Electronics Production | September 06, 2004
Chip opens the way to external sound
Providing PC and Mac platforms with up to eight audio output and now two audio input channels via a single FireWire connection, the latest version of Oxford Semiconductor’s OXFW970 FireWire audio controller IC allows next generation audio systems to be added to desktop and notebook systems.
Harnessing the high bandwidth and quality of service characteristics of FireWire (IEEE1394) and FireWire800 (IEEE1394b), OXFW970 multi-channel audio solutions avoid the need to install separate sound cards in desktop computers. In addition, FireWire’s power carrying capability means that smaller speakers will not require external power supplies. Linked to a FireWire bus by an IEEE1394 PHY, OXFW970 handles serial audio data conforming to the IEC61883-6 transmission protocol and AM824 audio format. Sampling 24-bit audio packets at 96kHz, the chip provides four I2S stereo audio outputs, producing eight digital audio outputs for 7.1 surround sound speaker systems, and two audio inputs for musical instrument and microphone line inputs required in emerging GarageBand™ applications. The 100-pin TQFP packaged OXFW970 features an embedded ARM7 processor, high-speed buffer manager, RAM and 512kbits of on-board flash memory. Firmware upgrades are implemented using the FireWire interface and programming utilities provided by Oxford Semiconductor. Eight GPIO pins further extend the device capabilities, enabling for example control of an external DAC using a serial control interface.