Pcm And I2C Interface - Quectel UMTS Series Hardware Design

4.4. PCM and I2C Interface

The module provides one Pulse Code Modulation (PCM) digital interface for audio design, which supports
the primary mode (short frame synchronization) and the module works as both master and slave.
The module can only be used as primary devices in applications related to I2C interfaces.
In short frame 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, 2048 kHz PCM_CLK at 8 kHz PCM_SYNC, and also supports 4069 kHz
PCM_CLK at 16 kHz PCM_SYNC.
The module supports a 16-bit linear encoding format. The following figure shows the sequence diagram of
short frame mode. (PCM_SYNC = 8 kHz, PCM_CLK = 2048 kHz).
PCM_CLK
PCM_SYNC
PCM_DOUT
PCM_DIN
Table 15: Pin Definition of PCM Interface
Pin Name
PCM_SYNC
PCM_CLK
UC200A-GL_Hardware_Design
1 2
MSB
MSB
Figure 21：Timing Sequence for Short frame mode
Pin No. I/O
26 DIO
27 DIO
125 µs
255
LSB
LSB
Description
PCM data frame sync
PCM clock
UMTS/HSPA+ Module Series
256
MSB
MSB
Comment
1.8 V power domain.
In master mode, it serves as an
output signal.
In slave mode, it is used as an
input signal.
If unused, keep it open.
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