CM108AH
Highly Integrated USB Audio I/O Controller
DESCRIPTION
FEATURES
The CM108AH is a highly integrated single-chip USB
Supports USB 2.0 full speed operation
audio solution. All essential analog modules are
Compliant with USB audio device class
specification 1.0
embedded in the CM108AH, including dual DAC and
earphone driver, ADC, microphone booster, PLL,
Supports USB suspend/resume modes and remote
wakeup with volume control pins
regulator and USB transceiver modules. It is
perfectly suited to USB headset, USB earphone or
Single 12MHz crystal input with on-chip PLL and
embedded USB transceiver
USB audio-interface box applications. As well,
many features are programmable with jumper pins
Jumper pin for speaker mode (playback only) or
headset mode (playback plus recording)
or by external EEPROM.
Audio adjustments are easily controlled via
For headset mode, USB audio function topology
has 2 input terminals, 2 output terminals, 1
specific HID-compliant volume control pins. An
mixer unit, 1 selector unit, and 3 feature units
external codec or audio DSP can be connected to
the CM108AH via I2S pin for further processing.
Jumper pin allows for mixer unit enable/disable
when in headset mode
BLOCK DIAGRAM
VOLUP
VOLDN
MUTER LEDO MCU
MUTEP LEDR I/F GPIO BUZZ SPDIFO
interface logics
reset
power on
reset
sync by
VPR_CLK
0 ~ -45dB
38 steps
voltage linear
ROM
ISO out
processing
( with x2 mod)
4 byte
FIFO
Vref
16 bit
DAC
12. 288/11. 2896 MHz
with adjustment
USB
TRX
+
Vref
LOBS
+
+
-
USBDP
USBDM
EEPROM
interface
16 bit
DAC
Vref
-
CS
SK
DW
DR
Vref
USB control
processing
USB
interface
LOR
+
-
3.3V
+
Vref
-
USB interrupt
processing with4
byte FIFO
5 - > 3. 3
regulator
-
PWRSEL
MODE
PDSW SEL pins
REGV
LOL
0 ~ -45dB
38 steps
sync by voltage linear
300 x 16 SRAM
VPL_ CLK
48 MHz
12 MHz
PLL1
High-Pass Filter
16 bit SigmaDelta ADC
+
Vref
-
XI
XO
ISO in
processing
PLL2
MICIN
+22.5~ - 0 dB
16 steps
+
12.288/
11. 2896 MHz
VREF
(2.25V)
+22. 5 ~ 0 dB
16 steps
IIS I/F
bandgap
4.5 V ( drive typ4mA)
TEST
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Copyright© C-Media Electronics Inc.
Vref
-
PLL3
Rev. 2.1︱ Page 1/27
BOOST
+22.5 dB boost enable
VREF
VBIAS
CM108AH
Highly Integrated USB Audio I/O Controller
TABLE OF CONTENTS
1
Description and Overview .............................................................................................. 3
2
Features ................................................................................................................... 3
3
Pin Descriptions .......................................................................................................... 5
3.1
Pin Assignment by Pin Number ............................................................................... 5
3.2
Pin-Out Diagram ................................................................................................ 5
3.3
Pin Signal Descriptions ........................................................................................ 6
4
I²S Interface .............................................................................................................. 8
5
Block Diagram ............................................................................................................ 9
6
Ordering Information ...................................................................................................10
7
Function Description ...................................................................................................11
7.1
9
7.1.1
Device Descriptor ...................................................................................11
7.1.2
Configuration Descriptor ..........................................................................12
7.1.3
Content Format for EEPROM (93C46) ............................................................13
7.1.4
USB Audio Topology Diagram .....................................................................14
7.2
Jumper Pins and Mode Setting: .............................................................................15
7.3
HID Feature ....................................................................................................16
7.4
8
USB Interface ..................................................................................................11
7.3.1
What’s HID? ..........................................................................................16
7.3.2
HID Descriptor .......................................................................................17
7.3.3
Windows Software Architecture for HID ........................................................18
Internal Registers .............................................................................................19
Electrical Characteristics ..............................................................................................22
8.1
Absolute Maximum Rating ...................................................................................22
8.2
Operation Conditions .........................................................................................22
8.3
Electrical Parameters ........................................................................................23
Audio Quality Graphs ...................................................................................................24
9.1
Line Out Frequency Response @ 48KHz Sample Rate (10K Ohm Loading) ..........................24
9.2
Line Out THD+N @ 48KHz Sample Rate (10K Ohm Loading) ...........................................24
9.3
Microphone Input Freq Response @ 48KHz Sample Rate ...............................................25
9.4
Microphone Input THD+N @ 48KHz Sample Rate ........................................................25
Reference .......................................................................................................................26
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CM108AH
Highly Integrated USB Audio I/O Controller
1
Description and Overview
The CM108AH is a highly integrated single-chip USB audio solution. All essential analog modules are embedded
in the CM108AH, including dual DAC and earphone driver, ADC, microphone booster, PLL, regulator and USB
transceiver modules. It is perfectly suited to USB headset, USB earphone or USB audio-interface box
applications. As well, many features are programmable with jumper pins or by external EEPROM.
