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USB Audio Design Guide 46/61

/* Enable Fall - bac k to aud io clas s 1.0 when c onnec ted to FS hub */

# i fndef A UDIO_C L ASS_FA L LBACK

# d efine A UDIO_C L ASS_FA L LBACK (1)

# e ndi f

Next, the ﬁle deﬁnes the audio properties of the application. This application has

stereo in and stereo out with an S/PDIF output that duplicates analogue channels 1

and 2:

/* Number of USB streaming c h a n nels - Default is 2 in 2 out */

# ifndef N U M _ USB_CHAN _ I N

# define N U M _ USB_CHAN _ I N (2) /* Devic e to Host */

# endif

# ifndef N U M _USB_CH A N _ O UT

# define N U M _USB_CH A N _ O UT (2) /* Host to D evice */

# endif

/* Number of IS2 chan s to DAC ..*/

# ifndef I 2 S _ C H ANS_DAC

# define I 2 S _ C H ANS_DAC (2)

# endif

/* Number of I2S chan s from ADC */

# ifndef I 2 S _ C H ANS_ADC

# define I 2 S _ C H ANS_ADC (2)

# endif

/* Enable DFU interface , Note , requires a driver for Windows */

# define DFU (1)

/* Master clock defines ( in Hz) */

# define MCLK_441 (256*44100) /* 44.1 , 88.2 etc */

# define MCLK_48 (512*4 8 0 0 0 ) /* 48, 96 etc */

/* Maximum frequency device runs at */

# define MAX_FREQ (192000)

/* Index of SPDIF TX chann e l ( duplicated DAC channels 1/2) */

# define S P D I F _TX_INDEX (0)

/* Default frequency device reports as running at */

/* Audio Class 1.0 friendly freq */

# define D E F A U L T _ F R EQ (48000)

Finally, there are some general USB identiﬁcation deﬁnes to be set. These are set

for the XMOS reference design but vary per manufacturer:

# d efine VEND O R_ID (0 x20B1 ) /* XMOS VID */

# d efine PID_A UDIO_ 2 (0 x 000 2 ) /* L1 USB Audio R efere nce Desi gn PID */

# d efine PID_A UDIO_ 1 (0 x 000 3 ) /* L1 USB Audio R efere nce Desi gn PID */

# d efine BCD_D EVICE (0 x0610 ) /* Dev ice rele ase numb er in BCD: 0 x JJM N

* JJ: Major , M: Minor , N : Sub - min or */

REV 6.1

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Request AudioReQuest N.Series Manual Pagina 46