GSM/GPRS Module
M85 Hardware Design
M85_Hardware_Design Confidential / Released 62 / 92
3.11.3. Reference Design
M85 can only work as a master, providing synchronization and clock source. The reference design is
shown as below.
PCM_SYNC
PCM_CLK
PCM_OUT
PCM_IN
PCM_SYNC
PCM_CLK
PCM_IN
PCM_OUT
Module
(Master)
Peripheral
(Slave)
Figure 43: Reference Design for PCM
3.11.4. AT Command
There are two AT commands about the configuration of PCM are listed as below.
―AT+QPCMON‖ can configure operating mode of PCM.
AT+QPCMON= mode,Sync_Type,Sync_Length,SignExtension,MSBFirst.
Table 20: QPCMON Command Description
Parameter
scope
Description
Mode
0~2
0: Close PCM
1: Open PCM
2: Open PCM when audio talk is set up
Sync_Type
0~1
0: Short synchronization
1: Long synchronization
Sync_Length
1~8
Programmed from one bit to eight bit
SignExtension
0~1
0: Zero padding
1: Sign extension
MSBFirst
0~1
0: MSB first
1: Not supported
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