XMOS xCORE-200 Multi-channel Audio board, Design Manual, Page: 100 / 112

USB Audio Design Guide 100/110
Macro VOLUME_RES_MIXER
Description The resolution of the volume control in db as a 8.8 fixed point number.
Default: 0x100 (1db)
7.1.10 Power
Macro SELF_POWERED
Description Report as self to the host when enabled, else reports as bus-powered.
This affects descriptors and XUD usage.
Default: 0 (Disabled)
Macro BMAX_POWER
Description Power drawn from the host (in mA x 2).
Default: 0 when SELF_POWERED enabled else 250 (500mA)
7.2 Required User Function Definitions
The following functions need to be defined by an application using the XMOS USB Audio framework.
7.2.1 External Audio Hardware Configuration Functions
Function AudioHwInit
Description This function is called when the audio core starts after the device boots up and
should initialize the external audio harware e.g. clocking, DAC, ADC etc
Type
void AudioHwInit(chanend ?c_codec)
Parameters
c_codec
An optional chanend that was original passed into audio() that
can be used to communicate with other cores.
Function AudioHwConfig
Description This function is called when the audio core starts or changes sample rate. It
should configure the extenal audio hardware to run at the specified sample rate
given the supplied master clock frequency.
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