DS90UB929-Q1 Datasheet, PDF (23/71 Pages) Texas Instruments – 720p HDMI to FPD-Link III Bridge Serializer

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Table 3 covers several common I2S sample rates:
Sample Rate (kHz)
32
44.1
48
96
192
32
44.1
48
96
192
32
44.1
48
96
192
Table 3. Audio Interface Frequencies
I2S Data Word Size (bits)
16
16
16
16
16
24
24
24
24
24
32
32
32
32
32
DS90UB929-Q1
SNLS457 – NOVEMBER 2014
I2S CLK (MHz)
1.024
1.411
1.536
3.072
6.144
1.536
2.117
2.304
4.608
9.216
2.048
2.822
3.072
6.144
12.288
8.3.16.2.1 I2S Transport Modes
By default, audio is packetized and transmitted during video blanking periods in dedicated Data Island Transport
frames. Data Island frames may be disabled from control registers if Forward Channel Frame Transport of I2S
data is desired. In this mode, only I2S_DA is transmitted to a DS90UB928Q-Q1,DS90UB940-Q1, or
DS90UB948-Q1 deserializer. If connected to a DS90UB926Q-Q1 deserializer, I2S_DA and I2S_DB are
transmitted. Surround Sound Mode, which transmits all four I2S data inputs (I2S_D[A..D]), may only be operated
in Data Island Transport mode. This mode is only available when connected to a DS90UB928Q-Q1,DS90UB940-
Q1, or DS90UB948-Q1 deserializer.
8.3.16.2.2 I2S Repeater
I2S audio may be fanned-out and propagated in the repeater application. By default, data is propagated via Data
Island Transport during the video blanking periods. If frame transport is desired, then the I2S pins should be
connected from the deserializer to all serializers. Activating surround sound at the top-level deserializer
automatically configures downstream serializers and deserializers for surround sound transport utilizing Data
Island Transport. If 4-channel operation utilizing I2S_DA and I2S_DB only is desired, this mode must be explicitly
set in each serializer and deserializer control register throughout the repeater tree (Table 8).
8.3.16.3 AUX Audio Channel
The AUX Audio Channel is a single separate I2S audio data channel that may be transported independently of
the main audio stream received in either HDMI Mode or DVI Mode. This channel is shared with the GPIO[1:0]
interface and is supported by DS90UB940-Q1and DS90UB948-Q1 deserializers.
8.3.16.4 TDM Audio Interface
In addition to the I2S audio interface, the DS90UB929-Q1 serializer also supports TDM format. Since a number
of specifications for TDM format are in common use, the DS90UB929-Q1 offers flexible support for word length,
bit clock, number of channels to be multiplexed, etc. For example, let’s assume that word clock signal (I2S_WC)
period = 256 * bit clock (I2S_CLK) time period. In this case, the DS90UB929-Q1 can multiplex 4 channels with
maximum word length of 64 bits each, or 8 channels with maximum word length of 32 bits each. Figure 13
illustrates the multiplexing of 8 channels with 24 bit word length, in a format similar to I2S.
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