AK7846B-L - AKM Semiconductor

ASAHI KASEI [AK4571]

MS0153-E-03 2005/06

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Features:

 USB Audio Controller

12 Mbps bit rate

USB Serial Interface Engine (SIE)

Audio Class Processing Block

4 Endpoints

USB transcei ver

 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/Att e nuation Control

+0dB to –47dB ( 1dB step )

Analog Bass Boost

 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)

 EEPROM Interface (Microwire Interface)

- can read Device/String Descriptor from EEPROM

- 1K/2K/4K bit EEPROM

 On-chip PL L

7 sampling frequencies:

8kHz, 11.025kHz, 16kHz, 22.05kHz, 32kHz,

44.1kHz, 48kHz

 Single Power Supply, Low Power

+3.3Volts±0.3V

 Package

48pin LQFP

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 2-

channel DAC can operate at different sampling rates.

The AK4571 has a programmable gain amplifier for an alog input

(IPGA). The gain range is from –31dB to +24d B 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.

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.

The AK4571 has a Microwire interface for an external

EEPROM, allowing customization of Vendor ID and product ID.

The high integration of the AK4571 reduces both the number of

external components required and the PCB ar ea required to build

USB devices, including small format products such as USB

headsets.

AK4571 USB Interface Audio CODEC

ASAHI KASEI [AK4571]

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Block Diagram

MICIN

ATT

LOUT

ROUT

ADC

DAC

Master

volume

FIFO

Audio

Control

Block

USB

Serial

Interface

Engine

USB

Transceiver

DP

DN

VD DGND VA

LFLT_44K PLL1

MICBIAS

XTLIN XTLOUT

CRYSTAL

RSTN

AMP1O AMP2I AMP2O LFLT_48K

VCOM VRAD

Config

ROM String

ROM

Power

Management

DAC

GAIN

EPS

W

PLL

Σ

GAIN

Mixer

M

Σ

VRDA EPDO SK

EEPROM I/F

EPEN

EMS

W

20dB

EPAI

CS

FIFO

EPSEL

VREF

AGND IMUTE OMUTE DEC INC

STB

Y

MSTAT

Bass

Boost

Bass

Boost

RBF

I

RBFO

LBFO

LBF

I

BGND

LFLT_SYS

ASAHI KASEI [AK4571]

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Ordering Guide

AK4571VQ 0 ∼ +70°C 48pinLQFP(0.5mm pitch)

AKD4571 Evaluation Board for AK4571

Pin Layout

XTALOUT

VD

DGND

BGND

EPSW

XTALIN

STB

Y

EMSW

LFLT_SYS

1

10

20

30

40

5

15 25

35

45

MICIN

A

MP1O

A

MP2I

A

MP2O

LBFI

RBFI

RBFO

ROUT

EPDI

EPAO

SK

CS

TESTMODE2

V

RD

A

V

RAD

A

GND

VA

DN

DP

RSTN

SUSN

OMUTE

DEC

INC

MSTAT

MICBIAS

IMUTE

EPSEL

EPEN

LFLT_44

K

LFLT_48

K

VCOM

LBFO

LOUT

TEST3

TEST1

TEST2

TESTMODE1

TESTMODE3

ASAHI KASEI [AK4571]

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Pin/Function

No. Signal Name I/O Ana / Dig Description

USB Interface

46 DP 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 I/O D USB bus Inverting Pin.

Reset, Crystal, PLL

45 RSTN I D Reset Pin. Low input resets the chip.

Schmitt Trigger input.

44 SUSN O D Suspend Pin

"L": Suspend Mode

“H”: Normal Mode

4 XTALOUT O A Crystal Oscillator Output, Connect Crystal Resonator. Conn ect capacitor

5 XTALIN I A Crystal Oscillator Input, Connect Crystal Resonator. Connect capacitor

9 LFLT_SYS O A System PLL loop filter Pin. Connect 2.7kΩ resistor and 22nF capa citor in

series externally.

10 LFLT_44K O A Codec PLL loop filter P in. Connect 120kΩ resisto r and 6.8nF capacitor in

series externally.

11 LFLT_48K O

A Codec PLL loop filter P in. Connect 120kΩ resisto r and 6.8nF capacitor in

series externally.

Analog Input/Output

12 VCOM O A Analog Common Voltage Reference Pin

27 VRAD O A ADC Common Voltage Reference Pi n.

28 VRDA O A ADC Common Voltage Reference Pi n.

14 MICIN I A Mono Channel Microphone Input

15 AMP1O O A M ono Channel 1st Amplifier Output Pin

16 AMP2I I A M ono Channel 2nd Amplifier Input Pin

17 AMP2O O A M ono Channel 2nd Amplifier Output Pin

Please Connect 1nF capacitor.

21 LOUT O A L e ft C h annel D/A Out

24 ROUT O A Right Channel D/A Out

19 LBFI I A Left Channel Bass Boost Filter Input Pin

20 LBFO O A Left Channel Bass Boost Filter Output Pin

22 RBFI I A Right Channel Bass Boost Filter Input Pin

23 RBFO O A Right Channel Bass Boost Filter Input Pin

13 MICBIAS O A 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 Control

6 EPSW O External Headphone Amplifier Power Switch Control Pin 1

“H”: Normal Operation

“L”: Suspend Mode

7 STBY O External Headphone Amplifier Power Switch Control Pin 2

“L”: Normal Operation

“H”: Suspend Mode

8 EMSW O Externa l Headphone Amplifier Mute Control Pin

“H”: MUTE ON

“L”: MUTE OFF

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No. Signal Name I/O Ana / Dig Description

EEPROM I/F

31 CS O D EE PROM I/F Chip Select Pin

32 SK O D Read Clock Pin

34 EPDI I D EEPROM Data Input Pin

33 EPAO O D E EPROM Address Output Pin

35 EPEN 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

36 EPSEL I D EEPROM Select

“L”: 1Kbit Type EEPROM is connected.

“H”: 2Kbit/4Kbit EEPROM is connected

HID Interface

39 IMUTE I D A/D Mute

Toggles mute status at the rising edge. If this pin is not used, please

connect this pin to DGND.

43 OMUTE I D 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.

41 INC I D 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.

42 DEC I D 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.

40 MSTAT O D Recording Mute Status Pin.

“H”: Mu te ON

“L”: Mute OFF

In suspend mode, this pin is “L”.

Power Supply

25 VA P A Analog Power Supply, 3.3V

26 AGND P A Analog Ground

1 VD P D Digital Power Supply, 3.3V

2 DGND P D Digital Ground

3 BGND P D B u lk Ground, 0V

Test Mode

18 TESTMODE1 I Please tie down to AGND for normal operation.

29 TESTMODE2 I Please tie down to AGND for normal operation.

30 TESTMODE3 I Please tie down to AGND for normal operation.

38 TEST1 I 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.

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Absolute Maximum Rating

AGND, DGND=0V

Parameter Symbol min Max Units

Power Supplies Analog

Digital

|DGND-AGND|

VA

VD

∆GND

-0.3

4.5

0.3

V

Input Current (any pins except for supplies) IIN - ±10 mA

Analog Input Voltage VINA -0.3 VA+0.3 V

Digital Input Voltage VIND -0.3 VD+0.3 V

Ambient Temperature Ta 0 70 °C

Storage Temperature Tstg -40 125 °C

Note 1. All voltages with respect to ground

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 Symbol min typ Max Units

Power Supplies

Analog

Digital

VA

VD

3.0

3.3

3.6

V

All voltages with respect to ground.

