Motorola Mobility LLC T56KT1 User Manual

PCM_FS - 8 kHz bit-wide frame-sync

PCM_DOUT - 16-bit linear audio data output

PCM_DIN - 16-bit linear audio data input

The 16-bit serial data is transferred in both directions after each sync signal's falling edge. The 
sync signal pulse duration is two clock periods, after which the serial data is transferred in both 
directions for 16 consecutive clock periods.

Following the 16-bit data transfer, the serial input and output data signals inactivate until the next 
sync pulse, which occurs every 125 µS (8 kHz). It is recommended the serial data signals will be 
High-Z during the inactive period.

 illustrates the PCM bus format of the voiceband audio configuration.

The G30 audio interface includes 2 modes of operation. Each operating mode defines the audio 
input and output devices to be used for each audio sound type and their programmable settings.

Basic audio mode is the G30 default power-up audio configuration. Several audio paths are 
available in this mode, and their settings can be programmed through the AT command set.

 describes the available audio paths in Basic mode.

Handset

MIC

SPKR_N, SPKR_P

Default audio path for speech and 
DTMF tones and ring.

Headset

HDST_INT

HDST_SPK

Alternate path for headset device.
Enable by setting HDST_INT inter-
face signal low.

Digital

PCM_DIN

PCM_DOUT

Enable digital path by 
AT+MADIGITAL=1