vol
D/A
PC_Beep
Phone
Master
Input
Volume
A/D
A/D
PCM IN
Figure 10. STAC9721/23 Mixer Functional Diagram
19
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Table 6. Mixer Functional Connections
Source
Function
Connection
PC_Beep
PHONE
MIC1
MIC2
LINE_IN
CD
VIDEO
AUX
PCM out
LINE_OUT
LNLVL_OUT
MONO_OUT
PC beep pass thru
speakerphone or DLP in
desktop microphone
second microphone
external audio source
audio from CD-ROM
audio from TV tuner or video camera
upgrade synth or other external source
digital audio output from AC'97 Controller
stereo mix of all sources
Additional stereo mix of all sources
MIC or mix for speakerphone or DLP out
from PC beeper output
from telephony subsystem
from MIC jack
from second MIC jack
from line-in jack
cable from CD-ROM
cable from TV or VidCap card
internal connector
AC-Link
To output jack
To output jack
to telephony subsystem
PCM in
digital audio input to AC'97 Controller
AC-Link
4.1 Mixer Input
The mixer provides recording and playback of any audio sources or output mix of all
sources. The STAC9721/23 supports the following input sources:
•
•
•
any mono or stereo source
mono or stereo mix of all sources
2-channel input w/mono output reference (mic + stereo mix)
* Note: any unused input pins should be tied together and connected to ground with a
capacitor (0.1 µF suggested), except the MIC1 and MIC2 inputs which require their own
0.1 µF capacitors to ground if not used.
4.2 Mixer Output
The mixer generates two distinct outputs:
•
•
•
stereo mix of all sources for output to the LINE_OUT
stereo mix of all sources for output to the LNLVL_OUT
mono, MIC only or mix of all sources for MONO_OUT
* Note: Mono output of stereo mix is attenuated by -6 dB to prevent clipping when left
and right channels are combined.
4.3 PC Beep Implementation
PC Beep is active on power up and defaults to an un-muted state. The user should mute
this input before using any other mixer input because the PC Beep input can contribute
noise to the LINE_OUT during normal operation.
20
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
4.4 Programming Registers:
Table 7. Programming Registers
REG
#
NAME
D15 D14 D13 D12 D11 D10 D9
00h
Reset
X
SE4
02h
Master Volume
Mute
X
X
04h
LNLVL Volume
Mute
X
06h
Master Volume Mono
Mute
0Ah
PC_BEEP Volume
0Ch
D8
D7
D6
D5
D4
D3
D2
D1
D0
DEFAULT
SE3 SE2
SE1 SE0
ID9
ID8
ID7
ID6
ID5
ML4 ML3 ML2 ML1 ML0
X
X
X
GL4
GL3
GL2
GL1
GL0
X
X
X
X
X
X
X
X
Mute
X
X
X
X
X
X
Phone Volume
Mute
X
X
X
X
X
0Eh
Mic Volume
Mute
X
X
X
X
10h
Line In Volume
Mute
X
X
GL4
12h
CD Volume
Mute
X
X
14h
Video Volume
Mute
X
16h
AUX Volume
Mute
18h
PCM Out Volume
1Ah
ID0
6940h
X
MR4 MR3 MR2 MR1 MR0
8000h
X
X
GR4 GR3 GR2 GR1 GR0
8000h
X
X
X
MM4 MM3 MM2 MM1 MM0
8000h
X
X
X
X
PV3
0000h
X
X
X
X
X
GN4 GN3 GN2 GN1 GN0
8008h
X
X
X
X
20dB
X
GN4 GN3 GN2 GN1 GN0
8008h
GL3
GL2
GL1
GL0
X
X
X
GR4 GR3 GR2 GR1 GR0
8808h
GL4
GL3
GL2
GL1
GL0
X
X
X
GR4 GR3 GR2 GR1 GR0
8808h
X
GL4
GL3
GL2
GL1
GL0
X
X
X
GR4 GR3 GR2 GR1 GR0
8808h
X
X
GL4
GL3
GL2
GL1
GL0
X
X
X
GR4 GR3 GR2 GR1 GR0
8808h
Mute
X
X
GL4
GL3
GL2
GL1
GL0
X
X
X
GR4 GR3 GR2 GR1 GR0
8808h
Record Select
X
X
X
X
X
SL2
SL1
SL0
X
X
X
X
1Ch
Record Gain
Mute
X
X
X
GL3
GL2
GL1
GL0
X
X
X
X
20h
General Purpose
X
X
3D
X
X
X
MIX
MS LPBK
X
X
X
22h
3D Control
X
X
X
X
X
X
X
X
X
X
X
DP3 DP2
26h
Powerdown Ctrl/Stat
X
X
X
X
REF ANL DAC ADC
28h
Extended Audio ID
ID1
ID0
X
X
X
X
AMAP
X
X
X
X
X
X
X
X
X
0200h
6Ch
Revision Code
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0000h
6Eh
Analog Special
X
X
X
X
X
X
X
X
X
X
X
X
X
X
70h
72h Enable
72h
Analog Current Adjust
X
X
X
X
X
X
X
X
X
X
X
X
X
74h
Multi-Channel Selection
X
X
X
X
X
X
X
X
X
X
X
X
X
76h
78h Enable
78h
Clock Access
X
X
7Ch
Vendor ID1
1
0
7Eh
Vendor ID2
0
1
X
EAPD PR6 PR5 PR4 PR3 PR2 PR1 PR0
ID4
ID3
PV2
X
ID2
PV1
ID1
PV0
X
SR2 SR1 SR0
0000h
GR3 GR2 GR1 GR0
8000h
X
X
X
X
0000h
X
X
0000h
000Fh
DAC ADC
-6dB -6dB
0000h
EN15 EN14 EN13 EN12 EN11 EN10 EN9 EN8 EN7 EN6 EN5 EN4 EN3 EN2 EN1 EN0
0000h
Bias1 Bias0
0000h
MC1 MC0
0000h
EN15 EN14 EN13 EN12 EN11 EN10 EN9 EN8 EN7 EN6 EN5 EN4 EN3 EN2 EN1 EN0
0000h
ALT PWD CLK
CLK CL2x INV
0
0
0
1
1
0
X
X
X
X
X
X
X
X
X
X
X
X
0000h
1
OSC
PWD
0
0
1
1
1
0
0
0
0
0
8384h
1
1
0
0
0
0
0
1
0
0
1
7609h
Notes:
1. All registers not shown and bits containing an X are reserved.
2. Any reserved bits, marked X, are not writable, and read back as zeros.
3. PC_BEEP default to 0000h, un-muted.
4. If optional bits D13, D5 of register 02h or D5 of register 06h are set to 1, then the corresponding attenuation is set to 46dB and the register
reads will produce 1Fh as a value for this attenuation/gain block.
