LTE-A  Module  Series 
   EP06  Series  Hardware  Design 
 
EP06_Series_Hardware_Design                                                               25 / 56 
 
 
 
Clock and mode can be configured by AT+QDAI command, and the default configuration is master mode 
using short frame synchronization format with 2048 kHz PCM_CLK and 8 kHz PCM_SYNC. In addition, 
the  module’s  firmware  has  integrated  the  configuration  on  some  PCM  codec’s  application  with  I2C 
interface. Refer to document [2] for details about the AT+QDAI command. 
   
The following figure shows a reference design of PCM interface with an external codec IC. 
PCM_DIN
PCM_DOUT
PCM_SYNC
PCM_CLK
I2C_SCL
I2C_SDA
CodecModule
1.8V
2.2K
2.2K
BCLK
FS
DACIN
ADCOUT
SCLK
SDIN
BIAS
MIC_BIAS
MIC+
MIC-
SPKOUT+
SPKOUT-
 
Figure 8: Reference Circuit of PCM Application with Audio Codec 
 
 
1.  It is recommended to reserve an RC (R = 22 Ω, C = 22 pF) circuit on the PCM lines, especially for 
PCM_CLK. 
2.  The module works as a master device pertaining to I2C interface. 
 
3.7. Control and Indicator Signals 
 
The following table shows the pin definition of control and indicator signals. 
 
Table 9: Pin Definition of Control and Indicator Signals   
Output signal to wake up the host.