* AKM assumes no responsibility for usage beyond the conditions set forth in this datasheet.

ASAHI KASEI [AK4571]

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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

(PGA is set to 0dB) AMP2I in put : USB Normal mode 83 dBA

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)

MICIN input AMP1O output 76 84 dBA

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)

USB Normal mode 84 dBA

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 Analog

Digital

Total

Power Down(Suspend)

35

15

50

0

52

23

75

150

mA

uA

ASAHI KASEI [AK4571]

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Filter Characteristics

Ta=25°C, VA=VD=3.3V, fs=44.1kHz

Parameter min typ max Units

ADC Digital Filter ( Decimation LPF)

Pass band (±0.2dB) 0 17.64 kHz

Stop band 26.5 kHz

Stop band Attenuation 70 dB

Group Delay 0.363 ms

ADC Digital Filter (HPF)

Frequency Response: -3dB

-0.5dB

-0.1dB

6.89

19.3

44.9

Hz

DAC Digital Filter

Pass band (±0.2dB) 0 17.64 kHz

Stop band 26.5 kHz

Stop band Attenuation 70 dB

Group Delay 0.312 ms

DAC Analog Post filter

Pass band Frequency Response - ±0.1 - dB

ASAHI KASEI [AK4571]

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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 Units

EPDI,EPEN, EPSEL, pin “H” level input voltage VIH 70%VD V

EPDI, EPEN, EPSEL pin “L” level input voltage VIL 30%VD V

RSTN pin “H” level voltage VIHR 2.4 V

RSTN pin “L” level voltage VILR 0.8 V

IMUTE, OMUTE, INC, DEC pin “ H” l e vel voltage VIHR 2.4 V

IMUTE, OMUTE, INC, DEC pin “L” level voltage VILR 0.8 V

SUSN, E PSW, STBY, EMSW, MSTAT pin

“H” level output voltage IOH= 2mA VOH 2.4 V

SUSN, E PSW, STBY, EMSW, MSTAT pin

“L” level output voltage IOL= -2mA VOL 0.6 V

CS, SK, EPAO pin “H” level output voltage IOH= 2mA VOH 2.4 V

CS, SK, EPAO pin “L” level output voltage IOL= -2mA VOL 0.6 V

DP, DN Single Ended Receiver Threshold for “H” level VIHR 2.0 V

DP, DN Single Ended Receiver Threshold for pin “L” level VILR 0.8 V

Input Leakage Current Iin ±10 µA

Pull down Resistance (only EPDI pin)@3.3V Ta=25°C Rpd 100

kΩ

Switching Characteristics

Ta=25°C, VA=VD=3.3V

Parameter Symbol Min Typ Max Units

Master Clock Frequency MCLK - 12.000 - MHz

Reset input width @RSTN pin(low active) Wrst 1.0 us

Time Width for USB Reset Signal Recognition

DP<VseL & DN< VseL to USB Reset mode Trst_rec 3.0

µs

Device Ready Time from USB Reset

After releasing from USB Res et to Device Rea d y

(Transaction can start) Tdrr 10 ms

Time Width for Suspend Recognition

Idle state ( DP > VseL & DN < VseL )

to Suspend mode Tsus_rec 4.36 ms

Resume Time from Suspend

First flip of DP/DN from Idle state

To Device Ready*) Tresm 30 ms

Imute input width with @IMUTE pin(High active) Wimute 10.005 ms

Omute,Dec,Inc input width with @OMUTE,DEC,INC

pin (High active) Wodi 2.001 ms

Device Ready: VREF, X’tal oscillator and PLL are stable and standard bus transa ctions can proceed

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Master

Clock

D-

D+

Trst

_

rec Tdrr Tsus

_

rec Tresm

recover

y

timeresume time

Figure 1. Mode Change with respect to Bus States

Transmitter/Receiver Characteristics

Ta=25°C; VD=3.3V; DGND=0V; CL=50pF

Parameter Symbol Pins Conditions Min Typ Max Units

Transmitter

Data Rate DR DP,DN 11.97 12 12. 03 MHz

Output Impedance (Hi) Roh DP, DN DP, DN=”H”

at Iout = -10mA 36 Ω

Output Impedance (Lo) Rol DP, DP DP, DN=”L”

at Iout = 10mA 36 Ω

“H” level Output Voltage Vohd DP, DN at Iout =-200uA 2.8 V

“L” level Output Vol t a ge Vol d DP, DN at Iout =2.2mA 0.3 V

Tri-state Leakage Current Iolk DP, DN 0 < DP, DN< 3.3V -10 10 µA

Rise/Fall Time Trf/Tff DP, DN 4 10 20 ns

Rise/Fall Time Matching Trfm DP, DN 100 %

Crossover Point Vcrs DP, DN 1.65 V

Receiver

Input Common Mode range CMR DP, DN 0.8 2.5 V

Differential Input Level Vdiff DP, DN | DP – DN | 0.2 V

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10%VD

90%VD

Trs

Trf

DP, DN

Tfs

Tff

Figure 2. Rise/Fall Time

V

crs

DP, DN

Figure 3. Crossover Point

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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 f or 44.1kHz sample rates (including derivatives of this sample rate) and third PL L generates the clock for 48kHz sample

rates (including derivatives).

The CODEC clocks ar e generated from the USB SOF, so they are synchronized with USB SOF. The ADC and DAC oper ate 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 app lication is sues the volu me/mute requ est in ord er to synchronize the software with the AK457 1. 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 n am e ca n be also cu stomized by using an external M icrow ire inte rf ace EEPROM. A Microwire ™ ty pe, 1K, 2K, or

4K EEPROM can be used.

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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 pi n 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 amplif ier. These pins are used to suppress the power-supply current during

suspend mode in addition to suppres sing “pop noise” during the transition of suspend/resum e. The AK4571 has two pins for power-control

because there ar e “activ e high” types and “a ctive low” ty pes of external h eadphone am plifiers. Thir d pin is f or the m ute contro l to suppress

transitional pop noise.

The USB bus consum es 200uA current even in suspend m ode. A regulator also con sumes current in standby mode. E ven with these dev ices

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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2 Functional Description

2.1 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 sam pling frequency , the AK4571 expects that 45 samples are transferred on ce per10 fram es. (Please see

Figure 4)

The average sampling frequency in Figure 4 is 44.1kHz.