21
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
4.4.1 Reset Register (Index 00h)
Writing any value to this register performs a register reset, which causes all registers to
revert to their default values. This register returns the AC’97 ID code of the part when
read.
4.4.2 Play Master Volume Registers (Index 02h, 04h, and 06h)
These registers manage the output signal volumes. Register 02h controls the stereo
master volume (both right and left channels), register 04h controls the optional stereo true
line level out, and register 06h controls the mono volume output. Each step corresponds
to 1.5 dB. The MSB of the register is the mute bit. When this bit is set to 1 the level for
that channel is set at -∞ dB. ML5 through ML0 is for left channel level, MR5 through
MR0 is for the right channel and MM5 through MM0 is for the mono out channel. If
optional bits D13 and D5 of register 02h and 04h, or D5 of register 06h are set to 1, then
the corresponding attenuation is set to 46dB and the register reads will produce 1Fh as a
value for this attenuation/gain block
Table 8. Play Master Volume Register
Mute
Mx5…Mx0
Function
Range
0
0
1
00 0000
01 1111
xx xxxx
0dB Attenuation
46.5 Attenuation
∞ dB
Attenuation
Req.
Req.
Req.
4.4.3 PC Beep Register (Index 0Ah)
This register controls the level for the PC Beep input. Each step corresponds to
approximately 3 dB of attenuation. The MSB of the register is the mute bit. When this
bit is set to 1 the level for that channel is set at -∞ dB. PC_BEEP supports motherboard
implementations. The intention of routing PC_BEEP through the STAC9721/23 mixer is
to eliminate the requirement for an onboard speaker by guaranteeing a connection to
speakers connected via the output jack. In order for this to be viable the PC_BEEP signal
needs to reach the output jack at all times. NOTE: the PC_BEEP is routed to L & R
Line outputs even when the STAC9721/23 is in a RESET state. This is so that Power On
Self Test (POST) codes can be heard by the user in case of a hardware problem with the
PC. For further PC_BEEP implementation details please refer to the AC'97 Technical
FAQ sheet. The default value of 0000h corresponds to 0 dB attenuation with mute off.
Table 9. PC_BEEP Register
Mute
PV3…PV0
Function
0
0
1
0000
1111
xxxx
0 dB Attenuation
45 dB Attenuation
∞ dB Attenuation
22
04/07/00
04/07/00
SigmaTel, Inc.
4.4.4
Data Sheet
STAC9721
Analog Mixer Input Gain Registers (Index 0Ch - 18h)
These registers control the gain/attenuation for each of the analog inputs. Each step
corresponds to approximately 1.5 dB. The MSB of the register is the mute bit. When
this bit is set to 1 the level for that channel is set at -∞ dB. Register 0Eh (Mic Volume
Register) has an extra bit that is for a 20dB boost. When bit D6 is set to 1, the +20 dB
boost is on. The default value is 8008, which corresponds to 0 dB gain, bost off, and
mute on. The default value for the mono registers is 8008h, which is to 0dB gain with
mute on. The default value for stereo registers is 8808h, which is 0 dB gain with mute
on.
Table 10. Analog Mixer Input Gain Register
4.4.5
Mute
Gx4…Gx0
Function
0
0
0
1
00000
01000
11111
xxxxx
+12 dB gain
0 dB gain
-34.5 dB gain
-∞ dB gain
Record Select Control Register (Index 1Ah)
Used to select the record source independently for right and left. The default value is
0000h, which corresponds to MIC in.
Table 11. Record Select Control Registers
SR2…SR0
Right Record Source
0
1
2
3
4
5
6
7
MIC
CD In (right)
Video In (right)
Aux In (right)
Line In (right)
Stereo Mix (right)
Mono Mix
Phone
Table 12. Left Record Select Control Registers
SL2…SL0
Left Record Source
0
1
2
3
4
5
6
7
MIC
CD In (L)
Video In (L)
Aux In (L)
Line In (L)
Stereo Mix (L)
Mono Mix
Phone
23
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
4.4.6 Record Gain Registers (Index 1Ch)
The 1Ch register adjusts the stereo input record gain. Each step corresponds to 1.5 dB.
The 22.5 dB setting corresponds to 0F0Fh. The MSB of the register is the mute bit.
When this bit is set to 1, the level for that channel(s) is set at -∞ dB.
The default value is 8000h, which is to 0 dB gain with mute on.
Table 13. Record Gain Registers
Mute
Gx3… Gx0
Function
0
0
1
1111
0000
xxxx
+22.5 dB gain
0 dB gain
-∞ gain
4.4.7 General Purpose Register (Index 20h)
This register is used to control some miscellaneous functions. Below is a summary of
each bit and its function. The MS bit controls the MIC1/MIC2 selector, and the MIX bit
controls the Mix/MIC selector. The LPBK bit enables loopback of the ADC output to the
DAC input without involving the AC-Link, allowing for full system performance
measurements. The 3D bit enables or disables the SS3D speaker separation 3D
enhancement.
Table 14. General Purpose Register
Bit
Function
3D
3D Stereo Enhancement
0 = off, 1 = on
MIX
MS
LPBK
Mono output select 0 = Mix, 1= MIC
Mic select 0 = MIC1, 1 = MIC2
ADC/DAC loopback mode
24
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
4.4.7 3D Control Register (Index 22h)
This register is used to control the 3D stereo enhancement function, SigmaTel Surround
3D (SS3D), built into the codec. SS3D provides for a wider soundstage and speaker
separation for 2-speaker arrangements. Register bits, DP3-DP2 are used to control the
separation ratios in the 3D control for LINE_OUT. The 3D bit in the general purpose
register (register 20h bit D13) must be set to 1 to enable SS3D functionality and for the
bits in 22h to take effect.
