RM0082
RS_Telecom IP
Doc ID 018672 Rev 1
777/844
Figure 97.
Buffer address generation
34.4.8 I2S
block
I2S interface is composed of 4 signals:
●
I2S block is very similar to TDM block, but the frame sync can only be compliant with
the Philips I2S definition.
●
I2S block can be master or slave for the clock and sync signals (please refer to
Table 721: I2S_CONF register (Offset 0x4C)
●
Buffering is limited to 1024 samples (512 left and 512 right samples representing 64ms
of voice). Data is stored always on 32 bits. Left and right channels are stored in two
different buffers.
●
In master mode, LRCK can be adjusted for 8, 16 or 32 bits width.
●
Data width can be less than LRCK width. Input (received on I2S_DIN) and output
(transmitted on DOUT) can be 8, 16 or 32 bits. The DOUT line can be high impedance
when out of samples. Data is always stored in 32 bit format in the buffer. A shift left
operation is possible to left align the data.
●
In master mode, the CLK signal can be generated from different sources:
–
ClkR_Osci1: MCLK clock from external MCLK crystal
–
ClkR_Gpio4: external oscillator from PL_GPIO4 pin.
–
ClkR_Synt_2: From frequency synthesizer (source is AHB frequency),
–
TDM_CLK: I2S and TDM interfaces use the same clock.
1 0
13
0
13
0
3
0
13
0
0
Frame CPT
Partial address
Bank bit
Channel 1
Buf_address[14:0]
Selected an the basis of number of samples given by
[21:20]bits of the Action Memory register
Selected an the
basis of number
of samples given
by
[26:24]bits of the
Action Memory
register
Offset
Table 699.
I2S interface pins
I2S_LRCK
Left and right channels synchronization (Master/slave)
I2S_CLK
I2S clock (Master/slave)
I2S_DIN
I2S input
I2S DOUT
I2S output (trim-state)