OXFW970 Data Sheet
Oxford Semiconductor Ltd.
Device
Overview
The OXFW970 is a cost-effective 1394-to-audio native bridge.
This highly-integrated device offers a two-chip solution to native bridge
applications using an external 1394 PHY. The device is compatible with
both 1394-1995, 1394a and 1394b PHYs.
Applications can receive up to two channels of audio and stream data to
multiple speakers via DACs, generating 7.1 audio channels.
Device
Functionality
Within the device, the link controller complies with 1394-1995, 1394a and
1394b specifications. The 1394 transaction layer is implemented using a
combination of the ARM7TDMI (low-power 32-bit RISC processor) and a
high-performance buffer manager.
The FIFO manager has a RAM bandwidth of 1600 Mbps. It stores 1394
packets, passing them to the appropriate destinations without processor
intervention.
Configuration data, including the IEEE organizational unique identifier
(OUI) and device serial number, is stored in the flash ROM which may
be uploaded from the 1394 bus even when blank. The device also
facilitates firmware uploads from the 1394 bus.
The audio core in the OXFW970 can handle the transfer of samples in
standard 61883-6 format to multiple serial-audio interfaces. Interfaces
are configured to support stereo audio (4 × 2-channels gives the
necessary left/right samples). The audio core can support two versions of
serial-audio protocol and communicate with devices that use different
numbers of bits per sample. Input channels are handled via the internal
UART.
The OXFW970 also provides the master clock (256 fs) to the external
DAC, to which the serial-audio interface is synchronized. Clock recovery
is performed to synchronize the master clock to the 1394 transmitting
node. The performance of clock jitter can be further enhanced by using a
suitable external circuit.
Eight GPIO pins can be used to extend the device capabilities. GPIOs can
be used to control an external DAC via a DAC serial control interface.
On the device, UART signals are multiplexed to support debugging; and
other signals are wired to generate device interrupts.
Figure 1
shows the OXFW970.
2
External—Free Release
DS-0004 Jun 05 (2)
OXFORD [ OXFORD SEMICONDUCTOR ]