Audio adjustments are easily controlled via specific HID-compliant volume control pins. An external codec or
audio DSP can be connected to the CM108AH via I2S pin for further processing. Plus, 3 GPIO pins can be
accessed with customer application software for additional value-adding applications.
2
Features
Supports USB 2.0 full speed operation
Compliant with USB audio device class specification 1.0
Supports USB suspend/resume modes and remote wakeup with volume control pins
Single 12MHz crystal input with on-chip PLL and embedded USB transceiver
Jumper pin for speaker mode (playback only) or headset mode (playback plus recording)
For headset mode, USB audio function topology has 2 input terminals, 2 output terminals, 1 mixer unit, 1
selector unit and 3 feature units
Jumper pin allows for mixer unit enable/disable when in headset mode
For speaker mode, the USB audio topology has 1 input terminal, 1 output terminal and 1 feature unit
Supports one control endpoint, one isochroous OUT endpoint, one isochroous IN endpoint, and one
interrupt IN endpoint
Alternate zero bandwidth setting for releasing playback bandwidth on USB Bus when device is inactive
Supports AES/EBU, IEC60958, S/PDIF consumer formats for stereo PCM data at S/PDIF output
Volume up, volume down, and playback mute pins support USB HID for host control synchronization
Record mute pin with LED indicator for record mute status
External EEPROM interface for vendor-specific USB VID, PID and serial number
EEPROM write function via vendor-specific request for mass production convenience
Customized embedded VID, PID, product and manufacturer strings and volume settings are available
3 GPIO pins with read/write via HID interface
Jumper pin to set the power mode (100mA or 500mA, Bus-powered or self-powered)
Isochronous transfer uses adaptive mode with internal PLL for synchronization
48K/44.1KHz sampling rate for both playback and recording
Soft mute function
Embedded high-performance 16-bit audio DAC with earphone phone amplifier
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CM108AH
Highly Integrated USB Audio I/O Controller
Host-side data loss noise-reduction function
Embedded 16-bit ADC input with microphone boost
Embedded power-on reset block
Embedded 5V to 3.3V regulator for single external 5V operation
Compatible with Win XP/Vista/7/8, Linux and Mac OS X without additional drivers (WinCE/Win Mobile are
supported by C-Media’s proprietary driver)
48-pin LQFP package
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CM108AH
Highly Integrated USB Audio I/O Controller
Pin Descriptions
3.1
Pin Assignment by Pin Number
Pin #
Signal Name
Pin #
Signal Name
Pin #
Signal Name
Pin #
Signal Name
1
SPDIFO
13
GPIO3
25
VBIAS
37
REGV
2
DI
14
DVSS1
26
VREF
38
MSEL
3
DO
15
GPIO4
27
MICIN
39
VOLUP
4
SK
16
SDIN
28
N.C.
40
PDSW
5
CS
17
ADSCLS
29
AVDD1
41
USBDP
6
MUTER
18
MUTEP
30
LOL
42
USBDM
7
PWRSEL
19
ADLRCK
31
LOBS
43
GPIO1
8
XI
20
ADMCLK
32
LOR
44
SDOUT
9
XO
21
LEDR
33
AVSS2
45
DAMCLK
10
MODE
22
ADSEL
34
AVDD2
46
DALRCK
11
N.C.
23
TEST
35
DVDD
47
DASCLK
12
LEDO
24
AVSS1
36
DVSS2
48
VOLDN
MSEL
REGV
PDSW
VOLUP
USBDP
GPIO1
USBDM
SDOUT
DALRCK
DAMCLK
Pin-Out Diagram
VOLDN
3.2
DASCLK
3
37
SPDIFO
DVSS2
1
DI
DVDD
DO
AVDD2
SK
AVSS2
CS
LOR
MUTER
LOBS
PWRSEL
LOL
XI
AVDD1
CM108AH
XO
MODE
N.C.
MICIN
N.C.
VREF
LEDO
VBIAS
25
TEST
Pin Assignments (top view)
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AVSS1
ADSEL
LEDR
ADMCLK
MUTEP
ADLRCK
ADSCLK
SDIN
GPIO4
DVSS1
GPIO3
13
CM108AH
Highly Integrated USB Audio I/O Controller
3.3
Pin Signal Descriptions
Pin #
Symbol
Type
Description
1
SPDIFO
2
DI
3
4
5
6
DO
SK
CS
MUTER
DO, 8mA, SR
DIO, 8mA,
PD, 5VT
DO, 4mA, SR
DO, 4mA, SR
DO, 4mA, SR
DI, ST, PU
7
PWRSEL
DI, ST
8
9
XI
XO
DI
DO
10
MODE
DI, ST
11
12
N.C.
