AKM AK4571 Usb interface audio codec Datasheet

ASAHI KASEI
[AK4571]
AK4571
USB Interface Audio CODEC
Features:
„ USB Audio Controller
12 Mbps bit rate
USB Serial Interface Engine (SIE)
Audio Class Processing Block
4 Endpoints
USB transceiver
General Description:
The AK4571 is a USB Interface audio CODEC. The AK4571
incorporates a 16-bit CODEC, PLLs, USB transceiver, SIE (serial
interface engine), audio class processing unit, FIFO and other
required signals into a single chip. The AK4571 can
simultaneously transmit and receive audio stream data through
USB bus. In addition to this, the single-channel ADC and 2channel DAC can operate at different sampling rates.
„ 16bit CODEC
- Single-channel A/D Converter
Microphone Pre-Amp (Fixed Gain: 20dB)
Mute/Volume Control
Programmable Gain Control
+24dB to –31dB ( 1dB step )
- D/A Converter
2 channels
- Mixer
Mute/Attenuation Control
+0dB to –47dB ( 1dB step )
Analog Bass Boost
The AK4571 has a programmable gain amplifier for analog input
(IPGA). The gain range is from –31dB to +24dB with 1dB steps. In
addition to the IPGA, the AK4571 also has a fixed +20dB
pre-amplifier. Analog input signals can be mixed directly with the
D/A signal and sent to the LINEOUT pins of the chip.
The analog outputs of the AK4571 can be attenuated up to
–47dB in 1dB steps. The AK4571 also has an analog bass boost
circuit. Bass Boost response can be modified by changing the
values of external resistors and capacitors.
The AK4571 has a Human Interface Device function that allows a
user to control the playback volume at the device side. The
playback volume on mixer applet moves up or down automatically
by the operation of HID buttons. The AK4571 also can mute
analog input signal locally in addition to mixer applet control.
„ HID Support
remote control of playback volume/mute
recording mute/status function
„ Power Management
control of external headphone amplifier
low power at suspend mode (< 1uA)
The AK4571 has advanced power management capabilities.
Suspend current is less than 1uA. The AK4571 can also control
the power of an external headphone amplifier to conform to the
USB suspend current requirement of 500uA maximum.
„ EEPROM Interface (Microwire Interface)
- can read Device/String Descriptor from EEPROM
- 1K/2K/4K bit EEPROM
The AK4571 has a Microwire interface for an external
EEPROM, allowing customization of Vendor ID and product ID.
„ On-chip PLL
7 sampling frequencies:
8kHz, 11.025kHz, 16kHz, 22.05kHz, 32kHz,
44.1kHz, 48kHz
The high integration of the AK4571 reduces both the number of
external components required and the PCB area required to build
USB devices, including small format products such as USB
headsets.
„ Single Power Supply, Low Power
+3.3Volts±0.3V
„ Package
48pin LQFP
MS0153-E-03
2005/06
-1-
ASAHI KASEI
[AK4571]
Block Diagram
VA AGND BGND
STBY
CS
RBFI
M
M
Bass
Boost
Bass
Boost
EPDO EPAI
SK
EPEN
EEPROM I/F
Power
Management
EPSW
EMSW
RBFO
LOUT
INC
VREF
MICBIAS
ROUT
VRAD VRDA MSTAT IMUTE OMUTE DEC
DGND VD VCOM
Config
ROM
Master
volume
Mixer
ATT
Σ
ATT
DAC
String
ROM
FIFO
DAC
Σ
EPSEL
FIFO
Audio
Control
Block
USB
Serial
Interface
Engine
USB
Transceiver
DP
DN
LBFI
LBFO
GAIN
MICIN
20dB
M
ADC
GAIN
AMP1O
AMP2I
M
FIFO
PLL
AMP2O LFLT_44K
LFLT_48K LFLT_SYS
XTLIN
PLL1
XTLOUT
RSTN
CRYSTAL
MS0153-E-03
2005/06
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ASAHI KASEI
[AK4571]
Ordering Guide
AK4571VQ
AKD4571
0 ∼ +70°C
48pinLQFP(0.5mm pitch)
Evaluation Board for AK4571
Pin Layout
40
EPSEL
35
DGND
BGND
XTALOUT
XTALIN
TEST2
45
1
TEST1
IMUTE
MSTAT
INC
DEC
OMUTE
RSTN
SUSN
DP
DN
TEST3
VD
EPDI
EPAO
SK
5
CS
EPSW
STBY
30
EMSW
LFLT_SYS
LFLT_44K
LFLT_48K
VCOM
EPEN
TESTMODE3
TESTMODE2
VRDA
10
VRAD
25
20
15
ROUT
RBFO
RBFI
LOUT
LBFO
LBFI
TESTMODE1
AMP2O
AMP2I
AMP1O
MICIN
MICBIAS
MS0153-E-03
AGND
VA
2005/06
-3-
ASAHI KASEI
[AK4571]
Pin/Function
No.
Signal Name
USB Interface
46
DP
I/O
Ana / Dig
I/O
D
USB bus Non-Inverting pin.
Since the AK4571 is a full-speed device, a 1.5kΩ resistor must be
connected between D+ node to VD.
47
DN
Reset, Crystal, PLL
45
RSTN
I/O
D
USB bus Inverting Pin.
I
D
Reset Pin. Low input resets the chip.
Schmitt Trigger input.
Suspend Pin
"L": Suspend Mode
“H”: Normal Mode
Crystal Oscillator Output, Connect Crystal Resonator. Connect capacitor
Crystal Oscillator Input, Connect Crystal Resonator. Connect capacitor
System PLL loop filter Pin. Connect 2.7kΩ resistor and 22nF capacitor in
series externally.
Codec PLL loop filter Pin. Connect 120kΩ resistor and 6.8nF capacitor in
series externally.
Codec PLL loop filter Pin. Connect 120kΩ resistor and 6.8nF capacitor in
series externally.
44
SUSN
O
D
4
5
9
XTALOUT
XTALIN
LFLT_SYS
O
I
O
A
A
A
10
LFLT_44K
O
A
11
LFLT_48K
O
A
O
O
O
I
O
I
O
A
A
A
A
A
A
A
O
O
I
O
I
O
O
A
A
A
A
A
A
A
Analog Input/Output
12
VCOM
27
VRAD
28
VRDA
14
MICIN
15
AMP1O
16
AMP2I
17
AMP2O
21
24
19
20
22
23
13
LOUT
ROUT
LBFI
LBFO
RBFI
RBFO
MICBIAS
External Headphone Amplifier Control
6
EPSW
O
7
STBY
O
8
EMSW
O
Description
Analog Common Voltage Reference Pin
ADC Common Voltage Reference Pin.
ADC Common Voltage Reference Pin.
Mono Channel Microphone Input
Mono Channel 1st Amplifier Output Pin
Mono Channel 2nd Amplifier Input Pin
Mono Channel 2nd Amplifier Output Pin
Please Connect 1nF capacitor.
Left Channel D/A Out
Right Channel D/A Out
Left Channel Bass Boost Filter Input Pin
Left Channel Bass Boost Filter Output Pin
Right Channel Bass Boost Filter Input Pin
Right Channel Bass Boost Filter Input Pin
Voltage Reference Output for the Microphone’s bias voltage
When the chip goes into Suspend mode, this pin goes to Hi-Z.
External Headphone Amplifier Power Switch Control Pin 1
“H”: Normal Operation
“L”: Suspend Mode
External Headphone Amplifier Power Switch Control Pin 2
“L”: Normal Operation
“H”: Suspend Mode
External Headphone Amplifier Mute Control Pin
“H”: MUTE ON
“L”: MUTE OFF
MS0153-E-03
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ASAHI KASEI
[AK4571]
No.
Signal Name
EEPROM I/F
I/O
Ana / Dig
Description
31
CS
O
D
EEPROM I/F Chip Select Pin
32
SK
O
D
Read Clock Pin
34
EPDI
I
D
EEPROM Data Input Pin
33
EPAO
O
D
EEPROM Address Output Pin
35
EPEN
I
D
36
EPSEL
I
D
EEPROM Enable Pin
"H": Read Device/String Descriptor from external EEPROM
”L”: Read Device/String Descriptor from internal ROM.
CS,SK,EPDI,EPAO are Hi-Z
EEPROM Select
“L”: 1Kbit Type EEPROM is connected.
“H”: 2Kbit/4Kbit EEPROM is connected
HID Interface
39
IMUTE
I
D
43
OMUTE
I
D
41
INC
I
D
42
DEC
I
D
40
MSTAT
O
D
P
P
P
P
P
A
A
D
D
D
Power Supply
25
VA
26
AGND
1
VD
2
DGND
3
BGND
Test Mode
18
TESTMODE1
29
TESTMODE2
30
TESTMODE3
38
TEST1
I
I
I
I
A/D Mute
Toggles mute status at the rising edge. If this pin is not used, please
connect this pin to DGND.
D/A Mute
Sets “1” to internal register at the rising edge, and reset to “0” at the
falling edge. If this pin is not used, please connect this pin to DGND.
D/A Volume Up Pin
Sets “1” to internal register at the rising edge, and reset to “0” at the
falling edge. If this pin is not used, please connect this pin to DGND.
D/A Volume Down Pin
Sets “1” to internal register at the rising edge, and reset to “0” at the
falling edge. If this pin is not used, please connect this pin to DGND.
Recording Mute Status Pin.
“H”: Mute ON
“L”: Mute OFF
In suspend mode, this pin is “L”.
Analog Power Supply, 3.3V
Analog Ground
Digital Power Supply, 3.3V
Digital Ground
Bulk Ground, 0V
Please tie down to AGND for normal operation.
Please tie down to AGND for normal operation.
Please tie down to AGND for normal operation.
Please tie down to DGND for normal operation.
37
TEST2
O
Please open state
48
TEST3
I
Please tie down to DGND for normal operation.
MS0153-E-03
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ASAHI KASEI
[AK4571]
Absolute Maximum Rating
AGND, DGND=0V
Parameter
Power Supplies
Analog
Digital
|DGND-AGND|
Input Current (any pins except for supplies)
Analog Input Voltage
Digital Input Voltage
Ambient Temperature
Storage Temperature
Note
1. All voltages with respect to ground
Symbol
min
Max
Units
VA
VD
∆GND
IIN
VINA
VIND
Ta
Tstg
-0.3
-0.3
4.5
4.5
0.3
±10
VA+0.3
VD+0.3
70
125
V
V
V
mA
V
V
°C
°C
-0.3
-0.3
0
-40
Warning: Operation at or beyond these limits may result in permanent damage to the device. Normal operation is not guaranteed at these
extremes.