Table 15. 3D Control Registers
DP3..DP0
LINE_OUT
Separation Ratio
00XX
0 (Off)
01XX
3 (Low)
10XX
4.5 (Med.)
11XX
6.0 (High)
The three separation ratios are implemented as shown above. The separation ratio defines
a series of equations that determine the amount of depth difference (High, Medium, and
Low) perceived during two-channel playback. The ratios provide an indication of how
much soundstage increase can be expected.
4.4.8 Powerdown Control/Status Register (Index 26h)
This read/write register is used to program powerdown states and monitor subsystem
readiness. The lower half of this register is read only status, a “1” indicating that the
subsection is “ready”. Ready is defined as the subsection’s ability to perform in its
nominal state. When this register is written, bits D7:D0 will not be affected. Bit D15
controls the External Amplifier Power Down pin.
When the AC-Link “Codec Ready” indicator bit (SDATA_IN slot 0, bit 15) is a 1, it
indicates that the AC-Link and AC'97 control and status registers are in a fully
operational state.
The AC'97 controller must further probe this Powerdown
Control/Status Register (D3:D0) to determine exactly which subsections, if any are ready.
Table 16. Powerdown Status Registers
BIT
FUNCTION
EAPD
External Amplifier Power Down
REF
Indicates VREF is at nominal level
ANL
Analog mixers, etc. ready
DAC
DAC section ready to playback data
ADC
ADC section ready to playback data
25
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
4.4.8.1 External Amplifier Power Down Control
The EAPD bit D15 of the Powerdown Control/Status Register (Index 26h) directly
controls the output of the EAPD output, pin 45, and produces a logical “1” when this bit
is set to logic high. This function is used to control an external audio amplifier power
down. EAPD = 0 places approximately 0V on the output pin, enabling an external audio
amplifier. EAPD = 1 places approximately DVDD on the output pin, disabling the
external audio amplifier. Audio amplifiers that operate with reverse polarity will likely
require an external inverter to maintain software driver compatibility.Extended Audio ID
Register (Index 28)
4.4.9 Extended Audio Register (Index 28h)
The Extended Audio ID register is a read only register. ID1 and ID0 echo the
configuration of the codec as defined by the programming of pins 45 and 46 externally.
“00” returned defines the codec as the primary codec, while any other code identifies the
codec as one of three secondary codec possibilities. The AMAP bit, D9, will return a 1
indicating that the codec supports the optional “AC’97 2.1 compliant AC-link slot to
audio DAC mappings”. The default condition assumes that 0, 0 are loaded in the MC1
and MC0 bits of the Multi-Channel Programming Register (Index 74h). With 0s in the
MCx bits, the codec slot assignments are as per the AC’97 specification
recommendations. If the MCx bits do not contain 0s, the slot assignments are as per the
table in the section describing the Multi-Channel Programming Register (Index 74h).
Table 17. Extended Audio ID Register Functions
BIT
FUNCTION
IDx
External CID pin status
AMAP
Multi-channel slot support
4.4.10 Revision (Index 6Ch)
The device Revision register (index 6Ch) contains a software readable revision-specific
code used to identify performance, architectural, or software differences between various
device revisions. Bits 7:0 of the Revision register are user readable; bits 15:8 are not
used at this time and will return zeros when read. The lower order bits of the Revision
Register (bits 7:0) are currently set to 00h, and will likely change if there are any
STAC9721/23 metal revisions.
4.4.11 Analog Special Register (Index 6Eh)
The Analog Special Register has two read/write bits used to control two functions
specific to the STAC9721/23. DAC –6dB is used to program the DAC outputs to a –6dB
signal level relative to the value of gain already programmed. Similarly, ADC –6dB
attenuates any signal input to the ADC by 6dB.
26
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
4.4.12 Analog Current Adjust (Index 70h and 72h)
The Analog Current Adjust register (index 72h) is a locked register and can only be
properly written and read from when ABBAh has been written into register 70h. The
BIASx bits allow the analog current to be adjusted with minimal reduction in
performance. The –50% analog current setting is not recommended when a 5V analog
supply is used. The –50% setting for 3.3V supplies is recommended to reduce power
consumption for notebook computers to its lowest level.
Table 18: Analog Current Adjust
BIAS1
BIAS0
Analog Current
0
0
0
1
1
0
1
1
Normal Current
-50% Analog
Current
-25% Analog
Current
+25% Analog
Current
4.4.13 Multi-Channel Programming Register (Index 74h)
This read/write register is used to program the various options for multi-channel
configurations. Only the two LSBs are used (MC0 and MC1), and they define which
AC-Link slot data is supplied to the two PCM output channels on the STAC9721/23.
The purpose of using slot 10 and 11 in the final configuration is to allow for the
possibility of an eight-channel architecture using several STAC9721/23 or STAC9708
devices in the multi-codec configuration. Also see “Multiple Codec Support” discussion
for information on the use of external pins CID1 and CID0.
27
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Table 19. Multi-Channel Programming Register
External
Pins
CID1, CID0
Extended
Audio ID
28h
ID1, ID0
Codec
Designation
MultiChannel
Selection
74h
MC1, MC0
PCM
OUT Left
PCM
OUT
Right
CID1 = DVdd
or floating,
CID0 = DVdd
or floating
CID1 = DVdd
or floating,
CID0 = GND
0, 0
Primary, 00
0, 1
Secondary, 01
CID1 = GND,
CID0 = DVdd
or floating
1, 0
Secondary, 10
CID1 = GND,
CID0 = GND
1, 1
Secondary, 11
0, 0
0, 1
1, 0
1, 1
0, 0
0, 1
1, 0
1, 1
0, 0
0, 1
1, 0
1, 1
0, 0
0, 1
1, 0
1, 1
Slot 3
Slot 7
Slot 6
Slot 10
Slot 3
Slot 7
Slot 6
Slot 10
Slot 7
Slot 3
Slot 10
Slot 6
Slot 6
Slot 10
Slot 3
Slot 7
Slot 4
Slot 8
Slot 9
Slot 11
Slot 4
Slot 8
Slot 9
Slot 11
Slot 8
Slot 4
Slot 11
Slot 9
Slot 9
Slot 11
Slot 4
Slot 8
4.4.14 Clock Access (Index 76h and 78h)
The Clock Access register (index 78h) is a locked register and can only be properly
written and read from when ABBAh has been written into register 76h. The
STAC9744/45 can operate as a remotely located secondary without a 24.576MHz master
clock input or local crystal. The STAC9744/45 can synchronize to the BIT_CLK after a
register adjustments. The first adjustment starts the synchronization process by enabling
the ALTCLK D13, PWD CL2x D12, CLK INV D11, and OSC PWD D1 bits of register
78h. With this adjustment, the STAC9744/45 will operate remotely without the 24.576
MHz master clock signal and without a local crystal. The XTAL_IN input should be
connected to DGND with a 10kΩ or larger resistor. The reserved bits of register 78h
should not be written to.