LEDO
13
GPIO3
14
DVSS1
15
GPIO4
16
SDIN
17
18
19
ADSCLK
MUTEP
ADLRCK
DO, SR, 8mA
DIO, 8mA,
PD, 5VT
P
DIO, 8mA,
PD, 5VT
DIO, 8mA,
PD, 5VT
DIO, 4mA, SR
DI, ST, PU
DO, 4mA, SR
20
ADMCLK
DIO, 4mA, SR
21
LEDR
DO, SR, 8mA
22
ADSEL
DI, ST, PD
23
TEST
DI, ST, PD
24
25
AVSS1
VBIAS
P
AO
26
VREF
AO
27
28
29
30
31
32
33
MICIN
N.C.
AVDD1
LOL
LOBS
LOR
AVSS2
AI
ADC I2S serial clock
Mute playback (edge trigger with de-bouncing)
ADC I2S left/right clock
11.2896MHz output for 44.1KHz sampled data and
12.288MHz output for 48KHz sampled data
LED for mute recording indicator, output H when recording is muted
ADC input source select pin
H: use external (via I2S) ADC
L: use internal ADC
(H: push up to 3.3V, L: push down to ground)
Test mode select pin,
H: test mode
L: normal operation
(H: push up to 3.3V, L: push down to ground)
Analog ground
Microphone bias voltage supply (4.5V), with small driving capability
Connecting to external decoupling capacitor for embedded bandgap
circuit, 2.25V output
Microphone input
P
AO
AO
AO
P
5V analog power for analog circuit
Line out: left channel
DC 2.25V output for line out bias
Line out: right channel
Analog ground
SPDIF output
EEPROM interface data read from EEPROM
EEPROM interface data write to EEPROM
EEPROM interface clock
EEPROM interface chip select
Mute recording (edge trigger with de-bouncing)
Chip power select pin, worked by MODE Pin
Speaker mode – H: 100mA self-powered
L: 500mA Bus-powered
Headset mode – H: 100mA Bus-powered,
L: 500mA Bus-powered
(H: push up to 3.3V, L: push down to ground)
Input pin for 12MHz oscillator
Output pin for 12MHz oscillator
Operating mode selection
H: speaker mode - playback only
L: headset mode - playback & recording
(H: push up to 3.3V, L: pull down to ground)
LED operation light: output H for power on, toggling for data transmit
GPIO pin
Digital ground
GPIO pin
ADC I2S data input
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CM108AH
Highly Integrated USB Audio I/O Controller
34
35
36
37
AVDD2
DVDD
DVSS2
REGV
P
P
P
AO
38
MSEL
DI, ST
39
VOLUP
DI, ST, PU
40
PDSW
DO, 4mA , OD
41
42
USBDP
USBDM
43
GPIO1
44
SDOUT
AIO
AIO
DIO, 8mA,
PD, 5VT
DO, 4mA, SR
45
DAMCLK
DO, 4mA, SR
46
47
48
DALRCK
DASCLK
VOLDN
DO, 4mA, SR
DO, 4mA, SR
DI, ST, PU
5V power supply for analog circuit
5V power supply for internal regulator
Digital ground
3.3V reference output for internal 5V to 3.3V regulator
Mixer enable select, worked by MODE pin,
H: with mixer/AA-path enabled (with default mute)
L: without mixer/AA-path disabled
(H: push up to 3.3V, L: push down to ground)
USB descriptors will also be changed accordingly
Volume up (edge trigger with de-bouncing)
Power down switch control signal (for PMOS polarity)
0: normal operation
1: power down mode (suspend mode)
USB Data D+
USB Data DGPIO pin
DAC I2S data output
11.2896 MHz output for 44.1KHz sampled data and
12.288 MHz output for 48KHz sampled data
DAC I2S left/right clock
DAC I2S serial clock
Volume down (edge trigger with de-bouncing)
Note : DI / DO / DIO – Digital Input / Output / Bi-Directional Pad
AI / AO / AIO – Analog Input / Output / Bi-Directional Pad
SR – Slew Rate Control
ST – Schmitt Trigger
PD / PU – Pull Down / Pull Up
5VT – 5 Volt Tolerant (3.3V Pad)
OD – Open Drain
U
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CM108AH
Highly Integrated USB Audio I/O Controller
4
I²S Interface
The CM108AH provides an I 2 S interface for both playback and recording. External ADC, DAC, or DSP can be
P
P
added to provide additional functions within the USB audio system. The CM108AH sends out master clock (fixed
at x256), LRCK (fixed at x64), and data clock data. Therefore, external ADCs, DACs, or DSPs should be set to
slave mode.