Recommended Operating Condition
AGND, DGND=0V
Parameter
Power Supplies
Analog
Digital
Symbol
min
typ
Max
Units
VA
VD
3.0
3.0
3.3
3.3
3.6
3.6
V
V
All voltages with respect to ground.
* AKM assumes no responsibility for usage beyond the conditions set forth in this datasheet.
MS0153-E-03
2005/06
-6-
ASAHI KASEI
[AK4571]
Analog Characteristics
Ta=25°C,VA=VD=3.3V, Signal Frequency=1kHz, Sampling Frequency Fs=44.1kHz BW=20Hz – 20kHz, TEST mode; unless otherwise
specified
Parameter
Min
typ
Max
Units
Mono ADC (1 channel)
Resolution
16
bits
S/N (A weight) @44.1kHz
83
dBA
(PGA is set to 0dB) AMP2I input : USB Normal mode
S/(N+D)
(-1.0dB analog input) USB Normal mode
73
dB
Full scale input Voltage
0.53
0.6
0.67
Vrms
MIC amplifier
S/N (A weight)
76
84
dBA
MICIN input AMP1O output
Gain 20dB Selected
+17
+20
+23
dB
Input Impedance
10
20
kΩ
Stereo DAC (2 channel)
Resolution
16
bits
S/N (A weight) @44.1kHz (DAC volume &master volume is set to 0dB)
84
dBA
USB Normal mode
S/(N+D)
(-1.0dB digital input) USB Normal mode
75
dB
Full scale output Voltage
0.53
0.6
0.67
Vrms
PGA
Step size
0
1.0
2.0
dB
Attenuation control range
-31
+24
dB
Input Impedance AMP2I input
10
20
kΩ
Master volume:
step size
0
1.0
2.0
dB
Attenuation control range
-47
0
dB
Output Load Resistance
10
kΩ
Output Load Capacitance
5
pF
Bass Boost
Internal Resistance
40
kΩ
External Resistance
360
400
kΩ
External Capacitance
5
pF
MIC Bias (Buffer Amp)
Output Voltage
1.94
2.2
2.46
Vdc
Output Current
2
mA
Power Supplies
mA
52
35
Analog
mA
23
15
Digital
mA
75
50
Total
uA
150
0
Power Down(Suspend)
MS0153-E-03
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ASAHI KASEI
[AK4571]
Filter Characteristics
Ta=25°C, VA=VD=3.3V, fs=44.1kHz
Parameter
ADC Digital Filter ( Decimation LPF)
min
typ
0
26.5
70
Pass band (±0.2dB)
Stop band
Stop band Attenuation
Group Delay
ADC Digital Filter (HPF)
max
Units
17.64
kHz
kHz
dB
ms
0.363
Frequency Response:
-3dB
-0.5dB
-0.1dB
DAC Digital Filter
6.89
19.3
44.9
0
26.5
70
Pass band (±0.2dB)
Stop band
Stop band Attenuation
Group Delay
DAC Analog Post filter
Hz
17.64
kHz
kHz
dB
ms
-
dB
0.312
Pass band Frequency Response
-
MS0153-E-03
±0.1
2005/06
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ASAHI KASEI
[AK4571]
Digital DC Characteristics
Ta=0 - 70°C; VD=3.0 - 3.6V; DGND=0V Measurement under static state
All digital pins except DP, DN. Schmitt hysteresis level of RSTN pin and levels of all test pins will not be tested.
Parameter
Symbol
Min
Typ
Max
EPDI,EPEN, EPSEL, pin “H” level input voltage
VIH
70%VD
EPDI, EPEN, EPSEL pin “L” level input voltage
VIL
30%VD
RSTN pin “H” level voltage
VIHR
2.4
RSTN pin “L” level voltage
VILR
0.8
IMUTE, OMUTE, INC, DEC pin “H” level voltage
VIHR
2.4
IMUTE, OMUTE, INC, DEC pin “L” level voltage
VILR
0.8
SUSN, EPSW, STBY, EMSW, MSTAT pin
VOH
2.4
“H” level output voltage IOH= 2mA
SUSN, EPSW, STBY, EMSW, MSTAT pin
VOL
0.6
“L” level output voltage
IOL= -2mA
CS, SK, EPAO pin “H” level output voltage
VOH
2.4
IOH= 2mA
CS, SK, EPAO pin “L” level output voltage
VOL
0.6
IOL= -2mA
DP, DN Single Ended Receiver Threshold for “H” level
VIHR
2.0
DP, DN Single Ended Receiver Threshold for pin “L” level
VILR
0.8
Input Leakage Current
Iin
±10
Rpd
100
Pull down Resistance (only EPDI pin)@3.3V Ta=25°C
Switching Characteristics
Ta=25°C, VA=VD=3.3V
Parameter
Symbol
Min
Typ
Master Clock Frequency
MCLK
12.000
Reset input width @RSTN pin(low active)
Wrst
1.0
Time Width for USB Reset Signal Recognition
Trst_rec
3.0
DP<VseL & DN< VseL to USB Reset mode
Device Ready Time from USB Reset
Tdrr
After releasing from USB Reset to Device Ready
(Transaction can start)
Time Width for Suspend Recognition
Idle state ( DP > VseL & DN < VseL )
Tsus_rec
4.36
to Suspend mode
Resume Time from Suspend
Tresm
First flip of DP/DN from Idle state
To Device Ready*)
Imute input width with @IMUTE pin(High active)
Wimute
10.005
Omute,Dec,Inc input width with @OMUTE,DEC,INC
Wodi
2.001
pin (High active)
Device Ready: VREF, X’tal oscillator and PLL are stable and standard bus transactions can proceed
MS0153-E-03
Units
V
V
V
V
V
V
V
V
V
V
V
V
µA
kΩ
Max
-
Units
MHz
us
µs
10
ms
ms
30
ms
ms
ms
2005/06
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ASAHI KASEI
[AK4571]
Trst_rec
Tdrr
Tsus_rec
Tresm
resume time
recovery time
D+
D-
Master
Clock
Figure 1. Mode Change with respect to Bus States
Transmitter/Receiver Characteristics
Ta=25°C; VD=3.3V; DGND=0V; CL=50pF
Parameter
Symbol
Transmitter
Pins
Data Rate
DR
DP,DN
Output Impedance (Hi)
Roh
DP, DN
Output Impedance (Lo)
Rol
DP, DP
“H” level Output Voltage
“L” level Output Voltage
Tri-state Leakage Current
Rise/Fall Time
Rise/Fall Time Matching
Crossover Point
Receiver
Vohd
Vold
Iolk
Trf/Tff
Trfm
Vcrs
DP, DN
DP, DN
DP, DN
DP, DN
DP, DN
DP, DN
Input Common Mode range
Differential Input Level
CMR
Vdiff
DP, DN
DP, DN
Conditions
DP, DN=”H”
at Iout = -10mA
DP, DN=”L”
at Iout = 10mA
at Iout =-200uA
at Iout =2.2mA
0 < DP, DN< 3.3V
| DP – DN |
MS0153-E-03
Min
Typ
Max
Units
11.97
12
12.03
MHz
36
Ω
36
Ω
2.8
-10
4
0.8
0.2
10
100
1.65
0.3
10
20
2.5
V
V
µA
ns
%
V
V
V
2005/06
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ASAHI KASEI
[AK4571]
Trf
Trs
Tff
Tfs
90%VD
DP, DN
10%VD
Figure 2. Rise/Fall Time
Vcrs
DP, DN
Figure 3. Crossover Point
MS0153-E-03
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ASAHI KASEI
[AK4571]
1
Device Overview
1.1
PLL and Sampling Rates
The AK4571 has three PLLs in addition to a crystal oscillation circuit. The first PLL generates a system clock at 48MHz, the second PLL
generates the clock for 44.1kHz sample rates (including derivatives of this sample rate) and third PLL generates the clock for 48kHz sample
rates (including derivatives).
The CODEC clocks are generated from the USB SOF, so they are synchronized with USB SOF. The ADC and DAC operate at one of seven
sampling rates, 8kHz, 11.025kHz, 16kHz, 22.05kHz, 32kHz, 44.1kHz, and 48kHz. The ADC and DAC can operate at different sampling
rates.
1.2
A/D Converter & D/A Converter
The AK4571 has a 16-bit single-channel A/D converter, and a 16-bit two-channel D/A converter. The AK4571 has a programmable gain
amplifier for the analog input (IPGA) with a range from –31dB to + 24dB in 1dB steps. In addition to the IPGA, the AK4571 has a fixed
20dB gain pre-amplifier. Therefore the total gain of the analog input is +44dB maximum. Analog output can be attenuated from 0dB to
47dB in 1dB steps. Analog input and the D/A signal can be mixed in the chip and sent to the Line outputs. The Lineout volume, the
microphone playback volume, and the microphone recording volume can be controlled directly from the PC
1.3
Bass Boost Control
The AK4571 has an analog bass boost circuit, and can boost the bass frequencies of the lineout signal by up to 20dB. Frequency response
and DC gain are adjusted by external resistors and capacitors. The Bass boost effect is controlled via the HID application.
1.4
Serial Interface Engine (SIE) & Audio Class Processing Block
The AK4571 has a Serial Interface Engine that processes lower-level protocols like CRC checking, bit stuffing, NRZI encoding/decoding,
in addition to higher-level protocol like USB standard requests. SIE also notifies the backend that it has received an Audio Class Request,
and passes the request to the backend. The backend decodes and processes Audio Class Request like mute requests, volume requests and
sampling frequency control requests. Therefore, the AK4571 does not require a micro-controller for this processing.
1.5
HID (Human Interface Device)
Since the AK4571 supports HID function, mute and volume can be controlled remotely. The host knows whether the playback
volume/mute button has been pressed or not by issuing an Interrupt Request periodically, and notifies the application that the status has
changed. The software application issues the volume/mute request in order to synchronize the software with the AK4571. Input/ Recording
signals can be also muted independently of the software application.
1.6
EEPROM I/F
The AK4571 has all of its descriptors in its internal ROM, so it does not require external an EEPROM. However vendor ID, vendor name,
product ID, and product name can be also customized by using an external Microwire interface EEPROM. A Microwire™ type, 1K, 2K, or
4K EEPROM can be used.
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ASAHI KASEI
[AK4571]
1.7
Power Management
The AK4571 starts its transition to suspend mode when the idle state of USB bus continues more than 3ms. The AK4571 suppresses the
power-supply current (typ.1uA) while in suspend mode because all blocks, including PLLs, pare placed in power-down mode. Under
normal operation the AK4571 supplies a bias voltage via the output buffer to the microphone. In suspend mode, the MICBIAS pin goes to
a Hi-Z state, and the AK4571 does not supplying this current to the microphone.