4.4.15 Vendor ID1 and ID2 (Index 7Ch and 7Eh)
These two registers contain four 8-bit ID codes. The first three codes have been assigned
by Microsoft using their Plug and Play Vendor ID methodology. The fourth code is a
SigmaTel, Inc. assigned code identifying the STAC9721/23. The ID1 register (index
7Ch) contains the value 8384h, which is the first (83h) and second (84h) characters of the
Microsoft ID code. The ID2 register (index 7Eh) contains the value 7609h, which is the
third (76h) of the Microsoft ID code, and 09h which is the STAC9721/23 ID code.
NOTE: The lower half of the Vendor ID2 register (index 7Eh) currently contains the
value 09h identifying the STAC9721/23. This value can be used by the audio driver, or
miniport driver in the case of WIN98, to adjust software functionality to match the
feature-set of the STAC9721/23. This portion of the register will likely contain different
28
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
values if the software profile of the STAC9721/23 changes, as in the case of silicon level
device modifications. This will allow the software driver to identify any required
operational differences between the existing STAC9721/23 and any future versions.
5.
Low Power Modes
The STAC9721/23 is capable of operating at reduced power when no activity is required. The state of
power down is controlled by the Powerdown Register (26h). There are 7 commands of separate power
down. The power down options are listed in Table 18. The first three bits , PR0..PR2, can be used
individually or in combination with each other, and control power distribution to the ADC’s, DAC’s and
Mixer. The last analog power control bit, PR3, affects analog bias and reference voltages, and can only
be used in combination with PR1, PR2, and PR3. PR3 essentially removes power from all analog
sections of the codec, and is generally only asserted when the codec will not be needed for long periods.
PR0 and PR1 control the PCM ADC’s and DAC’s only. PR2 and PR3 do not need to be "set" before a
PR4, but PR0 and PR1 must be "set" before PR4.
Table 20. Low Power Modes
GRP Bits
Function
PR0
PR1
PR2
PR3
PR4
PR5
PR6
PCM in ADC’s & Input Mux Powerdown
PCM out DACs Powerdown
Analog Mixer powerdown (Vref still on)
Analog Mixer powerdown (Vref off)
Digital Interface (AC-Link) powerdown (extnl clk off)
Internal Clk disable
LNLVL_OUT disable
Figure 11. Example of STAC9721/23 Powerdown/Powerup flow
PR0=1
PR1=1
ADCs off
PR0
Normal
PR0=0
&
ADC=1
Ready =1
PR2=1
DACs off
PR1
PR1=0
&
DAC=1
PR4=1
Analog off
PR2 or PR3
PR2=0
&
ANL=1
Default
Digital I/F off
PR4
Shut off
Coda-link
Warm Reset
Cold Reset
The above figure illustrates one example procedure to do a complete powerdown of STAC9721/23.
From normal operation, sequential writes to the Powerdown Register are performed to power down
STAC9721/23 a piece at a time. After everything has been shut off, a final write (of PR4) can be
executed to shut down the AC-Link. The part will remain in sleep mode with all its registers holding
their static values. To wake up, the AC'97 controller will send an extended pulse on the sync line,
issuing a warm reset. This will restart the AC-Link (resetting PR4 to zero). The STAC9721/23 can also
be woken up with a cold reset. A cold reset will reset all of the registers to their default states. When a
section is powered back on, the Powerdown Control/Status register (index 26h) should be read to verify
that the section is ready (stable) before attempting any operation that requires it.
29
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Figure 12. STAC9721/23 Powerdown/Powerup flow with analog still alive
PR0=1
PR1=1
ADCs off
PR0
Normal
PR0=0
&
ADC=1
PR4=1
DACs off
PR1
Digital I/F
off PR4
Shut off
Coda-link
PR1=0
Warm Reset
&
DAC=1
The above figure illustrates a state when all the mixers should work with the static volume settings that
are contained in their associated registers. This configuration can be used when playing a CD (or external
LINE_IN source) through STAC9721/23 to the speakers, while most of the system in low power mode.
The procedure for this follows the previous except that the analog mixer is never shut down.
30
04/07/00
04/07/00
SigmaTel, Inc.
6.
Data Sheet
STAC9721
MULTIPLE CODEC SUPPORT
The STAC9721/23 provides support for the multi-codec option according to the Intel AC'97, rev 2.1
specification. By definition there can be only one Primary Codec (Codec ID 00) and up to three
Secondary Codecs (Codec IDs 01,10, and 11). The Codec ID functions as a chip select. Secondary
devices therefore have completely orthogonal register sets; each is individually accessible and they do not
share registers.
6.1 Primary/Secondary Codec Selection
In a multi-codec environment the codec ID is provided by external programming of pins 45 and 46 (CID0
and CID1). The CID pin electrical function is logically inverted from the codec ID designation. The
corresponding pin state and its associated codec ID are listed in the "Codec ID Selection" table. Also see
slot assignment discussion, “Multi-Channel Programming Register (Index 74)”.
Table 21. Codec ID Selection
CID1 State
CID0 State
Codec ID
Codec Status
EXTENDED AUDIO
ID, 28h
ID1, ID0
+5V or floating
+5V or floating
0V
0V
+5V or floating
0V
+5V or floating
0V
00
01
10
11
Primary
Secondary
Secondary
Secondary
0, 0
0, 1
1, 0
1, 1
6.1.1 Primary Codec Operation
As a Primary device the STAC9721/23 is completely compatible with existing AC'97
definitions and extensions. Primary Codec registers are accessed exactly as defined in
the AC'97 Component Specification and AC'97 Extensions. The STAC9721/23 operates
as Primary by default, and the external ID pins (47 and 48) have internal pull-ups so that
these pins may be left as no-connects for primary operation.