The left channel of the CM108AH’s I 2 S bus is used for mono recording. Both I 2 S buses use a 5V tolerant pad in
P
P
P
P
order to easily interface with 5V or 3.3V devices. Playback data is simultaneously sent to both the DAC and I 2 S
P
bus. The recording source (ADC or I 2 S bus) can be selected by ADSEL jumper pin.
P
P
Right Channel
Left Channel
LRCK
SCLK
SDATA
MSB
-1
-2
+2
+1
LSB
MSB
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-1
-2
+2
+1
LSB
P
CM108AH
Highly Integrated USB Audio I/O Controller
Block Diagram
VOLUP
VOLDN
MUTER LEDO MCU
MUTEP LEDR I/F GPIO BUZZ SPDIFO
interface logics
reset
power on
reset
sync by
VPR_CLK
0 ~ -45dB
38 steps
voltage linear
ROM
USBDP
USBDM
USB
interface
EEPROM
interface
16 bit
DAC
ISO out
processing
( with x2 mod)
4 byte
FIFO
Vref
16 bit
DAC
12. 288/11. 2896 MHz
with adjustment
USB
TRX
+
Vref
LOBS
+
+
-
CS
SK
DW
DR
Vref
USB control
processing
LOR
+
Vref
-
3.3V
+
Vref
-
USB interrupt
processing with4
byte FIFO
5 - > 3. 3
regulator
-
PWRSEL
MODE
PDSW SEL pins
REGV
-
5
LOL
0 ~ -45dB
38 steps
sync by voltage linear
300 x 16 SRAM
VPL_ CLK
48 MHz
12 MHz
PLL1
High-Pass Filter
16 bit SigmaDelta ADC
+
Vref
-
XI
XO
ISO in
processing
PLL2
MICIN
+22.5~ - 0 dB
16 steps
+
12.288/
11. 2896 MHz
VREF
(2.25V)
+22. 5 ~ 0 dB
16 steps
IIS I/F
bandgap
4.5 V ( drive typ4mA)
TEST
CM108AH Block Diagram
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-
PLL3
Rev. 2.1︱ Page 9/27
BOOST
+22.5 dB boost enable
VREF
VBIAS
CM108AH
Highly Integrated USB Audio I/O Controller
6
Ordering Information
Operating Ambient
Model No.
Package
CM108AH
48-pin LQFP, 7mm × 7mm × 1.4mm (plastic)
Temperature
-15°C to +70°C
Note: Outline Dimensions are shown in inches and millimeters
48-Lead Thin Plastic Quad Flatpack (LQFP)
CM108AH Ordering Information
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Supply Range
DVdd = 5V, AVdd = 5V
CM108AH
Highly Integrated USB Audio I/O Controller
7
Function Description
7.1 USB Interface
The CM108AH integrates USB transceiver, PLL and regulator modules, meaning only a few passive components
are necessary for USB interface connection. Default USB descriptors are embedded in the CM108AH, so no
additional design effort is needed for generic USB operation.
For custom orders, customers can attach a
93C46 EEPROM to override the embedded VID, PID, product and manufacturer strings, and serial number for
each set. The CM108AH automatically detects the 93C46, and the overwrite function is performed at start up.
7.1.1 Device Descriptors
Offset
Field
Size
Value (Hex)
Description
0
bLength
1
12
Total: 18 bytes
1
bDescriptorType
1
01
Device descriptor
2
bcdUSB
2
0110
USB 1.1-compliant
4
bDeviceClass
1
00
5
bDeviceSubClass
1
00
6
bDeviceProtocol
1
00
7
bMaxPacketSize0
1
40
8
idVendor
2
0d8c
Vendor ID
10
idProduct
2
0139
Product ID programmable by MSEL and MODE pin
12
bcdDevice
2
0100
14
iManufacturer
1
01
String descriptor index describes manufacturer
15
iProduct
1
02
String descriptor index describes product
16
iSerialNumber
1
03
String descriptor index displays device serial no.