The AK4571 also has 3 pins for control of an external headphone amplifier. These pins are used to suppress the power-supply current during
suspend mode in addition to suppressing “pop noise” during the transition of suspend/resume. The AK4571 has two pins for power-control
because there are “active high” types and “active low” types of external headphone amplifiers. Third pin is for the mute control to suppress
transitional pop noise.
The USB bus consumes 200uA current even in suspend mode. A regulator also consumes current in standby mode. Even with these devices
consuming power the system can still conform to the 500uA USB specification because of the AK4571 low-power consumption and its
control of the microphone and headphone power circuits.
TheAK4571 is ready for operation 30ms after transitioning from suspend mode to normal operating mode.
1.8
USB Transceiver
The AK4571 includes a USB transceiver.
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ASAHI KASEI
[AK4571]
2
2.1
Functional Description
Synchronization of the host and the AK4571
The ADC and DAC in the AK4571 operate synchronously with the SOF (Start of frame) of the USB bus. USB’s Isochronous transfer
guarantees that audio stream data is transferred once per frame. However, USB does not specify the start point of the transfer in a frame.
The worst-case period between two transfers is about 2ms.therefore the AK4571 has a FIFO that stores 2ms audio stream data.
If the CODEC operates at 44.1kHz sampling frequency, the AK4571 expects that 45 samples are transferred once per10 frames. (Please see
Figure 4)
The average sampling frequency in Figure 4 is 44.1kHz.
N Frame
(N+1) Frame
44 samples
44 samples
(N+9) Frame
45 samples
(N+10) Frame
44 samples
Figure 4 Synchronization Scheme
The AK4571 transmits all A/D data stored to FIFO in the previous frame while updating the A/D data to FIFO in the current frame. The
sample count of 48kHz series D/A data per frame is fixed in all frames. For 44.1kHz, the appearance of 45 samples should be just one time
per 10 frames. If the D/A clock and SOF clock operated asynchronously, the FIFO would overrun or underrun, and an audible pop noise
would occur periodically. Therefore, CODEC clocks are synchronized with SOF clock. In order to achieve this synchronization, the
AK4571 has built-in two PLLs for CODEC clocks and generates clocks for both of 48kHz sample rate series and 44.1 sample rate series.
2.2
Power Management
USB devices fall into one of three power categories: 1) Low-power Bus-powered Devices (<100mA) 2) High-power Bus-powered
Devices(>100mA, <500mA) 3) Self-powered Devices.
As the AK4571 is a low-power consumption device, it can be defined as a Low-power Bus-powered Device and can be connected to a
bus-powered Hub. (High-power Bus-powered Devices can't be connected to a Bus-powered Hub)
USB specifications require a maximum of 500uA in suspend mode. This includes the current drawn between Vbus and ground through the
1.5 k ohm resistor tied to D+ line and Vbus. This current is about 200uA.
Two points should be considered in order to observe the USB suspend mode specification.
a) Suppression of the AK4571 current
All blocks including ADC, DAC, PLL go to power-down mode when the idle state continues for more than 3ms. Values like volume
and mute status are preserved in suspend mode.
b) Control of External Circuits
The USB specification does not permit more than 500µA of current in suspend mode. Therefore, the AK4571 must control the power
dissipation of the external headphone amplifier and microphone. Since the MICBIAS pin is in a Hi-Z state in suspend mode, the
AK4571 does not supply current to the microphone.
Headphone Amplifiers commonly have power-down pin and can be controlled externally. There are two types of power-control logic;
active-low and active-high. Some headphone amplifiers have a mute pin for suppressing pop noise. The AK4571 supports all of these
headphone amplifiers.
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ASAHI KASEI
[AK4571]
SOF
SUS_N(internal)
EMSW(Mute SW)
STBY
EPSW(STBY)
1.45ms
1.45ms
Figure 5 Suspend and Resume Sequence
MS0153-E-03
2005/06
- 15 -
ASAHI KASEI
[AK4571]
2.3
Bias Circuit for Microphone
The AK4571 supplies a bias voltage to the microphone through the MICBIAS pin. The output voltage is about 2.2 volts and output current
is 2mA maximum. Since the microphone's output signal level is very low, the noise level of the bias voltage should also be low. USB bus
transactions typically cause variation of the regulator's output. However, the AK4571 has a built-in voltage reference for mic bias, and
suppresses the bias noise caused by the regulator.
Coupling capacitors should be connected in parallel between the two resistors (i.e. Ra=300Ω, and Rb=4.7kΩ/2.2kΩ) in order to make the
bias circuit stable. The appropriate value, Rb, depends on the microphone ‘s characteristics.
The output is placed in a Hi-Z state in suspend mode.
2.4
EEPROM Interface
The AK4571 has all descriptors, including String Descriptors, in its internal ROM so it does not require an external EEPROM. The AK4571
also has an EEPROM interface so that an external EEPROM can be attached for customizing Vendor ID, Product ID, vendor name and
product name.
The EPEN pin should be “L” if the EEPROM is not used. CS, SK, EPAO pins are at a Hi-Z state in this configuration.
Please see “Descriptors in Detail” section for internal ROM information.
The EPEN pin should be “H” if an external EEPROM is used. The AK4571 reads the Device Descriptor from the EEPROM after a USB
Reset. The AK4571 starts to read String Descriptor just after receiving “GET Descriptor (String)” request.
With the AK4571 you can customize the following fields:
1) Device Descriptor (18 bytes)
2) String Descriptor (Language ID, Manufacturer Name, Product Name)
Microwire type (4 wire) , 1K/2K/4K bit EEPROM can be used (for example, AK93C45A/55A/65A)
If a 1Kbit EEPROM is selected, the length of Manufacturer name or Product name should be just 50 bytes. As each String
Descriptor requires 2-bytes of length information, the total length of each String Descriptor is 52 bytes.
If a 2K/4K bit EEPROM is selected, the length of Manufacturer name or Product name should be just 100 bytes. As each String
Descriptor requires 2-bytes of length information, the total length of each String Descriptor is 102 bytes.
If a 1K bit EEPROM is used, EPSEL pin should be “L” while EPSEL pin should be “H” for a 2K/4K EEPROM.
The length in both cases should be exactly 52 bytes or 102 bytes, no longer, no shorter.
Table 1 shows the relationship between EEPROM address and Descriptor.
Device Descriptor (18 bytes)
String Descriptor Lang ID (4 bytes index = 0)
String Descriptor iManufacturer (52 or 102 bytes: index =1)
String Descriptor iProduct (52 or 102 bytes: index = 2)
1K bit EEPROM
(AK93C45A)
00h -08h
09h –0Ah
0Bh-24h25h-3Eh
2K/4K bit EEPROM
(AK93C55A/65A)
00h-08h
09h-0Ah
0Bh-3Dh
3Eh-71h
Table 1 Relationship between EEPROM Address and Descriptor
Since the AK4571 cannot write data to the EEPROM, the EEPROM should be mounted on the PCB after it has been programmed with the
necessary data. Please refer to the AKM EEPROM datasheet for the write sequence. If EEPROM is not used (EPEN =”L"), an EEPROM
should not be mounted on the PCB because the CS, CK and EPAO outputs are Hi-Z when EPEN = “L”.
MS0153-E-03
2005/06
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ASAHI KASEI
[AK4571]
2.5
Bass Boost
The AK4571 has an analog bass boost that is activated by mounting a resistor and a capacitor between LBFO-LBFI, and RBFO-RBFI
respectively as Figure 6 shows. Bass frequencies can be amplified up to 20dB by selecting an appropriate resistor. Cut-off frequency shifts
as the capacitor value varies.
External
Circuit
Cb
Rb
LBFI/RBFI
LBFO/RBFO
Figure 6 Analog Bass Boost Circuit
Bass Boost
25
Gain[dB]
20
Rb=360k
Cb=1nF
Rb=360k
Cb=4.7nF
15
Rb=120k
Cb=2.2nF
10
5
0
10
100
1000
10000
100000
Frequency[Hz]
Figure 7 Bass Boost Characteristics
MS0153-E-03
2005/06
- 17 -
ASAHI KASEI
[AK4571]
2.6
2.6.1
HID (Human Interface Device)
HID Overview
The AK4571 has two pins for incrementing or decrementing the lineout volume (INC pin and DEC pin), and has a pin for the control of
mute (OMUTE pin). For example, the lineout volume slider in a Windows application automatically moves up at the rising edge of INC pin.
This means that the value in the Windows program is synchronized with the device's hardware value.
If a button is pressed, the internal bit assigned to it is set to “1”. Based on the USB spec for HID, the host knows whether the INC button
and/or DEC button and/or OMUTE buttons are pressed or not by periodically issuing an Interrupt transfer request. The AK4571 notifies the
host of the status change, but does not change the value itself. The application program changes the value by issuing a SET FEATURE
REQUEST.
2.6.2
HID Details
The AK4571 has Interface (#3) and Interrupt Endpoint (#4: 1 byte) commands for HID.
Figure 8 shows hierarchy of HID Interface.
Interface #3
Standard
Interface Descriptor
Interface Number
Interface Class(HID)
etc.
Descriptor Type
Length of Report Descriptor
etc.
HID Descriptor
EP address
Interrupt Endpoint
etc.
Endpoint Descriptor
Figure 8 Hierarchy of HID Interface
Interrupt Endpoint is 1 byte, and lower 3 bits are valid.
Bit 7
Bit 6
Bit 5
“0”
“0”
“0”
Bit 4
“0”
Bit 3
“0”
Bit 2
OMUTE
Bit 1
DEC
Bit 0
INC
Internal bits[2:0] are set to “1” at the rising edge of OMUTE, INC or DEC pins, and are cleared to “0” at the falling edge of these respective
pins. The AK4571 transmits 1 byte of data through the Interrupt Pipe. If none of the buttons are pressed or if a button is continually pressed,
the AK4571 sends NAK to the host.
MS0153-E-03
2005/06
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ASAHI KASEI
[AK4571]
bInterval
SOF
Interrupt
Transfer
“1”
NAK
NAK
NAK
“0”
NAK
OMUTE
DEC
INC
Figure 9 Interrupt Transfer Timing
illustrates a switch de-bounce circuit (highly recommended)
3.3V
IMUTE
OMUTE
DEC
INC
0.1u
47K
Figure 10 Switch De-Bounce Circuit
Figure 10 illustrates a switch de-bounce circuit (highly recommended)
If HID function is not used, please connect OMUTE pin, DEC pin, INC pin, to DGND.
2.6.3
IMUTE pin and MSTAT pin
The AK4571 has an IMUTE pin for mute control of the recording path. Mute status toggles on the rising edge of the IMUTE pin. Note that
pressing a physical button connected to IMUTE changes the internal state. This may cause an inconsistent mute state between the device
and the Windows application. MSTAT pin reflects the actual mute status of the device. This limitation comes from the fact that the
Windows OS does not support HID audio for recording. The MSTAT pin is forced to “L” in suspend mode regardless of previous state.