When used as the Primary Codec, the STAC9721/23 generates the master AC-Link
BIT_CLK for both the AC'97 Digital Controller and any Secondary Codecs. The
STAC9721/23 can support up to 4, 10 KΩ 50 pF loads on the BIT_CLK. This is to
insure that up to 4 Codec implementations will not load down the clock output.
6.1.2 Secondary Codec Operation
When the STAC9721/23 is configured as a Secondary device the BIT_CLK pin is
configured as an input at power up. Using the BIT_CLK provided by the Primary Codec
insures that everything on the AC-Link will be synchronous. As a Secondary device it
can be defined as Codec ID 01, 10, or 11 in the two-bit field(s) of the Extended Audio
and/or Extended Modem ID Register(s).
31
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
6.2 Secondary Codec Register Access Definitions
The AC'97 Digital Controller can independently access Primary and Secondary Codec registers by using
a 2-bit Codec ID field (chip select) which is defined as the LSBs of Output Slot 0. For Secondary Codec
access, the AC'97 Digital Controller must invalidate the tag bits for Slot 1 and 2 Command Address and
Data (Slot 0, bits 14 and 13) and place a non-zero value (01, 10, or 11) into the Codec ID field (Slot 0,
bits 1 and 0).
As a Secondary Codec, the STAC9721/23 will disregard the Command Address and Command Data
(Slot 0, bits 14 and 13) tag bits when it sees a 2-bit Codec ID value (Slot 0, bits 1 and 0) that matches its
configuration. In a sense the Secondary Codec ID field functions as an alternative Valid Command
Address (for Secondary reads and writes) and Command Data (for Secondary writes) tag indicator.
Secondary Codecs must monitor the Frame Valid bit, and ignore the frame (regardless of the state of the
Secondary Codec ID bits) if it is not valid. AC'97 Digital Controllers should set the frame valid bit for a
frame with a secondary register access, even if no other bits in the output tag slot except the Secondary
Codec ID bits are set.
This method is designed to be backward compatible with existing AC'97 controllers and Codecs. There is
no change to output Slot 1 or 2 definitions.
Table 22. Secondary Codec Register Access Slot 0 Bit Definitions
Output Tag Slot (16-bits)
Bit
15
14
13
12-3
2
†1-0
Description
Frame Valid
Slot 1 Valid Command Address bit (†Primary Codec only)
Slot 2 Valid Command Data bit
(†Primary Codec only)
Slot 3-12 Valid bits as defined by AC'97
Reserved
(Set to “0”)
2-bit Codec ID field
(00 reserved for Primary; 01, 10, 11 indicate Secondary)
† New definitions for Secondary Codec Register Access
7.
TESTABILITY
The STAC9721/23 has two test modes. One is for ATE in-circuit test and the other is restricted for
SigmaTel’s internal use. STAC9721/23 enters the ATE in circuit test mode if SDATA_OUT is sampled
high at the trailing edge of RESET#.
Once in the ATE test mode, the digital AC-Link outputs
(BIT_CLK and SDATA_IN) are driven to a high impedance state. This allows ATE in-circuit testing of
the AC'97 controller. This case will never occur during standard operating conditions. Once either of the
two test modes have been entered, the STAC9704/7 must be issued another rest with all AC-link signals
held low to return to the normal operating mode.
32
04/07/00
04/07/00
SigmaTel, Inc.
8.
Data Sheet
STAC9721
EXTENDED CODEC FUNCTIONALITY
8.1 Anti-Pop Circuitry
The STAC9721/23 provides an integrated output signal (APOP on pin 34) to aid in low-component-count
anti-pop implementations. An audible speaker "pop" can occur when the main power is applied to, or
removed from, the codec or audio output amplifier. In ac coupled systems, the speaker sided of the ac
coupling capacitor is shunted to ground through a transistor or FET; this prevents audible pops when the
system is powering on and off. A 10 µF capacitor on CAP1 provides a delay to hold-off power to the
output stages on power up. A 22 µF capacitor provides reserve power to sustain the output shunting
action until the power has been fully removed on power down. APOP is active logic high during shunting
operations; APOP is at logic low during normal operations.
9.
AC TIMING CHARACTERISTICS (Tambient = 25 °C, AVdd = DVdd = 5.0V or 3.3V ± 5%,
AVss=DVss+0V; 50pF external load)
9.1 Cold Reset
Figure 13. Cold Reset
Trst2clk
Tres_low
RESET#
BIT_CLK
Table 23. Cold Reset
Parameter
Symbol
Min
Typ
Max
Units
RESET# active low pulse width
RESET# inactive to BIT_CLK startup delay
Tres_low
Trst2clk
1.0
162.8
-
-
us
ns
# denotes active low.
33
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
9.2 Warm Reset
Figure 14. Warm Reset
Tsync_high
Tsync_2clk
SYNC
BIT_CLK
Table 24. Warm Reset
Parameter
Symbol
Min
Typ
Max
Units
SYNC active high pulse width
SYNC inactive to BIT_CLK startup delay
Tsync_high
Tsync2clk
1.0
162.8
1.3
-
-
us
ns
9.3 Clocks
Figure 15. Clocks
Tclk_low
BIT_CLK
Tclk_high
Tclk_period
Tsync_low
SYNC
Tsync_high
Tsync_period
Table 25. Clocks
Parameter
BIT_CLK frequency
BIT_CLK period
BIT_CLK output jitter
BLT_CLK high pulsewidth (note 1)
BIT_CLK low pulse width (note 1)
SYNC frequency
SYNC period
SYNC high pulse width
SYNC low_pulse width
Symbol
Tclk_period
Tclk_high
Tclk_low
Tsync_period
Tsync_high
Tsync_low
Min
Typ
Max
Units
36
36
-
12.288
81.4
40.7
40.7
48.0
20.8
1.3
19.5
750
45
45
-
MHz
ns
ps
ns
ns
kHz
us
us
us
Notes: 1) Worst case duty cycle restricted to 40/60.