17
bNumConfigurations
1
01
Configuration number = 1
Endpoint zero size = 64 bytes
Device compliant with Audio Device class
specification version 1.0
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CM108AH
Highly Integrated USB Audio I/O Controller
7.1.2
Configuration Descriptors
Offset
Field
Size
Value (Hex)
Description
0
1
bLength
bDescriptorType
1
1
09
02
2
wTotalLength
2
4
bNumInterfaces
1
04 or 03
Total: 9 bytes
Configuration descriptor
Total length of data returned for this configuration,
programmable by MSEL and MODE pin
Number of interfaces supported by this configuration,
changed by MODE pin:
EP0: control interface
EP1: ISO-OUT interface
EP2: ISO-IN interface (optional)
EP3: INT-IN (HID) interface
5
6
7
bConfigurationValue
iConfiguration
bmAttributes
1
1
1
01
00
A0 or E0
8
bMaxPower
2
32 or FA
Programmable by PWRSEL
Maximum power consumption of the USB,
programmable by MODE and PWRSEL pins
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CM108AH
Highly Integrated USB Audio I/O Controller
7.1.3
Content Format for EEPROM (93C46)
Addr
Addr
(Dec)
(Hex)
0
1
2
0x00
0x01
0x02
Description
Magic Word
0x670X
where X = bit 4, 3, 2, 1
bit 3, value within address 0x2A,0x2B is valid
1: valid 0: invalid
bit 2, manufacture string enable
1: enable(default) 0: disable
bit 1, serial number enable control 1: enable 0: disable(default)
bit 0, product string enable control 1: enable(default) 0: disable
VID 2-byte
PID 2-byte
3
4
~
9
10
11
~
25
0x03
0x04
~
0x09
0x0A
0x0B
~
0x19
26
0x1A
Manufacturer string length
(low byte)
27
~
41
0x1B
~
0x29
Manufacturer string: 30 bytes (default: C-Media Electronics Inc.)
42
0x2A
43
0x2B
44
~
END
0x2C
~
END
Serial number length (low byte)
Serial number first byte (high byte)
Serial number: 12 bytes
Product string length (low byte)
Product string first byte (high byte)
Product string: 30 bytes (default: USB PnP sound device)
bit 15 ~ 8
bit 7 ~ 0
Manufacturer string first bytet
(high byte)
DAC initial volume (7-bit)
ADC initial volume (5-bit)
bit
bit
bit
bit
bit
bit
bit
bit
max: 0x02
max: 0x00
min: 0x4a
min: 0x78
15 ~ bit 9
8
Shutdown DAC analog - 1: shutdown, 0: active (default)
7
Total power control - 1: enable, 0: disable (default)
6
Reserved, should be 0
5
MIC high pass filter - 1: enable (default), 0: disable
4
ADC synchronization mode - 1: enable, 0: disable (default)
3
MIC BOOST - 1: enable (default), 0: disable
2
DAC output terminal property set to SPK or HP
1: Headset, 0: Speaker (default)
bit 1
HID - 1: enable (default), 0: disable
bit 0
Remote wakeup enable/disable
1: enable, 0: disable (default)
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CM108AH
Highly Integrated USB Audio I/O Controller
7.1.4
USB Audio Topology Diagram
USB Out
IT
Speaker out
ID = 01
OT
ID = 06
Mixer Unit
ID = 0F
Feature Unit
(volume) (mute)
Feature Unit
ID = 09
(volume) (mute)
ID = 0D
enable or disable by
MSEL pin
USB IN
OT
Microphone In
ID = 07
IT
selector Unit
ID=02
Feature Unit
ID = 08
(volume) (mute)
ID= 0A
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CM108AH
Highly Integrated USB Audio I/O Controller
7.2 Jumper Pins and Mode Setting:
The CM108AH can be configured via several jumper pins. These jumper pin settings affect both USB descriptors
and USB audio topology.
7.2.1
MODE Pin and MSEL Pin
If the MODE pin is pushed up to 3.3V (speaker mode), a playback-only function is activated and no recording
function is declared to the host. At this setting, t h e MSEL pin is ignored and only one input terminal, one
output terminal and one feature unit is declared in the USB audio topology.
If the MODE pin is pulled low (headset mode), a full-duplex playback and recording function is reported to the
host. The MSEL pin setting activates one mixer unit and one feature unit.
When MSEL = 1, the mixer is enabled (AA-path enabled), but with default mute setting
When MSEL = 0, the mixer is disabled (AA-path disabled)
The above USB audio topology (7.1.4) is an example of headset mode with enabled mixer.
7.2.2
MODE Pin and PWRSEL Pin
The PWRSEL pin affects the power configuration of the CM108AH. Together with the MODE pin, there are a
total of 4 programmable combinations.
Combinations
3.3V
PWRSEL
GND
MODE
3.3V
GND
Speaker mode:
Headset mode:
Playback only
Playback and recording
(100mA self-powered)
(100mA Bus-powered)
Speaker mode:
Headset mode:
Playback only
Playback and recording
(500mA Bus-powered)
(500mA Bus-powered)
USB Audio Topology Diagram
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CM108AH
Highly Integrated USB Audio I/O Controller
7.3
HID Feature
The CM108AH’s HID feature allows users to set volume up, volume down, playback mute and recording mute
button pins, and reports the changes to the host to synchronize host side settings. In addition, all CM108AH
internal registers can be accessed via HID function call.