MSTAT = (Internal IMUTE status) & SUS_N;
Normal Operation: “H” -> Mute ON
“L” -> Mute OFF
Suspend State:
“L”
Figure 10 illustrates a switch de-bounce circuit (highly recommended)
If IMUTE pin is not used, please connect it to DGND.
MS0153-E-03
2005/06
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ASAHI KASEI
[AK4571]
2.7
Audio Format
The AK4571 supports only the 16-bit, 2’s compliment audio format, and outputs LSB first.
1) 16bit mono data format on the USB (A/D data)
Sample #
bit position
#1
mono
Lower
Upper
8 bit
8 bit
0-7
8-15
#2
mono
Lower
Upper
8bit
8 bit
0-7
8-15
#3
mono
Lower
Upper
8 bit
8 bit
8-15
8-15
…
…
…
…
2) 16bit stereo data format on the USB (D/A data)
Sample #
bit position
#1
Left channel data
Lower
Upper
8 bit
8 bit
0-7
8-15
Right channel data
Lower
Upper
8 bit
8 bit
0-7
8-15
Left channel data
Lower
Upper
8 bit
8 bit
0-7
8-15
MS0153-E-03
#2
Right channel data
Lower
Upper
8bit
8 bit
0-7
8-15
…
…
…
…
2005/06
- 20 -
ASAHI KASEI
[AK4571]
2.8
Device topology and function
USB audio devices must report their capabilities to the host and must report the topology that describes the connections between blocks.
Figure 11 shows the topology of the AK4571.
The host obtains the capabilities and connection diagram from the device by reading the Audio Control (AC) Interface Descriptor. The
volume, mute, and sampling rate are controlled via Audio Class Specific Requests.
1) IN Endpoint#1 for A/D data is related to the MIC signal that is described as [OT1]. The MIC signal is amplified via FU1 and is digitized
by the A/D converter and transmitted to the host.
2) OUT Endpoint#2 for D/A data is related to the Lineout. The D/A analog signal is mixed with the MIC analog signal that is amplified
through FU2. The mixed analog signal can be attenuated/boosted by FU3, and is output via Lineout.
3) Endpoint#3 for HID is related to playback mute and volume up/down.
OUTPUT
INPUT
Audio Streaming
Interface #1
IN Endpoint #1
Audio Control Interface #0
Microphone
MIC
(+20dB)
IPGA
SU1
IT1
FU1
ID:5
ID:1
A/D
OT1
ID:2
ID:7
FU2
ID:6
OPGA
MU1
D/A
(Analog)
IT2
ID:3
Audio Streaming
Interface #2
OUT Endpoint #2
D/A
FU3
Σ
ID:8
ID:9
LineOut
OT2
ID:4
HID Interface #3
IN Endpoint #3
Figure 11 AK4571 Topology
MS0153-E-03
2005/06
- 21 -
ASAHI KASEI
[AK4571]
2.8.1
Terminal/Units
a) Input Terminal (IT)
IT is abbreviation of Input Terminal: IT1 (Microphone Input ID:1), IT2 (D/A Input ID:3)
b) Output Terminal (OT)
OT is abbreviation of Output Terminal: OT1(A/D Output ID:2), OT2 (Lineout ID:4)
c) FU (Feature Unit)
The FU (Feature Unit) describes that the AK4571 has volume/mute/bass-boost functions by setting the bmaControls(0),
bmaControls(1) , bmaControls(2) to “1”. The bit position assigned to the bass-boost function is D8, the length of
bcontrolSize for FU3 is 0x02, and others are 0x01.
bmaControl(0) means master channel. The AK4571 controls DAC mute or bass-boost via the master channel, and controls DAC
volume via channel 1 and channel 2 controls. Since the AK4571 input is a single-channel, it controls both ADC mute and volume via the
master channel.
e) MU (Mixer Unit)
The MU (Mixer Unit) describes mixing and volume control functions. Each input channel is connected to all output channels per the
USB Audio Class specification shown in Figure 12. Only mixing function is available in the AK4571 because the volume is controlled
via Feature Unit. Therefore, bitmap of bmControl in Mixer Unit Descriptor is all “0”.
Mixer Unit 1
Master Channel
(Microphone)
Lch Lineout
D/A Lch
Rch Lineout
D/A Rch
Figure 12 Channel Connection
f) SU (Selector Unit)
Selector Unit is unnecessary for the AK4571's topology. Windows application does not display playback MIC volume slider if the
AK4571 does not define Selector Unit.
MS0153-E-03
2005/06
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ASAHI KASEI
[AK4571]
2.8.2
Descriptor Overview
When the AK4571 is connected to the USB bus, the host assigns unique address to the device first, and starts reading of the device’s
information via a default pipe. Descriptors consist of (1) Device Descriptor, (2) Configuration Descriptor, (3) Interface Descriptor, (4)
Endpoint Descriptor.
The AK4571 is defined as a device with one configuration and four interfaces.
It has one Endpoint (EP) for Interface#0, one EP for Interface#1 (ADC), one for Interface#2 (DAC), and one for Interface#3 (HID)
Device
Device
Descriptor
Configuration
Configuration
Descriptor
Interface
Interface 0
Interface 1
Interface 2
Interface 3
Standard Audio Control
Interface Descriptor
Standard AS Interface
Descriptor Alt. Setting 0
Standard AS Interface
Descriptor Alt. Setting 0
Standard AS Interface
Descriptor Alt. Setting 0
Class-Specific Audio Control
Interface Descriptor
Standard AS Interface
Descriptor Alt. Setting 1
Standard AS Interface
Descriptor Alt. Setting 1,2
HID Descriptor
Input Terminal
Descriptor
Class-Specific Audio Streaming
Interface Descriptor
Class-Specific Audio Streaming
Interface Descriptor
Output Terminal
Descriptor
Class-Specific AS Format Type
Descriptor
Class-Specific AS Format Type
Descriptor
Feature Unit
Descriptor(Mute,Volume,AGC)
Mixer Unit Descriptor
Selector Unit Descriptor
Standard AS Isochronous
Endpoint Descriptor
Standard AS Isochronous
Endpoint Descriptor
Class-Specific AS Isochronous
Endpoint Descriptor
Class-Specific AS Isochronous
Endpoint Descriptor
IN Endpoint
(Isochronous)
Standard HID Interrupt
Endpoint Descriptor
IN Endpoint
(interrupt)
OUT Endpoint
(Isochronous)
Figure 13 Descriptor Hierarchy
MS0153-E-03
2005/06
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ASAHI KASEI
[AK4571]
„ Device Descriptor
Device Descriptor includes product name, manufacturer name, product revision, etc. And it also includes the number of configurations (The
AK4571 is a one configuration device).
„ Configuration Descriptor
Configuration Descriptor includes the device type, which is described as bus-powered device or self-powered device, power consumption,
number of interfaces, etc. The AK4571 is defined as a low-power bus-powered device with four interfaces.
„ Interface Descriptor
The AK4571 has four interfaces as follows.
a) Audio Control (AC) Interface
b) Audio Streaming (AS) Interface1 for A/D converter
c) Audio Streaming (AS) Interface2 for D/A converter
d) HID Interface for Mute & Volume Control
AC Interface includes topology information, Input/Output Terminal information, and Function information in addition to the standard Class
Interface Descriptor.
AS Interface also includes audio format and sampling frequencies.
The AK4571 has two alternates for Interface#1 (ADC), and Interface#2 (DAC). The default state is Alt0, and Alt 0 does not occupy USB
bandwidth.
Alt 1 is used as the interface for audio streaming data. The bandwidth occupied by A/D data and D/A data are 100 bytes and 200 bytes
respectively, and each value is described in the wMaxPacketSize field in the Standard Endpoint Descriptor in each interface.
„ Endpoint Descriptor
Endpoint 0 (EP0: default pipe) is used for AC Interface. The EP for the AS interface includes IN/OUT, synchronization type, maximum
packet length, etc.
The AK4571 also has one Interrupt Endpoint for the HID Interface. The AK4571 returns one byte of information at the Interrupt transfer
just after the playback volume or mute buttons are pressed. If no buttons are pressed, the AK4571 returns NAK.
MS0153-E-03
2005/06
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ASAHI KASEI
[AK4571]
3
Descriptors in Detail
3.1
Device Descriptor
Offset
0
1
2
4
5
6
7
8
10
Field
bLength
bDescriptorType
BcdUSB
bDeviceClass
bDeviceSubClass
bDeviceProtocol
bMaxPacketSize0
IdVendor
IdProduct
12
14
15
16
17
bcdDevice
IManufacturer
Iproduct
ISerialNumber
bNumConfigurations
3.2
Configuration Descriptor
Size
1
1
2
1
1
1
1
2
2
Value
0x12
0x01
0x0110
0x00
0x00
0x00
0x08
0x0556
0x0004
2
1
1
1
1
0x0100
0x01
0x02
0x00
0x01
Description
Size of this descriptor in bytes
DEVICE descriptor
1.10 - current revision of USB spec.
Device defined at Interface level
Unused
Unused
8 bytes
AKM’s Vendor ID
Upper 00 means Audio Product
Lower 03 means AKM product ID
Device release code
“ AKM ”
“ AK4571”
Unused
One configuration
Table Device Descriptor
Offset
0
1
2
4
5
6
7
8
Field
Blength
bDescriptorType
WTotalLength
BnumInterfaces
bConfigurationValue
IConfiguration
BmAttributes
MaxPower
Size
1
1
2
1
1
1
1
1
Value
0x09
0x02
0x011C
0x04
0x01
0x00
0x80
0x31
Description
Size of this descriptor
CONFIGURATION descriptor
length of entire configuration block
total 284 bytes including this interface
descriptor.
