forked from PAWPAW-Mirror/lib_xua
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4.0 KiB
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63 lines
4.0 KiB
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XMOS USB Audio Hardware Platforms
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A range of hardware platforms for evaluating USB Audio on XMOS devices.
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Specific, in depth, details for each platform/board are out of scope of this library documentation however, the features of the most popular platform are described below with the view of providing a worked example.
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Please also see application note AN00246.
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xCORE-200 Multi-Channel Audio Board
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...................................
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`The XMOS xCORE-200 Multi-channel Audio board <https://www.xmos.com/support/boards?product=18334>`_
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(XK-AUDIO-216-MC) is a complete hardware and reference software platform targeted at up to 32-channel USB and networked audio applications, such as DJ decks and mixers.
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The Multichannel Audio Platform hardware is based around the XE216-512-TQ128 multicore microcontroller; an dual-tile xCORE-200 device with an integrated High Speed USB 2.0 PHY, RGMII (Gigabit Ethernet) interface and 16 logical cores delivering up to 2000MIPS of deterministic and responsive processing power.
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Exploiting the flexible programmability of the xCORE-200 architecture, the Multi-channel Audio Platform supports either USB or network audio source, streaming 8 analogue input and 8 analogue output audio channels simultaneously - at up to 192kHz.
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For full details regarding the hardware please refer to `xCORE-200 Multichannel Audio Platform Hardware Manual <https://www.xmos.com/support/boards?product=18334&component=18687>`_.
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The reference board has an associated firmware application that uses `lib_xua` to implemented a USB Audio Devicce. Full details of this application can be found in the USB Audio Design Guide.
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Analogue Input & Output
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+++++++++++++++++++++++
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A total of eight single-ended analog input channels are provided via 3.5mm stereo jacks. Each is fed into a CirrusLogic CS5368 ADC.
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Similarly a total of eight single-ended analog output channels are provided. Each is fed into a CirrusLogic CS4384 DAC.
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The four digital I2S/TDM input and output channels are mapped to the xCORE input/outputs through a header array. This jumper allows channel selection when the ADC/DAC is used in TDM mode
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Digital Input & Output
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++++++++++++++++++++++
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Optical and coaxial digital audio transmitters are used to provide digital audio input output in formats such as IEC60958 consumer mode (S/PDIF) and ADAT.
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The output data streams from the xCORE-200 are re-clocked using the external master clock to synchronise the data into the audio clock domain. This is achieved using simple external D-type flip-flops.
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MIDI
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++++
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MIDI I/O is provided on the board via standard 5-pin DIN connectors. The signals are buffered using 5V line drivers and are then connected to 1-bit ports on the xCORE-200, via a 5V to 3.3V buffer.
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Audio Clocking
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++++++++++++++
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A flexible clocking scheme is provided for both audio and other system services. In order to accommodate a multitude of clocking options, the low-jitter master clock is generated locally using a frequency multiplier PLL chip. The chip used is a Phaselink PL611-01, which is pre-programmed to provide a 24MHz clock from its CLK0 output, and either 24.576 MHz or 22.5792MHz from its CLK1 output.
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The 24MHz fixed output is provided to the xCORE-200 device as the main processor clock. It also provides the reference clock to a Cirrus Logic CS2100, which provides a very low jitter audio clock from a synchronisation signal provided from the xCORE-200.
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Either the locally generated clock (from the PL611) or the recovered low jitter clock (from the CS2100) may be selected to clock the audio stages; the xCORE-200, the ADC/DAC and Digital output stages. Selection is conntrolled via an additional I/O, bit 5 of PORT 8C.
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LEDs, Buttons and Other IO
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++++++++++++++++++++++++++
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An array of 4*4 green LEDs, 3 buttons and a switch are provided for general purpose user interfacing. The LED array is driven by eight signals each controlling one of 4 rows and 4 columns.
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A standard XMOS xSYS interface is provided to allow host debug of the board via JTAG.
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