7.3.1
What’s HID?
USB protocols can configure devices at startup or when they are plugged in at run time. These devices are
categorized into various device classes. Each device class defines the common behavior and protocols for
devices that serve similar functions. The HID (Human Interface Device) class is one of the device classes.
The HID class consists primarily of devices that are used to control the operation of computer systems.
Typical examples of HID class devices include:
Keyboards and pointing devices: mice, trackballs and joysticks
Front-panel controls: knobs, switches, buttons and sliders
Controls that might be found on VCR remote controls, games or simulation devices: data gloves,
throttles, and steering wheels
Devices that may not require human interaction but provide data in a similar format to HID class
devices: bar-code readers, thermometers or voltmeters
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CM108AH
Highly Integrated USB Audio I/O Controller
7.3.2
HID Descriptors
HID Interface Descriptor
Offset
Field
Size
Value (Hex)
Description
0
bLength
1
09
Size of this descriptor: 9 bytes
1
bDescriptorType
1
04
Interface descriptor type
2
bInterfaceNumber
1
03
Interface number: 3
3
bAlternateSetting
1
00
Alternate: 0
4
bNumEndpoints
1
01
Number of endpoints used by this interface: 1
5
bInterfaceClass
1
03
Interface class: HID
6
bInterfaceSubClass
1
00
Subclass: no
7
bInterfaceProtocol
1
00
Must be set to 0
8
iInterface
1
00
String descriptor index that describes this interface
Offset
Field
Size
Value (Hex)
0
bLength
1
09
Total: 9 bytes
1
bDescriptorType
1
21
HID descriptor type
2
bcdHID
2
0100
HID class version 1.0
4
bCountryCode
1
00
5
bNumDescriptors
1
01
6
bDescriptorType
1
22
7
wDescriptorLength
2
0030
HID Descriptor
Description
Report descriptor
Total size of the optional descriptor: 48 bytes
Interrupt IN Endpoint Descriptor
Offset
Field
Size
Value (Hex)
Description
0
bLength
1
07
Total: 7 bytes
1
bDescriptorType
1
05
Endpoint descriptor type
2
bEndpointAddress
1
83
In Endpoint Number = 3
3
bmAttributes
1
03
Interrupt endpoint type
4
wMaxPacketSize
2
0004
6
bInterval
1
2
Maximum packet size: 4 bytes
2ms
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CM108AH
Highly Integrated USB Audio I/O Controller
7.3.3
Windows Software Architecture for HID
Applications
C-Media SDK
Reports
Winmm.dll
User32.exe or User.exe
Keyboard-class driver
Direct input
Joy stick-class driver
Mouse-class driver
HID class driver(HIDCLASS.SYS)
Gameport
USB
Gameport
MiniDriver(HIDGAME.SYS)
USB hub driver
(USBHUB.SYS)
MiniDriver(
HIDUSB.SYS)
Enumerator(GAMEUM.SYS)
USB class driver (USBD.SYS)
PCI enumerator
Note: Please contact our sales for a C-Media SDK sample if needed
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HID.dll
Audio Driver
(Device specification)
CM108AH
Highly Integrated USB Audio I/O Controller
7.4 Internal Registers
All of CM108AH’s internal registers can be accessed via generic HID functional calls without the need to
develop a kernel mode driver. In total, 4 bytes of data can be read or written from the HID. The input report is
for read and the output report is for write. These internal registers of are used to control GPIO pin, S/PDIF
output and EEPROM data access.
HID_IR0 (HID input report byte 0)
Offset: 0x00
Bits
Read/Write
7-6
R
Description
00: HID_IR1 is used as GPI,
Default
0x0
10: values written to HID_IR0-3 are also mapped to
EPROM_DATA0-1 and EEPROM_CTRL
Others: reserved
5-4
R
Reserved
0x0
3
R
0: no activity on record/mute button
0x0
2
R
1
R
1: record/mute button pressed then released
0: no activity on playback/mute button
0x0
1: playback/mute button pressed then released
0: volume-down button released
0x0
1: volume-down button pressed
0
R
0: volume-up button released
0x0
1: volume-up button pressed
HID_IR1 (HID input report byte 1)
Offset: 0x01
Bits
Read/Write
Description
Default
When HID_IR0[7:6] == 2’b00: HID_IR1[3:0] is the input from
7-0
R
GPIO4 ~ GPIO1 in input mode
0x00
When HID_OR0[7] == 1’b1: mapped from EEPROM_DATA0
HID_IR2 (HID input report byte 2)
Offset: 0x02
Bits
Read/Write
7-0
R
Description
When HID_OR0[7] == 1’b1: mapped from EEPROM_DATA1
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Default
0x00
CM108AH
Highly Integrated USB Audio I/O Controller
HID_IR3 (HID input report byte 3)
Offset: 0x03
Bits
Read/Write
7-0
R
Description
When HID_OR0[7] == 1’b1: mapped from EEPROM_CTRL
Default
0x00
HID_OR0 (HID output report byte 0)
Offset: 0x04
Bits
Read/Write
Description
7-6
R/W
0: HID_OR1-2 are used for GPO; HID_OR0, 3 are used for
SPDIF
1: reserved
2: values written to HID_OR0-3 are also mapped to
EEPROM_DATA0-1, EEPROM_CTRL (See Note)
3: reserved
5
R/W
Reserved
4
R/W
3-0
R/W
When HID_OR0[7] ==
When HID_OR0[7] ==
When HID_OR0[7] ==
channel
When HID_OR0[7] ==
1’b0: valid bit in SPDIF frame
1’b1: reserved
1’b0: first nibble of SPDIF status
Default
0x0
0x0
0x0
0x0
1’b1: reserved
Note 1: When EEPROM access is done, HID interrupt will occur. USB host can get the result from interrupt pipe (endpoint 3).
