LTE-A Module  Series 
                                                            EM120R-GL&EM160R-GL Hardware Design 
EM120R-GL&EM160R-GL_Hardware_Design                                                                         43  / 79 
 
 
 
3.9. PCM Interface* 
 
EM120R-GL&EM160R-GL  support  audio  communication  via  Pulse  Code  Modulation  (PCM)  digital 
interface. The PCM interface supports the following modes: 
 
⚫  Primary mode (short frame synchronization, works as both master and slave) 
⚫  Auxiliary mode (long frame synchronization, works as master only) 
 
In primary mode, the data is sampled on the falling edge of the PCM_CLK and transmitted on the rising 
edge. The PCM_SYNC falling edge represents the MSB. In this mode, the PCM interface supports 256, 
512, 1024 or 2048 kHz PCM_CLK at 8 kHz PCM_SYNC, and also supports 4096 kHz PCM_CLK at         
16 kHz PCM_SYNC. 
 
In auxiliary mode, the data is sampled on the falling edge of the PCM_CLK and transmitted on the rising 
edge. The PCM_SYNC rising edge represents the MSB. In this mode, PCM interface operates with a   
256 kHz PCM_CLK and an 8 kHz, 50% duty cycle PCM_SYNC only. 
 
EM120R-GL&EM160R-GL  support  16-bit  linear data  format.  The  following  figures  show  the primary 
mode’s  timing  relationship  with 8 kHz PCM_SYNC and 2048 kHz PCM_CLK, as well as the auxiliary 
mode’s timing relationship with 8 kHz PCM_SYNC and 256 kHz PCM_CLK.