44 samples 44 samples 45 samples

N

Frame (N+1) Frame (N+9) Frame

44 samples

(N+10) Frame

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 fram es. For 44.1kH z, the appearance of 45 sam ples should be just one ti m e

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 maxim um of 500uA in suspend mode. Thi s 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 m ode when the idle state continues for more than 3m s. Values like volum e

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 m ode. Ther efore, the AK4571 m ust control th e 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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STB

Y

EMSW(Mute SW)

SUS_N(internal)

SOF

EPSW(STBY)

1.45ms 1.45ms

Figure 5 Suspend and Resume Sequence

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2.3 Bias Circuit for Microphone

The AK4571 supplies a bias voltage to the microphone through the MI CBIAS pin. The output voltage i s about 2.2 volts and output current

is 2mA maximum. Since the m icrophone's outpu t 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 descrip tors, including String Descriptors, in it s internal ROM so it does not require an ext ernal 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.

1K bit EEPROM

(AK93C45A) 2K/4K bit EEPROM

(AK93C55A/65A)

Device Descriptor (18 bytes) 00h -08h 00h-08h

String Descriptor Lang ID (4 bytes index = 0) 09h –0Ah 09h-0Ah

String Descriptor iManufacturer (52 or 102 bytes: index =1) 0Bh-24h- 0Bh-3Dh

String Descriptor iProduct (52 or 102 bytes: index = 2) 25h-3Eh 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 programm ed 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”.

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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 frequenc ies can be am plified up to 20dB by selecting an appropriate resistor. Cut-off frequency shif ts

as the capacitor value varies.

LBFI/RBFI LBFO/RBFO

Cb

Rb

External

Circuit

Figure 6 Analog Bass Boost Circuit

Bass Boost

0

5

10

15

20

25

10 100 1000 10000 100000

Frequency[Hz]

Gain[dB]

Rb=360k

Cb=4.7nF

Rb=360k

Cb=1nF

Rb=120k

Cb=2.2nF

Figure 7 Bass Boost Characteristics

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2.6 HID (Human Interface Device)

2.6.1 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 exam ple, the lineout volu me slider in a Windows application autom atically moves u p at the rising edg e 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 p eriodically 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.

Standard

Interface Descriptor

HID Descriptor

Endpoint Descriptor EP address

Interrupt Endpoint

etc.

Descriptor T ype

Length of Report Descriptor

etc.

Interface Number

Interface Class(HID)

etc.

Interface #3

Figure 8 Hierarchy of HID Interface

Interrupt Endpoint is 1 byte, and lower 3 bits are valid.

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

“0” “0” “0” “0” “0” OMUTE DEC 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 t hese respective

pins. The AK4571 transmits 1 byte of data throug h the Interrupt Pipe. If none of the buttons are pressed or if a button is continually pr essed,

the AK4571 sends NAK to the host.

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SOF

Interrupt

Transfer

OMUTE

DEC

INC

“1” NAK “0” NAK NAK

bInterval

NAK

Figure 9 Interrupt Transfer Timing

illustrates a switch de-bounce circuit (highly recommended)

3.3V IMUTE

OMUTE

DEC

INC

47

K

0.1u

Figure 10 Switch De-Bounce Circuit

Figure 10 illustrates a switch de-bounce circuit (highly recom mended)

If HID function is not used, please connect OMUTE pin, DEC pin, INC pi n, to DGND.

2.6.3 IMUTE pin and MSTAT pin

The AK4571 has an IMUTE pin for m ute control of the recording path. Mute status toggles on th e rising edge of th e IMUTE pin. Note that

pressing a physical button connected to IMUTE changes the internal state. This may cause an inco nsistent mute state bet ween 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 recom mended)

If IMUTE pin is not used, please connect it to DGND.

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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 # #1 #2 #3 …

mono mono mono … Lower

8 bit Upper

8 bit Lower

8bit Upper

8 bit Lower

8 bit Upper

8 bit …

bit position 0-7 8-15 0-7 8-15 8-15 8-15 …

2) 16bit stereo data format on the USB (D/A data)

Sample # #1 #2 …

Left channel data Right channel data Left channel data Right channel data … Lower

8 bit Upper

8 bit Lower

8 bit Upper

8 bit Lower

8 bit Upper

8 bit Lower

8bit Upper

8 bit …

bit position 0-7 8-15 0-7 8-15 0-7 8-15 0-7 8-15 …

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2.8 Device topology and func tion

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 th at 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.

A

udio Streaming

Interface #1

IN Endpoint #1

A

udio Streaming

Interface #2

OUT Endpoint #2

ID:1

ID:4

IT 1

Microphone

IT 2

ID:3

A

udio Control Interface #0

ID:2

IPGA

OPGA

ID:5

Σ

MU1

FU1

FU2

FU3

ID:8

OT2

LineOut

ID:6

OT1

OUTPUT

INPUT

MIC

(+20dB)

D/A

(Analog)

ID:9

A/D

D/A

HID Interface #3

IN Endpoint #3

ID:7

SU1

Figure 11 AK4571 Topology

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2.8.1 Terminal/Un its

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 contro ls. 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 m ixing function is availa ble in the AK4571 because the volume is controlled

via Feature Unit. Therefore, bitmap of bmControl in Mixer Unit D escriptor is all “0”.

Lch Lineout

Rch Lineout

D/A Lc

h

D/A Rc

h

Master Channel

(Microph one )

Mix er Un i t 1

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.

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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)

Configuration

Descriptor

Device

Descriptor

Stan da r d Au di o C o ntrol

Interface Descri p tor

Class-Specific Audio Control

Interface Descri p tor

Standard AS Interface

Des cript or Al t. Setti n g 0

Class-Specific AS Format Type

Descriptor

Standa r d AS Iso chron ous

Endpoint Descriptor

Cla s s -Spe ci f ic AS I s oc hron ous

Endpoint Descriptor

Standard AS Interface

Des cript or Al t. Setti n g 1

Class-Specific Audio Streaming

Interface Descriptor

I

nter

f

ace

I

N Endpoint

(

I

soch

r

onous)

C

on

fi

gurat

i

on

D

ev

i

ce

Standard AS Interface

De s cr iptor Alt . S et t i ng 0

Class-Specific AS Format Type

Descriptor

Stan da rd AS Iso chron ous

Endpoint Descriptor

Class-Specific AS Isochronous

Endpoint Descriptor

Standard AS Interface

De s cr iptor Alt . S et t i ng 1, 2

Class-Specific Audio Streaming

Interface Descri p tor

Input Terminal

Descriptor

Output Terminal

Descriptor

Featur e Uni t

Descriptor(Mute,Volume,AGC)

I

nterface 1

I

nterface 2

Mixer Unit D e s cript o

r

Sele ct or Unit D e s cript o

r

OUT Endpoint

(

Isochronous

)

Standard AS Int er face

Des cript or Al t. Setti n g 0

HID Descriptor

I

nterface 3

Standard HID Interrupt

Endpoint Descriptor

I

N Endpoint

(inte

rr

upt)

I

nterface 0

Figure 13 Descriptor Hierarch y

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 Device Descriptor

Device Descripto r includes product name, manufacturer nam e, product revision, etc. And it also includes th e 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 in formation, Input/Output Terminal inf ormation, 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.