Note 2: HID_OR0 is used for SPDIF when SPDIF_CONFIG[5] == 1’b0
HID_OR1 (HID output report byte 1)
Offset: 0x05
Bits
Read/Write
Description
Default
When HID_OR0[7:6] == 2’b00: HID_OR1[3:0] is the output to
0x00
GPIO4 ~ GPIO1 in output mode
7-0
R/W
0: GPO drives L
1: GPO drives H
When HID_OR0[7:6] == 2’b01: reserved
When HID_OR0[7:6] == 2’b1x: mapped to EEPROM__DATA0
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CM108AH
Highly Integrated USB Audio I/O Controller
HID_OR2 (HID output report byte 2)
Offset: 0x06
Bits
Read/Write
Description
When HID_OR0[7:6] == 2’b00: HID_OR2[3:0] is the mode
Default
0x00
setting for GPIO4 ~ GPIO1
7-0
R/W
0: set GPIO to input mode
1: set GPIO to output mode
When HID_OR0[7:6] == 2’b01: reserved
When HID_OR0[7:6] == 2’b1x: mapped to EEPROM_DATA1
HID_OR3 (HID output report byte 3)
Offset: 0x07
Bits
Read/Write
Description
When HID_OR0[7] == 1’b0: category byte of SPDIF status
7-0
R/W
channel
When HID_OR0[7] == 1’b1: mapped to EEPROM_CTRL
Note: HID_OR3 is used for SPDIF when SPDIF_CONFIG[5] == 1’b0
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Default
0x00
CM108AH
Highly Integrated USB Audio I/O Controller
8
Electrical Characteristics
8.1
Absolute Maximum Rating
Symbol
8.2
Parameters
Value
Unit
Dvmin
Min. digital supply voltage
– 0.3
V
Dvmax
Max. digital supply voltage
+6
V
Avmin
Min. analog supply voltage
– 0.3
V
Avmax
Max. analog supply voltage
+6
V
Dvinout
Voltage on any digital input or output pin
–0.3 to +5.5
V
Avinout
Voltage on any analog input or output pin
–0.3 to +5.5
V
TBstgB
Storage temperature range
-40 to +125
P0PC
ESD (HBM)
ESD human body mode
4000
V
ESD (MM)
ESD machine mode
200
V
Latch Up
JEDEC standard no.78, Mar. 1997
200
mA
Operation Conditions
Operation conditions
Min
Typ
Max
Unit
Analog supply voltage
4.5
5.0
5.5
V
Digital supply voltage
4.5
5.0
5.5
V
Total power consumption
-
35
mA
Suspend-mode power consumption
-
500
uA
-15
-
Operating ambient temp.
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70
PoPC
CM108AH
Highly Integrated USB Audio I/O Controller
8.3
Electrical Parameters
Min.
Typ.
Max.
