CM109 Datasheet, PDF (12/36 Pages) C-Media Electronics – USB I/O Controller

CM109
High Integration / Low Cost USB Audio Controller
for PC Internet Phone
7. FUNCTION DESCRIPTIONS
7.1 USB Interface
CM109 integrates USB transceiver, PLL, and regulator so only a few passive
components are necessary for the USB interface connection. Default USB descriptors
are embedded in CM109; therefore no additional design effort is needed for a generic
USB operation. PID changes with the jumper pin setting so different setting have
different PID. For customized product, customer can attach a 93C46 EEPROM to
override the embedded VID, PID and provide addition serial number for each set.
CM109 automatically detects 93C46 existence and performs the overwrite function
during power up.
7.1.1 Device Descriptor
Offset
Field
0
bLength
1
bDescriptorType
2
bcdUSB
4
bDeviceClass
5 bDeviceSubClass
6
bDeviceProtocol
7 bMaxPacketSize0
8
idVendor
10
idProduct
Size
1
1
2
1
1
1
1
2
2
12
bcdDevice
2
14
iManufacturer
1
15
iProduct
1
16
iSerialNumber
1
17 bNumConfigurations 1
Value
(Hex)
Description
12 Total 18 Bytes
01 Device Descriptor
0110 USB 1.1 compliant.
00
00
00
40 Endpoint zero Size = 64 bytes
0d8c Vendor ID
0008 ~ Product ID
000F Programmable by MSEL and
MODE pin
0100 Device compliant to the Audio
Device Class specification
version 1.00
01 Index of string descriptor
describing manufacturer
02 Index of string descriptor
describing product
03 Index of string descriptor
describing the device’s serial
number
01 Configurations number = 1
Note: VID, PID, and serial number can be overridden by external EEPROM content
Date: 08/Sep/2005
- 11 -
Version: 1.3a