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3 Descriptors in Detail

3.1 Device Descriptor

Offset Field Size Value Description

0 bLength 1 0x12 Size of this descriptor in bytes

1 bDescriptorType 1 0x01 DEVICE descriptor

2 BcdUSB 2 0x0110 1.10 - current revision of USB spec.

4 bDeviceClass 1 0x00 Device defined at Interface level

5 bDeviceSubClass 1 0x00 Unused

6 bDeviceProtocol 1 0x00 Unused

7 bMaxPacketSize0 1 0x08 8 bytes

8 IdVendor 2 0x0556 AKM’s Vendor ID

10 IdPr oduct 2 0x0004 Upper 00 means Audio Product

Lower 03 means AK M product I D

12 bcdDevice 2 0x0100 Device release code

14 IManufacturer 1 0x01 “ AKM ”

15 Iproduct 1 0x02 “ AK4571”

16 ISerialNumber 1 0x00 Unused

17 bNumConfigurations 1 0x01 One configuration

Table Device Descriptor

3.2 Configuration Descriptor

Offset Field Size Value Description

0 Blength 1 0x09 Size of this descriptor

1 bDescriptorType 1 0x02 CONFIGURATION descriptor

2 WTotalLength 2 0x011C length of entire configuration block

total 284 bytes including this interface

descriptor.

4 BnumInterfaces 1 0x04 Four interfaces

5 bConfigurationValue 1 0x01 index of this configuration

6 IConfiguration 1 0x00 null string

7 BmAttributes 1 0x80 supports Bus Powered Device

8 MaxPower 1 0x31 98mA

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3.3 Interface Descriptor # 0

3.3.1 Standard Audio Control Interface Descriptor

Offset Field Size Value Description

0 bLength 1 0x09 Size of this descriptor

1 bDescriptorType 1 0x04 INTERFACE descriptor

2 bInterfaceNumber 1 0x00 Index of this interface

3 bAlternateSetting 1 0x00 Index of this setting

4 bNumEndpoints 1 0x00 only uses Endpoint 0

5 bInterfaceClass 1 0x01 AUDIO

6 bInterfaceSubclass 1 0x01 AUDIO_CONTROL

7 bInterfaceProtocol 1 0x00 not vendor or class specific

8 IInterface 1 0x00 null string

Table Standard Interface Descriptor

3.3.2 Class-Specific Audio Control Interface Descriptor

Offset Field Size Value Description

0 BLength 1 0x0A Size of this descriptor

1 bDescriptorType 1 0x24 CS_INTERFACE

2 bDescriptorSubtype 1 0x01 HEADER subtype

3 BcdADC 2 0x0100 Revision of class specification – 1.00

5 wTotalLength 2 0x0065 Total size of class-specific Audio Control

Interface descriptors 101 bytes

(includes this descriptor)

7 binCollection 1 0x02 The number of streaming interfaces

8 baInterfaceNr(0) 1 0x01 Streaming interface number 1 belongs to

this audio control interface. IN Interface

9 baInterfaceNr(1) 1 0x02 Streaming interface number 2 belongs to

this audio control interface. OUT Interface

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3.3.3 Terminal Descriptor(ID=3)

D/A Input Terminal

Offset Field Size Value Description

0 Blength 1 0x0C Size of this descriptor

1 BDescriptorType 1 0x24 CS_INTERFACE

2 bDescriptorSubtype 1 0x02 INPUT_TERMINAL subtype

3 BterminalID 1 0x03 ID of this terminal

4 WterminalType 2 0x0101 Terminal is USB streaming OUT

6 BassocTerminal 1 0x04 Associated with Output Terminal is 0x04

7 BnrChannels 1 0x02 Two channel

8 WChannelConfig 2 0x0003 Left/Right Front

10 IchannelNames 1 0x00 Unused

11 Iterminal 1 0x00 Unused

3.3.4 Terminal Descriptor(ID=4)

Lineout Terminal

Offset Field Size Value Description

0 Blength 1 0x09 Size of this descriptor

1 BdescriptorType 1 0x24 CS_INTERFACE

2 bdescriptorSubtype 1 0x03 OUTPUT_TERMINAL subtype

3 BterminalID 1 0x04 ID of this terminal

4 WterminalType 2 0x0301 Terminal is Speaker

6 BassocTerminal 1 0x03 Associate with Input Terminal 0x03

7 BsourceID 1 0x08 From Feature Unit (ID8)

8 Iterminal 1 0x00 Unused

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3.3.5 Terminal Descriptor(ID=1)

Analog Microphone Input Terminal

Offset Field Size Value Description

0 Blength 1 0x0C Size of this descriptor

1 bDescriptorType 1 0x24 CS_INTERFACE

2 bDescriptorSubtype 1 0x02 INPUT_TERMINAL subtype

3 BterminalID 1 0x01 ID of this terminal

4 WTerminalType 2 0x0201 Ter minal is Microphone

6 BAssocTerminal 1 0x02 Associated with Output Terminal 0x02

7 BNrChannels 1 0x01 One channel

8 WChannelConfig 2 0x0000 Mono sets no position bit

10 IChannelNames 1 0x00 Unused

11 Iterminal 1 0x00 Unused

3.3.6 Terminal Descriptor (ID=2)

A/D Output Terminal

Offset Field Size Value Description

0 Blength 1 0x09 Size of this descriptor

1 BdescriptorType 1 0x24 CS_INTERFACE

2 bdescriptorSubtype 1 0x03 OUTPUT_TERMINAL subtype

3 BterminalID 1 0x02 ID of this terminal

4 WterminalType 2 0x0101 Terminal is USB streaming

6 BassocTerminal 1 0x01 Associate with Input Terminal is 0x01

7 BsourceID 1 0x05 From Feature Unit (ID5)

8 Iterminal 1 0x00 Unused

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3.3.7 Feature Unit Desciptor(ID=5)

Microphone Recording Volume Unit

Offset Field Size Value Description

0 Blength 1 0x08 Size of this descriptor

1 BdescriptorType 1 0x24 CS_INTERFACE

2 BdescriptorSubtype 1 0x06 FEATURE_UNIT descriptor subtype

3 BunitID 1 0x05 ID of this feature Unit

4 BsourceID 1 0x07 From Selector Unit

5 BcontrolSize 1 0x01 One byte Control Array

6 bmaControls(0) 1 0x03 D0(Mute), D1(Volume) supported

7 Ifeature 1 0x00 Unused

3.3.8 Feature Unit Desciptor(ID=6)

Microphone Playback Volume Unit

Offset Field Size Value Description

0 Blength 1 0x08 Size of this descriptor

1 BdescriptorType 1 0x24 CS_INTERFACE

2 BdescriptorSubtype 1 0x06 FEATURE_UNIT descriptor subtype

3 BunitID 1 0x06 ID of this feature Unit

4 BsourceID 1 0x01 From Input Terminal (Microphone)

5 BcontrolSize 1 0x01 One byte Control Array

6 bmaControls(0) 1 0x03 D0(Mute) D1(Volume) supported

7 Ifeature 1 0x00 Unused

3.3.9 Feature Unit Desciptor(ID=8)

Lineout Volume/Bass Boost Unit

Offset Field Size Value Description

0 blength 1 0x0D Size of this descriptor

1 bdescriptorType 1 0x24 CS_INTERFACE

2 bdescriptorSubtype 1 0x06 FEATURE_UNIT descriptor subtype

3 bunitID 1 0x08 ID of this feature Unit

4 BsourceID 1 0x09 From Mixer Unit(ID9)

5 BcontrolSize 1 0x02 Two byte Control Array

6 bmaControls(0) 1 0x0101 D0(Mute) , D8(Bass Boost)is enable for

channel0

8 bma Cont rol s(1) 1 0x0002 D1(V olum e) cont rol is en abl e for c ha nnel 1

10 bmaCon tro ls(2) 1 0x0002 D1(Vo lum e) con tro l is enab le fo r ch anne l 2

12 IFeature 1 0x00 Unused

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3.3.10 Mixer Unit Desciptor( ID=9)