Unit
DAC (10K Ohm Loading)
Resolution
-
16
-
Bits
THD + N (-3dBr)
-
-74.29
-
dB
SNR
-
93.6
-
dB
Silent SNR
-
98.2
-
dB
Dynamic range
-
93.8
-
dB
Frequency response 48KHz
20
-
20K
Hz
Frequency response 44.1KHz
20
-
20K
Hz
Output voltage (rms)
-
1.25
-
Vrms
Output voltage swing
0.5
-
4.0
V
DAC (32 Ohm loading)
Resolution
-
16
-
Bits
THD + N (-3dBr)
-
-71.1
-
dB
SNR
-
93.7
-
dB
Silent SNR
-
98.2
-
dB
Dynamic range
-
93.8
-
dB
Frequency response 48KHz
20
-
20K
Hz
Frequency response 44.1KHz
20
-
20K
Output voltage (rms)
-
1.25
-
Vrms
Output voltage swing
0.5
-
4.0
V
ADC
Resolution
-
16
-
bit
THD + N (-3dBr)
-
-76.1
-
dB
SNR
-
83.1
-
dB
Dynamic range
-
81.6
-
dB
Frequency response 48KHz
20
-
19.2K
Hz
Frequency response 44.1KHz
20
-
17.6K
Hz
Input range
0
-
2.88
Vpp
Amplification
Volume control level
-45
-
0
dB
Volume control step
-
38
-
Steps
Microphone Input
Boost gain
-
+22.5
-
dB
Gain adjustment range
0
-
22.5
dB
Gain adjustment steps
-
16
-
Steps
Mixer gain adjustment
-33.0
-
12.0
dB
-
32
-
Steps
Mixer gain adjustment steps
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CM108AH
Highly Integrated USB Audio I/O Controller
9
Audio Quality Graphs
9.1
Line Out Frequency Response @ 48KHz Sample Rate (10K Ohm Loading)
Audio Precision
09/26/08 14:33:51
dx=-19.980 kHz
+1
dy=-3.132 dB
+0
-0.01
-1
d
B
r
-2
-3
-3.143
A
-4
-5
-6
20
50
100
200
500
1k
2k
5k
10k
19.998k
20k
Hz
Sweep
Trace
Color
Line Style
Thick
Data
Axis
1
1
1
2
Cyan
Yellow
Solid
Solid
1
1
Fas ttes t.Ch.1 Am pl!Norm alize
Fas ttes t.Ch.2 Am pl!Norm alize
Left
Left
Com m ent
Vis ta-Frequency Res pons e-M48k.at27
9.2
Line Out THD+N @ 48KHz sample rate (10K Ohm Loading)
Audio Precision
09/26/08 14:27:07
+0
-10
-20
-30
-40
d
B
r
-50
A
-70
-60
-80
-90
-100
-110
-120
20
50
100
200
500
1k
2k
Hz
Sweep
Trace
Color
Line Style
Thick
Data
Axis
1
1
1
2
Cyan
Yellow
Solid
Solid
2
2
Anlr.THD+N Ampl
Anlr.THD+N Ampl
Left
Left
Vista-D-A THD+N.at27
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Comment
5k
10k
20k
CM108AH
Highly Integrated USB Audio I/O Controller
9.3
Microphone Input Frequency Response @ 48KHz Sample Rate
Audio Precision
A-D FREQUENCY RESPONSE
dx=-19.980 kHz
-1
09/26/08 14:52:45
dy=+1.389 dB
-1.2
-1.4
-1.423
-1.6
-1.8
d
B
F
S
-2
-2.2
-2.4
-2.6
-2.8
-2.812
-3
20
50
100
200
500
1k
2k
5k
10k
20k
20k
Hz
Sweep
Trace
Color
Line Style
Thick
Data
Axis
1
1
1
2
Yellow
Cyan
Solid
Solid
1
1
DSP Anlr.Level A
DSP Anlr.Level B
Left
Left
Comment
Cursor1
*-2.812 dBFS
-2.812 dBFS
Vista-A-D Frequency Response.at2c
9.4
Microphone Input THD+N @ 48KHz Sample Rate
Audio Precision
A-D THD+N vs FREQUENCY
09/26/08 14:51:13
+0
-20
-40
d
B
F
S
-60
-80
-100
-120
20
50
100
200
500
1k
2k
5k
Hz
Sweep
Trace
Color
Line Style
Thick
Data
Axis
1
1
1
2
Yellow
Cyan
Solid
Solid
1
1
DSP Anlr.THD+N Am pl A
DSP Anlr.THD+N Am pl B
Left
Left
Vis ta-A-D THD+N.at2c
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Com m ent
10k
20k
CM108AH
Highly Integrated USB Audio I/O Controller
Reference
USB specification 1.1 and 2.0-compliant
USB audio device class specification 1.0-compliant
USB human interface device class specification 1.11-compliant
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CM108AH
Highly Integrated USB Audio I/O Controller
－End of Datasheet－
C-MEDIA ELECTRONICS INC.
6F., 100, Sec. 4, Civil Boulevard, Taipei, Taiwan 106 R.O.C.
TEL：886-2-8773-1100
FAX：886-2-8773-2211
E-MAIL：sales@cmedia.com.tw
Disclaimer:
Information furnished by C-Media Electronics Inc. is believed to be accurate and reliable. However, no responsibility is assumed by C-Media Electronics Inc. for its use, nor for any
infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise
under any patent or patent rights of C-Media. Trademark and registered trademark are the property of their respective owners.
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