User's Guide

LM940 HW Design Guide
1VV0301352 Rev. 2 Page 50 of 68 2017-07-19
8. AUDIO SECTION
Audio Interface
The LM940 module supports digital audio interfaces.
Digital Audio
The LM940 module can be connected to an external codec through the digital interface.
The product provides a single Digital Audio Interface on the following pins:
Digital Audio Interface Signals
Pin no. Signal I/O Function Type COMMENT
51 DVI_WAO O
PCM Frame
Sync
B-PD 1.8V
49 DVI_RX I PCM Data In B-PD 1.8V
47 DVI _TX O PCM Data Out B-PD 1.8V
45 DVI _CLK O PCM Clock B-PD 1.8V
LM940 PCM has the following characteristics:
 PCM Master mode using short or long frame sync modes
 16 bit linear PCM format
 PCM clock rates of 256 kHz, 512 kHz, 1024 kHz and 2048 kHz (Default)
 Frame size of 8, 16, 32, 64, 128 & 256 bits per frame
 Sample rates of 8 kHz and 16 kHz
NOTE – If the Digital Audio Interface is not used, the signals can be
left floating.