CM108 Datasheet, PDF (5/29 Pages) C-Media Electronics – USB Audio I/O Controller

CM108
Integration Dual DAC, Earphone Driver, ADC,
Microphone Booster, PLL, Regulator, and USB Transceiver
1. DESCRIPTION AND OVERVIEW
CM108 is a highly integrated single chip USB audio solution. All essential analog modules
are embedded in CM108, including dual DAC and earphone driver, ADC, microphone booster,
PLL, regulator, and USB transceiver. It is very suitable for USB headset, USB earphone or
USB audio interface box application. Many features are programmable with jumper pins or
external EEPROM. In addition, audio adjustment can be easily controlled via specific HID
compliant volume control pins. For value added application, external codec or audio DSP can
be connected to CM108 via I²S pin for further processing. 4 GPIO pins can be accessed with
customer application software for additional value added application.
2. FEATURES
Compliant with USB 2.0 Full Speed Operation
Compliant with USB Audio Device Class Specification v1.0
Supports USB Suspend / Resume Mode 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 +
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 for Mixer Unit Enable / Disable under Headset Mode
For Speaker Mode, USB Audio Function Topology has 1 Input Terminal, 1 Output
Terminal, and 1 Feature Unit
Support One Control Endpoint, One Isochronous Out Endpoint, One Isochronous In
Endpoint, and One Interrupt In Endpoint
Date: Nov/01/2004
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Version: 1.5