Four interfaces
index of this configuration
null string
supports Bus Powered Device
98mA
MS0153-E-03
2005/06
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ASAHI KASEI
[AK4571]
3.3
Interface Descriptor # 0
3.3.1 Standard Audio Control Interface Descriptor
Offset
0
1
2
3
4
5
6
7
8
3.3.2
Offset
0
1
2
3
5
Field
bLength
bDescriptorType
bInterfaceNumber
bAlternateSetting
bNumEndpoints
bInterfaceClass
bInterfaceSubclass
bInterfaceProtocol
IInterface
Size
1
1
1
1
1
1
1
1
1
Value
0x09
0x04
0x00
0x00
0x00
0x01
0x01
0x00
0x00
Description
Size of this descriptor
INTERFACE descriptor
Index of this interface
Index of this setting
only uses Endpoint 0
AUDIO
AUDIO_CONTROL
not vendor or class specific
null string
Table Standard Interface Descriptor
Class-Specific Audio Control Interface Descriptor
Field
BLength
bDescriptorType
bDescriptorSubtype
BcdADC
wTotalLength
Size
1
1
1
2
2
Value
0x0A
0x24
0x01
0x0100
0x0065
7
8
binCollection
baInterfaceNr(0)
1
1
0x02
0x01
9
baInterfaceNr(1)
1
0x02
Description
Size of this descriptor
CS_INTERFACE
HEADER subtype
Revision of class specification – 1.00
Total size of class-specific Audio Control
Interface descriptors 101 bytes
(includes this descriptor)
The number of streaming interfaces
Streaming interface number 1 belongs to
this audio control interface. IN Interface
Streaming interface number 2 belongs to
this audio control interface. OUT Interface
MS0153-E-03
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ASAHI KASEI
[AK4571]
3.3.3
Terminal Descriptor(ID=3)
D/A Input Terminal
Offset
Field
0
Blength
1
BDescriptorType
2
bDescriptorSubtype
3
BterminalID
4
WterminalType
6
BassocTerminal
7
BnrChannels
8
WChannelConfig
10
IchannelNames
11
Iterminal
3.3.4
Size
1
1
1
1
2
1
1
2
1
1
Value
0x0C
0x24
0x02
0x03
0x0101
0x04
0x02
0x0003
0x00
0x00
Description
Size of this descriptor
CS_INTERFACE
INPUT_TERMINAL subtype
ID of this terminal
Terminal is USB streaming OUT
Associated with Output Terminal is 0x04
Two channel
Left/Right Front
Unused
Unused
Value
0x09
0x24
0x03
0x04
0x0301
0x03
0x08
0x00
Description
Size of this descriptor
CS_INTERFACE
OUTPUT_TERMINAL subtype
ID of this terminal
Terminal is Speaker
Associate with Input Terminal 0x03
From Feature Unit (ID8)
Unused
Terminal Descriptor(ID=4)
Lineout Terminal
Offset
Field
0
Blength
1
BdescriptorType
2
bdescriptorSubtype
3
BterminalID
4
WterminalType
6
BassocTerminal
7
BsourceID
8
Iterminal
Size
1
1
1
1
2
1
1
1
MS0153-E-03
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ASAHI KASEI
[AK4571]
3.3.5
Terminal Descriptor(ID=1)
Analog Microphone Input Terminal
Offset
Field
Size
0
Blength
1
1
bDescriptorType
1
2
bDescriptorSubtype
1
3
BterminalID
1
4
WTerminalType
2
6
BAssocTerminal
1
7
BNrChannels
1
8
WChannelConfig
2
10
IChannelNames
1
11
Iterminal
1
3.3.6
Value
0x0C
0x24
0x02
0x01
0x0201
0x02
0x01
0x0000
0x00
0x00
Description
Size of this descriptor
CS_INTERFACE
INPUT_TERMINAL subtype
ID of this terminal
Terminal is Microphone
Associated with Output Terminal 0x02
One channel
Mono sets no position bit
Unused
Unused
Value
0x09
0x24
0x03
0x02
0x0101
0x01
0x05
0x00
Description
Size of this descriptor
CS_INTERFACE
OUTPUT_TERMINAL subtype
ID of this terminal
Terminal is USB streaming
Associate with Input Terminal is 0x01
From Feature Unit (ID5)
Unused
Terminal Descriptor (ID=2)
A/D Output Terminal
Offset
Field
0
Blength
1
BdescriptorType
2
bdescriptorSubtype
3
BterminalID
4
WterminalType
6
BassocTerminal
7
BsourceID
8
Iterminal
Size
1
1
1
1
2
1
1
1
MS0153-E-03
2005/06
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ASAHI KASEI
[AK4571]
3.3.7
Feature Unit Desciptor(ID=5)
Microphone Recording Volume Unit
Offset
Field
Size
0
Blength
1
1
BdescriptorType
1
2
BdescriptorSubtype
1
3
BunitID
1
4
BsourceID
1
5
BcontrolSize
1
6
bmaControls(0)
1
7
Ifeature
1
3.3.8
Value
0x08
0x24
0x06
0x06
0x01
0x01
0x03
0x00
Description
Size of this descriptor
CS_INTERFACE
FEATURE_UNIT descriptor subtype
ID of this feature Unit
From Input Terminal (Microphone)
One byte Control Array
D0(Mute) D1(Volume) supported
Unused
Value
0x0D
0x24
0x06
0x08
0x09
0x02
0x0101
Description
Size of this descriptor
CS_INTERFACE
FEATURE_UNIT descriptor subtype
ID of this feature Unit
From Mixer Unit(ID9)
Two byte Control Array
D0(Mute) , D8(Bass Boost)is enable for
channel0
D1(Volume) control is enable for channel 1
D1(Volume) control is enable for channel 2
Unused
Feature Unit Desciptor(ID=8)
Lineout Volume/Bass Boost Unit
Offset
Field
Size
0
blength
1
1
bdescriptorType
1
2
bdescriptorSubtype
1
3
bunitID
1
4
BsourceID
1
5
BcontrolSize
1
6
bmaControls(0)
1
8
10
12
Description
Size of this descriptor
CS_INTERFACE
FEATURE_UNIT descriptor subtype
ID of this feature Unit
From Selector Unit
One byte Control Array
D0(Mute), D1(Volume) supported
Unused
Feature Unit Desciptor(ID=6)
Microphone Playback Volume Unit
Offset
Field
Size
0
Blength
1
1
BdescriptorType
1
2
BdescriptorSubtype
1
3
BunitID
1
4
BsourceID
1
5
BcontrolSize
1
6
bmaControls(0)
1
7
Ifeature
1
3.3.9
Value
0x08
0x24
0x06
0x05
0x07
0x01
0x03
0x00
bmaControls(1)
bmaControls(2)
IFeature
1
1
1
0x0002
0x0002
0x00
MS0153-E-03
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ASAHI KASEI
[AK4571]
3.3.10 Mixer Unit Desciptor(ID=9)
Mixer Unit (D/A and Microphone)
Offset
0
1
2
3
4
5
6
7
Field
blength
bdescriptorType
bdescriptorSubtype
bunitID
bnrInPins
baSourceID(1)
baSourceID(2)
bnrChannels
Size
1
1
1
1
1
1
1
1
Value
0x0D
0x24
0x04
0x09
0x02
0x06
0x03
0x02
Description
Size of this descriptor
CS_INTERFACE
MIXER_UNIT subtype
ID of this terminal
Number of Input Pin
From Feature Unit 2(ID6)
From IT(ID3)
8
10
11
wChannnelConfig
iChannelNames
bmControl
2
1
1
0x0003
0x00
0x00
12
Imixer
1
0x00
Index of String descriptor
Value
0x07
0x24
0x05
0x07
0x01
0x01
0x00
Description
Size of this descriptor
CS_INTERFACE
Selector_UNIT descriptor subtype
ID of this feature Unit
Inputs Pins
From Input Terminal
Unused
Number of logical output channels in the
Mixer’s output audio channel cluster
describes the spatial location L/R front
Index of String descriptor
bit map no control
3.3.11 Selector Unit Desciptor(ID=7)
Offset
0
1
2
3
4
5
6
Field
blength
bdescriptorType
bdescriptorSubtype
bunitID
bNrInPins
bSourceID(1)
IFeature
Size
1
1
1
1
1
1
1
MS0153-E-03
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ASAHI KASEI
[AK4571]
3.4
Interface Descriptor #1
3.4.1 Standard Interface descriptor <Alternate Setting 0> (A/D Audio Streaming Data)
Zero Bandwidth
Offset
0
1
2
3
4
5
6
7
8
Field
bLength
bDescriptorType
bInterfaceNumber
bAlternateSetting
bNumEndpoints
bInterfaceClass
bInterfaceSubclass
bInterfaceProtocol
iInterface
Size
1
1
1
1
1
1
1
1
1
Value
0x09
0x04
0x01
0x00
0x00
0x01
0x02
0x00
0x00
Description
Length of this descriptor
INTERFACE descriptor
Index of this interface
Index of this setting
0 Endpoint
AUDIO
AUDIO_STREAMING
Unused
null string
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[AK4571]
3.4.2
Offset
0
1
2
3
4
5
6
7
8
3.4.3
Offset
0
1
2
3
4
5
3.4.4
Offset
0
1
2
3
4
5
6
7
8
11
14
17
20
23
26
Standard Interface descriptor <Alternate Setting 1> (A/D Audio Streaming Data)
Field
bLength
bDescriptorType
bInterfaceNumber
bAlternateSetting
bNumEndpoints
bInterfaceClass
bInterfaceSubclass
bInterfaceProtocol
iInterface
Size
1
1
1
1
1
1
1
1
1
Value
0x09
0x04
0x01
0x01
0x01
0x01
0x02
0x00
0x00
Description
Length of this descriptor
INTERFACE descriptor
Index of this interface
Index of this setting
1 Endpoint
AUDIO
AUDIO_STREAMING
Unused
null string
Class-specific audio streaming interface descriptor <Alt 1>
Field
bLength
bDescriptorType
bDescriptorSubtype
bTerminalLink
bDelay
wFormatTag
Size
1
1
1
1
1
2
Value
0x07
0x24
0x01
0x02
0x00
0x0001
Description
Length of this descriptor
CS_INTERFACE descriptor
AS_GENERAL
Unit ID of terminal(Output Terminal ID)
Interface delay
PCM
Value
0x1D
0x24
0x02
0x01
0x01
0x02
0x10
0x07
0x001F40
0x002B11
0x003E80
0x005622
0x007D00
0x00AC44
0x00BB80
Description
Size of this descriptor
CS_INTERFACE
FORMAT_TYPE
FORMAT_TYPE_I
One channel
Two bytes per slot
16 bits
Seven frequencies
8000Hz
11025Hz
16000Hz
22050Hz
32000Hz
44100Hz
4800Hz
Type I format type descriptor
Field
blength
bDescriptorType
bdescriptorSubtype
bformatType
bNrChannels
bSubFrameSize
bBitResolution
bSamFreqType
tSamFreq[0]
tSamFreq[1]
tSamFreq[2]
tSamFreq[3]
tSamFreq[4]
tSamFreq[5]
tSamFreq[6]
Size
1
1
1
1
1
1
1
1
3
3
3
3
3
3
3
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[AK4571]
3.4.5
Offset
0
1