Mixer Unit (D/A and Microphone)

Offset Field Size Value Description

0 blength 1 0x0D Size of this descriptor

1 bdescriptorType 1 0x24 CS_INTERFACE

2 bdescriptorSubtype 1 0x04 MIXER_UNIT subtype

3 bunitID 1 0x09 ID of this terminal

4 bnrInPins 1 0x02 Number of Input Pin

5 baSourceID(1) 1 0x06 From Feature Unit 2(ID6)

6 baSourceID(2) 1 0x03 From IT(ID3)

7 bnrChannels 1 0x02 Number of logical output channels in the

Mixer’s output audio channel cluster

8 wChannnelConfig 2 0x0003 describes the spatial location L/R front

10 iChannelNames 1 0x00 Index of String descriptor

11 bmControl 1 0x00 bit map no control

12 Imixer 1 0x00 Index of String descriptor

3.3.11 Selector Unit Desciptor(ID=7)

Offset Field Size Value Description

0 blength 1 0x07 Size of this descriptor

1 bdescriptorType 1 0x24 CS_INTERFACE

2 bdescriptorSubtype 1 0x05 Selector_UNIT descriptor subtype

3 bunitID 1 0x07 ID of this feature Unit

4 bNrInPins 1 0x01 Inputs Pins

5 bSourceID(1) 1 0x01 Fr om Input Terminal

6 IFeature 1 0x00 Unused

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3.4 Interface Descriptor #1

3.4.1 Standard Interface descriptor <Alternate Setting 0> (A/D Audio Streaming Data)

Zero Bandwidth

Offset Field Size Value Description

0 bLength 1 0x09 Length of this descriptor

1 bDescriptorType 1 0x04 INTERFACE descriptor

2 bInterfaceNumber 1 0x01 Index of this interface

3 bAlternateSetting 1 0x00 Index of this setting

4 bNumEndpoints 1 0x00 0 Endpoint

5 bInterfaceClass 1 0x01 AUDIO

6 bInterfaceSubclass 1 0x02 AUDIO_STREAMING

7 bInterfaceProtocol 1 0x00 Unused

8 iInterface 1 0x00 null string

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3.4.2 Standard Interface descriptor <Alternate Setting 1> (A/D Audio Streaming Data)

Offset Field Size Value Description

0 bLength 1 0x09 Length of this descriptor

1 bDescriptorType 1 0x04 INTERFACE descriptor

2 bInterfaceNumber 1 0x01 Index of this interface

3 bAlternateSetting 1 0x01 Index of this setting

4 bNumEndpoints 1 0x01 1 Endpoint

5 bInterfaceClass 1 0x01 AUDIO

6 bInterfaceSubclass 1 0x02 AUDIO_STREAMING

7 bInterfaceProtocol 1 0x00 Unused

8 iInterface 1 0x00 null string

3.4.3 Class-specific audio streaming interface descriptor <Alt 1>

Offset Field Size Value Description

0 bLength 1 0x07 Length of this descriptor

1 bDescriptorType 1 0x24 CS_INTERFACE descriptor

2 bDescriptorSubtype 1 0x01 AS_GENERAL

3 bTerminalLink 1 0x02 Unit ID of terminal(Output Terminal ID)

4 bDelay 1 0x00 Interface delay

5 wFormatTag 2 0x0001 PCM

3.4.4 Type I format type descriptor

Offset Field Size Value Description

0 blength 1 0x1D Size of this descriptor

1 bDescriptorType 1 0x24 CS_INTERFACE

2 bdescriptorSubtype 1 0x02 FORMAT_TYPE

3 bformatType 1 0x01 FORMAT_TYPE_I

4 bNrChannels 1 0x01 One channel

5 bSubFrameSize 1 0x02 Two bytes per slot

6 bBitResolution 1 0x10 16 bits

7 bSamFreqType 1 0x07 Seven frequencies

8 tSamFreq[0] 3 0x001F40 8000Hz

11 tSamFreq[1] 3 0x002B11 11025Hz

14 tSamFreq[2] 3 0x003E80 16000Hz

17 tSamFreq[3] 3 0x005622 22050Hz

20 tSamFreq[4] 3 0x007D00 32000Hz

23 tSamFreq[5] 3 0x00AC44 44100Hz

26 tSamFreq[6] 3 0x00BB80 4800Hz

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3.4.5 Standard Endpoint descriptor

Offset Field Size Value Description

0 bLength 1 0x09 Length of this descriptor

1 bDescriptorType 1 0x05 ENDPOINT descriptor

2 bendpointAddress 1 0x81 Endpoint 1, IN direction

3 bmAttributes 1 0x05 Isochronous, asynchronous

4 wMaxPacketSize 2 0x0064 2byte*50sample*1ch=100 byte/frame

6 bInterval 1 0x01 One packet every frame (Must be set to 1)

7 bRefresh 1 0x00 Unused

8 bSynchAddress 1 0x00 Unused

3.4.6 Class-specific isochronous audio data e n dpoint descriptor

Offset Field Size Value Description

0 bLength 1 0x07 Size of this descriptor

1 bDescriptorType 1 0x25 CS_ENDPOINT

2 bDescriptorSubtype 1 0x01 EP GENERAL

3 bmAttributes 1 0x01 sample rate control

4 bLockDelayUnits 1 0x00 Unused

5 wLockDelay 2 0x0000

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3.5 Interface Descriptor #2

3.5.1 Standard Audio Streaming Interface descriptor <Alternate Setting 0> (D/A Audio Streaming Data)

Zero Bandwidth

Offset Field Size Value Description

0 bLength 1 0x09 Length of this descriptor

1 bDescriptorType 1 0x04 INTERFACE descriptor

2 bInterfaceNumber 1 0x02 Index of this interface

3 bAlternateSetting 1 0x00 Index of this setting

4 bNumEndpoints 1 0x00 endpoints 0

5 bInterfaceClass 1 0x01 AUDIO

6 bInterfaceSubclass 1 0x02 AUDIO_STREAMING

7 bInterfaceProtocol 1 0x00 Unused

10 iInterface 1 0x00 null string

3.5.2 Operational Interface descriptor <Alternate Setting 1> (D/A Audio Streaming Data)

Offset Field Size Value Description

0 BLength 1 0x09 Length of this descriptor

1 bDescriptorType 1 0x04 INTERFACE descriptor

2 bInterfaceNumber 1 0x02 Index of this interface

3 bAlternateSetting 1 0x01 Index of this setting

4 bNumEndpoints 1 0x01 Strea ming Endpoint

5 bInterfaceClass 1 0x01 AUDIO

6 bInterfaceSubclass 1 0x02 AUDIO_STREAMING

7 bInterfaceProtocol 1 0x00 Unused

8 iInterface 1 0x00 null string

3.5.3 Class-specific audio streaming interface descriptor<Alternate Setting 1>

Offset Field Size Value Description

0 bLength 1 0x07 Length of this descriptor

1 bDescriptorType 1 0x24 CS_INTERFACE descriptor

2 bDescriptorSubtype 1 0x01 AS_GENERAL

3 bTerminalLink 1 0x03 Unit ID of Terminal(Input Terminal)

