75 lines
2.6 KiB
ReStructuredText
75 lines
2.6 KiB
ReStructuredText
Required User Function Definitions
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==================================
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The following functions need to be defined by an application using the XMOS USB Audio framework.
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External Audio Hardware Configuration Functions
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-----------------------------------------------
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.. c:function:: void AudioHwInit(chanend ?c_codec)
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This function is called when the audio core starts after the
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device boots up and should initialize the external audio harware e.g. clocking, DAC, ADC etc
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:param c_codec: An optional chanend that was original passed into
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:c:func:`audio` that can be used to communicate
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with other cores.
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.. c:function:: void AudioHwConfig(unsigned samFreq, unsigned mclk, chanend ?c_codec, unsigned dsdMode, unsigned sampRes_DAC, unsigned sampRes_ADC)
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This function is called when the audio core starts or changes
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sample rate. It should configure the extenal audio hardware to run at the specified
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sample rate given the supplied master clock frequency.
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:param samFreq: The sample frequency in Hz that the hardware should be configured to (in Hz).
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:param mclk: The master clock frequency that is required in Hz.
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:param c_codec: An optional chanend that was original passed into
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:c:func:`audio` that can be used to communicate
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with other cores.
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:param dsdMode: Signifies if the audio hardware should be configured for DSD operation
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:param sampRes_DAC: The sample resolution of the DAC stream
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:param sampRes_ADC: The sample resolution of the ADC stream
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Audio Streaming Functions
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-------------------------
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The following functions can be optionally used by the design. They can be useful for mute lines etc.
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.. c:function:: void AudioStreamStart(void)
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This function is called when the audio stream from device to host
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starts.
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.. c:function:: void AudioStreamStop(void)
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This function is called when the audio stream from device to host stops.
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Host Active
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-----------
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The following function can be used to signal that the device is connected to a valid host.
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This is called on a change in state.
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.. c:function:: void AudioStreamStart(int active)
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:param active: Indicates if the host is active or not. 1 for active else 0.
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HID Controls
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------------
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The following function is called when the device wishes to read physical user input (buttons etc).
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.. c:function:: void UserReadHIDButtons(unsigned char hidData[])
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:param hidData: The function should write relevant HID bits into this array. The bit ordering and functionality is defined by the HID report descriptor used.
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