34
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
9.4 Data Setup and Hold
STAC9721
(50pF external load)
Figure 16. Data Setup and Hold
Tsetup
BIT_CLK
SDATA_IN
SDATA_OUT
Thold
SYNC
Thold
Tsetup
Table 26. Data Setup and Hold
Parameter
Symbol
Min
Typ
Max
Units
Setup to falling edge of BIT_CLK
Hold from falling edge of BIT_CLK
Tsetup
Thold
10
10
-
-
ns
ns
Note 1: Setup and hold time parameters for SDATA_IN are with respect to the AC'97 controller.
9.5 Signal Rise and Fall Times - (50pF external load; from 10% to 90% of Vdd)
Figure 17. Signal Rise and Fall Times
BIT_CLK
Triseclk
Tfallclk
Trisedin
Tfalldin
SDATA_IN
Table 27. Signal Rise and Fall Times
Parameter
Symbol
Min
Typ
Max
Units
BIT_CLK rise time
BIT_CLK fall time
SDATA_IN rise time
SDATA_IN fall time
Triseclk
Tfallclk
Trisedin
Tfalldin
2
2
2
2
-
6
6
6
6
ns
ns
ns
ns
35
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
9.6 AC-Link Low Power Mode Timing
Figure 18. AC-Link Low Power Mode Timing
SYNC
Slot 1
Slot 2
Write to
0x20
Data
PR4
BIT_CLK
SDATA_OUT
Don't care
Ts2_pdown
SDATA_IN
Note: BIT_CLK not to scale
Table 28. AC-Link Low Power Mode Timing
Parameter
Symbol
Min
Typ
Max
Units
End of Slot 2 to BIT_CLK, SDATA_IN low
Ts2_pdown
-
-
1.0
us
36
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
9.7 ATE Test Mode
Figure 19. ATE Test Mode
RESET#
SDATA_OUT
Tsetup2rst
Hi-Z
SDATA_IN, BIT_CLK
Toff
Table 29. ATE Test Mode
Parameter
Symbol
Min
Typ
Max
Units
Setup to trailing edge of RESET#
(also applies to SYNC)
Setup to trailing edge of RESET#
(also applies to SYNC)
Rising edge of RESET# to Hi-Z delay
ToffTsetup2rst
15.0
-
-
ns
Tsetup2rst
15.0
-
-
ns
Toff
-
-
25.0
ns
Notes:
1. All AC-Link signals are normally low through the trailing edge of RESET#. Bringing SDATA_OUT high for the
trailing edge of RESET# causes STAC9721/23’s AC-Link outputs to go high impedance which is suitable for
ATE in circuit testing.
2. Once either of the two test modes have been entered, the STAC9721/23 must be issued another RESET# with all
AC-Link signals low to return to the normal operating mode.
# denotes active low.
37
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
10. ELECTRICAL SPECIFICATIONS:
10.1
Absolute Maximum Ratings:
Voltage on any pin relative to Ground
Operating Temperature
Storage Temperature
Soldering Temperature
Output Current per Pin
10.2
Vss - 0.3V TO Vdd + 0.3V
0 oC TO 70 o C
o
-55 C TO +125 o C
260 oC FOR 10 SECONDS
± 4 mA except Vrefout = ± 5mA
Recommended Operating Conditions
Table 30. Operating Conditions
PARAMETER
Power Supplies
+ 3.3V Digital
+ 5V Digital
+ 5V Analog
+ 3.3V Analog
Ambient Temperature
MIN
TYP
MAX UNITS
3.135
4.75
4.75
3.135
3.3
5
5
3.3
3.465
5.25
5.25
3.465
V
V
V
V
0
-
70
oC
SigmaTel reserves the right to change specifications without notice.
38
04/07/00
04/07/00
SigmaTel, Inc.
10.3
Data Sheet
STAC9721
Power Consumption
Table 31: Power Consumption at Default Analog Current
PARAMETER
MIN
Digital Supply Current
+ 5V Digital: DAC and ADC Active
+ 3.3V Digital: DAC and ADC Active
+ 3.3V Digital: DAC and ADC Muted
Analog Supply Current
+ 5V Analog: PC_BEEP Muted
+ 3.3V Analog: PC_BEEP Muted
Power Down Status
PR0 +5V Analog Supply Current
PR1 +5V Analog Supply Current
PR2 +5V Analog Supply Current
PR3 +5V Analog Supply Current
PR0,1,2,3 +5V Analog Supply Current
PR4 +3.3V Digital Supply Current
PR4 +5V Digital Supply Current
PR5 No Effect
TYP
MAX UNITS
30
20
7
mA
mA
mA
38
34
mA
mA
28
37
28
1.1
0.6
0.1
0.1
mA
mA
mA
mA
mA
mA
mA
Table 32: Power Consumption at 3.3V Analog, Low Current Mode*
PARAMETER
MIN
Digital Supply Current
+ 3.3V Digital with DAC and ADC Active
Analog Supply Current
+ 3.3V Analog with DAC and ADC Muted
Power Down Status
PR0 +3.3V Analog Supply Current
PR1 +3.3V Analog Supply Current
PR2 +3.3V Analog Supply Current
PR3 +3.3V Analog Supply Current
PR0,1,2,3 +3.3V Analog Supply Current
PR4 +3.3V Digital Supply Current
PR5 No Effect
TYP
MAX UNITS
20
mA
19
mA
15
19
15
0.4
0.4
0.1
mA
mA
mA
mA
mA
mA
* -50% Analog Current Setting (Recommended for 3.3V Analog only): Register 70h=ABBAh, 72h=0002h
39
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Table 33: Reduced Analog Power Settings Typical Supply Current
Condition
Default Analog Current
Reset
All Un-Muted
ADC, LINE Thru, PC_BEEP active
DAC, LINE Thru, PC_BEEP active
All but DAC and ADC
-25% Analog Current
Reset
All Un-Muted
ADC, LINE Thru, PC_BEEP active
DAC, LINE Thru, PC_BEEP active
All but DAC and ADC
-50% Analog Current
Reset
All Un-Muted
ADC, LINE Thru, PC_BEEP active
DAC, LINE Thru, PC_BEEP active
All but DAC and ADC
+25% Analog Current
Reset
All Un-Muted
ADC, LINE Thru, PC_BEEP active
DAC, LINE Thru, PC_BEEP active
All but DAC and ADC
40
04/07/00
3.3V Analog
5V Analog
30
65
36
51
41
40
82
60
57
47
24
52
29
41
33
32
67
50
46
37
17
38
21
30
24
This Setting Not
Recommended
35
75
43
54
48
46
94
69
67
55
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
AC-Link Static Digital Specifications (Tambient = 25 oC, DVdd = 5.0V or 3.3V ± 5%,
10.4
AVss=DVss=0V; 50pF external load)