4 bDelay 1 0x00 Interface delay

5 wFormatTag 2 0x0001 PCM

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3.5.4 Type I for m at type descript or<Alt ernate Setting 1>

Offset Field Size Value Description

0 blength 1 0x1D Size of this descriptor

1 bDescriptorType 1 0x24 CS_INTERFACE

2 bDescriptorSubtype 1 0x02 FORMAT_TYPE

3 bFormatType 1 0x01 FORMAT_TYPE_I

4 bNrChannels 1 0x02 Two channels

5 bSubFra meSize 1 0x02 Two bytes per slot

6 bBitResolution 1 0x10 16 bits

7 bSamFreqType 1 0x07 Six frequencies

8 tSamFreq[0] 3 0x001F40 8000Hz

11 tSamFreq[1] 3 0x002B11 11025Hz

14 tSamFreq[2] 3 0x003E80 16000Hz

17 tSamFreq[3] 3 0x005622 22050Hz

20 tSamFreq[4] 3 0x007D00 32000Hz

23 tSamFreq[5] 3 0x00AC44 44100Hz

26 tSamFreq[6] 3 0x00BB80 48000Hz

3.5.5 Endpoint descriptor

Offset Field Size Value Description

0 bLength 1 0x09 Length of this descriptor

1 bDescriptorType 1 0x05 ENDPOINT descriptor

2 bEndpointAddress 1 0x02 Endpoint 2, OUT direction

3 bmAttributes 1 0x09 Adaptive Isochronous

4 wMaxPacketSize 2 0x00C8 2byte*(48+2)sample*2ch=200 byte/frame

6 bInterval 1 0x01 1millisecond (Must be set to 1)

7 bRefresh 1 0x00 Unused

8 bSynchAddress 1 0x00 Unused

3.5.6 Class-specific isochronous audio data endpoint descriptor

Offset Field Size Value Description

0 bLength 1 0x07 Size of this descriptor

1 bDescriptorType 1 0x25 CS_ENDPOINT

2 bDescriptorSubtype 1 0x01 EP_GENERAL

3 bmAttributes 1 0x01 Sa mple rate control

4 bLockDelayUnits 1 0x00 Unused

5 wLockDelay 2 0x0000 Unused

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3.6 Interface #3 (HID Class)

3.6.1 Standard Interface Descriptor

Offset Field Size Value Description

0 bLength 1 0x09 Size of this descriptor

1 bDescriptorType 1 0x04 INTERFACE descriptor

2 bInterfaceNumber 1 0x03 Index of this interface

3 bAlternateSetting 1 0x00 Index of this setting

4 bNumEndpoints 1 0x01 endpoint 1

5 bInterfaceClass 1 0x03 HID

6 bInterfaceSubclass 1 0x00 Non-Boot Device

7 bInterfaceProtocol 1 0x00 Unused

8 iInterface 1 0x00 null string

3.6.2 HID Descriptor

Offset Field Size Value Description

0 bLength 1 0x09 Size of this descriptor

1 bDescriptorType 1 0x21 HID

2 bcdHID 2 0x0110 HID spec rev #1.10

4 bCoundtryCode 1 0x00

5 bNumDescriptor 1 0x01

6 bDescriptorType 1 0x22 Report Descriptor

7 bDescriptorLength 2 0x001f 31 bytes

3.6.3 Endpoint Descriptor

Offset Field Size Value Description

0 bLength 1 0x07 Length of this descriptor

1 bDescriptorType 1 0x05 ENDPOINT descriptor

2 bendpointAddress 1 0x83 Endpoint 3, IN direction

3 bmAttributes 1 0x03 Interrupt

4 wMaxPacketSize 2 0x0001

6 wInterval 1 0x40 64ms Interval

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String descriptor

String descriptors use UNICODE.

3.6.4 Language ID (0x00) Index

Offset Field Size Value Description

0 bLength 1 0x04 Length of this descriptor

1 bDescriptorType 1 0x03 STRING descriptor

2 bString 2 0x0409 “English(US)”

3.6.5 iManufacterer(0x01) Field in Device Descriptor for AKM

Offset Field Size Value Description

0 bLength 1 0x34 Length of this descriptor

1 bdescriptorType 1 0x03 STRING descriptor

2 bString 50 0x0041

0x004B

0x004D

0x0020

“AKM ”

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3.6.6 iProduct (0x02) Field in Device Descriptor

Offset Field Size Value Description

0 bLength 1 0x34 Length of this descriptor

1 bDescriptorType 1 0x03 STRING descriptor

2 bString 50 0x0041

0x004B

0x0034

0x0035

0x0037

0x0031

0x0020

“AK4571 ”

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4 Standard Device Requests

4.1 Clear Feature

The AK4571 return ACK without ERROR

Offset Field Size Value Description

0 bmRequestType 1 0x00

0x02 Device

Endpoint

1 bRequest 1 0x01 CLEAR_FEATURE

2 wValue 2 0x0000

0x0001 clear ENDPONT0 HALT

clear REMOTE_WAKEUP

4 wIndex 2 0x0000

6 wLength 2 0x000

4.2 Get Configuration

The AK4571 returns “1”.

Offset Field Size Value Description

0 bmRequestType 1 0x80

1 bRequest 1 0x08 GET_CONFIGURATION

2 wValue 2 0x0000

4 wIndex 2 0x0000

6 wLength 2 0x0001

4.3 Get Descriptor

The AK4571 returns the descriptor that is specified in wValue fiel d.

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

4 wIndex 2 0x0000

0x0001

0x0002

0x0003

Audio Control Interface

Audio Streaming Interface for A/D

Audio Streaming Interface for D/A

HID Interface

6 wLength 2 0x0001 AK4571 has both a zero bandwidth Audio Streaming

Interface and a normal Audio Streaming Interface.

