Data Sheet
ADAU1442/ADAU1445/ADAU1446
Rev. D | Page 41 of 92
LRCLKx
BCLKx
SDATA_INx
LRCLKx
BCLKx
SDATA_INx
BCLK POLARITY
07696-
032
Figure 31. Serial Input BCLK Polarity
L
R
L
R
L
R
LRCLKx
LRCLK POLARITY
07696-
033
Figure 32. Serial Input LRCLK Polarity
Word Length Bits (Bits[7:6])
These bits set the word length of the input data to 16, 20, or
24 bits. If the input signal has more data bits than this word
length, the extra bits are truncated. The fourth setting is flexible
MSB Position Bits (Bits[5:3])
These bits set the position of the MSB in the data stream.
TDM Type (Bits[2:0])
These bits set the number of channels contained in the data
stream. The possible choices are TDM2 (stereo), TDM4, TDM8
or flexible TDM, TDM16, and packed TDM4 mode. For more
Mode section. If the word length bits (Bits[7:6]) are set to 11 for
flexible TDM mode, then TDM type bits (Bits[2:0]) must also
be set for flexible TDM mode (that is, set to 010).
generate either an LRCLK clock signal (50% duty cycle) or an
LRCLK synchronization pulse at the specified frequency (fS,NORMAL,
fS,DUAL, or fS,QUAD). When a pulse is generated, its width is equal to
one single internal BCLK. Each channel requires 32 BCLK cycles
per LRCLK. Therefore, for TDM4, 128 BCLK cycles are required;
for TDM8, 256 BCLK cycles; for TDM16, 512 BCLK cycles; for
TDM2, 64 BCLK cycles (except when the LRCLK signal is a 50%
duty cycle signal (that is, not a pulse) or when it is running in I2S or
left-justified mode); and for packed TDM4, 64 BCLK cycles.
SERIAL OUTPUT PORTS
The serial output ports convert 16-, 20-, and 24-bit audio signals
coming from the audio processor to standard I2S and TDM signals
on the serial data outputs. They support TDM2, TDM4, TDM8,
and TDM16 time division multiplexing schemes and I2S, left-
justified, right-justified, and MSB delay-by-12 and delay-by-16
modes. Different clock polarities and multiple word lengths are
supported, as well as the capability to drive in master mode or
to be driven in slave mode.
The serial output ports are composed of up to nine clock domains
(Clock Domain 3 to Clock Domain 11) and up to nine serial
data signals (SDATA_IN0 to SDATA_IN8).
In slave mode, the nine serial output clock domains are driven
directly from the corresponding nine pairs of LRCLKx and
BCLKx pins on the IC. Three pairs of LRCLKx and BCLKx pins
(LRCLK[11:9] and BCLK[11:9]) are hardwired to Clock
Domains[11:9], which are serial outputs. The remaining six
pairs of LRCLKx and BCLKx pins (LRCLK[8:3] and BCLK[8:3])
are multiplexed to Clock Domains[8:3] as either inputs or outputs.
The multiplexer can be set to use these signals as output clock
domains by writing to Bits[5:0] of the clock pad multiplexer
register (Address 0xE240) as explained i
n Table 27. This
configuration is also valid in master mode.
Table 27. Output Clock Domain Multiplexing
Clock Domain
Chip Pins
Register 0xE240 Setting
0
LRCLK9, BCLK9
N/A
1
LRCLK10, BCLK10
N/A
2
LRCLK11, BCLK11
N/A
3
LRCLK3, BCLK3
Set Bit 0 to 1
4
LRCLK4, BCLK4
Set Bit 1 to 1
5
LRCLK5, BCLK5
Set Bit 2 to 1
6
LRCLK6, BCLK6
Set Bit 3 to 1
7
LRCLK7, BCLK7
Set Bit 4 to 1
8
LRCLK8, BCLK8
Set Bit 5 to 1
Figure 33 shows in detail how the clocks are routed to and from
the serial output ports. For the assignable clock domains (Clock
Domains[8:3]), the clock pad multiplexer allows each clock
domain to be individually routed to either the serial input ports
or to the serial output ports. In slave mode, the clock domain