Table 34. AC-Link Static Specifications
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
Input Voltage Range
Vin
-0.30
V
-
-
DVdd +
0.30
0.35xDVdd
Low level input range
Vil
V
High level input voltage
Vih
-
-
V
-
-
V
Vol
0.65xDVd
d
0.90xDVd
d
-
High level output voltage
Voh
Low level output voltage
-
0.1xDVdd
V
Input Leakage Current (AC-Link inputs)
-
-10
-
10
uA
Output Leakage Current (Hi-Z’d AC-Link
outputs)
Output buffer drive current
-
-10
-
10
uA
-
-
5
10.5
mA
STAC9721 Analog Performance Characteristics (Tambient = 25 oC, AVdd = 5.0V ± 5%, DVdd
= 3.3V ± 5%, AVss=DVss=0V; 1 kHz input sine wave; Sample Frequency = 48 kHz; 0 dB = 1 Vrms,
10KΩ/50pF load, Testbench Characterization BW: 20 Hz – 20 kHz, 0 dB settings on all gain stages)
Table 35. Analog Performance Characteristics
PARAMETER
MIN
TYP
MAX
UNITS
-
1.0
0.1
-
Vrms
-
1.0
-
Vrms
Analog S/N:
CD to LINE_OUT 5V
Other to LINE_OUT 5V
90
-
98
98
-
dB
Analog Frequency Response2
20
-
20,000
Hz
85
75
96
87
-
dB
85
75
96
86
-
dB
20
-
0.02
19,200
%
Hz
19,200
-
28,800
Hz
28,800
-
∞
Hz
+85
-
−
dB
Full Scale Input Voltage:
Line Inputs
Mic Inputs1
Full Scale Output Voltage:
Line Output 5V
3
Digital S/N
D/A 5V
A/D 5V
Digital S/N3
D/A 5V
A/D 5V
Total Harmonic Distortion:
Line Output4
D/A & A/D Frequency Response5
Transition Band
Stop Band
6
Stop Band Rejection
41
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Out-of-Band Rejection7
-
+40
−
dB
Group Delay
-
-
1
ms
Power Supply Rejection Ratio (1kHz)
-
+40
dB
Crosstalk between Input channels
-
-
−
-70
Spurious Tone Rejection
-
+100
−
dB
Attenuation, Gain Step Size
-
1.5
−
dB
Input Impedance
10
-
−
KΩ
Input Capacitance
-
15
−
pF
Vrefout
-
0.5 x AVdd
−
0.5
V
dB
0.5
dB
Interchannel Gain Mismatch ADC
Interchannel Gain Mismatch DAC
-
Gain Drift
100
DAC Offset Voltage
10
Deviation from Linear Phase
ppm/deg. C
50
1
External Load Impedance
10
Mute Attenuation (Vrms input)
90
dB
mV
degree
K ohm
96
dB
Notes:
With +20 dB Boost on, 1.0Vrms with Boost off
± 1 dB limits
The ratio of the rms output level with 1 kHz full scale input to the rms output level with all
zeros into the digital input. Measured “A weighted” over a 20 Hz to a 20 kHz bandwidth.
(AES17-1991 Idle Channel Noise or EIAJ CP-307 Signal-to-noise Ratio).
4. 0 dB gain, 20 kHz BW, 48 kHz Sample Frequency
5. ± 0.25dB limits
6. Stop Band rejection determines filter requirements. Out-of-Band rejection determines
audible noise.
7. The integrated Out-of-Band noise generated by the DAC process, during normal PCM audio
playback, over a bandwidth 28.8 to 100 kHz, with respect to a 1 Vrms DAC output.
1.
2.
3.
42
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
STAC9723 Analog Performance Characteristics (Tambient = 25 oC, AVdd = DVdd = 3.3V ±
10.6
5%, AVss=DVss=0V; 1 kHz input sine wave; Sample Frequency = 48 kHz; 0 dB = 1 Vrms, 10KΩ/50pF load,
Testbench Characterization BW: 20 Hz – 20 kHz, 0 dB settings on all gain stages)
Table 36. Analog Performance Characteristics
PARAMETER
Full Scale Output Voltage:
Line Inputs to line output 3.3V
Line Inputs to LINE_OUT 3.3V @ Line In =
1 Vrms and @ Gain setting of 4.5-6 dB
Line Inputs to LINE_OUT 3.3V @ Line In =
0.6 5 Vrms and @ gain setting of 0dB
PCM to LINE_OUT 3.3V @ full scale PCM input
@PCM gain setting of 0dB
PCM to Line Output 3.3V
MIC Inputs to LINE_OUT 3.3V @ MIC In
= 1 Vrms and @ gain setting of 0dB
Full Scale Output Voltage:
Line Inputs to line output 3.3V
Line Inputs to LINE_OUT 3.3V @ Line In =
1 Vrms and @ Gain setting of -6 dB
Line Inputs to LINE_OUT 3.3V @ Line In =
0.5 Vrms and @ gain setting of 0dB
PCM to LINE_OUT 3.3V @ full scale PCM input
@PCM gain setting of 0dB
PCM to Line Output 3.3V
MIC Inputs to LINE_OUT 3.3V @ MIC In
= 1 Vrms and @ gain setting of 0dB
Analog S/N:
CD to LINE_OUT 3.3V
Other to LINE_OUT 3.3V
Analog Frequency Response2
MIN
TYP
MAX
UNITS
-
0.65
-
Vrms
-
-
0.65
Vrms
0.65
Vrms
0.555
Vrms
0.5
Vrms
0.5
-
Vrms
0.5
Vrms
0.5
Vrms
0.5
Vrms
0.5
Vrms
-
20
90
90
-
20,000
85
75
90
85
-
20
-
0.02
19,200
%
Hz
19,200
-
28,800
Hz
28,800
-
∞
Hz
+85
-
−
dB
Out-of-Band Rejection
-
+40
−
dB
Group Delay
-
-
1
ms
Power Supply Rejection Ratio (1kHz)
-
+40
dB
Crosstalk between Input channels
-
-
−
-70
dB
Spurious Tone Rejection
-
+100
−
dB
Attenuation, Gain Step Size
-
1.5
−
dB
Input Impedance
10
-
−
Input Capacitance
-
15
−
KΩ
pF
Hz
3
Digital S/N
D/A 3.3V
A/D 3.3V
Total Harmonic Distortion:
Line Output4
D/A & A/D Frequency Response5
Transition Band
Stop Band
6
Stop Band Rejection
7
43
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
Vrefout
-
STAC9721
0.5 x
AVdd
Interchannel Gain Mismatch ADC
Interchannel Gain Mismatch DAC
-
Gain Drift
100
DAC Offset Voltage
10
Deviation from Linear Phase
External Load Impedance
10
Mute Attenuation (0 dB)
90
96
−
V
0.5
dB
0.5
dB
50
ppm/ oC
mV
1
degree
KΩ
dB
Notes:
1. With +20 dB Boost on, 1.0Vrms with Boost off
2. ± 1 dB limits
3. The ratio of the rms output level with 1 kHz full scale input to the rms output level with all
zeros into the digital input. Measured “A weighted” over a 20 Hz to a 20 kHz bandwidth.