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4.5 Get Status

4.5.1 Get Status

Offset Field Size Value Description

0 bmRequestType 1 0x80

0x81

0x82

DEVICE

INTERFACE

ENDPOINT

1 bRequest 1 0x00 GET_STATUS

2 wValue 2 0x0000 ZERO

4 wIndex 2 0x0000

0x0001

0x0002

0x0003

0x0000

0x0081

0x0002

0x0083

0x0084

bmRequestType is “DEVICE"

bmRequestType is “I NTERFACE “

bmRequestType is I” NTERFACE"

bmRequestType is “I NTERFACE “

bmRequestT ype is “ENDP OINT"

bmRequestT ype is “ENDP OINT" *)

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 reques t prior to SET_INTE RFACE reque st, it return s 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 config uration state, and returns ACK. As the AK4571 is d efined as a single-config uration devic e, only “0x 00” 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

0x0001

others

Unconfigured State

AK4571 is set to configuration state

Unconfigured State

4 wIndex 2 0x0000 Zero

6 wLength 2 0x0000 Zero

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4.8 Set Feature

Offset Field Size Value Description

0 bmRequestType 1 0x00

0x02 Device

Endpoint

1 bRequest 1 0x03 SET_FEATURE

2 wValue 2 0x0000

0x0001 ENDPOINT(0) HALT

REMOTRE_WAKEUP

4 wIndex 2 0x0000

6 wLength 2 0x000

If wValue is ENDPOINT(0) HALT, the AK4571 ret urns 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 int erf ace that i s specif ied in wIndex field. Either Alt0 or Alt1 can be set

for Iterface#1 or Interfac e #2. Onl y Al t 0 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

0x0001 Zero bandwidth Alternat e S etting

Normal Isochronous Streaming

4 wIndex 2 0x0000

0x0001

0x0002

0x0003

Audio Control Interface

Audio Streaming Interface IN

Audio Streaming Interface OUT

HID Interface

6 wLength 2 0x0000 Zero

4.10 Synch Frame

The AK4571 does not support this request.

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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. Both left channel and right channel of lineout are muted at the same time.

Offset Field Size Value Description

0 bmRequestType 1 0x21

1 bRequest 1 0x01 SET_CUR

2 wValue 2 0x0100 MUTE_CONTROL | CHANNEL_0

4 wIndex 2 0x0500

0x0600

0x0800

Mute for MIC Recording Volume | interface 0

Mute for MIC Playback Volume | interface 0

Mute for LineOut Volume | interface 0

6 wLength 2 0x0001 The Length of Mute Control Parameter Block

Parameter:

Offset Field Size Value Description

0 bMute 1 0x01

0x00 TRUE

FALSE

If invalid data is set, (i.e the param eter is not one of the above values) , the AK4571 return s STALL at d ata phase, and keeps previous value.

5.1.2 Bass Boost

Offset Field Size Value Description

0 bmRequestType 1 0x21

1 bRequest 1 0x01 SET_CUR

2 wValue 2 0x0900 BASS_BOOST | CHANNEL_0

4 wIndex 2 0x0800 LineOut BASS BOOST | interface 0

6 wLength 2 0x0001 The Length of Mute Control Parameter Block

Parameter:

Offset Field Size Value Description

0 bBassBoost 1 0x01

0x00 TRUE

FALSE

If invalid data is set, (i.e the param eter is not one of the above values) , the AK4571 return s STALL at d ata phase, and keeps previous value.

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5.1.3 Volume Control

The ADC volume is controlled vi a the master cha nnel, and the DA C volum e is controlled via channel 1 (Left channel) and channel

2 (Right channel) independently.

Offset Field Size Value Description

0 bmRequestType 1 0x21

1 bRequest 1 0x01 SET_CUR

2 wValue 2 0x0200

0x0201

0x0202

A/D: VOLUME_CONTROL | Master Channel

DAC: VOLUME_CONTROL | CHANNEL_1

DAC: VOLUME_CONTROL | CHANNEL_2

4 wIndex 2 0x0500

0x0600

0x0800

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)

6 wLength 2 0x0002 Volume Control

Parameter:

Offset Field Size Value Description

0 wVolume 2 0xZZZZ The val ue 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

minimu m 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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5.2 Set Selector Unit Control Request

5.2.1 Selector Control

Offset Field Size Value Description

0 bmRequestType 1 0x21

1 bRequest 1 0x01 SET_CUR

2 wValue 2 0x0000 ZERO

4 wIndex 2 0x0700 SELECTOR UNIT CONTROL | Interface 0

6 wLength 2 0x0001 The Length of Mute Control Parameter Block

Parameter:

Offset Field Size Value Description

0 bSelector 1 0xZZ The value is set by host

The AK4571 returns ACK, but ignores this value.

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5.3 Get Feature Unit Control Request

5.3.1 Mute Control

Offset Field Size Value Description

0 bmRequestType 1 0xA1

1 bRequest 1 0x81 GET_CUR

2 wValue 2 0x0100 MUTE_CONTROL | CHANNEL_0

4 wIndex 2 0x0500

0x0600

0x0800

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)

6 wLength 2 0x0001 The Length of Mute Control Parameter Block

The AK4571 returns current value.

Offset Field Size Value Description

0 bMute 1 0x01

0x00 TRUE

FALSE

Default: Mute OFF (0x00): FU1 (ID5), FU3 (ID8)

Mute ON (0x01): FU2 (ID6)

5.3.2 Bass Boost Control

Offset Field Size Value Description

0 bmRequestType 1 0xA1

1 bRequest 1 0x81 GET_CUR

2 wValue 2 0x0900 BASS_BOOST | CHANNEL_0

4 wIndex 2 0x0800 Feature Unit | interface 0

6 wLength 2 0x0001 The Length of Mute Control Parameter Block

The AK4571 returns current value.

Offset Field Size Value Description

0 bBassBoost 1 0x01

0x00 TRUE

FALSE

Default BASS BOOST OFF(0x00):

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5.3.3 Volume Control

Offset Field Size Value Description

0 bmRequestType 1 0xA1

1 bRequest 1 0x81

0x82

0x83

0x84

GET_CUR

GET_MIN

GET_MAX

GET_RES

2 wValue 2 0x0200

0x0201

0x0202

VOLUME_CONTROL | Master CH (FU5, FU6)

VOLUME_CONTROL | CHANNEL_1 (F U8)

VOLUME_CONTROL | CHANNEL_2 (F U8)

4 wIndex 2 0x0500

0x0600

0x0800

MIC Recording Volume | inter face 0

MIC Playback Volume | interface 0

Lineout Volume | interface 0

Lower Byte: Audio Control Interface(0x00)

6 wLength 2 0x0002 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 pla yback 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)

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5.4 Get Selector Unit Control Request

5.4.1 Selector Control

Offset Field Size Value Description

0 bmRequestType 1 0xa1

1 bRequest 1 0x81 GET_CUR

2 wValue 2 0x0000 ZERO

4 wIndex 2 0x0700 SELECTOR UNIT CONTROL | interface 0

6 wLength 2 0x0001 The Length of Selector Control Parameter Block

Parameter:

Offset Field Size Value Description

0 bSelector 1 0xZZ ”0x01”

5.5 Get Mixer Unit Control Request

5.5.1 Mixer Control

Offset Field Size Value Description

0 bmRequestType 1 0xa1

1 bRequest 1 0x81

0x82

0x83

0x84

GET_CUR

GET_MIN

GET_MAX

GET_RES

2 wValue 2 0x0000 ZERO

4 wIndex 2 0x0900 MIXER UNIT | interface 0

6 wLength 2 0x000C 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 word s for GET_CUR, GET_MIN, and

GET_MAX requests.

