The Oxygen Express™-series HD CM8888 is a high- quality PCI Express multi-channel audio processor with an Intel HD Audio specification-compatible audio chip. It is also a controller that can link HDA codecs or bridge high-quality I2S codecs. The CM8888 can be built into home audio electronics or personal computers to provide high-fidelity sound, providing a professional audio processing center.

It supports up to 14 outgoing channels and 12 ingoing channels. The 14 outgoing channels are composed of 4 playback DMA’s, including a multi-channel DMA (32 bits, 8 channels, 192k), a S/PDIF & HDMI DMA (each 32 bits, 2 channels, 192k), and a RTC (real-time communication) DMA (32 bits, 2 channels, 192k) channels. The 12 ingoing channels are spread out in 3 recording DMAs (up to 32 bits, 192k).




  • Compatible with PCI Express 1.1 interface, with bus mastering and burst modes


  • Embedded 8051-based MCU transcodes HD Audio commands to link various external I2S codecs (external 4 or 8KB serial EEPROM is required)
  • Embedded ROM code for MCU transcoding of HD Audio commands for embedded DACs and ADCs
  • Built-in HD Audio and I2S controllers offer flexibility in choosing external codecs for different product applications
  • Digital mixer to mix all input data to output streams

Audio I/O

  • Intel HD Audio Link supports 1 external HDA codec
  • Six pairs of I2S serial audio output interfaces (12-ch out)
  • Six pairs of I2S serial audio input interfaces (12-ch in)
  • Integrated 192K/176.4K/96K/88.2K/48K/44.1K, and 16/24/32-bit S/PDIF transmitter with a 2-source selector/mux (from playback DMA digital mixing, S/PDIF input), including WMA-Pro output support
  • Integrated 192K/176.4K/96K/88.2K/48K/44.1K, and 16/24/32-bit S/PDIF receiver with 2-input internal selector/switch for media center/AV receiver features
  • Built-in MPU-401 MIDI UART I/O port for pro audio applications
  • All input data can be mixed to output streams for low-latency record monitoring/mixing output

Control Interfaces

  • SPI control interfaces with up to 8 external audio devices (5 output devices and 3 input devices)
  • I2C Interface supports both master and slave modes (master for external audio devices and slave for additional MCU applications such as remote controls)
  • Interrupt pin for external MCU read transaction
  • Serial EEPROM programming interface for customizing sub-vendor and sub-device IDs (and vendor/device IDs as well), storing HDA power-on pin configuration data (replacing the MB BIOS function) and 8051 ROM codes (HDA command transcoder
  • Maximum 8 jack-detection pins (5 for output jacks and 3 for input jacks)
  • Maximum 16 GPIO pins for external devices control and other purposes
  • LED indicator control pin functions while protected content is playing


  • 24.576MHz crystal input required with embedded PLL for adaptive clock rate
  • Single 3.3V power supply
  • 3.3 V digital I/O pads with 5V tolerance
  • Fully compatible with all mainstream southbridges (Intel, nVIDIA, VIA, SiS)
  • LQFP-128 package
  • Default target codecs: CM9882A for HDA; CS5381 (ADC)+PCM1795(DAC) for I2S
  • Support Xear™ technology by Cmedia vendor driver