(AES17-1991 Idle Channel Noise or EIAJ CP-307 Signal-to-noise Ratio).
4. 0 dB gain, 20 kHz BW, 48 kHz Sample Frequency
5. ± 0.25dB limits
6. Stop Band rejection determines filter requirements. Out-of-Band rejection determines
audible noise.
7. The integrated Out-of-Band noise generated by the DAC process, during normal PCM audio
playback, over a bandwidth 28.8 to 100 kHz, with respect to a 1 Vrms DAC output.
44
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Appendix A
SPLIT INDEPENDENT POWER SUPPLY OPERATION
In PC applications, one power supply input to the STAC9721/23 may be derived from a supply regulator
(as shown in Figure 3) and the other directly from the PCI power supply bus. When power is applied to
the PC, the regulated supply input to the IC will be applied some time delay after the PCI power supply.
Without proper on-chip partitioning of the analog and digital circuitry, some manufacturer's codecs would
be subject to on-chip SCR type latch-up.
SigmaTel’s STAC9721/23 specifically allows power-up sequencing delays between the analog (AVddx)
and digital (VDddx) supply pins. These two power supplies can power-up independently and at different
rates with no adverse effects to the codec. The IC is designed with independent analog and digital
circuitry that prevents on-chip SCR type latch-up.
.
3.3V or 5V ± 5%
3.3V or 5V ± 5%
0.1uF
10uF
0.1uF
1uF
25
AVdd1
0.1uF
0.1uF
38
1
AVdd2
DVdd1
9
DVdd2
2
27pF
XTL_IN
12
13
24.576MHz
PC_BEEP
XTL_OUT
3
SDATA_OUT
5
27pF
PHONE
14
BIT_CLK
8
15
AUX_R
16
17
18
22 ohms
6
AUX_L
SigmaTel
STAC9721/23
VIDEO_L
VIDEO_R
EMI
Filter
SDATA_IN
10
27pF
SYNC
11
RESET
45
CID0
46
CD_L
CID1
19 CD_GND
27
20
Vref
CD_R
21
22
23
0.1uF
Vrefout
MIC2
Optional Anti-Pop Circuit
31
CAP1
LINE_IN_L
33
CAP3
24
32
LINE_IN_R
100uF
CAP2
47
EAPD
35
LINE_OUT_L
820pF
29
10uF
34
APOP
1uF
0.1uF
1uF
28
MIC1
36
LINE_OUT_R
AFILT1
37
820pF
MONO_OUT
30
AFILT2
AVss1
26
AVss2
42
DVss1
4
DVss2
7
NOTE: Pins 31, 33, 34, 40
LNLVL_OUT_L
39
LNLVL_OUT_R
41
** Teminate ground
plane as close to power
supply as possible
43, 44, and 48 are No Connects
Analog Gnd
45
04/07/00
Digital Gnd
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
Appendix B
+5.0V/+3.3V POWER SUPPLY OPERATION NOTES
The STAC9721 is capable of operating from a single 5V supply connected to both DVdd and AVdd.
Even though the STAC9721 has digital switching levels of 0.2Vdd to 0.5Vdd (See AC Link Electrical
Characteristics in this data book), we recommend that all digital interface signals to the AC-Link be 5V.
If digital interface signals below 5V are used, then appropriate level shifting circuitry must be provided to
ensure adequate digital noise immunity.
The STAC9721 can also operate from a 3.3V digital supply connected to DVdd while maintaining a 5V
analog supply on AVdd. On-chip level shifters ensure accurate logic transfers between the analog and
digital portions of the STAC9721. If digital interface signals above 3.3V are used (i.e. a +5V AC-Link
interface), then appropriate level shifting circuitry must be provided to ensure adequate digital noise
immunity and to prevent on-chip ESD protection diodes from turning on. (See Appendixes A concerning
SPLIT INDEPENDENT POWER SUPPLY OPERATION).
The STAC9723 must be run from a 3.3V supply connected to both DVdd and AVdd. If digital interface
signals above 3.3V are used (i.e. a +5V AC-Link interface), then appropriate level shifting circuitry must
be provided to ensure adequate digital noise immunity and to prevent on-ship ESD protection diodes
from turning on.
*Always operate the STAC97xx digital supply from the same supply voltage as the digital
controller supply.
*All the analog inputs must be ac-coupled with a capacitor of 0.1 µF or greater. It is recommended
Ω be connected from the signal side of the capacitor to analog GND as
that a resistor of about 47KΩ
shown below.
> 1.0 uF
Analog Input
SIGNAL
47K
*All the analog outputs must be ac-coupled. If an external amplifier is used, make sure that the
Ω and use an ac-coupling capacitor of 1.0 µF.
input impedance of the amplifier is at least 10KΩ
46
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
- NOTES -
47
04/07/00
04/07/00
SigmaTel, Inc.
Data Sheet
STAC9721
For more information, please contact:
SigmaTel, Inc.
6101 W. Courtyard Dr., Bldg. 1, Suite 100
Austin, Texas 78730
Tel (512) 343-6636x29, Fax (512) 343-6199
email: [email protected]
http://www.sigmatel.com
48
04/07/00
04/07/00