adau1442 Analog Devices, Inc., adau1442 Datasheet - Page 75

• Manufacturer Part Number: adau1442
• Description: Sigmadsp Digital Audio Processor With Flexible Audio Routing Matrix
• Manufacturer: Analog Devices, Inc.

The ADAU144x is able to operate in a flexible TDM mode, which
allows it to interface to a wide variety of digital audio devices.
SERIAL INPUT FLEXIBLE TDM INTERFACE MODES
AND SETTINGS
The flexible TDM mode is available for the SDATA_IN0 and
SDATA_IN1 serial input ports. By using this mode, it is possible
to override the default settings of the serial port and flexibly
route the contents of an arbitrary TDM input stream to the
input channels.
For this mode to be active, the word length bits of the corre­
sponding serial ports must be set to 11 (TDM8 or flexible TDM).
In flexible TDM mode, each flexible TDM stream includes 32
bytes (called slots) of information for every frame on the frame
clock. Combining the two serial input ports, this allows for a
total of 64 bytes in the flexible stream.
It is important to note that, unlike in the FARM, where signals
must be routed as stereo pairs, the data on the flexible TDM
stream can be assigned to input channels individually. Each of
the 24 input channels is capable of taking data from any slot (or
combination of slots) in the flexible TDM stream, as long as data
retrieval starts with Input Channel 0 and increases sequentially.
Because the audio data can be input in 8-, 16-, or 24-bit format,
SDATA_IN0
SDATA_IN1
...
...
SDATA_IN0
SDATA_IN1
31
63
LRCLKx
32 33 34 35 36 37 38
0
1
...
...
2
31
63
3
32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
0
4
1
5
2
6
3
39 40 41
7
4
8
5
Figure 56. Flexible TDM Interface Mode—Input Routing Example
9
6
10 11
42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
Figure 55. Flexible TDM Interface Mode—Input Streams
7
12
8
13 14 15 16 17 18 19 20
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Rev. PrA| Page 75 of 92
FRAME
a single channel may occupy more than one slot. An 8-bit channel
occupies one slot, a 16-bit channel occupies two slots, and a 24-bit
channel occupies three slots. To route flexible TDM data to the
input channels, the starting slot number (most significant byte)
and the bit depth (number of bytes, or slots, in the stream) must
be set in the corresponding input channel register (Flexible TDM
to Input Channel[23:0] registers). An example of the input flexible
TDM interface mode is shown in Figure 56.
In this example, Input Channel 0 comes from Slot 4, Slot 5, and
Slot 6 on the flexible TDM stream (a 24-bit audio channel). Input
Channel 1 comes from Slot 12 (an 8-bit audio channel). Input
Channel 2 comes from Slot 21 and Slot 22 on the input stream
(a 16-bit audio channel). Input Channel 3 comes from Slot 39,
Slot 40, and Slot 41 (a 24-bit audio channel). For the audio inputs
with a bit depth of less than 24 bits, the LSBs are filled with 0s.
Note that the assignment of slots to input channels needs to be
in order, with the lowest slot number starting at Input Channel 0
and increasing sequentially. This is done to ensure compatibility
with the automatic input channel assignment (see the Automatic
Input Channel Assignment section).
The default setting of all nine bits high (0x01FF) indicates that the
input channel is configured in the standard serial input interface
mode and does not use the flexible TDM interface mode.
21 22
23 24 25 26 27 28 29 30 31
32
0
...
...
10
11
12
13
14
15
16
17
18
19
20
21
22
23
0
1
2
3
4
5
6
7
8
9
CHANNELS
(24 CH)
INPUT
32
0
...
...
10, 11
12, 13
14, 15
16, 17
18, 19
20, 21
22, 23
0, 1
2, 3
4, 5
6, 7
8, 9