CS47L35 datasheet(114/300 Pages) CIRRUS

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DS1085F3

CS47L35

4.7 Digital Audio Interface Control

Note: The CS47L35 is a 24-bit device. If the user operates the CS47L35 in 32-Bit Mode, the 8 LSBs are ignored on the

receiving side and not driven on the transmitting side. It is therefore recommended to add a pull-down resistor if

necessary to the RXDAT line and the TXDAT line in TDM mode.

4.7 Digital Audio Interface Control

This section describes the configuration of the CS47L35 digital audio interface paths.

AIF1 supports up to six input signal paths and up to six output signal paths; AIF2 and AIF3 support up to two channels of

input and output signal paths. The digital audio interfaces can be configured as master or slave interfaces; mixed master/

slave configurations are also possible.

Each input and output signal path can be independently enabled or disabled. The AIF output (TX) and AIF input (RX) paths

use shared BCLK and LRCLK control signals.

The digital audio interface supports flexible data formats, selectable word length, configurable time-slot allocations, and

TDM tristate control.

The audio interfaces can be reconfigured while enabled, including changes to the LRCLK frame length and the channel

time-slot configurations. Care is required to ensure that any on-the-fly reconfiguration does not cause corruption to the

active signal paths. Wherever possible, it is recommended to disable all channels before changing the AIF configuration.

4.7.1

AIF Sample-Rate Control

The AIF RX inputs may be selected as input to the digital mixers or signal-processing functions within the CS47L35 digital

core. The AIF TX outputs are derived from the respective output mixers.

The sample rate for each digital audio interface AIFn is configured using the respective AIFn_RATE field—see Table 4-21.

Note that sample-rate conversion is required when routing the AIF paths to any signal chain that is configured for a different

sample rate.

Figure 4-47. TDM with Processor as Master

TXDAT

LRCLK

RXDAT

BCLK

TXDAT

LRCLK

RXDAT

BCLK

Processor

CS47L35

or similar

CODEC

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