User's Manual

NEMO Bluetooth Radio Module
Solutions for a Real Time World Datasheet
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Copyright Unigen Corporation, 2008
Digital Audio Interface (I²S)
The digital audio interface supports the industry standard formats for I²S, left-justified (LJ) or
right-justified (RJ). The interface shares the same pins as the PCM interface, which means each
audio bus is mutually exclusive in its usage. Table 7 lists these alternative functions.
Table 9: Alternative Functions of the Digital Audio Bus Interface on the PCM Interface
PCM Interface I²S Interface
BT_PCM_TXD_P SD_OUT
BT_PCM_RXD_P SD_IN
BT_PCM_SYNC_P WS
BT_PCM_CLK_P SCK
Table 8 describes the values for the PS Key (PSKEY_DIGITAL_AUDIO_CONFIG) that is used to
set-up the digital audio interface. For example, to configure an I²S interface with 16-bit SD data
set PSKEY_DIGITAL_CONFIG to
0x0406.
Table 10: PSKEY_DIGITAL_AUDIO_CONFIG
Bit Mask Name Description
D[0] 0x0001 CONFIG_JUSTIFY_FORMAT
0 for left justified, 1 for right
justified.
D[1] 0x0002 CONFIG_LEFT_JUSTIFY_DELAY
For left justified formats: 0 is MSB of
SD data occurs in the first SCLK
period following WS transition. 1 is
MSB of SD data occurs in the second
SCLK period.
D[2] 0x0004 CONFIG_CHANNEL_POLARITY
For 0, SD data is left channel when
WS is high. For 1 SD data is right
channel.
D[3] 0x0008 CONFIG_AUDIO_ATTEN_EN
For 0, 17 bit SD data is rounded
down to 16 bits. For 1, the audio
attenuation defined in
CONFIG_AUDIO_ATTEN is applied
over 24 bits with saturated rounding.
Requires CONFIG_16_BIT_CROP_EN
to be 0.
D[7:4] 0x00F0 CONFIG_AUDIO_ATTEN Attenuation in 6 dB steps.