Offset Value Description

0 0x0000 Mic 1ch ---- LineOut Lch: 0dB

2 0x0000 Mic 1ch ---- Lineout Rch: 0dB

4 0x0000 DAC Lch ---- Lineout Lch: 0dB

6 0x8000 DAC Lch ---- Lineout Rch: -127dB

8 0x8000 DAC Rch ---- Lineout Lch: -127dB

10 0x0000 DAC Rch ---- Lineout Rch: 0dB

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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 Field Size Value Description

0 bmRequestType 1 0x22

1 bRequest 1 0x01 SET_CUR

2 wValue 2 0x0100 Upper byte: SAMPLING_FREQ_CONTROL (0x01)

Lower byte : zero

4 wIndex 2 0x0081

0x0002 Endpoint Address (0x81: A/D)

Endp oint Address (0x02: D/A )

6 wLength 2 0x0003 T he Length of Sampling Frequency Parameter Block

Parameter:

Offset Field Size Value Description

0 iSampleFreq 3 0xYYYYYY 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 i gnores

the entered value without returning STALL and keeps the previously entered value.

5.6.2 Get Endpoint Control Request for IN endpoint

Offset Field Size Value Description

0 bmRequestType 1 0xA2

1 bRequest 1 0x81 GET_CUR

2 wValue 2 0x0100 Upper byte: SAMPLING_FREQ_CONTROL (0x01)

Lower byte : zero

4 wIndex 2 0x0081

0x0002 Endpoint Address (0x81: A/D)

Endp oint Address (0x02: D/A )

6 wLength 2 0x0003 T he Length of Sampling Frequency Parameter Block

Parameter:

Offset Field Size Value Description

0 iSampleFreq 3 0xYYYYYY 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

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5.7 HID Related Request

5.7.1 Get Descriptor (HID/Report)

Offset Field Size Value Description

0 BmRequestType 1 0x81

1 BRequest 1 0x06 GET_DESCRIPTOR

2 wValue 2 0x2100

0x2200 HI D Descript or

Report Descriptor

4 wIndex 2 0x0003 Interface Number (#3)

6 wLength 2 0xZZZZ Descriptor Length (ZZZZ is assigned by host)

The AK4571 returns a HID Descri pt or if wValue is 0x2100. The AK4571 returns the following 31 bytes if wValue is 0x2200.

Report Descriptor

Usage Page (Consumer) 0x05, 0x0c

Usage (Consumer Control) 0x09, 0x01

Collection (Application) 0xA1, 0x01

Logical Minimum (0) 0x15, 0x00

Logical Maximum (1) 0x25, 0x01

Usage (Volume Increment) 0x09, 0xE9

Usage (Volume Decrement) 0x09, 0xEA

Report Size (1) 0x75, 0x01 Data Length (1 bit)

Report Count (2) 0x95, 0x02 Number of Data (INC, DEC)

Input (Data, Variable, Absolute, No_Wrap,

No_Preferred) 0x81, 0x2A

Usage (Mute) 0x09, 0xE2

Report Count (1) 0x95, 0x01

Input (Data, Variable, Relative, No_Wrap,

No_Preferred) 0x81, 0x2E

Report Count (5) 0x95, 0x05

Input (Constant) 0x81, 0x01

End Collection 0xC0

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5.7.2 Get Report Request

Offset Field Size Value Description

0 bmRequestType 1 0xA1 Class Specific Request

1 BRequest 1 0x01 GET_REPORT

2 Wvalue 2 0x0100 Report Type (I N) and Report ID

4 Windex 2 0x0003 Interface No (#3)

6 WLength 2 0xZZZZ 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 Field Size Value Description

0 BmRequestType 1 0x80

1 BRequest 1 0x06 GET_DESCRIPTOR (String)

2 wValue 2 0x03?? 0x03?? is assigned by host:

0x0300: LangID

0x0301: iManufacturer

0x0302: iProduct

4 wIndex 2 don't care

6 wLength 2 0xZZZZ Descriptor Length (ZZZZ is assigned by host)

The AK4571 returns String Descriptor that is specified in wValue.

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6 System Block Diagram

Figure 14 shows the system block diagram when a 1Kbit EEPROM is used.

XTALOUT

DGND

BGND

XTALIN

EPSW

1

MICIN

AMP1O

AMP2I

AMP2O

LBFI

RBFI

RBFO

ROUT

EPDI

EPAO

SK

CS

TESTMODE2

VRDA

VRAD

AGND

VA

RSTN

SUSN

OMUTE

INC

MSTAT

MICBIAS

IMUTE

EPSEL

EPEN

STBY

EMSW

VCOM

LBFO

LOUT

TEST1

TEST2

TESTMODE1

TESTMODE3

4.7µ

0.1µ

+

4.7µ

0.1µ

+

12MHz

47K

3.3n

47K

0.1u

DEC

VD

47K

0.1u 47K

0.1u

10µ

1µ

+

MIC

1µ

4.7µ 0.1µ

+

4.7µ 0.1µ

+

4.7µ 0.1µ

+

2.7k

4.7K/2.2K

0.1µ

1n

1µ

10K<

1µ 10K<

Cb

Rb Rb

Cb

Cb: 4.7n

Rb: 360K

Gain=19dB, fc=94Hz

DP

DN

1.5K

VD

LFLT_SYS

LFLT_44K

LFLT_48K

TEST3

22n

120k

6.8n

10p*)

300

*) 10pF is recommended to get a stable analog performance.

10p*)

Figure 14 System Block Diagram

ASAHI KASEI [AK4571]

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7 Package

1

12

48 13

7.0

9.0 ± 0.2

7.0

9.0 ± 0.2

0.22 ± 0.08

48

p

in LQFP

(

Unit:mm

)

0.10

37 24

2536

0.16 ± 0.07

1.40

±

0.05

0.13 ± 0.13

1.70Max

0° ∼ 10°

0.10 M

0.5

±

0.2

0.5

ASAHI KASEI [AK4571]

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8 Marking

AK4571VQ

XXXXXXX

1

1) Pin #1 indication

2) Date Code: XXXXXXX (7 digits )

3) Marking Code: AK4571VQ

4) Asahi Kasei Logo

ASAHI KASEI [AK4571]

MS0153-E-03 2005/06

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IMPORTANT NOTICE

• These produc ts and their spec ifications are subject t o change without n otice. Before consider ing any use or

application, consult the Asahi Kasei Microsystems Co., Ltd. (AKM) sales office or authorized distributor concerning

their curr ent 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 u nder the law and regulations of the coun try of export pertain ing 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 relat ed device or system, an d AKM assumes no re sponsibility relating to any su ch use, except with the

express written c onsent of the Representative Dir ector of AKM. As used here:

(a) A hazar d related device or system is one designe d 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 reasonabl y be expected to resu lt in loss of life or in significant injury or damage to perso n or property.

(b)A critic al com po nent is one who se failur e to f unction o r perf orm may reas ona bl y be expec ted t o r esult, whet h er

directly or indirect ly, in the loss of the safety or effect iveness of the device or system cont aining it, and which

must theref ore meet very high standards of perf ormance and reliability.

• It is the responsibility of the buyer or distributor of an AKM product who distri butes, disposes of, or otherwise places

the product with a third party to notify that party in advance of the above con tent and cond itions, and th e 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 pr oduct in the absence of such notification.