Audio Interfaces

I

The LM4931 supports both master and slave I2S transmission at either 16 or 32 bits per word at clock rates up to 3.072MHz

(48kHz stereo, 32bit). The basic format is shown below:

PCM

The PCM interface is both master and slave and is compatible with National Semiconductor’s AAI, Motorola’s SSI, and Texas

Instrument’s McBSP audio codec interfaces. The protocol is short frame sync MSB first 2’s complement 16 bit linear. The MSB

always follows the sync pulse. In the case of companded data the first 8 bits are used and the interface can be slowed to 8 clock

cycles per sync. In PCM_LONG mode the PCM_SYNC signal is inverted relative to that shown below.

20100907

FIGURE 6.

20100965

FIGURE 7.

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