2
3
4
6
7
8
3.4.6
Offset
0
1
2
3
4
5
Standard Endpoint descriptor
Field
bLength
bDescriptorType
bendpointAddress
bmAttributes
wMaxPacketSize
bInterval
bRefresh
bSynchAddress
Size
1
1
1
1
2
1
1
1
Value
0x09
0x05
0x81
0x05
0x0064
0x01
0x00
0x00
Description
Length of this descriptor
ENDPOINT descriptor
Endpoint 1, IN direction
Isochronous, asynchronous
2byte*50sample*1ch=100 byte/frame
One packet every frame (Must be set to 1)
Unused
Unused
Class-specific isochronous audio data endpoint descriptor
Field
bLength
bDescriptorType
bDescriptorSubtype
bmAttributes
bLockDelayUnits
wLockDelay
Size
1
1
1
1
1
2
Value
0x07
0x25
0x01
0x01
0x00
0x0000
Description
Size of this descriptor
CS_ENDPOINT
EP GENERAL
sample rate control
Unused
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[AK4571]
3.5
Interface Descriptor #2
3.5.1 Standard Audio Streaming Interface descriptor <Alternate Setting 0> (D/A Audio Streaming Data)
Zero Bandwidth
Offset
0
1
2
3
4
5
6
7
10
3.5.2
Offset
0
1
2
3
4
5
6
7
8
3.5.3
Offset
0
1
2
3
4
5
Field
bLength
bDescriptorType
bInterfaceNumber
bAlternateSetting
bNumEndpoints
bInterfaceClass
bInterfaceSubclass
bInterfaceProtocol
iInterface
Size
1
1
1
1
1
1
1
1
1
Value
0x09
0x04
0x02
0x00
0x00
0x01
0x02
0x00
0x00
Description
Length of this descriptor
INTERFACE descriptor
Index of this interface
Index of this setting
endpoints 0
AUDIO
AUDIO_STREAMING
Unused
null string
Operational Interface descriptor <Alternate Setting 1> (D/A Audio Streaming Data)
Field
BLength
bDescriptorType
bInterfaceNumber
bAlternateSetting
bNumEndpoints
bInterfaceClass
bInterfaceSubclass
bInterfaceProtocol
iInterface
Size
1
1
1
1
1
1
1
1
1
Value
0x09
0x04
0x02
0x01
0x01
0x01
0x02
0x00
0x00
Description
Length of this descriptor
INTERFACE descriptor
Index of this interface
Index of this setting
Streaming Endpoint
AUDIO
AUDIO_STREAMING
Unused
null string
Class-specific audio streaming interface descriptor<Alternate Setting 1>
Field
bLength
bDescriptorType
bDescriptorSubtype
bTerminalLink
bDelay
wFormatTag
Size
1
1
1
1
1
2
Value
0x07
0x24
0x01
0x03
0x00
0x0001
Description
Length of this descriptor
CS_INTERFACE descriptor
AS_GENERAL
Unit ID of Terminal(Input Terminal)
Interface delay
PCM
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[AK4571]
3.5.4
Offset
0
1
2
3
4
5
6
7
8
11
14
17
20
23
26
Type I format type descriptor<Alternate Setting 1>
Field
blength
bDescriptorType
bDescriptorSubtype
bFormatType
bNrChannels
bSubFrameSize
bBitResolution
bSamFreqType
tSamFreq[0]
tSamFreq[1]
tSamFreq[2]
tSamFreq[3]
tSamFreq[4]
tSamFreq[5]
tSamFreq[6]
3.5.5
Endpoint descriptor
Offset
0
1
2
3
4
6
7
8
Field
bLength
bDescriptorType
bEndpointAddress
bmAttributes
wMaxPacketSize
bInterval
bRefresh
bSynchAddress
3.5.6
Offset
0
1
2
3
4
5
Size
1
1
1
1
1
1
1
1
3
3
3
3
3
3
3
Size
1
1
1
1
2
1
1
1
Value
0x1D
0x24
0x02
0x01
0x02
0x02
0x10
0x07
0x001F40
0x002B11
0x003E80
0x005622
0x007D00
0x00AC44
0x00BB80
Value
0x09
0x05
0x02
0x09
0x00C8
0x01
0x00
0x00
Description
Size of this descriptor
CS_INTERFACE
FORMAT_TYPE
FORMAT_TYPE_I
Two channels
Two bytes per slot
16 bits
Six frequencies
8000Hz
11025Hz
16000Hz
22050Hz
32000Hz
44100Hz
48000Hz
Description
Length of this descriptor
ENDPOINT descriptor
Endpoint 2, OUT direction
Adaptive Isochronous
2byte*(48+2)sample*2ch=200 byte/frame
1millisecond (Must be set to 1)
Unused
Unused
Class-specific isochronous audio data endpoint descriptor
Field
bLength
bDescriptorType
bDescriptorSubtype
bmAttributes
bLockDelayUnits
wLockDelay
Size
1
1
1
1
1
2
Value
0x07
0x25
0x01
0x01
0x00
0x0000
Description
Size of this descriptor
CS_ENDPOINT
EP_GENERAL
Sample rate control
Unused
Unused
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[AK4571]
3.6
Interface #3 (HID Class)
3.6.1 Standard Interface Descriptor
Offset
0
1
2
3
4
5
6
7
8
3.6.2
Offset
0
1
2
4
5
6
7
3.6.3
Offset
0
1
2
3
4
6
Field
bLength
bDescriptorType
bInterfaceNumber
bAlternateSetting
bNumEndpoints
bInterfaceClass
bInterfaceSubclass
bInterfaceProtocol
iInterface
Size
1
1
1
1
1
1
1
1
1
Value
0x09
0x04
0x03
0x00
0x01
0x03
0x00
0x00
0x00
Description
Size of this descriptor
INTERFACE descriptor
Index of this interface
Index of this setting
endpoint 1
HID
Non-Boot Device
Unused
null string
Size
1
1
2
1
1
1
2
Value
0x09
0x21
0x0110
0x00
0x01
0x22
0x001f
Description
Size of this descriptor
HID
HID spec rev #1.10
HID Descriptor
Field
bLength
bDescriptorType
bcdHID
bCoundtryCode
bNumDescriptor
bDescriptorType
bDescriptorLength
Report Descriptor
31 bytes
Endpoint Descriptor
Field
bLength
bDescriptorType
bendpointAddress
bmAttributes
wMaxPacketSize
wInterval
Size
1
1
1
1
2
1
Value
0x07
0x05
0x83
0x03
0x0001
0x40
Description
Length of this descriptor
ENDPOINT descriptor
Endpoint 3, IN direction
Interrupt
64ms Interval
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[AK4571]
String descriptor
String descriptors use UNICODE.
3.6.4
Language ID (0x00) Index
Offset
Field
Size
0
bLength
1
1
bDescriptorType
1
2
bString
2
3.6.5
Offset
0
1
2
Value
0x04
0x03
0x0409
Description
Length of this descriptor
STRING descriptor
“English(US)”
iManufacterer(0x01) Field in Device Descriptor for AKM
Field
Size
Value
Description
bLength
1
0x34
Length of this descriptor
bdescriptorType
1
0x03
STRING descriptor
bString
50
0x0041
“AKM
”
0x004B
0x004D
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
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[AK4571]
3.6.6
Offset
0
1
2
iProduct (0x02) Field in Device Descriptor
Field
Size
Value
bLength
1
0x34
bDescriptorType
1
0x03
bString
50
0x0041
0x004B
0x0034
0x0035
0x0037
0x0031
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
0x0020
Description
Length of this descriptor
STRING descriptor
“AK4571
”
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ASAHI KASEI
[AK4571]
4
Standard Device Requests
4.1
Clear Feature
The AK4571 return ACK without ERROR
Offset
Field
Size
Value
0
bmRequestType
1
0x00
0x02
1
bRequest
1
0x01
2
wValue
2
0x0000
0x0001
4
wIndex
2
0x0000
6
wLength
2
0x000
4.2
Get Configuration
The AK4571 returns “1”.
Offset
Field
0
bmRequestType
1
bRequest
2
wValue
4
wIndex
6
wLength
Size
1
1
2
2
2
Value
0x80
0x08
0x0000
0x0000
0x0001
Description
Device
Endpoint
CLEAR_FEATURE
clear ENDPONT0 HALT
clear REMOTE_WAKEUP
Description
GET_CONFIGURATION
4.3
Get Descriptor
The AK4571 returns the descriptor that is specified in wValue field.
Offset
Field
Size
Value
Description
0
bmRequestType
1
0x80
1
bRequest
1
0x06
GET_DESCRIPTOR
2
wValue
2
0xZZZZ
ZZZZ is assigned by host:
High Byte is Desc. type, Low Byte is Index.
DEVICE : 0x0100 : (Index is 0 only)
CONFIGURATION : 0x0200
4
wIndex
2
0x0000
6
wLength
2
0xZZZZ
Descriptor Length (ZZZZ is assigned by host)
4.4
Get Interface
The AK4571 returns the current alternate value for the interface that is specified in wIndex field. “0x00” or “0x01” is returned for
Interface#1, or Interface#2. Only “0x00” is returned for Interface#0 or Interface3.
Offset
Field
Size
Value
Description
0
bmRequestType
1
0x81
1
bRequest
1
0x0A
GET_INTERFACE
2
wValue
2
0x0000
ZERO
Audio Control Interface
4
wIndex
2
0x0000
Audio Streaming Interface for A/D
0x0001
Audio Streaming Interface for D/A
0x0002
HID Interface
0x0003
6
wLength
2
0x0001
AK4571 has both a zero bandwidth Audio Streaming
Interface and a normal Audio Streaming Interface.
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[AK4571]
4.5
Get Status
4.5.1 Get Status
Offset
0
Field
bmRequestType
Size
1
Value
Description
0x80
DEVICE
0x81
INTERFACE
0x82
ENDPOINT
1
bRequest
1
0x00
GET_STATUS
2
wValue
2
0x0000
ZERO
bmRequestType is “DEVICE"
4
wIndex
2
0x0000
bmRequestType is “INTERFACE “
0x0001
bmRequestType is I”NTERFACE"
0x0002
bmRequestType is “INTERFACE “
0x0003
bmRequestType is “ENDPOINT"
0x0000
bmRequestType is “ENDPOINT" *)
0x0081
bmRequestType is “ENDPOINT" *)
0x0002
bmRequestType is “ENDPOINT" *)
0x0083
0x0084
6
wLength
2
0x0002
*)This request is valid after “SET_INTERFACE request (except for Alt0)" for each interface is issued. If the AK4571 receives
GET_STATUS request prior to SET_INTERFACE request, it returns STALL. If SET_INTERFACE request with Alt1 is issued,
GET_STATUS request is valid even if alternate value is returned to “0”.
The AK4571 has the following two bytes.
a) Device: 0x0000 (Bus Powered, No-remote wakeup)
b) Interface: 0x0000
c) Endpoint: 0x0000
4.6
Set Address
The AK4571 stores wValue, and returns ACK. It responds to the requests in which this address is specified after receiving this request.
