Pcm Interface - Quectel 5G Series Hardware Design

4.4. PCM Interface

RM500Q-GL supports audio communication via Pulse Code Modulation (PCM) digital interface. The PCM
interface supports the following modes:
⚫
Primary mode (short frame synchronization): the module works as both master and slave
⚫
Auxiliary mode (long frame synchronization): the module 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 kHz, 512 kHz, 1024 kHz 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.
The module supports 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.
PCM_CLK
PCM_SYNC
PCM_DOUT
PCM_DIN
RM500Q-GL_Hardware_Design
125 μs
1 2
MSB
MSB
Figure 22: Primary Mode Timing
RM500Q-GL Hardware Design
255 256
MSB
LSB
MSB
LSB
5G Module Series
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