BCM89359 Advance Data Sheet
I2S Interface
I2S Interface
The BCM89359 supports I S digital audio port for Bluetooth audio. The I S signals are:
2
2
2
•
•
•
•
I S clock: BT_I2S_CLK
2
I S Word Select: BT_I2S_WS
2
I S Data Out: BT_I2S_DO
2
I S Data In: BT_I2S_DI
BT_I2S_CLK and BT_I2S_WS become outputs in master mode and inputs in slave mode, whereas BT_I2S_DO
always stays as an output. The channel word length is 16 bits, and the data is justified so that the MSB of the
2
2
left-channel data is aligned with the MSB of the I S bus, in accord with the I S specification. The MSB of each
data word is transmitted one bit clock cycle after the BT_I2S_WS transition, synchronous with the falling edge
of the bit clock. Left-channel data is transmitted when BT_I2S_WS is low, and right-channel data is transmitted
when BT_I2S_WS is high. Data bits sent by the BCM89359 are synchronized with the falling edge of
BT_I2S_CLK and should be sampled by the receiver on the rising edge of BT_I2S_CLK.
The clock rate in master mode is either of the following:
48 kHz x 32 bits per frame = 1.536 MHz
48 kHz x 50 bits per frame = 2.400 MHz
The master clock is generated from the input reference clock using a N/M clock divider.
In the slave mode, any clock rate is supported to a maximum of 3.072 MHz.
Broadcom®
September 9, 2014 • 89359-DS100-R
Page 52
BROADCOM CONFIDENTIAL
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