Offset
Field
Size
Value
Description
0
BmRequestType
1
0x00
Zero
1
BRequest
1
0x05
SET_ADDRESS
2
wValue
2
0xZZZZ
Device Address : ZZZZ is assigned by host
4
wIndex
2
0x0000
Zero
6
wLength
2
0x0000
Zero
4.7
Set Configuration
The AK4571 is set to the configuration state, and returns ACK. As the AK4571 is defined as a single-configuration device, only “0x00” or
“0x01” are valid terms.
Offset
Field
Size
Value
Description
0
bmRequestType
1
0x00
Zero
1
bRequest
1
0x09
SET_CONFIGURATION
2
wValue
2
0x0000
Unconfigured State
0x0001
AK4571 is set to configuration state
others
Unconfigured State
4
wIndex
2
0x0000
Zero
6
wLength
2
0x0000
Zero
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[AK4571]
4.8
Offset
0
Set Feature
Field
bmRequestType
Size
1
Value
Description
0x00
Device
0x02
Endpoint
1
bRequest
1
0x03
SET_FEATURE
2
wValue
2
0x0000
ENDPOINT(0) HALT
0x0001
REMOTRE_WAKEUP
4
wIndex
2
0x0000
6
wLength
2
0x000
If wValue is ENDPOINT(0) HALT, the AK4571 returns STALL. If wValue is REMOTE_WAKEUP, the AK4571 returns ACK without
additional processing because it does not have a remote wakeup function.
4.9
Set Interface
The AK4571 set alternate value that is specified in wValue for the interface that is specified in wIndex field. Either Alt0 or Alt1 can be set
for Iterface#1 or Interface #2. Only Alt0 is valid for Interface#0 or Interface#3.
Offset
Field
Size
Value
Description
0
bmRequestType
1
0x01
ONE
D7
0 = Host to device
D6..5 0 = Standard request
D4..0 1 = Recipient is interface
1
bRequest
1
0x0B
SET_INTERFACE
2
wValue
2
0x0000 or
Zero bandwidth Alternate Setting
0x0001
Normal Isochronous Streaming
4
wIndex
2
0x0000
Audio Control Interface
0x0001
Audio Streaming Interface IN
0x0002
Audio Streaming Interface OUT
0x0003
HID Interface
6
wLength
2
0x0000
Zero
4.10 Synch Frame
The AK4571 does not support this request.
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ASAHI KASEI
[AK4571]
5
Device Specific Requests
If the AK4571 receives a request that is not supported, or if it receives an invalid parameter, the AK4571 returns STALL.
5.1
Set Feature Unit Control Request
5.1.1 Mute Control
Mute is controlled via the master channel.
Offset
Field
Size
0
bmRequestType 1
1
bRequest
1
2
wValue
2
4
wIndex
2
6
wLength
Parameter:
Offset
Field
0
bMute
2
Size
1
Both left channel and right channel of lineout are muted at the same time.
Value
Description
0x21
0x01
SET_CUR
0x0100
MUTE_CONTROL | CHANNEL_0
0x0500
Mute for MIC Recording Volume | interface 0
0x0600
Mute for MIC Playback Volume | interface 0
0x0800
Mute for LineOut Volume | interface 0
0x0001
The Length of Mute Control Parameter Block
Value
0x01
0x00
Description
TRUE
FALSE
If invalid data is set, (i.e the parameter is not one of the above values), the AK4571 returns STALL at data phase, and keeps previous value.
5.1.2
Bass Boost
Offset
Field
0
bmRequestType
1
bRequest
2
wValue
4
wIndex
6
wLength
Parameter:
Offset
Field
0
bBassBoost
Size
1
1
2
2
2
Value
0x21
0x01
0x0900
0x0800
0x0001
Description
SET_CUR
BASS_BOOST | CHANNEL_0
LineOut BASS BOOST | interface 0
The Length of Mute Control Parameter Block
Size
1
Value
0x01
0x00
Description
TRUE
FALSE
If invalid data is set, (i.e the parameter is not one of the above values), the AK4571 returns STALL at data phase, and keeps previous value.
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[AK4571]
5.1.3
Volume Control
The ADC volume is controlled via the master channel, and the DAC volume is controlled via channel 1 (Left channel) and channel
2 (Right channel) independently.
Offset
0
1
2
Field
bmRequestType
bRequest
wValue
Size
1
1
2
4
wIndex
2
6
wLength
2
Value
0x21
0x01
0x0200
0x0201
0x0202
0x0500
0x0600
0x0800
0x0800
0x0002
Description
SET_CUR
A/D: VOLUME_CONTROL | Master Channel
DAC: VOLUME_CONTROL | CHANNEL_1
DAC: VOLUME_CONTROL | CHANNEL_2
A/D Feature Unit ID: 0x05 (MIC REC Master CH)
A/D Feature Unit ID: 0x06 (MIC PLAY Master CH)
D/A Feature Unit ID: 0x08 (Lineout Lch Volume)
D/A Feature Unit ID: 0x08 (Lineout Rch Volume)
Lower Byte: Audio Control Interface (0x00)
Volume Control
Parameter:
Offset
Field
Size
Value
Description
0
wVolume
2
0xZZZZ
The value is set by host
The data format for volume follows USB’s “Device Class Definition for Audio Devices". If the parameter value is larger than the
maximum value, the AK4571 defaults to the maximum value. If the parameter is smaller than minimum value, it defaults to the
minimum value.
„ Volume for FU1 (ID5: MIC Recording), and FU2 (ID6: MIC Playback)
The AK4571 recognizes the lower byte of the USB Audio Volume format as 00H.
Volume Value
USB Audio Class
Format
24.0dB
0x7FFF
--------------24.0dB
0x1800
23.0dB
0x17FF
--------------0.0dB
0x0000
--------------30.0dB
0xE200
-31.0dB
0xE1FF
-------31.0dB
0x8000
„ Volume for FU 3 (ID 8: LineOut)
The AK4571 recognizes the lower byte of the USB Audio Volume format as 00H.
Volume Value
USB Audio Class
Format
0.0dB
0x7FFF
--------------0.0dB
0x0000
-1.0dB
0xFF00
-2.0dB
0xFE00
---------------46.0dB
0xD200
-47.0dB
0xD100
---------------47.0dB
0x8000
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ASAHI KASEI
[AK4571]
5.2
Set Selector Unit Control Request
5.2.1 Selector Control
Offset
0
1
2
4
6
Field
bmRequestType
bRequest
wValue
wIndex
wLength
Size
1
1
2
2
2
Value
0x21
0x01
0x0000
0x0700
0x0001
Parameter:
Offset
Field
Size
Value
0
bSelector
1
0xZZ
The AK4571 returns ACK, but ignores this value.
Description
SET_CUR
ZERO
SELECTOR UNIT CONTROL | Interface 0
The Length of Mute Control Parameter Block
Description
The value is set by host
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ASAHI KASEI
[AK4571]
5.3
Get Feature Unit Control Request
5.3.1 Mute Control
Offset
Field
Size
0
bmRequestType 1
1
bRequest
1
2
wValue
2
4
wIndex
2
6
wLength
2
The AK4571 returns current value.
Offset
Field
Size
0
bMute
1
Default:
5.3.2
Mute OFF (0x00):
Mute ON (0x01):
Bass Boost Control
Offset
Field
Size
0
bmRequestType 1
1
bRequest
1
2
wValue
2
4
wIndex
2
6
wLength
2
The AK4571 returns current value.
Offset
Field
Size
0
bBassBoost
1
Default
Value
0xA1
0x81
0x0100
0x0500
0x0600
0x0800
Description
0x0001
GET_CUR
MUTE_CONTROL | CHANNEL_0
Mute for MIC Recording Volume | interface 0
Mute for MIC Playback Volume | interface 0
Mute for Lineout Volume | interface 0
Lower Byte : Audio Control Interface(0x00)
The Length of Mute Control Parameter Block
Value
0x01
0x00
Description
TRUE
FALSE
FU1 (ID5), FU3 (ID8)
FU2 (ID6)
Value
0xA1
0x81
0x0900
0x0800
0x0001
Description
GET_CUR
BASS_BOOST | CHANNEL_0
Feature Unit | interface 0
The Length of Mute Control Parameter Block
Value
0x01
0x00
Description
TRUE
FALSE
BASS BOOST OFF(0x00):
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ASAHI KASEI
[AK4571]
5.3.3
Volume Control
Offset
0
1
Field
bmRequestType
bRequest
Size
1
1
2
wValue
2
4
wIndex
2
6
wLength
2
Value
0xA1
0x81
0x82
0x83
0x84
0x0200
0x0201
0x0202
0x0500
0x0600
0x0800
0x0002
Description
GET_CUR
GET_MIN
GET_MAX
GET_RES
VOLUME_CONTROL | Master CH (FU5, FU6)
VOLUME_CONTROL | CHANNEL_1 (FU8)
VOLUME_CONTROL | CHANNEL_2 (FU8)
MIC Recording Volume | interface 0
MIC Playback Volume | interface 0
Lineout Volume | interface 0
Lower Byte: Audio Control Interface(0x00)
Volume Control
The AK4571 returns the following wVolume (two bytes). When it receives a request with other combinations, it returns STALL.
bRequest
wValue
wIndex
wVolume (2 bytes) Desciptorn
0x81
0x0200
0x0500
0xZZZZ
Returns current MIC volume of recording path.
0x81
0x0200
0x0600
0xZZZZ
Returns current MIC volume of playback path.
0x81
0x0201
0x0800
0xZZZZ
Returns current Left channel volume of Lineout
0x81
0x0202
0x0800
0xZZZZ
Returns current Right channel volume of Lineout
0x82
0x0200
0x0500
0xE100
Returns minimum MIC recording volume (-31dB)
0x82
0x0200
0x0600
0xE100
Returns minimum MIC playback volume (-31dB)
0x82
0x0201
0x0800
0xD100
Returns minimum Lineout volume (-47dB)
0x82
0x0202
0x0800
0xD100
Returns minimum Lineout volume (-47dB)
0x83
0x0200
0x0500
0x1800
Returns maximum MIC recording volume (+24dB)
0x83
0x0200
0x0600
0x1800
Returns maximum MIC playback volume (+24dB)
0x83
0x0201
0x0800
0x0000
Returns maximum Line Out Volume (0dB)
0x83
0x0202
0x0800
0x0000
Returns maximum Line Out Volume (0dB)
0x84
0x0200
0x0500
0x0100
Returns resolution of MIC recording volume (1dB)
0x84
0x0200
0x0600
0x0100
Returns resolution of MIC playback volume (1dB)
0x84
0x0201
0x0800
0x0100
Returns resolution of LineOut Volume (1dB)
0x84
0x0202
0x0800
0x0100
Returns resolution of LineOut Volume (1dB)
Default:
0dB(0x0000)
MS0153-E-03
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ASAHI KASEI
[AK4571]
5.4
Get Selector Unit Control Request
5.4.1 Selector Control
Offset
0
1
2
4
6
Field
bmRequestType
bRequest
wValue
wIndex
wLength
Parameter:
Offset
Field
0
bSelector
Size
1
1
2
2
2
Value
0xa1
0x81
0x0000
0x0700
0x0001
Description
GET_CUR
ZERO
SELECTOR UNIT CONTROL | interface 0
The Length of Selector Control Parameter Block
Size
1
Value
0xZZ
Description
”0x01”
Value
0xa1
0x81
0x82
0x83
0x84
0x0000
0x0900
0x000C
Description
5.5
Get Mixer Unit Control Request
5.5.1 Mixer Control
Offset
0
1
Field
bmRequestType
bRequest
Size
1
1
2
4
6
wValue
wIndex
wLength
2
2
2
GET_CUR
GET_MIN
GET_MAX
GET_RES
ZERO
MIXER UNIT | interface 0
The Length of Mixer Control Parameter Block
Parameter:
Offset
Field
Size
Value
Description
0
bMixer
12
0xZZ
The AK4571 returns 6 words of “0x0100” for GET_RES request, and returns the following 6 words for GET_CUR, GET_MIN, and
GET_MAX requests.
Offset
0
2
4
6
8
10
Value
0x0000
0x0000
0x0000
0x8000
0x8000
0x0000
Description
Mic 1ch
Mic 1ch
DAC Lch
DAC Lch
DAC Rch
DAC Rch
-------------------
LineOut Lch:
Lineout Rch:
Lineout Lch:
Lineout Rch:
Lineout Lch:
Lineout Rch:
MS0153-E-03
0dB
0dB
0dB
-127dB
-127dB
0dB
2005/06
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ASAHI KASEI
[AK4571]
5.6
Endpoint Control Request
The ADC and DAC can independently operate at seven sampling frequencies. The sampling rate is set by a Set Endpoint Control Request.
The AK4571 supports SET_CUR/GET_CUR for the bRequest field, but does not support GET_MIN, GET_MAX, or GET_RES for the
bRequest field.
5.6.1
Set Endpoint Control Request
Offset
0
1
2
Field
bmRequestType
bRequest
wValue
Size
1
1
2
Value
0x22
0x01
0x0100
4
wIndex
2
wLength
2
0x0081
0x0002
0x0003
6
Parameter:
Offset
Field
0
iSampleFreq
SET_CUR
Upper byte: SAMPLING_FREQ_CONTROL (0x01)
Lower byte : zero
Endpoint Address (0x81: A/D)
Endpoint Address (0x02: D/A)
The Length of Sampling Frequency Parameter Block
Description
The following seven values are valid. Others are
invalid.
0x001F40 : 8kHz
0x002B11 : 11.025kHz
0x003E80 : 16kHz
0x005622 : 22.05kHz
0x007D00 : 32kHz
0x00AC44 : 44.1kHz
0x00BB80 : 48kHz
The sampling rates of the ADC and DAC can be set independently. If the value entered is not one of the valid settings, the AK4571 ignores
the entered value without returning STALL and keeps the previously entered value.
5.6.2
Size
3
Description
Value
0xYYYYYY
Get Endpoint Control Request for IN endpoint
Offset
0
1
2
Field
bmRequestType
bRequest
wValue
Size
1
1
2
Value
0xA2
0x81
0x0100
4
wIndex
2
wLength
2
0x0081
0x0002
0x0003
6
Parameter:
Offset
Field
0
iSampleFreq
Size
3
Value
0xYYYYYY
Description
GET_CUR
Upper byte: SAMPLING_FREQ_CONTROL (0x01)
Lower byte : zero
Endpoint Address (0x81: A/D)
Endpoint Address (0x02: D/A)
The Length of Sampling Frequency Parameter Block
Description
The following seven values are valid. Others are
invalid.
0x001F40 : 8kHz
0x002B11 : 11.025kHz
0x003E80 : 16kHz
0x005622 : 22.05kHz
0x007D00 : 32kHz
0x00AC44 : 44.1kHz ( default of this LSI )
0x00BB80 : 48kHz
MS0153-E-03
2005/06
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ASAHI KASEI
[AK4571]
5.7
HID Related Request
5.7.1 Get Descriptor (HID/Report)
Offset
Field
Size
0
BmRequestType
1
1
BRequest
1
2
wValue
2
4
6
wIndex
wLength
2
2
Value
0x81
0x06
0x2100
0x2200
0x0003
0xZZZZ
Description
GET_DESCRIPTOR
HID Descriptor
Report Descriptor
Interface Number (#3)
Descriptor Length (ZZZZ is assigned by host)
The AK4571 returns a HID Descriptor if wValue is 0x2100. The AK4571 returns the following 31 bytes if wValue is 0x2200.
Report Descriptor
Usage Page (Consumer)
Usage (Consumer Control)
Collection (Application)
Logical Minimum (0)
Logical Maximum (1)
Usage (Volume Increment)
Usage (Volume Decrement)
Report Size (1)
Report Count (2)
Input (Data, Variable, Absolute, No_Wrap,
No_Preferred)
Usage (Mute)
Report Count (1)
Input (Data, Variable, Relative, No_Wrap,
No_Preferred)
Report Count (5)
Input (Constant)
End Collection
0x05, 0x0c
0x09, 0x01
0xA1, 0x01
0x15, 0x00
0x25, 0x01
0x09, 0xE9
0x09, 0xEA
0x75, 0x01
0x95, 0x02
0x81, 0x2A
Data Length (1 bit)
Number of Data (INC, DEC)
0x09, 0xE2
0x95, 0x01
0x81, 0x2E
0x95, 0x05
0x81, 0x01
0xC0
MS0153-E-03
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ASAHI KASEI
[AK4571]
5.7.2
Get Report Request
Offset
0
1
Field
bmRequestType
BRequest
Size
1
1
Value
0xA1
0x01
Description
Class Specific Request
GET_REPORT
2
4
6
Wvalue
Windex
WLength
2
2
2
0x0100
0x0003
0xZZZZ
Report Type (IN) and Report ID
Interface No (#3)
Report Descriptor Length
The AK4571 transmits one byte data that is the same format as Interrupt transaction. If it receives a request, it sends the internal register
value that reflects the button-press state of OMUTE, INC and DEC pins. Note that the AK4571 does not clear the register after it receives
this request. (It clears the register only on an Interrupt transfer)
5.8
String Related Request
Offset
0
1
2
Field
BmRequestType
BRequest
wValue
4
6
wIndex
wLength
Size
1
1
2
2
2
Value
0x80
0x06
0x03??
don't care
0xZZZZ
Description
GET_DESCRIPTOR (String)
0x03?? is assigned by host:
0x0300: LangID
0x0301: iManufacturer
0x0302: iProduct
Descriptor Length (ZZZZ is assigned by host)
The AK4571 returns String Descriptor that is specified in wValue.
MS0153-E-03
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ASAHI KASEI
[AK4571]
6
System Block Diagram
Figure 14 shows the system block diagram when a 1Kbit EEPROM is used.
VD
0.1u
0.1u
47K
0.1u
47K
47K
0.1u
47K
VD
1.5K
47K
DP
DN
3.3n
4.7µ
+
TEST3
0.1µ
TEST2
MSTAT
LFLT_SYS
CS
RBFO
ROUT
RBFI
LOUT
+
4.7µ
AGND
+
VA
6.8n
6.8n
0.1µ
VRAD
LBFO
LBFI
AMP2I
VCOM
AMP1O
120k
MICIN
MICBIAS
LFLT_48K
+
VRDA
TESTMODE1
AMP2O
LFLT_44K
4.7µ
EPDI
EPAO
SK
TESTMODE3
TESTMODE2
STBY
EMSW
22n
EPEN
XTALIN
10p
120k
EPSEL
EPSW
*)
2.7k
TEST1
IMUTE
12MHz
INC
DGND
BGND
XTALOUT
10p*)
DEC
OMUTE
SUSN
RSTN
1
0.1µ
+
4.7µ
0.1µ
4.7µ
0.1µ
1µ
Cb
Cb
300
1µ
Rb
10µ
1n
+
0.1µ
1µ
MIC
Rb
1µ
<example>
Gain=19dB, fc=94Hz
Rb: 360K
Cb: 4.7n
10K<
10K<
4.7K/2.2K
*) 10pF is recommended to get a stable analog performance.
Figure 14 System Block Diagram
MS0153-E-03
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ASAHI KASEI
[AK4571]
7
Package
48pin LQFP(Unit:mm)
1.70Max
9.0 ± 0.2
0.13 ± 0.13
7.0
1.40 ± 0.05
25
24
48
13
7.0
37
1
9.0 ± 0.2
36
12
0.16 ± 0.07
0.5
0.22 ± 0.08
0.10 M
0° ∼ 10°
0.10
0.5 ± 0.2
MS0153-E-03
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ASAHI KASEI
[AK4571]
8
Marking
AK4571VQ
XXXXXXX
1
1) Pin #1 indication
2) Date Code: XXXXXXX (7 digits)
3) Marking Code: AK4571VQ
4) Asahi Kasei Logo
MS0153-E-03
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ASAHI KASEI
[AK4571]
IMPORTANT NOTICE
• These products and their specifications are subject to change without notice. Before considering any use or
application, consult the Asahi Kasei Microsystems Co., Ltd. (AKM) sales office or authorized distributor concerning
their current status.
• AKM assumes no liability for infringement of any patent, intellectual property, or other right in the application or use
of any information contained herein.
• Any export of these products, or devices or systems containing them, may require an export license or other official
approval under the law and regulations of the country of export pertaining to customs and tariffs, currency
exchange, or strategic materials.
• AKM products are neither intended nor authorized for use as critical components in any safety, life support, or other
hazard related device or system, and AKM assumes no responsibility relating to any such use, except with the
express written consent of the Representative Director of AKM. As used here:
(a) A hazard related device or system is one designed or intended for life support or maintenance of safety or for
applications in medicine, aerospace, nuclear energy, or other fields, in which its failure to function or perform
may reasonably be expected to result in loss of life or in significant injury or damage to person or property.
(b)A critical component is one whose failure to function or perform may reasonably be expected to result, whether
directly or indirectly, in the loss of the safety or effectiveness of the device or system containing it, and which
must therefore meet very high standards of performance and reliability.
• It is the responsibility of the buyer or distributor of an AKM product who distributes, disposes of, or otherwise places
the product with a third party to notify that party in advance of the above content and conditions, and the buyer or
distributor agrees to assume any and all responsibility and liability for and hold AKM harmless from any and all
claims arising from the use of said product in the absence of such notification.
MS0153-E-03
2005/06
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